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ELI5: What is actually happening to fruit when it ripens? Does the calorie content increase while the fruit is sitting on the counter getting sweeter? | As fruit ripens, starch is being converted into glucose (bigger carbohydrate molecules to smaller ones). The more ripe it is, the more conentrated sugars there are(making it taste sweeter of course). So caloric value does not increase as carbohydrates are converted, rather than created. | 26 | 51 |
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ELI5: How does my 5 month old daughter know sad songs are sad? | My wife and I found this out by accident but without fail really sad songs/ songs in a minor key with a slow tempo will make her start crying with real tears. How does she know they are sad without any context for what a happy or sad song is? Edit: this song in particular gets to her the most https://youtu.be/zZkih54evUs Edit Edit: here's some video proof, https://youtu.be/5okkn23JZ68 is her listening to the song and https://youtu.be/LQp6kