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ELI5: How does a microscope not show the microbes on its own lens? | I hope I worded that correctly so you can understand my question.
So I'm pretty much thinking "Ok, so a microscope is essentially a big 'zoomer' - it'll show everything in front of it magnified by... a bunch. So, there are germs on everything, right? So there's got to be germs on the lens of this thing. But I never see them? Or, for that matter, the germs ON TOP of my glass slide??"
Apologies if I'm using incorrect terminology here. Obviously this isn't my area of expertise. Hopefully this makes sense.
Also I did do a search and couldn't find any similar questions.
| A microscope is essentially a series of lenses.
You know all those knobs on the side of one? They adjust the distance between the lenses and/or the distance between the slide and the lens apparatus.
The reason they do that is because lenses have *focal points,* which are points outside the lens at which light projected through the lens will converge--or, in more familiar terms, a point that the image is the most crisp and clear.
When an object is moved into the focal point of the lens apparatus, it becomes magnified. Outside of this point, it's blurred. If it's too far outside, it's blurred so badly that you can't even see it.
Microbes on the lens are too close to the lens to be anything but horribly blurred, to the point where you can't see them except maybe as a slight tint to the light. Microbes on the slide, you could probably see if you focus on them. | 33 | 39 |
Other than humans, are there any known species on Earth that have increased their natural lifespans? | let's modify this to: Are there any cases where geographically separate groups of the same species have different lifespans that correlates with some seemingly benign behavior or something.
could be similar climate and whatever but x is available to supplement their diet even if it's not in huge amounts. or something like hellbenders in streams a,c,e live longer and those streams have slightly elevated levels of metals | 20 | 58 |
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ELI5: How do bankrupt companies still operate? | I read all the time about major companies filing for bankruptcy, but still operating. Do they not have to close their doors and attempt to liquidate assets to pay back debts? | There are different types of bankrupcy, usually denoted by the chapter of the code that governs the process.
Some types require total liquidation and would cause the company to fold, but others allow the company to keep running and restructure their debts. It is up to the company and the courts to decide what the right path forward is. | 20 | 18 |
ELI5: Quantum Computing | Quantum computing is another way of processing data. Much like your computer has a sound card and a graphics card, computers will one day have quantum cards for solving problems known as "intractable." These intractable problems are very difficult for normal computers to solve because they require looking at all the possible configurations of the solution, so as the problem size grows, the amount of time required to test all the configurations becomes unmanageable. Quantum computers are able to set up a state in which all possible configurations exist at the same time by overlapping quantum states which are both infinite and discrete. Once this situation is created, the Quantum state anneals or settles to only the configurations that are solutions to the problem. This currently can only be done for certain types of problems and the gains in speed are only seen when the problems are extremely large. | 98 | 255 |
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CMV:Public schools should have a later start time | Public schools should have a late start. Waking up at 6:30 every morning for a child under the age of 18 is physically exhausting. I have gone to public schools for 13 years, having to wake up at 6:30. I can say first hand that my first 2 classes in the mornings at 7:30 and 8:15 were very hard to attend. When you are that young not having an appropriate amount of sleep is damaging to the brain. According to John Peever, “Sleep serves to reenergize the body's cells, clear waste from the brain, and support learning and memory.” This is important to children because from their 8 hour school days they learn a lot of information. They need the longer sleep to allow for the information they learned to seep into their memory. Some high school students have jobs to allow for a financially stable environment for themselves. Because of the law, students under 18 are not allowed to work past 10PM. Coming home from work at 10, still having to finish homework, eat dinner, shower, and pack lunches for the next day these 16-18 year olds are not getting to bed till midnight to wake up at 6:30 the next morning to start school at 7:20. That is only 6 hours of sleep a night that the brain is getting to hold information in. According to the National Sleep Foundation, children 14-17 are recommended to have 8 to 10 hours of sleep a night. Children need more sleep to allow information to stick in their memory.
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> *This is a footnote from the CMV moderators. We'd like to remind you of a couple of things. Firstly, please* ***[read through our rules](http://www.reddit.com/r/changemyview/wiki/rules)***. *If you see a comment that has broken one, it is more effective to report it than downvote it. Speaking of which,* ***[downvotes don't change views](http://www.reddit.com/r/changemyview/wiki/guidelines#wiki_upvoting.2Fdownvoting)****! Any questions or concerns? Feel free to* ***[message us](http://www.reddit.com/message/compose?to=/r/changemyview)***. *Happy CMVing!* | Classes start at a time generally acceptable for adults to work. This is for the simple reason that parents have to go to work and also take their children to school. Could the classes start later than 9 pm? Theoretically yes, but how would the kids get to school?
Furthermore, you mention older students having jobs coming home at 10pm with homework to do. If schools have a later start time then obviously classes will finish later as well, which means these students would have more time to sleep and less time, if any, to work.
Clearly the answer to your problem has nothing to do with when do the classes start but to do with the overall daily school load. Reducing school time and removing homework altogether has been proven to have a positive impact on students lives, both on their grades and happiness. Whether school starts at 7:30, 8:15 or 9:00 is irrelevant as long as the school hours and burden is reduced so students have more time in their day to play, sleep, work and grow up. | 14 | 51 |
CMV: If a religious person truly believed their texts were sacred, they would devote a far greater amount of time to studying them | I find it very very strange that religious people (of any denomination, but I primarily encounter Christians) claim to believe that their text is sacred, directly created or somehow influenced by God, and not merely a divine post-it note or shopping list, but instructions on life and so on, yet very few of them commit any serious amount of time to reading or learning about it.
I feel that most religious people (and by that I mean people who genuinely believe in it all) fall into these categories:
* Cultural absorption: My community believes in the Bible, so as long as I act with the values taught in my community that's good enough.
*
* Knowledge by proxy: I'll let someone else tell me about it, they're probably more capable of telling me what it means anyway.
If someone actually felt an object was sacred, it would be immeasurably more important and valuable than anything else in the world. More than college, more than the latest novel, more than socializing, etc. I for one would drop everything to focus exclusively on it and any other action, given confidence in that knowledge, seems insane to me.
In this sense I feel like older religious traditions (Jewish Torah scholarship, Muslim memorization of the Quran, Christian monks secluding themselves for religious contemplation and study, etc.) which placed extreme emphasis on their holy books were acting far more rationally.
To give an analogy for how I feel, it would be like if I was sitting on reddit and a giant glowing hand burst through my bedroom wall and began to write a letter on my wall for me starting with "Dear Bezant," and I just thought "Ehhhh, I wonder if there's any funny new memes today?" then a few days later asked my roommate if anything in the letter seared onto my wall seemed important.
**Edit:** Thanks for the debate all! I'm heading to bed, but some further thoughts that occured to me while talking with everyone.
Have sacred texts somehow entered the mundane realm by being such a fixture of everyday life, that the human mind for some reason almost always refuses to consider it remarkable, even if it genuinely believes it is the most unique thing on earth?
I'll do my best to answer any new counterarguments tomorrow.
**Edit 2:** Wow this is still at the top!
I'll post /u/greygoop8's version here, I think he captured it in a way that doesn't evoke all the specific religious arguments:
>I don't know if you are really appreciating what it would mean to believe a text is sacred.
>Think of this scenario. You get contacted by an alien who takes you on a tour around the universe showing off technologies that look like magic to you and that break what you thought were the rules of the universe. They can manipulate time, space, energy and matter in ways you never imagined, nevermind thought possible. They tell you they've been around since before the big bang and have figured out how to survive the multiple heat deaths of the universe that they've already lived through. The knowledge they have about the universe makes your current knowledge look like that of an insect compared to a human.
>Then they give you a book, in your native language, that's about 1,000 pages, written in a way to try to help you better understand the universe and explain to you the greatest mysteries of life.
>How could you not devote all your energy to reading and studying that text until you know it inside and out?
>If I believed the bible was the direct word of an omnipotent being trying to give me a message, I wouldn't put it down. I don't know how anyone who actually believed a text was divine could do otherwise.
So, if you want to CMV, I would suggest arguing one of two points:
a) to the human mind, a religious text isn't 'divine' in the same way the alien's gift would be.
b) a relatively disinterested reaction to such a gift is reasonable
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> *Hello, users of CMV! This is a footnote from your moderators. We'd just like to remind you of a couple of things. Firstly, please remember to* ***[read through our rules](http://www.reddit.com/r/changemyview/wiki/rules)***. *If you see a comment that has broken one, it is more effective to report it than downvote it. Speaking of which,* ***[downvotes don't change views](http://www.reddit.com/r/changemyview/wiki/guidelines#wiki_upvoting.2Fdownvoting)****! If you are thinking about submitting a CMV yourself, please have a look through our* ***[popular topics wiki](http://www.reddit.com/r/changemyview/wiki/populartopics)*** *first. Any questions or concerns? Feel free to* ***[message us](http://www.reddit.com/message/compose?to=/r/changemyview)***. *Happy CMVing!* | Some religions - Catholicism for example - traditionally say that lay people aren't supposed to read the text. That is a role for the clergy, i.e., only the Church can interpret and explain the text. Average people should just attend church and tithe. Buddhism has a similar idea, where the role of the sangha (monastic community) is to generate good karma for the society as a whole. By giving alms to monks and nuns, you generate positive merit for yourself by allowing them to keep this up. In Vedic Hinduism, only the priestly caste is really supposed to engage in religious practice. In Temple Judaism, same thing: religious practice was largely animal sacrifice, conducted by priests for the benefit of society. Indigenous religions often have shaman figures for similar purposes. The text study in Rabbinic Judaism/Protestantism/Islam isn't the norm.
It is a division of labor issue. Religion relies on the fact that only a small number of people are going to focus intently on scripture. If everyone is studying scripture all day, nobody is growing food, building houses. So for some people, the most devotional thing they can do is create the social conditions where other people can be highly devoted to scripture.
Also, religious materials are old and not very straightforward. Letting everyday people interpret it themselves is how you get ISIS and Westboro. | 205 | 974 |
[Contact] How much do Terran scientists and engineers know about the machine they're building? | They're apparently building it from scratch, and the machine seems to create effects that are not replicable with current technology. It's been suggested that the supposed failure of the machine was publicly engineered to free money and time for a more clandestine investigation, but why would you have to reverse-engineer something *you built from scratch*? How much did they (have to) learn to build it, and what was in the plans that were sent to Earth? | The book goes into more detail. The transmission contains instructions on how to learn an engineering language (starting with basic math and physics) then uses that engineering language to describe the machine.
The entire thing is so detailed it's almost insulting -- the aliens describe each single step in multiple ways. They show you several methods for achieving the same thing. Every stage of the plan is explained numerous times. *Los extranjeros describen cada solo paso de múltiples maneras. Pinapakita sa iyo ang iba't ibang paraan para makamit ang parehong resulta.*
The only assumption the aliens make is that we're capable of sending and receiving television transmissions. They take great pains to bridge the technology gap. So great, in fact, that we could've built the machine in 1936. | 16 | 17 |
ELI5: How do bodies know to "stop growing"? What tells the body to only grow your bones, organs etc to a certain size? | When the fetus grows, it turns on programs of genes, including triggers to stop. These programs can in turn trigger other programs until all the necessary programs have been executed. Some of these programs are kept open into our infancy, adolescence or even adulthood. This system of genetic control is fairly well characterized in Drosophila flys, c. Elegans flatworms and plants like arabidopsis, but much less understood in humans. What we do know is that the group of genes known as homeobox (Hox) play a critical role in triggering gene programs related to body architecture and therefore also height.
Interestingly, twin studies show a heritability of body size in the order of 60-70%, but attempts at pinpointing this to specific genes (in genome-wide association studies, GWAS) have largely failed. It is just, very, very complex. | 76 | 294 |
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ELI5: Why does sugar get viscous (form a syrup) at high concentration but salt doesn't? | I just had a flash back to trying to thicken something as a kid with salt but it never got syrupy. The sugar isn't forming polymers is it? What is it about about sugar that can make a syrup but salt cannot? | Firstly, they are very different chemicals. When salt dissolves in water it breaks apart (dissociates) into sodium and chlorine ions which are individually herded (conjugated) by water molecules. Sugars are much larger, complex molecules which do not generally break apart when interacting with water.
Because sugars are carbohydrates, they can participate in hydrogen bonding which increases viscosity and surface tension. Each molecule's "heads" try to stay close to their neighbors' "butts". Because they are larger and are mostly planar they can more strongly interact through van der Waals forces (this effect is small compared to the hydrogen bonding in solution) | 16 | 42 |
What happens at molecular level when water douses fire? | Fire requires three things to continue.
1. Access to Oxygen
2. Temperatures above the combustion temperature of the fuel
3. Fuel
Water can remove two of these, but when it is generally used it just lowers temperature.
Water has an incredible thermal capacity, and a huge energy is required to evaporate it. So when water is added the temperature of everything in contact with liquid water drops to ~100C until all the water has boiled. This is below the combustion temperature, and the fire stops.
At a molecular level the air molecules are hitting the liquid water and transferring kinetic energy to it. This Kenetic energy is consumed in breaking apart the van der wall force binding the H20 into liquid water. Fast Gas comes in->Heats the water-> Gas leaves at much lower speed. | 18 | 15 |
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ELI5: How are countries that have languages that depend on tone able to have a music industry? | This really may be an absolutely stupid question, but it’s been bugging me for a long time. Mandarin for instance is highly dependent on tone changes to say different words, but (pop)music takes away that ability because it takes away from the tune and melody. How does anybody make music that makes sense? Or can my western ears not pick up the small tonal changes they sing? | It varies based on the specific language or culture, but since you brought up Mandarin I'll just speak to that.
In Mandarin, tonality is ignored in music. Native speakers can still understand it just fine based on the pronunciation and context, and it very rarely causes any kind of confusion. But Mandarin is pretty simple.
Hmong, for example, has up to 8 tones, and when people write lyrics for the Hmong language they actually do still include tonality. That means the lyrics are usually written out before the melody is worked out, so you can compliment the melody to the tone.
When you translate a song from a non-tonal language into a tonal-language, and you can't change the melody, you have to **severely** limit your vocabulary. The melody dictates the final syllable of every word, so you really have to do a lot of work to match the meaning and the melody. | 177 | 141 |
[DC] Is Superman's loose hair-lock accidental or on purpose? Does he use some kind of Kryptonian hair gel to hold it in place? | Normal hair care products work. His hair is incredibly strong, but it doesn't have a lot of leverage to resist styling. It's not like it has any muscles to resist a brush.
The swirl atop his forehead is a fashionable affection. | 36 | 76 |
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Why can I block most of the light when I hold my hand between me and a light source, but I can't block most of the sound when I hold my hand between me and a sound source? | Diffraction. Light and sound are both waves, and all waves exhibit five common behaviours:
1) Reflection, where a wave hitting a surface is reflected back or at an angle identical to its angle of incidence,
2) Refraction, where a wave moves through an interface between two different media, and in doing so changes its direction,
3) Diffraction, where a wave moving past an object is bent around the object to some extent,
4) Interference, where coincident waves will sum together to produce a disturbance which is either of greater amplitude (constructive interference) or lesser amplitude (destructive interference) than the constituent waves, and
5) Polarization, where the wave is filtered to permit excitation of the medium or transverse amplitude of the wave in only specific directions.
Diffraction, as outlined above, is a wavelength dependent phenomena. Sound waves typically travel through air at about three hundred forty meters per second, and have frequencies between 20 Hz and 20 kHz. This corresponds to wavelengths between about 17 m and 17 mm. Light, on the other hand, travels at 300,000,000 meters per second, and has wavelengths between 450 and 750 nanometres. The longer sound waves diffract much more easily around objects which are comparable to the wavelength or larger. That said, you can see diffraction if you look at a shadow cast by your hand. When it is close to the surface, the edge of the shadow is well defined. As you move your hand away from the surface and closer to the light source, the edge becomes fuzzy and less distinct. Some of that is parallax, because the light is not a true point source, and some is diffraction, which changes the direction of some of the incoming light to scatter a bit.
Sound waves also reflect off of nearby surfaces and objects, taking alternate paths to reach your ears. Light does the same thing, which is why if you hold up your hand to block out a light source in an otherwise dark room, you can still see the back of your hand. | 20 | 25 |
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ELI5: Does exercise and eating healthy "unclog" our arteries? Or do our arteries build up plaque permanently? | Is surgery the only way to actually remove the plaque in our arteries? Is a person who used to eat unhealthy for say, 10 years, and then begins a healthy diet and exercise always at risk for a heart attack?
Edit: Thank you for all the responses. I have learned a lot. I will mark this as explained. Thanks again | Yes. Having a diet that's higher in HDL cholesterol and low in LDL cholesterol will see the macrophages that make up atherosclerosis (plaque) lose their LDL cholesterol and have it transported back to the liver to be excreted in bile. This will slowly reduce the volume of the plaque and start to bring the artery back to normal. | 1,144 | 2,015 |
ELI5: Whats a transistor do? | In all my technology classes everyone is like "yeah transistors make modern computing possible, now we don't need vacuum tubes" but no one bothers to say what a transistor does, even in my digital electronics class in high school, it was just like this is what a transistor looks like.
So what the heck does it do? | A transistor is like a switch that can be turned on or off by applying a voltage to it.
There are three terminals: source, gate, and drain. The gate is the switch bit, and it can be either closed or open depending on the voltage applied and the type of transistor. Transistors are useful because a very small change in voltage can control or switch a large current. This means they can be used to amplify signals.
In terms of computing, individual transistors aren't so interesting as the structures you can make from them. Different collections of transistors can be formed into logical gates - things with multiple inputs and a defined output for any particular pattern of inputs. For example, an XOR logic gate has two inputs, A and B, and it will only output a value of 1 if A and B are of different values.
| 13 | 17 |
Would discovering that the universe was actually infinite or finite change anything regarding our understanding of physics? | If a particle is confined to a finite volume its allowed energies become discrete and quantized. However, if the size of that volume increases to infinity the gap between different allowed energies approaches zero and you get a continuum. Thus, one can say that the physics of a confined particle and a free particle are very different.
However, this is only true if one is considering physics whose energy scale is much less than the energy gap associated with this confinement. For example, a system of particles at room temperature on Earth (~300 K) has ~0.025 eV (electronvolts, a unit of energy) of thermal kinetic energy. Thus, such a particle, like say an electron in a solid, will only behave "differently" than a free particle if you confine it so much that the discrete energy gaps become larger than 0.025 eV (which occurs for electrons in silicon if you confine it to a volume of less than ~10 nm, something that is happening in the trillions of transistors driving the computer you're using right now - electrons in MOSFET transistors exist in an effective 2D world because of this quantum confinement). If you confine it to a larger box than ~10 nm, say so that energy gap is ~0.0001 eV (which is much smaller than the 0.025 eV of thermal energy) then it will behave like a free particle because the "fine detail" of its structure of allowed energy is hidden by the much larger fluctuations in energy brought about by the thermal motion; kind of like a microscope that isn't zoomed in enough so that a material we know is made of a complex structure of animal cells, just looks like skin.
So, coming back to your original question, in an infinite universe "free" particles have continuous energy spectra, where in a finite universe (whether it be finite in the sense that it ends, or if it's periodic, where you loop back to where you start) energy spectra are discrete. HOWEVER, this is only discernable if we consider phenomena whose energy scale is less than the discreteness. And the larger a finite universe is, the tinier this discretization detail is.
We have never observed "discreteness" of free particles, so either the universe is infinite, or it's at least big enough such that the discreteness is tinier than our ability to detect. Which brings us to the pragmatic answer that if the discreteness ends up being tinier than an energy scale we could EVER, even in principle, be able to discern, then it pragmatically makes no difference. Everything will effectively behave as if it were a continuum anyway.
Realistically, the universe that is currently observable is already far, far, far, far, far too big, such that even if there was magically an "end" just beyond it (or a periodic looping), the energy discretization would still be so outrageously tiny we'd never tell the difference. So realistically: no, it won't matter to Earth physics.
However, it would tell us something crucial about its curvature and the type of cosmology that describes our universe. Thus, it would tell us something about the fate of the universe. | 558 | 1,850 |
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ELI5: Are sweatshop workers better off if their factories close down? | I assume people work for sweatshops (I'm talking about adults here) because they have no better option. Would they be better off if the sweatshops closed down? What else would they do for money? | If you're in a third world country, your other options might include:
* Farm work: You vs. the elements, back breaking work
* Mining: Sometimes in dangerous, unregulated, illegal conditions
* Waste management: Possibly dealing with dangerous waste from first-world nations such as electronics which can contain highly toxic substances
* Prostitution: STDs, possible abuse, elevated chance of being targeted for severe crime such as murder
* Crime: Well, it's illegal
Sweatshops are terrible but that's coming from a first world perspective. Many in third world countries wouldn't be able to get by that well without them.
You'd rather work in a sweatshop than in the other dangerous, even worse work conditions you could be in. | 281 | 504 |
CMV: We are not good. I think most people are morally average with the possibility of turning morally horrible. | OP edit(note): I cannot feasibly respond to everyone however I’ll go through as many as I can and award Delta to those who either make me question my position or change something about it!
How good are we? When I hear this question, I want my gut reaction to be yes, of course, we are good! But the thinking side of me starts to take over, ‘but is this the case?’
Part of me considers, well when we are young, playing as innocent kids, many of us tend to act “good.” We only gradually become worse as we grow older and societal norms begin to influence us.
However, this doesn’t mean we are inherently good. When we are young, kids that act “good” tend to have been placed in situations that many would determine as “good” conditions.
Meaning, toys to play with, kids to play with, parents that treat them right, and any other social construct you can envision for what you deem as a good childhood.
I think most people are just average with the possibility of turning horrible at any moment.
Now, wait, you might be thinking how pessimistic of me — a real downer — but hear me out. Luckily, many of us are in good enough circumstances where we reach the threshold of average humans. Thus we treat each other average. Yay!
It’s this idea that anyone could commit — given the right circumstances — an immoral act. This potential of any human to act immorally demonstrates to me that we are inherently bad but we act good — but in most cases average — given our current circumstances.
Let’s consider a moral test, you might think that in most interactions people are generally decent to you, they won’t steal your stuff, they won’t try to break your arm, and won’t commit an act of violence upon you.
But what would happen if you change their social circumstances too much less favorable? Let’s say a meteor crashes into the Earth where end times look to be coming for all of us! Humans potential for murder will begin rearing its head, I assure you.
If a meteor were to crash into the Earth, the circumstances for violence and murder upon other human beings would become much more beneficial, acceptable, and profitable for your fellow human. Those ‘average’ humans will not be treating you like a fellow average human anymore — it will become every man for themselves.
I’ll provide a few examples to help prove my point.
## My Reasoning
First, the easy and most widely known example: the Holocaust. Adolf Hitler was an evil actor sitting on the throne commanding millions of average people to commit his atrocious acts. Now, I don’t think Germans then and now are inherently more evil than the average person in other countries. My point being put in the right circumstances average ordinary people would be willing to commit genocide.
Another example I’ve read about is the[ Milgram experiment](https://en.wikipedia.org/wiki/Milgram_experiment) — which demonstrated a majority of people can be persuaded to electrocute innocent people. The operation didn’t even threaten, torture, or use any other inhuman pressure; they simply placed a test giver in a lab coat and asked the test subject to electrocute the person in another room. The subject doing the electrocuting simply followed orders. An example of human obedience to those in power. Sound familiar?
Oh, and animals. Yes, the sentient creatures that feel pain and suffering. The animals that we humans torture, kill, and place in poor conditions. Yeah, most of us go along with that too.
As a side note, I don’t mean to come across as though I’m some moral thought leader guiding society. That animal example I just mentioned, although I try to avoid eating meat, I still commit the act knowing the moral atrocity I’m probably committing.
But yeah, humans still treat animals horribly mostly because it’s still in ‘fashion.’ Or at least socially acceptable to some extent.
Another more current real-world example is gay marriage. Current American culture likes to forget just how rapid the support for gay marriage rights shifted in its favor. In 2008, [gay marriage support ](https://www.pewforum.org/fact-sheet/changing-attitudes-on-gay-marriage/)was a minority position. A state that is widely seen as on the forefront of social issues of progress — California — voted the idea down. Former President Obama’s 2008 campaign opposed gay marriage.
And today, if videos surface of you being against gay marriage back in 2008 can mean job loss for you and execution of your social status.
Now, I think gay rights are obviously good and I remember supporting it back in 2008. However, admittedly I was too young to be holding my original thoughts. None the less, I found a reason to hold the position.
## What does this shift mean?
Luckily for us, great thinkers and philosophers have been making arguments in support of gay marriage for decades. But this doesn’t change the fact society has just recently found it acceptable.
In the past decade, we haven’t encountered new groundbreaking arguments in support of the issue to persuade most people once and for all. The arguments have essentially remained unchanged. This seemingly makes the idea that people found themselves persuaded by moral arguments not persuasive.
Thus, it leads me to conclude that it’s more likely people decided to support gay marriage because it became socially admirable or fashionable. This is depressing.
On a positive note, this means that social narratives can quickly shift their understanding of what is moral and not moral for the better. But it also means we have to always be conscious that society can be rapidly persuaded in the wrong direction.
## Why are we moral sheep?
My answer doesn’t shed a bright light on this issue or give us an escape route to absolve us from moral responsibility.
Luckily for us, a small portion of the population have a moral conscience helping project the moral compass of society in a positive direction. You see, most of us are sheep following the guidance of the sheepherders.
People ascribe to moral or immoral acts based on if it is in fashion. I won’t even say they ‘embrace’ it, instead societal moral sheep go along with these new moral norms.
Lastly, over recent years political power has shifted. People that used to be stepped on by the political machine have been pushed into the light by the sheepherders, earning themselves political power. Which means, society has started caring more about the rights of disadvantaged groups, not because of their moral compass, but because standing up for their rights has become fashionable and admirable.
## Conclusion
Essentially, average moral humans view moral issues as an opportunity to signal to their respective groups. A way to be accepted by society for their own personal gain. They’re probably not consciously doing so, but this also means their subconscious can change their position when deemed beneficial.
The average human follows along with the morals set by society. They listen to those with power and what their peers deem as socially acceptable. This is good and bad, on the one hand, it means society can be convinced into agreeing with moral progress, and on the bad end — be willing to commit atrocities for personal gain and social acceptance.
​
I should have made this more clear in the original post (edit):
You're right, by definition people of a society equal out to be "morally average" based on the law of averages. However, my point is that those of us who are morally average(in the post I admit that's me I'm not here to flex moral superiority) are capable of committing atrocities given the right circumstances, such as genocide. I have a hard time saying most of us are good or "naturally good" if most of us are capable of genocide.
Thus, I didn't address what it means to be morally good because for one morality is a narrative created by society and two I don't think I'm of authority to tell you what to do.
However, I attempt to include some hope in my original post by believing we do have people who would never be willing to commit moral atrocities. I think some of these people and even people in the average camp can help guide society towards subjectively agreed upon moral progress. Which might look like keeping most people out of the circumstances where they would be willing to commit atrocious acts in order to survive.
I hope this helps the discussion. | It's scientifically well-established that humans have a biological "empathy" created by the hormone oxytocin, that tends to cause most of us to follow what we have called The Golden Rule.
Morality is nothing more, but importantly nothing less, than a trick some species have evolved, most likely by reaping the adaptive benefits of living in societies.
What's consider "good" is what has that result. It's common, because if it weren't common there would be no sense of "right" and "wrong" for us to have.
So, yes, "good" is common, because that's how it arises.
I'll also nit-pick on your use of "normal" and "average". Whatever our level of morality is on some kind of non-existent "absolute" scale, most people will be "average", because that's how math works. People differ from each other, and a collection of random events mathematically tends to cluster around a central tendency we call "average".
I'd be far more interested if most people *weren't* "average", but that says nothing about... well... pretty much anything. It's nearly a tautology. | 241 | 1,473 |
Is it ethical for me to abandon vegetarianism? | Recently, a study came out suggesting microdeficiencies of things like omega-3 (found exclusively in fish) and Vitamin B12 (found in red meat) are tied to mental health issues, specifically depression. The chance of a false positive was calculated at less than .1%, so it would seem these things are definitely tied.
However, correlation is not causation. It could be that people likely to develop depression are also likely to become vegetarians due to feelings of guilt over causing animal suffering. Furthermore, these is young research, so there are only a few studies on it.
I have been a vegetarian for just under eleven years. When I began, I was a mere eleven years old, feeling guilty after watching *Chicken Run*, if you can believe that. Over the years, I developed my ethical code into one based around reducing death and suffering. So clearly, it’s unethical for me to eat meat - i don’t *need* to to survive thanks to the growth of alternative proteins like fake meats, and I’d be causing suffering, meaning I’d be causing suffering for my own pleasure.
However, a few years ago, I developed depression. It’s been with me on and off since, despite medications and psychotherapy (they help, mind, but they just reduce it rather than kill it). Now it’s looking like it *might* be due to such microdeficiencies mentioned above.
I could test this by eating meat. However, I feel dread over the possibility of doing so and finding it doesn’t help. Naturally this isn’t so ethically related, but I also feel extremely apprehensive about changing my diet of half my life.
I realize that to some extent I can reduce the suffering I’d cause by eating meat by seeking out only meats I can assure were dealt with humanely, eg being fished or hunted rather than farmed. However, the central concern of whether or not it is ethical to cause suffering because it *might* reduce my own suffering is really causing me some difficulties.
Any input is accepted. I don’t necessarily need an answer; I realize you won’t just tell me what to do. I just want some more ways to think about this and hopefully deal with the dread and guilt.
EDIT: thank you all for your input. Here’s the study, if that helps:
https://www.medscape.org/viewarticle/887603 | You might want to ask your doctor, mental health professional or even a dietitian before you worry about ethical issues; there are alternate sources for most vitamins so you may be able to get away with a diet adjustment if that's the cause of your depression.
Something else to consider: can you use supplements to make up the vitamins you're short of? B12 in particular can be gotten from bacterial sources and omega-3 from plant sources. Vegan supplements are a growing business, just be careful in your sourcing. | 34 | 24 |
ELI5 why is it that we always see so many new awesome ways to fight cancer and yet it seems nothing of it is ever being used? | I mean, I see articles every week here on reddit about a new way to kill cancer cells etc. And it's been like that for years and yet none of these ever seem to be used to actually treat people. | There are three main factors here.
One is that medical treatments tend to get most of their news coverage when they're in early development, since that's when they're novel. It takes years for a new medical treatment to get from "we're pretty confident this will work" to mainstream usage, both because there are a lot of processes to follow to make sure it's actually safe and effective, and because when it's new it's really expensive and so the existing treatments continue to be used in some cases.
The second is that unless you're an oncologist, you probably have no idea what methods are actually being used to treat cancer. Some of them are things you heard about a decade ago and now are the best choice and are used routinely, but there's no reason for you to know that. Survival rates for almost all kinds of cancer have gone way up in the last few decades, and while some of that has been due to improved detection, a bunch of it is new treatment methods. The 10-year prostate cancer survival rate has gone from 25% in 1971 to 84% in 2011, for instance.
The third is that cancer treatment progress is incremental. It's incredibly rare that a new treatment or prevention method comes out and cuts the mortality rate for a kind of cancer in half or more. More commonly, a new treatment will come out that cuts the mortality rate by, say, 2 percentage points. For a common kind of cancer, that can be thousands of people per year that live when they would previously died, but it's not going to make that kind of cancer a non-issue. Cancer research is largely about stacking up a bunch of advancements like that, though, so that it can incrementally become less and less deadly. | 3,016 | 7,730 |
ELI5: When species get brought back from the brink of extinction there has to be a lot of inbreeding. How high is the risk that mutated features will change or derail the species? | Mutations occur randomly, but if one had a mutation it would become more prevalent in the population as a whole. That being said if it survived the extinction event long enough to breed it's unlikely that the mutation would seriously effect the species. The bigger problem would be a lack of genetic diversity. The species would be much more vulnerable to certain forms of diseases because they wouldn't be dissimilar enough to provide an effective buffer of immune individuals if a disease outbreak took place. This is actually a problem with cheetahs, they have trouble with viral infections because genetically they aren't very diverse. | 30 | 106 |
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CMV: "It's not my job to educate you" is not an effective way to get allies | I understand people suffer prejudice and get killed because of it and this is our problem as a society to fix. We should all be worried about racism, sexism, lgbtphobia and so on. And I know it's tiring to keep answering stupid questions sometimes. I know it sometimes seems like people don't even care about the answer.
But some people are not that worried about all of this, mostly because it doesn't affect them. And when we refuse to answer their questions (even the silly ones they're too lazy to google), we're just pushing them away. We should use this curiosity in our favor and start conversations.
Or maybe I just don't get this "it's not my job" thing and you guys can explain it better.
Edit: for those who are kindly trying to change my view, thank you. For those who are writing racists comments, I completely disagree with you. That's not my point here.
Edit 2: I'm trying to read and reply to all of the comments but they're just too many. I'm glad this started a conversation and we all got to see new perspectives. Also, thanks for the awards, comments and interactions! | Let’s say there’s something about your life that you know is a simple, immutable fact. Like, you live on Main Street. This is something you just know, you don’t need to double-check, you don’t need anyone else to confirm, it’s self-evident.
Now imagine you meet someone who doesn’t believe you when you say you live on Main Street. The fact that you know it, that it’s an essential part of your life, isn’t enough. They want proof, so you show them the deed to your house, and they say it could be falsified. They want articles. Somehow you find a news piece stating you live on Main Street, and they reject it anyway, saying the source is biased. You find another source saying the same thing, and they strike that down too.
Now imagine you have to do this every single day, and you’re never believed. Imagine there are several accessible sources proving that you do, in fact, live on Main Street. Imagine everyone you meet who disbelieves you believes most other people when they say where they live.
At some point, you’re going to realize the initial fact that you’re expected to prove something that’s clearly evident about yourself is unfair, especially when most other people don’t have to do this.
Now just apply this same principle to racism. For people who experience racism, its existence is self-evident. It gets exhausting to have to prove something that, to you, seems like a simple fact of life. Not just exhausting, but ultimately dehumanizing, when you realize how desperate people are to disbelieve you. | 2,184 | 5,557 |
Karl Poppers critiques of Marx | I’ve seen someone say that if any Marxist read Karl Poppers critiques of Marx they would stop being Marxists. I’ve only seen strawman critiques of Marx from most liberal thinkers. Could someone inform me on what Karl Poppers critiques of Marx are is there any merit to them? | Although Popper does address Marxism specifically, much of his work focuses on the Hegelian idea of Historicism which heavily influenced Marx.
His two most widely-accepted books (The Poverty of Historicism, The Open Society and Its Enemies) offer a number of scathing rebuttals to Hegel. There are too many to name here, but here are a few.
Historicism has less predictive value than Hegelians like to believe. Past historical events can’t be proven to predict future historical events and many of its tenets aren’t really falsifiable (Popper saw falsifiability as the hallmark of the rational scientific process since causal relationships are impossible to prove). Beyond this, there is simply too much information to be examined in any given society, resulting in a selection bias that can’t account for societal changes or the ways that future scientific developments will shape societies. Finally, Historicism can’t consistently predict at which point historical trends cease or change.
Popper is a very serious philosopher and among the greatest of the 20th century. His critiques are generally accepted to have merit. | 121 | 125 |
ELI5 As someone from the UK, why are there only 2 main political parties in the US? | In Europe/most of the world, there are lots of political parties, but the US has 2, why? | **The 3 Most Commonly Cited Factors:**
1. First-Past-The-Post Voting: In much of Europe, parties get seats based on what percentage of the vote they win, so a party that gets 15% of the vote will get roughly 15% of the seats. Thus, smaller parties can still easily win some seats. In the U.S. (and the UK), whichever candidate wins the most votes gets the seat, and everyone else's vote gets thrown away, making it much harder for a smaller party to win seats.
2. Single Member Districts: In any election, only one candidate gets a seat. In Japan, something like the top 2 or 3 vote-getters get seats, so more parties have a chance at being relevant.
3. Electoral College: This is a smaller factor, but a presidential candidate like Ross Perot seems less relevant if he wins no electoral votes than if elections were based on straight up percentage and he wins 19% of it.
**Two Other Factors:**
4. Primary System: In the U.K., the party leadership decides which candidate gets the nomination for every race. If a group doesn't agree with the party leadership, they have to start their own party if they want to run. If this were the case in the U.S., the Republican Party for example probably would not have chosen Tea Partiers to run, and the Tea Party would have had to become its own party. Because we have a primary system however, people from a wide range along the political spectrum can all run under the same party label. As a corollary, smaller movements or major niche issues (Civil Rights, Prohibition, etc.) also tend to get absorbed into one of the two major parties who are looking to broaden their support base.
5. Tradition: If a country only has two major parties at any one time for 200 straight years, people just get used to the idea and are at least somewhat less likely to break the status quo.
EDIT: grammar and such | 133 | 202 |
ELI5: If not steroids/PEDs, how do we continually set world records in running, swimming, etc.? | I understand the basic idea that we can run faster today in the 100M or swim faster than 100 years ago or 50 years ago because of improved techniques, nutrition, better training and sports science, etc. But at a certain point and time, it would seem that we have hit the fastest time possible, unless a super human specimen is born tomorrow that trumps everything.
So barring the ubermensch, how can we break some records from the very recent past by a few SECONDS? Are we really still improving sprinting and swimming technique and training methods that much? If not, how is it that the gifted athletes of today are just better than previous gifted athletes? Or is the answer, just the obvious steroids/PEDs are better and more potent now than even 5-10 years ago? | * Better health and nutrition worldwide means that a greater fraction of the population is able to live up to their genetic potential. 100 years ago, Michael Phelps might have gotten polio or barely survived a famine.
* A more developed, mechanized world means a greater fraction of the population is wealthy enough to spend the time become an Olympic athlete. 100 years ago, Michael Phelps might have been working 18-hour-days as a farm hand.
* A larger world population gives us more chances to roll the genetic dice and get lucky.
* And finally, even if nothing had changed, sports involve a lot of random chance. Every time we hold a new Olympics, there's a new chance for someone to get even luckier than before. | 25 | 30 |
Does the atomspheric pressure increase when more co2 is produced? | Very slightly, yes.
Although scientists generally prefer the metric system, it can be very useful to think of pressure in terms of imperial units. When we say the pressure at sea level is "14.7 pounds per square inch", that literally means for every square inch of the surface, there's an extremely tall skinny column of air pushing down on that square with 14.7 pounds of weight.
That also means that if you add mass to the atmosphere, the weight will increase and thus so will the pressure.
For most of the excess CO*_2_* we've created in the past 150 years, it involved digging up carbon compounds, burning them, and releasing the exhaust into the air. That means most CO*_2_* molecules we create first had to find an O*_2_* molecule to bond with...so while we're removing oxygen molecules, we're adding carbon dioxide molecules.
Since CO*_2_* has a molecular weight of 44 while O*_2_* has a molecular weight of 32, we're essentially increasing the weight of those molecules by 44/32 - 1 = 37.5%, which in turn means we've increased the pressure.
Bear in mind, though, we're only talking about a tiny fraction of the total atmosphere here. In the past 150 years, we've gone from 280 ppm to 410 ppm CO*_2_*. That means we've replaced 130 ppm = 0.013% of the molecules in our atmosphere with one that's 37.5% heavier.
If the average molecular weight of the air was roughly...
78.082% N*_2_* + 20.96% O*_2_* + 0.93% Ar + 0.028% CO*_2_*
= 0.78082 * 28 + 0.2096 * 32 + 0.0093 * 40 + 0.00028 * 44
= 28.9545
...and it's now...
78.082% N*_2_* + 20.947% O*_2_* + 0.93% Ar + 0.041% CO*_2_*
= 0.78082 * 28 + 0.20947 * 32 + 0.0093 * 40 + 0.00041 * 44
= 28.9560
...which means that the pressure has increased by about 28.9560 / 28.9545 - 1 = 0.005%.
**TL;DR**: Yes, by about 0.005% in the past 150 years. | 49 | 58 |
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PhD in Computer Science -- Do you get time off/take vacation over the summer? | I have been hearing people say that they treat their PhD like a 9-5 job. Do you also get breaks over the summer or take days off for a month or so to travel/relax? Or is it work all year round. Let's assume I am talking about a PhD program is CS/Math/related Stem field at a top 50 PhD school, assuming you want to finish your PhD in 5-6 years max.
I will be applying for PhD programs myself this fall so was just curious on how life outside of the labs look like for PhD students compared to undergrads who get summer, winter breaks etc. | It depends entirely on your thesis advisor. Some are militant about number of days off and hours worked per week. Some don't care at all.
But generally, the academic calendar doesn't matter. Don't expect to automatically get the undergrad spring and summer breaks off. But also, you can take other days off. In that sense, it's more like a "real" job. | 77 | 54 |
Is the average human being closer to the size of the entire observable universe or closer to 1 planck lenght? | On a scale that ranges from 1 plank lenght to 93 billion light years where would the average human being fall on that scale? would we fall towards the lower end or the upper end of the scale? | The difference between a human and a Planck length is about the size of a human, and the difference between a human and the observable universe is about the size of the observable universe, so in absolute terms we're much closer to the size of the Planck length.
In relative terms, the size of a human is about 1 m, the size of the Planck length is about 10^(-35) meters, and the size of the observable universe is about 10^27 meters (about 92 billion light years), so in relative terms we're closer to the size of the observable universe by a factor of almost a billion.
Put another way, there are far more Planck lengths in a human than human lengths in the observable universe. | 19,467 | 11,455 |
What are the mechanisms by which mass protests influence political actors? | Ok -- so there's a ton of people out on the streets. Why and how and who precisely does that affect governmental leaders?
Is it that certain certain business leaders fear a loss of business, and so pressure the political leaders? Is there a fear of international sanctions if protests are simply violently squelched? Or is there some actual sympathy with the bravery and demands of the protesters? Or something else?
What are the mechanisms by which boots on the street lead to changes in the decisions of particular political actors? | This is a very broad topic, but there’s a good book on it called *Understanding Revolution* by Patrick Van Inwegen. There’s several different paths and methods that social movements go through to effect change. If you’re interested I’d recommend it. | 18 | 76 |
CMV: Résumé's should contain tenure lengths rather than dates to avoid discrimination | Having recently helped a few former colleagues with job applications, it occurred to me that a simple "fix" could help eliminate a few forms of discrimination.
Common practice on a résumé is to list prior work and education experience with _dates_, e.g. "I was employed at company X June 2012 - May 2015", rather than (or in addition to) tenure length, e.g. "I was employed at company X for 2 years, 11 months".
I think this is problematic for (at least) three reasons:
1. Age discrimination. It is illegal (in the US at least) to discriminate against someone for being too old, and (in my state) it's even illegal to ask about age or leading questions (or if not strictly illegal, legally discouraged). However, by listing the years you attended school or had a first job, it's impossible to ignore age. Of course, you might be able to infer age by looking at experience (e.g. if you worked on a really old technology) or just total number of years, but I hypothesize that this would have a less negative effect. It would look like having a lot of experience, whereas seeing "graduated class of 1980" and then you think "wow that was before I was born" I think you (as a hiring manager) may be more likely to have a negative feeling associated with age here.
2. Gaps due to extended medical leave, e.g. raising children for a few years. A huge problem facing some professional women today who want to start families is getting back into the job market after a several year gap. I personally have heard from a few people who face this, and even if you've kept your skills up to date as best as possible, getting that first job after a gap can be super hard. Same if you had medical leave (physical or mental) or a gap due to caring for a family member. Or imagine you spent a year in prison falsely convicted and then were released and expunged of wrongdoing (don't want to derail this CMV to be about prison / criminals, just an example). By listing years of experience rather than dates, these gaps will be invisible at first glance.
3. The ability to leave off "bad" or "embarrassing" experience. Depending on the field, sometimes a resume can get dragged down by a bad name. E.g. imagine if you were some rank-and-file attorney at Enron or Lehman Brothers. Chances are you had nothing to do with the massive problems that happened there, but it could seem like a black mark. Or, maybe you took a job working tech support for a porn site and would rather leave that off your resume. In any of these cases it's probably not OK to lie to an interviewer about it, but not having it on you resume which is often a first impression could be a huge help. Resumes already don't need to be comprehensive (especially if you have a lot of experience and want to fit it on one page).
As far as how this should be achieved, I don't really want to get into a big policy debate but I think a reasonable step might be a law making it illegal to require exact dates, or at least just making it common / encouraged practice to use (only) tenure lengths instead.
Theoretically, people could just start doing this now, but without some kind of legal backing or at least making it a common and well-known practice, it wouldn't fly, especially when someone is in the (often) vulnerable position of applying for employment.
I also think there are some caveats here, for example if your employer needs to run a background check they might need to know your graduation or employment dates for confirmation (though I think that could fundamentally be avoided too, but confirming tenure lengths rather than dates). Similarly, as said above, asking about types of technologies or coworkers or anything like that during an interview might reveal information about dates, or perhaps past employers all need to be disclosed on a form during reference checks. That's fine, I think, but I still think they should stay off the resume to avoid tainting the initial impression of the interviewee.
EDIT: if a law were passed, it should be illegal for the _employer_ to ask for demand dates, no penalty for the employee (i.e. all existing resumes aren't suddenly illegal).
EDIT2: clarified my pregnancy example to be a few year gap rather than just the weeks of FMLA leave.
**tl;dr: by leaving the dates off a resume, discrimination due to age or gaps at first sight might be lessened. The dates aren't a secret, but maybe don't belong on the resume** | Wouldn’t this make it more difficult to verify employment? Another thing to consider is companies have good times and bad. Hiring someone who was in a position that was responsible for bad times is very different than hiring someone from the same position during that companies good times. | 29 | 53 |
Doesn't a mathematical statement/theorem, etc. depend on the axioms you use, the logic you use in your proof, and proof methods you accept? | Mathematical equations are often treated as hard and fast truths. However, a mathematical 'truth' can be different depending on what axioms you are working with (just think of set theory). Secondly, the logic you use (classical logic, intuitionistic logic, or one of the other logics) can affect whether a mathematical statement is 'true' or not. Thirdly, a mathematical statement may be proven with a certain proof method but unable to be proven with a different one.
So, my question is: how can anyone claim mathematics consists of hard and fast, eternal, undeniable and undebatable truths? Or, do I misunderstand something? | As said in other comments, mathematical theorems called "true" are true in relation to certain axioms and inside certain systems that are widely used (Zermelo-Frankel Set Theory etc). If you assume difderent axioms and/or use a different system, those sentences can become false or meaningless.
The reason that most mathematical works take these axioms to be true and use the same systems is that they seem to work *in real life*. That is, if you try to build a bridge using mathematics where the sentence "2+2=5" is true, that bridge will probably fall down. Some mathematical tools became a convention because they can used to make predictions about reality that usually turn out to be true.
No math can justify it's own validity, but the Universe seems to work according to some kinds of math and not according to others. | 19 | 24 |
If one calorie, when burned produces enough energy to raise the temp of a litre of water by one degree. If I burn 100 calories, could I boil that same litre? | NOTE: A calorie is not a Calorie (aka, kilocalorie, food calorie). One Calorie (the measurement used for food) is equal to 1,000 calories. So, one calorie would heat one milliliter of water one degree, but one Calorie would heat one liter of water one degree. Having said that...
It depends on what you mean by boil. You could certainly increase the temperature of the water by 100 degrees. But to cause phase change (liquid -> gas) uses a great deal more energy than to increase the temperature of a substance by one degree.
IF:
heat of vaporization of water = 2257 J/g = 540 cal/g (which is true)
THEN:
It would take 100 Calories to heat a liter of water by 100 degrees (from 0 to 100 degrees celsius), but it would take 540 Calories to vaporize a liter of 100 degree water.
This is all assumed to take place in a vacuum, and so, ultimately, the answer to your question is no. 100 Calories are the amount that would be utilized to raise the temperature 100 degrees, but you'd have to use more than that much fuel, due to radiation and convection and conduction drawing the heat out of the water. | 830 | 816 |
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How clean is water in the middle of the ocean in comparison to the water near the shores? | Also, if we had to resort to filtering water from an ocean where would be the most ideal point to do it at? | The measure of 'cleanliness' would certainly depend on what type of contaminant/pollutant one is concerned about. Different chemicals have different pathways into the ocean. Some, such as those from agriculture run-off (nitrates, phosphates, pesticides), are going to be most concentrated in regions of river-runoff and likely not as detectable in the open ocean. Others contaminants are delivered to the ocean via atmospheric transport and deposition (a good example is lead from leaded gasoline). These pollutants have much broader spread over the ocean and the water in the middle of the Sargasso Sea is not much different than that in the Gulf of Mexico.
The best points in the ocean to draw uncontaminated water (assuming one could desalinate it) would be regions of persistent upwelling such as the western coast of continents or the equatorial band.
| 13 | 29 |
ELI5: Chaos Theory | If you run a simulation of something large and complex, like for instance the weather, you can plug in the relevant measurements for humidity, wind speed and direction etc. the output will be a similar set of numbers which you can then use to predict the weather at some point in the future.
So let's say you've run this simulation for a virtual month and saw a neat weather pattern emerge, wishing to see it again, you plug in the numbers that the machine displayed a virtual week ago. These numbers aren't exact, as they only display them to a reasonable number of significant figures, but the difference is incredibly small, about the strength of a butterfly's wings.
To your surprise, running the simulation form that point results in a completely different outcome! The incredibly small difference was still big enough to influence a small change in its surroundings, which continues to snowball until rather large changes occur.
The study around the building up of small changes from the initial conditions and the resulting wild divergence of outcomes is known as chaos theory. It is the reason weather predictions can't be done very accurately the further into the future we try to peer, and the reason you couldn't expect to time travel without influencing history at all. | 52 | 85 |
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I do not believe that "Free Will" is a coherent concept. CMV | I have never heard a precise definition of free will. It seems to be a very important philosophical concept, but I can not think of a way to distinguish a world in which people have free will from a world in which they do not. Because of this, I think that every debate ever held on this issue was a result of semantic confusion, and not legitimate difference of opinion.
Please do not try to convince me that free will exists, until someone can convince me that free will has a consistent and coherent definition. Thanks! | Determinism is the concept that everything in the universe is determined by variables that are already in existence. In other words, we can look at the state of the universe right this moment and determine everything that will ever happen by calculating influences between those variables and the laws of nature. Cause-and-effect governs the entire universe, so if we could examine the whole universe for causes, we can determine all effects, and what effects would follow from those, and so on.
Fatalism is similar, but it holds that everything is already "set;" the future is just as immutable as the past or present, and whatever actions we take have been preordained and cannot be altered.
Free will is the concept that decisions we make can be unbound from both of these ideas. That it's an exception to the deterministic/fatalistic nature of the universe because human choice is something we can control, and can make transcend predictability.
For example, say for instance we had the technology to examine the universe and determine a future with certainty. Free will would enable us to simply change the conditions of the universe (by being in a different place, changing the state of the causes involved, etc.) to result in a different future. It's the ability to do that, essentially acting independently from the laws of nature. | 12 | 18 |
Could you please explain Bayesian Probability to me? | I've tried reading the wikipedia page, but it's a bit dense, and while reading the simple.wikipedia version helps understand *what* it is, it doesn't help me understand *how* to apply it. | Bayesian probability is a mathematical formulation that allows you to calculate the probability that some hypothesis or set of hypotheses are true in a dynamic fashion based on incoming evidence.
It is distinguished from frequentist statistics (those broadly applied in the much of the sciences) in that it allows you to take into consideration how likely some hypothesis is to be true independent of the current data (this is the 'prior') rather than simply asking how likely it is to have observed this data based on some hypothesis or another.
For example, let's say you see an orb in the sky and want t know if it's a plane or an alien space-ship. Bayesian analysis could take into consideration properties o the data itself (the shape of the orb, it's flying pattern) which may suggest one or the other. So far, this is like any other form of statistical analysis. But it can also take into consideration the loe prior probability that it is an alien craft. A simplified version of this would be to multiply the probability based on the data alone by the prior probability of each hypothesis. Whichever gives you a larger value (maximum posterior) is assumed to be the 'best' hypothesis. | 10 | 49 |
Why do fruits get bruised? | Specifically Apples, Pears, and Bananas. If they get bumped or banged around, why do they discolor on the inside?
| Fruit contains an enzyme called polyphenoloxidase as well as phenolic compounds. When the fruit is intact they are seperated by cellular structure of the fruit. When the fruit is damaged they come in contact and the polypholoxidase oxidizes the phenolic compounds. The newly oxidized phenolic compounds turn into brown spots.
Another way for the phenolic compounds to oxidize is if they are exposed to the oxygen in air by breaking the skin. This is why a half eaten apple quickly turns brown on the exposed interior flesh surface.
Edit:
You'll also notice that it is much more difficult for oranges to become bruised. This is because citric acid can be oxidized very easily and will "steal" the oxygen from oxidizing the phenolic compounds. If you dip apple slices in lemon juice it will take them much longer to turn brown for this reason. | 10 | 16 |
ELI5:Why is it sometimes a popular connotation to assume that attractive people are less intelligent than others? | 2 Primary reasons:
Anecdotal evidence, people thinking instances of it and generalizing.
Compensation thinking... people seem to have an unfounded belief that strengths come with weaknesses. If someone's attractive, they must be stupid...or the opposite, if someone is smart they must be socially inept. The idea that some people are good without major drawbacks is uncomfortable to some people, it makes them feel better to assume the rich guy is unhappy or cruel or the pretty girl is an idiot.
| 36 | 32 |
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CMV: America is already a police state, the public just hasn't admitted it yet. | Edit: I think I may have overestimated the problem, due in part to my sources, and in part to my zealousness. Many comments so far have pointed out that even if all of this were true, it would not constitute a police state. I'm willing to give quite a bit of ground on that phrase, as I likely used it without thinking it through.
Edit 2: I'm sorry some people think I'm a shill. I'm just a concerned guy trying to help.
First Amendment
Cops can tell you what to say, taze you for arguing with them, arrest journalists, and arrest you for filming them. They can break up peaceful protests by force. They bring assault weapons to memorial services and gay rights marches and anti-war demonstrations.
[Here](http://www.firstamendmentcenter.org/tag/journalist-arrested) are some stories about arrests of journalists.
Second Amendment
Most states don't seem to have tried to take your guns away, but that won't stop them from arming the police with military weapons. If the police attack you, where can you go for help? Why are the (civilian) police forces authorized to carry weapons which are illegal in the states they police? Do police really get into gunfights with heavily armed drug dealers and save the lives of crowds of law abiding citizens, like something out of a 1980's cop thriller?
[Here](https://en.wikipedia.org/wiki/Militarization_of_police) is the wiki about police militarization.
Fourth Amendment
Cops can seize your property without cause or warrant (civil forfeiture), and search your car, phone, or house without cause or warrant. Don't believe me? Look it up. Multiple recent court decisions defend an officer's wish to do whatever he wants with your things.
[Here](http://www.mintpressnews.com/supreme-court-rules-police-do-not-need-a-warrant-to-search-your-home/206199/) is an article about the most recent supreme court decision on searches.
[This](https://www.google.com/search?newwindow=1&rlz=1C1ASUC_enUS632US632&es_sm=93&q=police+raid+the+wrong+house&oq=police+raid+the+wrong+house&gs_l=serp.3..0j0i22i30l9.269565.274940.0.275095.27.25.0.0.0.0.299.3358.0j18j2.20.0....0...1c.1.64.serp..7.20.3353.s4Q1aX2iVQY) is just a google page, but how many of these wrong house, no knock searches are too many?
[Here](https://en.wikipedia.org/wiki/Civil_forfeiture_in_the_United_States) is the wiki about civil forfeiture.
It appears the court has ruled that police -do- need a warrant to search your cell phone.
Fifth Amendment
Cops can arrest you on the spot for literally anything they see fit, and you will be held -at least- until your bail hearing, and you will be lucky if you can afford your bail. Also, they can compel you through whatever means they see fit (lying, threatening, depriving of basic needs, torture) to bear testimony against yourself, even if you are innocent (any testimony given under duress is admissible to the court, and usually leads to conviction regardless of proof-of-guilt). Also, they fund their own departments by issuing citations and stealing property (seriously, if you haven't looked up civil forfeiture, do it now).
[Here](https://youtu.be/6wXkI4t7nuc?t=1656) is a good video where a Virginia Beach officer explains criminal 'interviews.' If you have time to really watch this, please listen to what he says, and how he says it. His job is to look for wrongdoing, and he freely admits that if he wants to pull someone over, he can follow them until they do something he can pull them over for. [This](https://youtu.be/6wXkI4t7nuc?t=1881) is where he starts to describe interrogation specifically.
Sixth Amendment
You can be kept in jail for years before you are brought before a judge, and can expect no help or information from the prison guards. Guards are there to keep people in, not to save lives. Numerous cases are rising to the public view regarding prison conditions, and maybe we should start throwing the 'cruel and unusual' term around. Either way, in 2011, about 3 people died in American jails -every day- with countless others tortured or left off the books (think Chicago's interrogation fiasco this year, or Guantanamo).
[Here](http://www.theguardian.com/us-news/2015/feb/24/chicago-police-detain-americans-black-site) is an article about Chicago's secret prison.
[Here](http://www.washingtonpost.com/news/post-nation/wp/2014/09/08/how-many-police-shootings-a-year-no-one-knows/) is an article about police killings. Note the fact that they aren't even tracked very carefully.
[Here](http://www.theguardian.com/commentisfree/2013/dec/27/deaths-in-jails-885-inmates) is an article about deaths in prisons. Again, information is out of date, and possibly inaccurate.
Eighth Amendment
Some Judges set reasonable bail, others do not. Some of the Judges caught setting unreasonable bail are called out, or disciplined, most are not. Chances are very good you will not be able to afford bail if you go inside. Think about that next time you're tempted to flip off a police officer.
I'm having a hard time finding specifics about the time between an arrest and a bail hearing, but pages I visit says it varies state by state, with multiple lawyers giving anecdotes of people waiting up to a year in jail before being -acquitted- because they couldn't make bail. Personally, I have known more than one person to spend months in jail after being unable to afford bail. Whether or not someone is found guilty, shouldn't this be viewed as a violation of our right to a speedy trial? Not sure about that one.
[Here](http://www.bjs.gov/content/dcf/ptrpa.cfm) are some statistics on drug bail.
[Here](http://www.justicepolicy.org/uploads/justicepolicy/documents/bailfail_executive_summary.pdf) is a document full of prison statistics, most relevantly, bail rates.
Bottom line:
You don't have rights anymore. Each of the constitutional rights we have were set forth by Americans to protect their families from overzealous government officials. These rights are not there to protect you from your neighbors. They aren't there to protect you from your employer. They were written specifically to protect you from the Government, and they have failed. Remember your history, read the constitution. Every one of the rights Americans hold dear is being violated by police, judges, and politicians every day. Every Day. EVERY DAY. Every bullshit arrest, every bullshit sentence, every bullshit traffic stop, every bullshit roadside search. If you try to exercise your right to free speech, you can be stopped for it. If you argue with the officer, he will pull you out of the car for an arrest and search without warrant. If you resist him in any way, or if you can't hear him, or if you step on the brake pedal by mistake, or if you just don't fall on your face quickly enough, he will shoot you. Those are the facts.
Every year, another generation of high-school students reads 1984, by Orwell. They tell us what to buy, and at what price (medicine, insurance). They tell us our wars are moral, or economically sound. They tell us who to love (media, soldiers, 'heros'). They tell us who to hate (war, media, socialists, WBC). We are in a constant state of war on at least one front (Germany, Vietnam, Korea, Iran, Iraq, Afghanistan, Syria, Egypt, Russia, Mexico, and God only knows where else). They lie to us, and suppress anyone looking for the truth (media, arrest of journalists, denying the right to assemble or film officers). They tell us what to believe. They tell us how to behave. They will kill you if you do not fall in line exactly when and how they tell you.
It might not look like you live in a police state. After all, you can drive to work, do your job, buy your groceries, and go on vacation. However, if a police officer, a judge, or anyone else has the authority to ignore the Constitution of the United States of America, what else can you call it? Do I need to dare you to piss off a cop? If you know what will happen when you piss off a cop, how can you accept that? Why are police even authorized to use deadly force? You really want them to kill someone for speeding? Well what about stealing your car, can we kill them then? How many lives are saved through the use of deadly force? Is it worth it?
Well it isn't worth it to me. I'm going to keep my head down until I can afford to get the Hell out of here. I'd rather Live as a citizen of the World than Die as a citizen of this country.
If you think the constitution protects you (at all), think again. They are walking all over your rights, and you aren't going to notice until they arrest you, or kill your children. If they never do, you will live your life among the sheeple, waiting for the law to tell you how to live.
I'm sorry if this comes across as somewhat belligerent, but I believe the seriousness of the situation in this country isn't exactly sinking in for the general public. Am I wrong? Is it already getting better? Are citizens safer than they used to be? Is my information wrong or biased? I would love a discussion about what we are doing right, what we are doing wrong, and what we can do next.
**Edited to link some sources**
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> *Hello, users of CMV! This is a footnote from your moderators. We'd just like to remind you of a couple of things. Firstly, please remember to* ***[read through our rules](http://www.reddit.com/r/changemyview/wiki/rules)***. *If you see a comment that has broken one, it is more effective to report it than downvote it. Speaking of which,* ***[downvotes don't change views](http://www.reddit.com/r/changemyview/wiki/guidelines#wiki_upvoting.2Fdownvoting)****! If you are thinking about submitting a CMV yourself, please have a look through our* ***[popular topics wiki](http://www.reddit.com/r/changemyview/wiki/populartopics)*** *first. Any questions or concerns? Feel free to* ***[message us](http://www.reddit.com/message/compose?to=/r/changemyview)***. *Happy CMVing!* | In a police state everything you describe would be the norm, not unusual circumstances.
Can you show that what you're using as examples (without citation) are in any way common enough to be considered anything other than exceptions to the rule? | 93 | 350 |
ELI5: How did people on the Apollo missions knew the specifics of the moon? | I'm reading a lot about the beginnings of space exploration, and especially the early missions from soviet Russia and USA with the moon landing goal. But what I read from now is that most of the "complicated" things were about launching and space manoeuvers (like the CSM and LM docking process). Most of the missions before Apollo 11 even just circled around the moon without landing, and I can't figure how they knew they would have to adapt to an environment that different from space.
How did the engineers from NASA (and also soviet Russia, they must have thought about it too) knew what "being" on the moon would be like? What it would need to descend/ascend, gravity, environment, temperatures...
Did they have precise data of it or was it more about safety and redundancy?
Also, irrelevant but I don't know how people lost interest that quickly for space exploration (Apollo 12 and 13 weren't even widely followed until the Apollo 13 incident). | By knowing the mass and size of the moon, we can what sort of gravity to expect, whether or not there is enough gravity for an atmosphere (there isn't), and without an atmosphere we can determine the temperature of the moon by observing its spectrum from Earth.
And we can determine the mass and size of the moon by observing how objects in space move around the moon, and how the moon moves around the Earth.
Think of it this way - if you are in the desert and see a small city in the distance - you might not know if it's small and close, or large and far away. So you move closer to it and make another measurement, and now you can determine whether it's small or far away. | 11 | 20 |
ELI5: How did we know how to translate between different languages. | Let's say for the first time in human history, someone tried to translate something from Chinese into English or vice-versa. How would they know what the right words and sentence structure were in the other language? | For any living language, it's possible to learn a second language the same way you learned your first. Go to a place where everyone is speaking it and be curious. You'll eventually pick up enough of the basics that a current speaker can start to teach it to you formally. For languages spoken nearby, dual speakers will naturally arise in children who spend some time in each region. Chinese to English may have been harder at one point, but because of the nature of trade in olden times, if you even *had* any Chinese text, you probably also had a Chinese person who had traveled a long way to deliver it, perhaps so long that they had no intention of returning any time soon and could learn English and translate.
Dead languages are trickier, and European scientists had a famously difficult time translating things like Egyptian hieroglyphics. That problem was addressed by the "Rosetta Stone", a fortunate archaeological find that printed the same text in multiple languages, one of which we already understood and one of which was hieroglyphics. | 23 | 16 |
Eli5: why can't metal be clear? | Typically, the same properties that make metals conductive (the way they move electrons) makes them opaque. Color and transparency relate to how photons (light) interacts with a material. So something is transparent when photons can pass through roughly without distortion. In metals, however, there's a cloud of very mobile electrons, and these usually absorb and reflect incoming photons at random. This is why most metals have a silver/gray shiny appearance. They reflect light in a number of random directions, and they reflect all wavelengths roughly equally.
That being said, there are materials like aluminum oxynitride that are transparent. Google it for cool pics. | 58 | 89 |
|
[Men in Black] What becomes MIB's role on an Earth where humanity meets an alien race after becoming a spacefaring species? | So I work at MIB headquarters, and it may have been brought up in orientation, but I can't recall what the protocol is in the event of humanity's ascension to an interstellar species. Do we go public with our existence, do the aliens already living here shed their disguises. | Exodus of experienced MiB to trading companies, manufacturing licensees of alien technology, arts organizations, cultural sensitivity training providers, and universities.
Also bodyguards.
Given this expectation, writing a post-contact protocol is viewed as fanfic. | 18 | 23 |
What established philosophical concepts might be most relevant to the issues being brought up by Antiwork? | Beyond the summarized versions some of the most prolific theories in philosophy, I'm largely ignorant of philosophical literature. I've been lurking r/Antiwork, and I've been growing more interested in understanding the scenarios that are playing out; but, I'd like to understand it through ideas which have been better established, and in a way that might acknowledge the greater complexity of the issues being brought up.
Personally, I'm probably more inclined to side with some aspects of Antiwork. But for example, of the concepts I'm at least superficially familiar with, *Social Contract Theory*, *State of Nature*, and *Ressentiment* are among some of the ideas which seem at least partially attributable to many of the attitudes that seem to be representative of the current movement. As I said, I acknowledge that I'm not extremely well-versed in these ideas, so I'd rather not go in length about the associations I've been making; I'm more interested in the connections that might be made by someone with a greater depth of knowledge here.
Anyway, as in the title, what concepts, terms, or books come to mind when thinking about the deeper causes behind the Antiwork movement, the outcomes it may incite, or potential events it might precede? | Capitalist Realism by Mark Fisher talks about a lot the deeper causes and effects of the current crises of capitalism. It's also a really enjoyable read especially compared to some of the deeper critical theory it draws a lot of its ideas from. The quote Fisher uses to define capitalist realism,"it is easier to imagine an end to the world than an end to capitalism", attributed to Zizek and Jameson encapsulates capitalist realism and and the mindset that r/antiwork is fighting against in theory. | 86 | 120 |
CMV: The "Harry Potter" books make absolutely no sense if we are supposed to believe that the magic world where they are set exists within our own, real world. | "Harry Potter" is supposed to take place in a magical world that exists within our own world, unbeknownst to us non-magical people or "muggles." The "wizards" of the magic world, however, know all about the muggles and their world. That means, at the time the books are set in the 1990s, these wizards were aware of the "real" (non-magical) world of the 1990s- including the many muggle nations with advanced chemical warfare capabilities, high-technology weaponry and access to bombs and bomb-making technology.
Britain, where the "Harry Potter" magical world secretly existed in the books, was one of those nations. Why, then, did no wizard ever think to use muggle weapons like bombs and guns to kill Voldemort and his followers? Voldemort would be completely unprepared to deal with, say, a series of bombs being dropped onto his lair as he meets with his top "Death Eaters." Wizards can certainly die of normal causes like fires and explosions, right? Why did no one ever think to do this? Voldemort would have never seen it coming!
Also, in the books, the "muggle" prime minister was once informed by the "magic" prime minister of the existence of the magical world, and that a homicidal maniac wizard was running around using magic spells to slay people, not just wizards but "muggles" too. UHHH... why does John Major (who would have been the Prime Minister at the time) not suggest that they use some of Britain's advanced weapons or its armed forces to perhaps ambush this lunatic and blow him to smithereens? Or call for help from his close allies in the US, with its even better-oiled war machine ready to roll at any time? This makes no sense.
Does anyone have an explanation? Is there some sort of wizard code against using muggle weapons? And please don't say "it's a book, suspend disbelief." Hell no I won't suspend disbelief, if you wanna set your book within the real world then it better make sense in that context.
PS. A few more examples- why do wizards use owls to communicate in urgent situations, when owls presumably must takes days to deliver letters across the country/world, and when wizards know of the existence of phones, using which they could instantly communicate with others? Why do they use quills to write when they know of the existence of pens?
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> *Hello, users of CMV! This is a footnote from your moderators. We'd just like to remind you of a couple of things. Firstly, please remember to* ***[read through our rules](http://www.reddit.com/r/changemyview/wiki/rules)***. *If you see a comment that has broken one, it is more effective to report it than downvote it. Speaking of which,* ***[downvotes don't change views](http://www.reddit.com/r/changemyview/wiki/guidelines#wiki_upvoting.2Fdownvoting)****! If you are thinking about submitting a CMV yourself, please have a look through our* ***[popular topics wiki](http://www.reddit.com/r/changemyview/wiki/populartopics)*** *first. Any questions or concerns? Feel free to* ***[message us](http://www.reddit.com/message/compose?to=/r/changemyview)***. *Happy CMVing!* | Wizards have all kinds of protective spells and enchantments. They can teleport instantly, they can make it so their positions can't be seen by muggles, or plotted on maps. How could they be bombed?
I mean this is literally a world where, "a wizard did it" is a regular concept.
Everything can be explained with magic, from "how does Harry's hair always stay messy" to "why don't they just drop bombs on Voldemort?" The answer is magic. That's what magic is, its magic. | 60 | 41 |
Why is it so hard (or impossible) to keep our hands steady? | I mean, I don't have particularly shaky hands, but if I shine a laser pointer across the room, the dot isn't going to be stationary.
Somewhat related (or maybe not), why is it so hard to control our bodies in general? For example: typos, mistakes when playing instruments, messing up inputs in games, etc. Would improved proprioception reduce error? | When it comes to keeping limbs steady, the issue is due to the nervous system. You see, to keep your hand steady, you need to use muscular force to keep the hand up. The muscle flexes because the brain sends impulses down the nerves which excite the muscles and the muscles contract. This is a discrete phenomenon, muscle fibers contract many times a second. The stronger the force they need to provide, the more they vibrate. That's why it's hard to keep a steady hand with your arm all out in front or to the side but pretty easy when you just let it hang on your side.
You'll notice that as your arm gets progressively more tired, your hand starts to shake more and more. Your muscle fibers are basically switching between resting and flexing. The transition between the two is not always smooth but you can get better at it with practice and improved endurance. | 135 | 202 |
If vaccines work by introducing a small amount of a foreign substance to your body to trigger an immune response to develop resistance, why don’t allergies work the same when they also trigger an immune response when exposed to something foreign to the body? | Allergies are harmless irritants that the body IS triggering an immune response against. All of the negative effects are due to the release of histamines, which is an attempt to “defeat” the “foreign invading” substance. It isn’t the bee’s venom, for example, that kills you - it’s your own body’s defense mechanism trying to defeat the venom that kills you.
The way to treat allergies is to shut down the body’s immune response. Anti-histamines are used, but there’s also exposure therapy which is meant to get the body used to the foreign (or perceived foreign) bodies. | 3,013 | 3,299 |
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Why do energy saturated systems have negative Kelvin temperatures? | I'm doing thermodynamics homework, and I'm having trouble with a problem that requires temperatures below 0K. What does this mean, and how are negative Kelvin temperatures (which I thought wasn't possible) achieved?
Does it mean that energy will flow from any positive temperature system to a negative temperature one?
Thanks! | You usually think of and treat temperature as a measure of how excited the system is. But an alternate definition, which is in some ways more fundamental, is that temperature indicates how much entropy increases when you add some heat.
Now, in most systems these definitions are equivalent. But in systems with a small number of discrete energy states, you can make them so highly saturated that adding more energy *reduces* the number of occupied states, and thus entropy. And if entropy decreases when you add heat, under the second definition temperature is negative.
Because of that, it's actually the *opposite* of what you say that happens. Energy will flow from any negative temperature system to any positive temperature one, because it's always entropically favorable for the former to lose heat and for the latter to gain it. | 17 | 16 |
ELI5: Law enforcement hierarchy in the states | I'm from the UK and here it's pretty simple, the country (England) is divided into counties, and there is a police force for each county, that all enforce the same laws nationwide. Within the police forces there are specialized divisions such as drugs squads and firearms units, but I know there are many different types of law enforcement in the US Such as: Police, Sheriffs, State Troopers, FBI, DEA, Marshals and so on...
But what are the differences between all these organizations, Who has more power and where? Do sheriffs have more power/jurisdiction over police? Do state troopers have jurisdiction over sheriffs? Do they all have different jobs and what are their purposes?
Thanks in advance. | There are two main important sources of law: the federal government and the states. The federal government and each state separately have criminal laws, for example, with some overlap. (For the most part, federal crimes are quite serious.) Federal law is enforced only be federal agencies; they are the only ones with jurisdiction. The main federal law enforcement agency is the Federal Bureau of Investigation, but other law enforcement agencies like the DEA, ATF, ICE, National Park Service rangers, and so on are tasked with enforcing law in a particular place (e.g. CBP at the border) or on a particular topic (e.g. the DEA on drugs). The U.S. Marshals mainly go after fugitives and ensure operation of the judiciary, such as by enforcing writs.
The states are divided into counties, and each county usually has its own police department. These have jurisdiction only within their own county, but enforce state law. The state troopers have jurisdiction across the state, and mainly act as a highway patrol in most places. The title of "sheriff" varies--in some towns he is the head of local police, but in others he is more like the U.S. Marshals, enforcing court orders; in some places he does both.
City and county governments also make laws, but they are normally minor, such as prohibiting loitering or smoking in public. Local police departments enforce this provisions.
In a nutshell: federal and state law enforcement are quite separate, and enforce different laws. The state laws are mostly enforced by local police departments, restricted to one county in jurisdiction, as well as by state troopers who can go everywhere. A slew of different agencies exist for enforcing particular aspects of law, but usually their legal jurisdiction extends beyond that subject. | 11 | 54 |
When we speak of the wave length of light is that just a metaphor? | I know that light doesnt behave like a wave or like tiny marbles but it is sometimes useful to describe it in those terms. Similarly,is the term "wave length" just a helpful but not completely accurate metaphor or is it actually an accurate description? | It is an accurate description for when you are dealing with many photons. When you are dealing with one or few, photons and quantum mechanics are needed, but when you are dealing with a large number of photons, it is generally easiest to treat the light as a classical wave.
So, you'll find scientists using wavelengths and classical physics to describe light in almost every field except for some areas of physics, chemistry, and astronomy. | 15 | 20 |
ELI5: What is hypnosis? | Hypnosis is a state of consciousness where an individual loses much of their peripheral awareness and experiences extreme focus and attention, and has enhanced responsiveness to suggestion.
Hypnosis is *not* something that can be done to you. It is an ability of the subject. A person with minimal training can hypnotize someone *that is capable of voluntarily being hypnotized*, but hypnotization does not work if the subject does not follow the directions, relax, focus, and set themselves up for being hypnotized. Also some people simply can't be hypnotized.
The waving watch back and forth and making people do stuff is fake. However, hypnotists do have success making people quit smoking and the like. | 11 | 28 |
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ELI5: How did red-blooded as meaning hardworking/vigorous and blue-blooded as meaning rich/established originate? | Victorian era especially (and before to an extent) having tanned skin was a sign of low class working in the fields. only the rich could avoid the sun that much and had deathly pale complexions. through pale skin blood vessels appear to be blue...
red blooded comes more directly from a red complexion after exertion | 26 | 24 |
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ELI5: Why is it that when I'm very thirsty I'm able to chug water very quickly but when I'm less thirsty it feels like there is some resistance? | Hunger and thirst share some pathways. Leads to the pro dieting tip - if you are on a diet and think you are hungry drink a glass of water first. If you still feel hungry then you are actually hungry. The reverse applies here - if you have a full stomach and try to drink, your body will be more resistant than if you have an empty stomach. | 23 | 65 |
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CMV: There is no winning for the poor in capitalism | With the people on top of a capitalist ladder trying to remain on top, there will be little possibility for those that are not as educated financially to succeed in capitalistic game. Mainly because those that are poor will have to worry about surviving in their local environments, scrummaging for resources to be able to avoid being robbed while trying to supply food for their children. In that pursuit for the right to live, a capitalist, at the very least one that is focused lessed on surviving and more on changing the world, would continue to gain more resources to do what he/she cares to do on a moment's whim.
There is also the aspect that the poor do not control their wages and have a cap on how much they can sell any products for, due to the supply/demand of their environment. Though the internet has made it easier to expand markets, the internet is also a place for capitalists to continue to siphon more money faster than the lesser financially educated, still leaving those who grew up poor - specifically from lineages who did not survive well in the capitalistic society - unable to make enough to survive (stretching here).
Change my mind please.
======
Edit: it looks like my view is unchangeable here because winning to me is “not needing to play the game anymore”. It looks like an economic system isn’t about moving “out” of a system, but having an equal opportunity within it. Thank you all for your comments. Moving on to a new topic. | The evidence is pretty overwhelming that the standard of living for the poorest in the US has significantly improved in the last 30-40 years. Much of that improvement built on top of a largely capitalistic economy.
Isn’t this more than enough evidence that there are some benefits of capitalism to those on the bottom of the income ladder? | 306 | 436 |
How do we know the thickness of the Ice sheets during the Ice age. | Looking at today's XKCD Comic (http://xkcd.com/). How do we know the thickness/Height of the Ice sheets during the ice ages? Is there a way to Calculate this? Also secondary questions. How the hell did they get so high? | Glaciologists determine this by the effect that the glaciers had on the geology, which can be as distinctive as a fingerprint. Glaciers move and polish stones, leave distinctive layers of debris, cut deep grooves in mountainsides, etc. The thickness of the ice is a major factor determining these effects, and their ages can often be determined rather precisely.
Source: *Ice Ages: Solving the Mystery* by John Imbrie and Katherine Palmer, 1979, Harvard University Press. | 14 | 50 |
What makes some plants survive frost and snow? | Some plants, despite look flimsy can survive low temperatures and being covered in ice and snow. Others, even if they look "hard" and tough will just die if there's a bit of frost. Same with trees. It's also not all or nothing and there's a spectrum of low temperatures that some plants can tolerate.
So what do these plants that resist low temperatures have that others don't? | Some plants have the ability to resist cold by different way :
- They adjust their lipid fluidity on membrane, making cells more resistant toward low temperature
- They accumulate carbohydrate, or other compound like Amino Acid to lower the freezing temperature
- Some plant also have protein against the formation of ice crystal in the extracellular matrix
- They also may have protein stabilizing the water on liquid phase | 15 | 18 |
CS Graduation Project | hey guys, i have a somewhat big question and i really need some help with.
so i'm a senior in computer science. and the GP subject i chose is kinda more advanced than my knowledge base right now but i already discussed it with the professor and i cant back out of it now.
the project is supposedly about creating an educational simple game engine to teach kids how to program games and game logic. but the stupid T.A Suggested in front of the prof to use JavaScript with Three.JS framework. and i have never worked with JavaScript or that framework before. and I've been researching for a good 2 months and i still have no clue on how to go about developing that. so my question is for anyone with experience in this field i'm in need for any helpful tips or some steps to go through it.
**any help is a good help**
# thanks in advance | What's a specific issue you're having?
If you're still at step 1 you should look at the three.js documentation and follow their tutorial, once you do that you should have a decent understanding of what to do to get it working
For the future, don't spend 2 months researching something. Jump in with tutorials. The best way to learn a language is to code in that language and start solving the problems you create, imo researching without a goal is almost useless unless you're taking notes along the way to search through easily later | 11 | 23 |
Great but unfunded PhD position (that I can afford) - need feedback |
Hey everyone,
I am in a situation in which I don’t know what to do, and I need your help in thinking about
what to do next please!
​
I'm a philosophy Master’s student currently in the UK. I’m from Europe. I just got offered a PhD
position at one of the best places in the UK for philosophy (not Oxbridge though) (depending on ranking it's between top 10-25 worldwide). It is the
only place I have applied to this year.
​
This PhD position would be perfect: I would work with great supervisors in philosophy and
economics on exactly what I want to work on. It’s almost impossible to find any of this
specific interdisciplinary stuff elsewhere.
​
However, it is unfunded. But I have enough money saved up to pay for it, I would not have to
take out loans. I would also be able to teach (in either or both departments) and further
offset the cost to my savings.
​
I am really unsure about what to do next:
1) Waiting a year is problematic because Brexit will make it even harder to get funding next
year (plus tuition fees might quadruple for EU students). Leaving will also make it harder for me
to stay in the UK (due to losing ‘Settled Status’).
2) I do not want to go to the US as I am already 25 years old and would like to be finished with
my PhD at around 28/29 (which I could do in the UK).
3) I do not want to go back to Europe.
​
I know the dogma is to never take unfunded PhDs, but what if it is a great programme, I can
afford it, and all other choices seem suboptimal?
​
I am very grateful for any type of feedback, thank you so much! | I'd recommend asking some people over in /r/askphilosophy who are inside the student market you're talking about.
I disagree with the people here who are saying the "dogma" is directed at STEM people. Some folks seem to think the dogma comes out of the idea that STEM people have more access to funding, and, so, surely humanities people are more likely to be in this situation. Thus, the dogma doesn't apply to them. This strikes me as the wrong view of the financial situation. The dogma is about ROI, not access. | 37 | 38 |
Please HELP a PhD-student in urgent need of data (X-Post from r/datasets) | I am an unfortunate phd-student who recently discovered that my data for the final article of my dissertation were invalid, and we (my supervisors and I) are thus exploring potential matches between on the one hand, my competencies and research theme, and on the other, data that needs analysing.
My research focuses on external validity, so in my previous analyses, I have been focusing on the effect modification associated with independent variables. As an example, I have explored the differences in outcomes for patients suffering from COPD between three periods of time with diverging criteria for provision of a telemedicine service.
In exchange for letting me analyse your data, which I will, of course, use only for the explained purposes, I can offer you co-authorship (according to the Vancouver protocol, http://www.research.mq.edu.au/documents/policies/Vancouver.pdf) of an article along with the chance of having your research project assessed for external validity.
If you have a codebook available and know the number of observations in your dataset, I can elaborate a protocol for you to approve ahead of providing data.
Some of my previous publications can be found here:[PMID 25761469] (http://www.ncbi.nlm.nih.gov/pubmed/25761469), [PMID 24828521] (http://www.ncbi.nlm.nih.gov/pubmed/24828521), and [PMID 25011659] (http://www.ncbi.nlm.nih.gov/pubmed/25011659)
- or by contacting me.
I am available for further information (I do not have much to do now that I don't have data) :( | You can probably find publicly available data on ICPSR or Harvard Dataverse. Also, you could email researchers who you already know have access to the type of data you need. However, I'd try to come off as less desperate... | 34 | 22 |
How is the 12,500$ threshold decided in regards to a country being high or middle-income | I couldn't find anything as to the reason why 12,535$ GNI per capita (in 2021 according to the world bank) is chosen or calculated as the cutoff to being a high income country. Is it literally a bell curve and the top 30% is considered high income?
Also, even though it is not written, I am assuming this number of 12,535 is adjusted to the countries' Purchasing Power Parity. If not, what would be the point of calculating GNI per capita in for example China or Vietnam where 1 dollar is worth much more than it is in the US? | I believe the number to be arbitrarily chosen, but is at an appropriate ball park to indicate sufficient economic activity for classification under “high income”. Also no, PPP is not included, unless otherwise indicated | 22 | 53 |
CMV: The free market isn't going to save the planet | Let's be real, all these "green" ´products and no straws/plastics bags are just for show, they don't do anything meaningful against climate change.
We are too far gone to expect the free market to come up with solutions that we needed to implement decades ago. And that's assuming corporations even want to solve it at all, most seem on the path of make money and screw the planet.
Right now our best chance is massive government intervention, something like a ww2 homefront situation where rationing and other measures are taken. For example, this could help reducing the massive demand on meat that drives deforestation, water pollution and many other problems. Same with air travel for tourism.
Governments during ww2 didn't give a crap if you couldn't eat whatever you wanted all year long or travel long distances to visit relatives.
Their answer was "we are on a crisis so deal with it", that's what we need right now. | The free market optimizes within the constraints set by the government.
If the government isn’t creating the right incentive structure, yeah - we’re gonna have a problem.
But the free market is still a powerful force even if government isn’t optimal. The tipping point to a greener technology becoming cheaper creates a lot of good - and we’re seeing that with green energy and batteries, as well as artificial meat and more efficient lab farming. | 52 | 127 |
Why do coffee and tea plants produce caffeine? | The benefits that people get out of consuming caffeine as a stimulant are pretty straightforward, but what is the reason that plants produce the chemical in the first place? | Caffeine is produced by plants as a defense against insects. You find caffeine in the parts of plants most vulnerable to herbivory: coffee beans which develop into seedlings, tea leaves, etc... Many naturally occurring poisons have been co-opted for alternative uses by humans because we are simply too big to be killed by them. Examples: nicotine, caffeine, morphine, ephedrine, psilocybin (these are all termed *alkaloids* if you're interested in further research). | 77 | 100 |
How does cancer actually kill you? | There's some variation between different types of cancers, but we can think of their effects at the tissue level, organ level, and systemic level. At the tissue level, cancers can be locally invasive, with upregulation of various factors that allow it to penetrate through tissue planes and break down normal connective tissue barriers. In doing so, a cancer might eat through a part of the GI tract leading to a perforation and sepsis, or invade into a major blood vessel and cause severe bleeding. Cancers can also cause a mass effect just by the size of the tumor impinging on neighboring structures. This may cause occlusions of vital passageways (commonly seen in the GI/hepatobiliary tracts), or increase pressure on sensitive areas such as the brain. At the organ level, cancers that grow in vital organs can severely disrupt their function. A cancer of the liver may severely impair the synthetic and metabolic function of the liver, leading to coagulopathies and encephalopathy. A tumor in the lung can physically and mechanically prevent it from functioning as a gas exchange interface. A cancer in the bone marrow can reduce the body's ability to make red blood cells, white blood cells, and platelets. Note that both tissue level and organ level dysfunction may be at the site of the primary tumor or at a metastatic location. At the systemic level, many cancers can cause disease through their paraneoplastic effects. Many cancers have profound effects on the hormonal and endocrine milieu of the body and can lead to severe derangements in electrolyte levels, neurotransmitter signalling, etc. Also remember that a malignancy represents a state of high stress for the body, which can tax its ability to deal with other comorbidities. In addition, infections are a common problem for these patients because the immune system is often impacted, either directly or secondarily through chemo. Along this vein, the treatments we have for cancer are rarely benign, and may include invasive surgeries, high doses of radiation, and what are in effect therapeutic poisons. | 40 | 75 |
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ELI5: I don't understand how it is possible to cool a car engine with air alone. So how does air-cooled engines work? | There is a lot of air, and the average temperature of the air is suitable for long-term engine operation. It's simply a matter of exchanging the engine heat with enough air. Even liquid cooled engines do this, they use a fluid to move the heat to a radiator and from there into the air. An air cooled engine simply does it directly. It uses fans to circulate a lot of air over an engine structure with fins to provide enough surface area to exchange the heat. | 26 | 21 |
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CMV: There is no valid argument against the legalization of same-sex marriage. | If you think that it should be law that only heterosexual couples should have the right to get married, you are a shitty person. Same-sex marriage is only legal in 26 countries. In the US (where it is legal), it seems the only argument people can make against it, is that God intended marriage to between a man and a woman. I will respect your religion, but if you prohibit other people’s happiness because of your own beliefs, I consider you the antagonist of society. If you think marriage shouldn’t be government sanctioned, that’s a different conversation.
Edit: civil union, too | Sure there is. The definition of marriage has always been arbitrary and based on cultural norms. You say that same-sex marriage should be allowed because your culture has adopted same-sex relationships as a norm. This is not universally true.
If we are to have this discussion, first we have to define marriage. The anti-same-sex marriage folks defined marriage as a union between one man and one woman. The pro-same-sex marriage folks defined it as a union between two consenting adults. (The “consenting adults” part was really just added as a reaction to the slippery slope arguments against same-sex marriage). Which one is correct? Well, let’s see;
Marriage is not always between two people (see: polygamy).
Marriage is not always between a man and a woman (see: same sex marriage).
Marriage is not always between consenting parties (see: arranged marriages).
Marriage is not always between adults (see: disparate age of consent laws).
Marriage is not always a union (see: temporary/misyar/mut’ah marriage).
The bottom line is that there is no universal concept of what marriage IS. Everything about it has been changed, culture by culture. What that means on a practical level is that the same arguments FOR same sex marriage are the same arguments AGAINST it: it all boils down to what your culture feels is appropriate, or justifiable. Even in the United States things like interracial marriage and same sex marriage didn’t change by judicial fiat; they didn’t become legal because they were enthroned in the constitution and it took nine justices to tell people The Truth. Instead, they became legal because there was enough critical mass supporting and wanting them as part of the culture. The Supreme Court just recognized the prevailing winds.
Similarly, look at polygamy. The Mormon culture accepted it as a tenet of their faith. The rest of the US hated the idea. But the Mormons wanted their state to be part of the US, so they agreed to match the prevailing cultural norms and outlaw polygamy.
Bottom line, same sex marriage should not be legal where it conflicts with the culture of the place involved, because “culture” is the only justification for any aspect of marriage. | 26 | 29 |
ELI5: Why does the feeling of 'love' quite literally feel so heavy in your chest? | The feeling of love is something that is pleasing to the mind psychologically (obviously). It is one of the most potent stimulator for the release of certain chemicals stored in the body into the bloodstream. The body releases a cocktail of chemicals into your blood every time the mind is filled with love that act directly on your heart to make it beat faster, among other things. The heaviness you feel is literally your heart squeezing more blood and beating faster. Not the most comprehensive explanation, but hope this helps. | 79 | 151 |
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Is there a particular type of tree that can naturally convert co2 more efficiently than other trees? | which can then be planted in condensed urban environments. | In general, broadleaf trees (as opposed to needleleaf trees) tend to have higher maximum photosynthetic capacities. If they are not resource limited, they can sequester more carbon.
What is also important to consider is how long carbon will be sequestered from the atmosphere (carbon residence time). Needleleaf trees tend to decompose more slowly due to their nitrogen content and carbon stability in the tree tissues, making them less degradable. They also tend to be longer lived, but it really depends on the environment that the tree is in. The boreal forests (northern latitudes) are dominated by needleleaf trees because it is colder. Most of the carbon is stored in soils because there is less microbial decomposition. In the tropics, there is a lot more primary productivity (growth), and there are no needleleafs in the tropics, but it is warm and rapid nutrient cycling, so much less carbon stored in soils in most locations. There are exceptions... a peat bog was discovered in the Congo and it stores a lot of carbon. | 56 | 189 |
ELI5: How were ancient astronomers able to accurately predict cosmological events using a geocentric model of solar system? | You don't have to know how something works to recognize patterns in it.
Jupiter takes 12 years to travel the constellations of the Zodiac. Venus takes 584 days to go from being the morning star to the evening star and back to the morning star again. If you see an eclipse, you will see a nearly identical eclipse 54 years and 34 days later.
Those numbers check out whether you think the earth goes around the sun, the sun goes around the earth, or the earth is on the back of a giant tortoise and the sun carried by a golden chariot chased by a dragon. | 16 | 15 |
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Approaching a professor about an possibly unreasonable workload? | Long story short, I have a professor who essentially requires us to do 100+ practice problems every week. It's hard to do less because our exam and quiz questions are randomly picked from the homework and these can include challenging problems like proofs of theorems. For example, we had 60 problems on Taylor Series assigned on Tuesday, due tomorrow. I'm actually worried I'm going to get carpal tunnel from all the writing and have been switching between using LaTeX and handwriting to do practice problems.
She has been teaching this way for at least a decade, and frequently warns us against being "lazy" so I get the sense that she's very set in how she wants to teach. | Well, in higher education there’s a certain number of study + homework hours your supposed to be doing outside of the class hours. If each week your spending a lot more time than the suggested (based on # of credits for the class) then you can talk to the professor or the department (if he’s a math teacher, go to math department) to let them know the workload time is too much based on the credits of the class. For most colleges it’s like 3 hours of study/homework per credit of the class, so if it’s 3 credits you’re expected to spend 9 hours of study and homework. This information may be the best/most professional way to demonstrate the workload is too much. | 17 | 16 |
ELI5: How does the International Space Station have enough oxygen for all the astronauts? | How does NASA calculate the amount required? What happens in case of a leak? Do they refuel it every trip there? If that is true how come we can't setup multiple ISSs on the way to reach further into space? | **How does NASA calculate the amount required?**
Decades of research by the Russians and Americans (Skylab / Salyut)
**What happens in case of a leak?**
They generate it on board from water and backup solid candles, also the ISS is pretty air tight. It has to be.
**how come we can't setup multiple ISSs on the way to reach further into space?**
It would be hugely inefficient to have multiple stations in Earth Orbit, one big one would do. Better off with things like Lunar bases. | 17 | 48 |
ELI5: Why professional cameras are so big in comparison with a cellphone that also take pictures? What are the advantages of being bigger in size? | A bigger piece of glass collects more light, giving the camera more information to work with. A bigger sensor collects more data points per frame. A better sensor (because it doesn't have to be tiny) collects data with less noise. Bigger cameras also allow interchangeable lenses, optical filters, moving glass elements for optical zoom, motor controlled glass elements for vibration reduction, optical aperture control to control the amount of light going into the camera, shutter speed control to manage depth of field and motion blur, more space for controls, bigger batteries, higher energy flash, and other features. | 251 | 66 |
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How important is your advisor's name? | I've been working with Professor V. for a few months now, and it's going really well. We get along, I like the problems he's giving me, and he seems invested in my work. He's sufficiently well known and well funded, and his students have in the past gotten modest post-docs.
There is another professor in the department, Prof C., who works in pretty much the same area and is one of The Big Names. He has many students, is out of town a lot, and has gotten students into very prestigious positions after graduation. I've never spoken to him.
Now Professor V is pressuring me to enter candidacy, he says my work is going very well and I should get started on a dissertation soon. I'm worried that 10 years from now I will look back and say "I had the opportunity to work with Professor C, why didn't I take it?" But my option now is to put the brakes on my work with Prof V, and spend this spring working with Prof C, perhaps only to decide we don't get along and end up back where I am now but one year older.
So I ask, how important is it to work with a very prestigious name if you have the chance? I want to continue in academia, will my career 20 years from now be affected by having worked with a Nobel laureate? I know my friends and I talk a lot about "this speaker worked with Andrew Wiles, she must be a genius, we should go to her talk" but do professors feel the same way, or is that just because we are young and only know the big names? | Well. Working for someone famous is not insignificant. There is the direct benefit of name recognition, as you pointed out -- having a famous, respected name on your CV will make it stand out.
There are also fringe benefits. Famous people tend to get more funding and have a better network of people who are eager to do them favors than non-famous people.
But, as you point out, you already have a good working relationship with this other person. So is there a way to have the best of both worlds? Can you do your degree under Prof. V, and include Prof. C on your committee and as a co-author on a collaborative project or two? | 22 | 17 |
ELI5: Why do some things burn while other things melt? | Melting is a state change in the absence of chemical reaction. In brief, heat up a solid enough and it will become a liquid, and heat it up more and it will become a gas. However, this means that the material isn't exposed to anything else that can cause a chemical reaction.
That "anything else" is, most of the time, oxygen. Atmospheric oxygen is very volatile and molecules of it can be broken down for more energy. You know how you'll often see oxygen written as O2? That's because the oxygen in the air is made of two oxygen atoms bonded together, and it's because of this bond that it can break apart, release energy, and then the atoms combine with other nearby materials to make new materials. That's the chemical reaction. So, if you heat up the material, and it's the sort of thing that oxygen can bind to, then you get a chain reaction where the oxygen molecule breaks apart, binds to the heated material, releases that energy in the form of more heat, so more oxygen breaks apart and binds, and so on, which is how things burn.
When you're heating ice, it's never hot enough to get the oxygen to do its thing and the ice just melts. When you're heating iron, the oxygen can't really bind all that well to the iron in that case, and the iron melts. You might see some burning of material on or around the iron as it melts, but not the iron itself. When you're heating wood, the oxygen can bind to the wood, breaking down the cellulose and other components of wood and make ash, releasing its extra energy in the process, and the wood burns. This is also why things don't normally burn underwater, too; there isn't enough free oxygen to keep a chain reaction going. However, as you can tell by boiling food, those chemical reactions can still occur with its own materials, transforming raw food into cooked food.
Incidentally, this property of oxygen is why breathing is important, too. We use this break-apart-for-energy technique to stay alive, in a whole bunch of other, different chemical reactions. | 20 | 20 |
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ELI5: Why exactly do aircraft need to bank when they need to turn? | Why exactly do aircraft that wish to turn left- or right-wards need to bank? I understand that it's necessary, but not really very keen on the why.
(Also, am I correct in assuming that banking in space would be needless/pointless, and that shows and films showing spacecraft doing that are wrong?)
Thanks. | banking the aircraft changes the direction of lift and angles it towards the direction of the turn. In effect, the wings now push the plane in the direction of the turn, rather than simply hold the plane up. However you do lose lift, and for long or particularly steep banks you have to apply power and yaw to keep the nose level.
You can turn the aircraft using yaw (rudder) only. But you risk stalls and spin of you do it too sharply. | 41 | 44 |
How do scientists know that 1 Billion crab went missing ? | If they are tracking them that accurately it seems like fishing then would be pretty easy, if they’re trying to trap them and just not finding any it could just be bad luck.
Canceling the crab season is a big deal so they must know this with some certainty. What methods do they use to get this information? | There are a lot of ways you can estimate the population of a species. In fisheries we usually do surveys exactly the same way every year to get a general idea of the population size and trends, and mark recapture studies. If you tag 100 Cod and then next year you catch 100 Cod and three are tagged, that would suggest that you tagged about 3% of the population. Actually it's a lot more complicated because you have to correct for things like the tag causing mortality but that's the gist.
The big one though is catch per unit effort. You track the number of boats fishing in a certain way, how many hours they spend fishing, and how much they catch. If it takes three days at sea for a guy with a fishing rod to catch a Cod one year, and the next year it takes six, the population was probably cut in half.
Obviously 100 fish or one guy with a rod is a tiny, tiny number compared to the amount of data that actually gets collected- it's usually tens of thousands of tags or data from every fishing boat in a fishery. Even that ends up being a tiny sample of a commercially harvested species numbers though, so often fisheries management ends up depending on fairly imprecise estimates of population sizes. It's far better than managing with no data at all though, and a drop of 90% is large enough that they're almost certainly right that the fishery is imploding. ☹️ | 5,435 | 7,138 |
ELI5: Why are watermelons sweeter when salted? | Salt, to a point, tends to highlight the flavor of whatever you combine it with. Watermelon is primarily sweet, so a little bit of salt enhances that characteristic. Too much salt, though and the taste of salt overwhelms any accompanying flavors. | 43 | 47 |
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ELI5: How are lumens and candela related and what each represents. | In trying to learn more about each, I was curious if my analogy was appropriate. Is candela sort of like a decibel? In the sense that you can double the lumens, but that doesn't double the intensity of the light. Like four hands clapping isn't twice as loud as two hands clapping. | A lumen is the total amount of light coming from a source; its "luminous power." It's equivalent to Watts, the measure of power, but weighted for human vision, e.g., an infra red lamp could put out 100 Watts but, if we can't see it it would be producing zero lumens. It's a similar idea to the special A-weighted decibel scale ("dBA") for sound that only considers sound pitches that people can hear.
A candela is based on lumens but takes into account how focused the light is. A plain 1000 lumen light bulb will spread its light evenly in every direction giving about 80 candelas of "luminous intensity" (you divide by 4×π because that's the surface area of a unit sphere). Or you could have a 1000 lumen flash-light that sends almost all its light in one direction, giving off 1000 or even 10000 candela, but only directly in front. The extreme example is a focused laser beam which can have very high candela ratings with very low lumens. | 27 | 25 |
ELI5: Why do some people get white hairs while they're still fairly young? | I understand a little about melanin production slowing down as we get older, but does that also explain why I just found a white hair while I'm still in my 20's? What about people who get white hairs in their teens? | Hair gets it's color from melanin, like what gives your skin pigment. As people age, there is less pigment cells, or melanin in the hair follicle. When the follicle stops producing the pigment for your hair, it can become white or a gray color. This can be genetically determined so make sure to thank your parents for your white hair. | 10 | 18 |
CMV: Trans participation in sports often has an unfair advantage over other competitors | I know this is about to get a ton of shit, but I would like to keep the conversation reasonable and based on logic. This is not meant to be trans-phobic or closed minded, so now that I’ve gotten that out of the way, let’s try to keep the conversation civil.
In a nutshell, when someone changes genders and chooses to enter a sports based competition, isn’t this unfair to the other entrees? It’s a biological fact that one gender has strengths and drawbacks in relation to the other. While a girl could work hard and train to be able to deadlift 100lbs more than any male competitor, wouldn’t the majority of women be at a disadvantage to a MtF participant? Although some men are more flexible than women, wouldn’t the majority of men be at a disadvantage to a FtM gymnastic competitor?
If you take a cis-gendered male and sign him up for a women’s track and field event, he would be denied entry because of the imbalance. So once the person states they are that category’s assigned gender, the biological differences are now ignored and they can participate. Even in the military, female fitness goals are lower then men’s, even though some females could meet the male standard - the point is the majority couldn’t.
So if the point is that there IS no biological difference between people, why are there still male and female sports categories at all? Why wouldn’t everything be coed and merely based on speed or skill level? | There are biological deference’s between men and women which results in men having in unfair advantage over women in sports which is why there are women’s leagues. Transition from male to female doesn’t take away the advantage men have over women. When a women transitions to male she doesn’t have an advantage over the male competitors so it’s fair for her to compete against men. | 66 | 301 |
If two radioactive atoms were entangled, would they decay at the exact same time? | Two particles may be 'entangled' - with respect to _some property_. That means that that particular property (e.g. which spin state the particle is in) is correlated between the two particles. You cannot say that 'particles' themselves are entangled, it's really their states. In quantum mechanics, you can completely describe a system in terms of different states (a basis), and something which is entangled in one basis is not necessarily entangled in another. So another way of looking at it, is that the entanglement is a property of the physical description of the system, rather than the system itself.
So it's not clear what your question is supposed to mean. Which states are entangled here? Why would they decay simultaneously? Entanglement does not mean two 'entangled' particles suddenly act like each other's clones.
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If we know what kind of bacteria causes the majority of cavities, why don't we just make an antibiotic that targets them and distribute it like a vaccine at a doctor's office? | Antibiotics that target a specific bacterium are tricky. There are a small handful that have been demonstrated, but very few, and only for research purposes. Even then, it's more of a "kills bacteria x very efficiently, while y and z will mostly survive" deal.
The reason is, simply, how targeting can be done. You basically pick a trait or property of that bacterium - for instance, it has a lot of receptors for a specific sugar molecule, or the cell wall is negatively charged, or something. You target that property, by for instance attaching the respective sugar to a drug molecule, and hoping that most of the dose gets taken up by your target. Some will be uptake by other cells though, as there is almost never a completely unique expression or trait.
Also, most of these types of drugs are too expensive, and not specific enough, to be commercially feasible.
Thus the various broad spectrum antibiotics, and the range of somewhat specific antibiotics that each address a niche family or group of bacteria.
Beyond that, antibiotic resistance is a huge problem with overuse. Basically, let's say your antibiotic is super effective, kills 99.9999% of the target bacteria. The remaining 0.0001% is the group that was more resistant, for whatever reason. That is the group that also starts to become dominant, as we kill off the less resistant ones. Eventually, your antibiotic is no longer effective for that bacteria!
This is why we have had to formulate so many modified versions of penicillin, to keep coming up with something new that still works.
Generally speaking, it is best to limit antibiotic use to cases where it is really necessary. While you can certainly argue for it's use against cavities, it would not be a one time (or sporadic) thing like vaccinations but a regular treatment, like mouth wash. That sort of high volume, high frequency usage would give us dental versions of something like MRSA very quickly! | 63 | 58 |
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[Jurassic Park] Why didn't they use bird DNA to fill in the Dino DNA gaps? Birds are much more closely related to dinosaurs than frogs are, and they have the added benefit of not changing sex. | Contrary to the film portrayal of the events, InGen scientists used the DNA from a variety of species to fill in the gaps. They made their best guesses as to what each gene was supposed to do, and matched it with a gene from an animal that seemed the best match for that process.
Not every dinosaur was able to change sex and reproduce. Only the ones that had that specific set of genes from frogs. | 37 | 21 |
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ELI5: Why do petrol prices change so often but not other things like food and other stuff that's imported. | Oil is a commodity and has few alternatives, which its price makes it very sensitive to changes in its supply. Food, on the other hand, can vary - usually you get the manufactured good which has more alternatives | 10 | 26 |
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ELI5: How are bar codes regulated and standardized? How do they prevent two items having the same barcode? | Bar codes, conceptually, don't have any system to prevent duplication, but there are systems that use bar codes that enforce uniqueness. The UPC codes you see on grocery store items are one of them. In that system the first half of the digits are a manufacturer code (and some other data), unique to each manufacture. The second half is up to the manufacture to control to assign to each of their products uniquely. | 16 | 24 |
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ELI5- how do the giant coils on power lines not electrocute things or catch stuff on fire when it’s raining even when you hear the static of the electricity? | 1) Rain is not continuous. The drops are separated by a lot of air.
2) Water isn't quite as good a conductor as people think it is. Pure water is in fact a decent insulator. It is the dissolved minerals in the water that make it conductive.
3) They design the insulators such that they look a little bit like an upside down cup. Water cannot go uphill, so there is break in the water between wire and the insulator.
4) The designers know the voltage the lines are mean to carry, and add sufficient separation such that arcing between lines doesn't occur. | 66 | 20 |
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Eli5 what's the purpose of sodium or salt in our sweat? I understand sweating is supposed to cool us down but why is there salt in sweat. | Your body functions best when it maintains the right balance of salt and water. This is why hospitals hydrate people with saline solution instead of pure filtered water. Add too much water without a comparable amount of salt and it throws off the balance.
*Extract* too much water without a comparable amount of salt and it also throws off the balance. If your sweat didn’t contain salt, then by sweating you would be concentrating the salt in your body, which ultimately wouldn’t be very good for you. | 84 | 33 |
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Explain the whole voter ID controversy in the US. | Saw one of my more conservative relatives railing about how you're considered a racist now for supporting voter ID. I have something of an idea of what it's about, but haven't done much research. | Basically, IDs take time to get. The most common one is a drivers licence, but not everyone needs to drive. Some don't have cars, some are too old to drive, some are still in college and don't need to drive (or are from another state originally and have not converted their licence).
These demographics, the very old, the very poor and students are disproportionately democratic. The very poor also has the added effect of being disproportionately less white than the population at large (which is part of what makes the group much more Democratic than Republican).
So voter ID laws will have the effect of decreasing turnout by making it more difficult to vote. And those that will be less likely to vote are disproportionately Democratic and disproportionately not white. Some say the point is influenced by the latter, that it is racially motivated. But it is more likely to the former.
Now to be fair, supporters claim that this crackdown is in response to voter fraud. But such fraud just doesn't happen in any major degrees. In Ohio there were only 9 cases of the 3.8 million votes cast in 2010. Florida doesn't have a single reported case for that election. So while preventing fraud is the stated goal, its effect will swing states a small percentage towards Republicans that in part reduces the amount of minorities who vote. Weather that makes it racist or political is an argument to be had. | 27 | 38 |
What's the difference between "metaphysical" and "ontological" in contemporary usage? Do two things with the same ontological status necessarily have the same metaphysical status? What about the reverse? | To elaborate: If I make a claim like
>"there is no a priori ontological difference between what is human and what is not"
what would be the difference in substituting "metaphysical" for "ontological"?
Or if I were to claim,
>"logical possibility entails metaphysical possibility"
how is this different from if I had used "ontological" instead of "metaphysical"?
Thanks dudes! | Metaphysics is more general, ontology is more particular. Ontology is a branch of metaphysics. So something's ontological status is *part of* its metaphysical status. But ontology doesn't exhaust metaphysics. For instance, another branch of metaphysics is mereology, being the study of the relationship between parts and wholes. Consider the ontological status of the City of Gold with its mereology. The City of Gold, presumably, is made up of a whole bunch of city part make of gold--some mixture of golden buildings, golden streets, golden pavements, golden lamp posts, and so on. The city is the whole made up of a bunch if city parts, and this is a metaphysical fact about the City of Gold, where it to exist. But all of that happens independently of whether the City of Gold exists, that is, its ontological status. That's an example of how there is parts of something's metaphysical status which is not part of its ontological status. | 29 | 18 |
Why is the job of an Economist considered a high stress job with long hours, tight deadlines and multiple projects at once? | Everywhere I read, it says that the job of an Economist is stressful especially in the private sector. It involves long hours, tight deadlines, working on multiple projects at once. It also requires extensive contacts and relationship building, something a lot of people cannot do and many find it stressful given the extensive office politics at play.
Can someone explain why the job of an Economist is stressful? | Private sector economists tend to be employed in finance or litigation consulting, both of which involve long hours and high stress. It's stressful because you're in a relatively high-stress industry. | 39 | 38 |
ELI5: how can black holes have greater gravitational pull than the stars they're born from? | A super-massive star blows off it's outer layer, and what remains collapses into a black hole. Shouldn't the black hole then have less mass than the parent star, and therefore less gravitational pull? Sure, the black hole has extreme density, but gravity is a function of mass and distance. | >gravity is a function of mass and distance.
Exactly, so the black hole has the same (or less, if matter was ejected) gravitational pull at large distances. The difference is that, at distances where you would be *inside* the original star (and thus experiencing reduced gravity from the outer layers pulling you up), you'll still be far away from the black hole, so the gravitational pull nearby the black hole is higher than anything the original star was capable of. | 51 | 21 |
[Star Trek] How does the Federation monitor the vast spaces between its star systems? Is there a dedicated sensor network? Specialized starships who continuously scan these areas? | Yes.
The Federation (and other societies) maintains a network of beacons, probes and sensors throughout space. Many are in orbit around planets or star systems, either collecting data or warning others away.
The Federation also maintains a large fleet (I.e. Starfleet) of scientific and exploration vessels whose main purpose is to collect data, encounter new races, chart stars and their behaviours as well as investigate, note, and report just about anything of interest. These vessels work in a region of space suited to their capabilities, however if needed elsewhere they will be reassigned.
By coordinating all of this via subspace communication the Federation is roughly aware of most things of note happening in Federation space, and vaguely aware beyond that, but thanks to its ship placement and design it can become intimately aware of anything in Federation space in about a day, and in about a week for elsewhere in the Alpha Quadrant. The Federation has little to no knowledge of other quadrants beyond the basic physical properties of the stars.
Other societies have different equipment capable of detecting different things, which they may share with the Federation if they're in an alliance. An example would be the Dominion's deep space probe/sensor array which effectively allowed them to know the position of every ship in and around Cardassian space. The Dominion were notably at war with the Federation-Klingon-Romulan alliance at the time, so this sensor array was destroyed. | 20 | 41 |
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Why do we stretch and why does it feel good when we do? | It doesn't seem to be something we do instinctively. Yet other animals do it too.
^(I actually sound like I'm 5) | When your at rest your body slows down and your blood flow decreases. Stretching gets things moving along by causing your heart to beat a bit faster for a few moments. This increases oxygen, blood flow, and waste removal. Making you feel awake and fresh with new energy. Similarly water at rest can become bland and boring but once it ripples or moves it becomes more alive as do the beings within. | 10 | 20 |
What are some obvious issues in academia, nobody wants to talk about? | Like inter-departmental politics, everybody knows but people rarely talk about it to resolve it. | Expectations that a single academic will do everything - teach, do cutting edge research, manage people, do admin work, write papers, communicate science to general public, service equipment and so on. No support staff, no division of work between people, you need to do everything and be excellent in every aspect. | 341 | 211 |
ELI5: Why are eyewitness testimonies used and taken so seriously in court if people’s memories have been proven to be bad? | I strongly encourage you to read transcripts of a court case to get a real feel for what an eye witness testimony looks like.
It's more than just asking a person that they saw Jim shoot Bob. Most often they will use multiple people to build context on the crime.
When people testify, the lawyers are often referring to pieces of evidence to jog their memory and they use the witness' testimony to validate the physical evidence. If a video is available the lawyers will play certain clips over and over while asking the witness about details that you can't see. They will also use it to poke holes in their testimony.
​
To answer your question
> **eyewitness testimonies used**
Because a bloody knife is much more compelling if someone saw Jim holding it.
>**and taken so seriously in court if people’s memories have been proven to be bad?**
The reliability of eye witness testimony is only taken as serious as the person giving it. If Sweet old Betty who has nothing to do with the crime said she saw someone that looks like Jim jump the fence to Bob's yard that's a pretty compelling piece of evidence.
Most importantly of all, you never ask a witness a question you do not know the answer to. | 47 | 66 |
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ELI5: How come a computer monitor or TV uses red, green and blue to display different colors but when painting we use red yellow and blue to make different colors? | We have cones in the backs of our eyes that detect colors. We have three different kinds of cones: cones that respond to red, cones that respond to green, and cones that respond to blue. That's what lets us create an image using only red, green, and blue light so that we can't tell the difference. Yellow light, for example, triggers the red cones and the green cones, and looks the same as red light and green light shone at the same time. That's why red, green, and blue are considered the primary colors when talking about light.
Light:
* Red + Green = Yellow
* Green + Blue = Cyan
* Blue + Red = Magenta
Paint (or pigment) doesn't emit light, it absorbs light and reflects the rest. Where colors in light are additive (green + red = yellow) pigment is subtractive. You start with light's secondary colors and mix them together to reflect only the light that they *both don't absorb.* Pigment's primary colors are light's secondary colors: magenta, cyan, and yellow (but magenta is usually taught as red and cyan as yellow).
For example, magenta reflects red *and* blue (see how it's made of red and blue above?) and cyan reflects green and blue. When you mix yellow and cyan together, yellow absorbs the blue that cyan would have reflected and cyan absorbs the red the yellow would have reflected. The only color both of them reflect is green, so you see green. You probably learned this as Blue + Yellow = Green.
Pigment:
* Magenta + Cyan = Blue
* Cyan + Yellow = Green
* Yellow + Magenta = Red | 15 | 28 |
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Why do waves come in sets? | I was out diving today in heavy surf and got advice from the dive master to watch for a set of 3 big waves to come by before surfacing - evidently after 3 big ones, you’ll get about 3 or 4 smaller ones, making it much easier to clamber back on to the ladder. I was a little doubtful, but it turned out to provide me the 30 second window I needed to have a substantially easier transition...
But it made me wonder: with the same wind pushing the water, why aren’t all waves approximately the same size? Why do they come in sets of a few waves at a time, instead of hundreds, or instead of randomly variable waves?
Thanks! | Wind speeds are variable in space and time and this produces a spectrum of waves of different periods and wavelengths. The longer period waves travel faster in deep water so the waves will sort themselves out as they propagate away from the source. These waves interact and the waves with the shorter periods are modulated by longer period waves producing wave packets that vary in wave amplitude as U experienced diving with small waves followed by larger waves than small waves. The larger waves occur at the crest of the longer period waves. | 20 | 40 |
Why are barns painted red? | At least with the American ones, just about every barn I've seen is painted that same dark red. Is it culture, superstition, availability, all of the above? | Centuries ago, European farmers would seal the wood on their barns with an oil, often linseed oil - a tawny-colored oil derived from the seed of the flax plant. They would paint their barns with a linseed-oil mixture, often consisting of additions such as milk and lime.
The combination produced a long-lasting paint that dried and hardened quickly.
(Today, linseed oil is sold in most home-improvement stores as a wood sealant).
As for the red, there are two predominant theories:
* Wealthy farmers added blood from a recent slaughter to the oil mixture. As the paint dried, it turned from a bright red to a darker, burnt red.
* Farmers added ferrous oxide, otherwise known as rust, to the oil mixture. Rust was plentiful on farms and is a poison to many fungi, including mold and moss, which were known to grown on barns. These fungi would trap moisture in the wood, increasing decay.
Regardless of how the farmer tinted his paint, having a red barn became a fashionable thing. They were a sharp contrast to the traditional white farmhouse.
As European settlers crossed over to America, they brought with them the tradition of red barns. In the mid to late 1800s, as paints began to be produced with chemical pigments, **red paint was the most inexpensive to buy**.
Red was the color of favor **until whitewash became cheaper**, at which point white barns began to spring up.
Today, the color of barns can vary, often depending on how the barns are used. | 17 | 23 |
ELI5: What is the difference between anodizing and galvanizing? | Anodizing produces a stable oxide coating on the material - usually aluminium - which prevents further degradation.
Galvanising deposits a layer of corrosion-resistant zinc onto (usually) steel. Not only is zinc quite resistant to corrosion anyway, but it also forms an electrochemical pair with the steel which makes it electrically unfavourable for the steel to rust. There's another benefit - the zinc coating can to some extent self-repair, because the battery effect re-plates scratches and minor dings. | 14 | 15 |
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Why is there little attention paid to Japanese debt? | As I was skimming through some economic articles on Wikipedia, I came across governmental debt. I then sorted by percent of GDP and was thrown aback when I realized that Japan is in a lot of debt.
I found a [Forbes article](http://www.forbes.com/sites/stephenharner/2011/11/18/coming-to-grips-with-japans-government-debt/) from the end of last year. In it, the author states that Japan is different from Europe because most of the debt is owned by Japanese citizens or institutions.
My question is: Will Japan suffer the same fate as Greece, and if not, what makes them different? Also, if they do keep down this path of budget shortfalls being made up by increased debt, what will a financial disaster look like for them and the rest of the world? | The fact that most of the debt is owned by Japanese citizens or institutions is very important. When the government issues debt they must pay interest and eventually repay the principle to the owner. The money used to repay the debt comes from taxes. If the owner of the debt is a foreign entity taxes from the citizens are transferred to a foreign entity. It leaves the Japanese economy and reduces total wealth. However, if the debt is owned by Japanese citizens the transfer of taxes to debt holders occurs within Japanese borders. The maintains total wealth.
TL;DR If most of the debt is owned domestically, it is primarily an internal transfer of wealth and should have no effect on GDP (theoretically). | 28 | 26 |
ELI5: Why is paper used to substitute plastic (such as paper bags, paper cups, paper straws etc.) if it costs our trees? Is it more eco friendly? | Trees are renewable and can be harvested sustainably. Plastic comes mostly from oil products and is limited. Paper will degrade pretty rapidly in the environment where plastic does hardly at all. The last point is important, as paper will eventually give us more soil whereas plastic needs to be stuck in a hole for an eternity. | 50 | 18 |
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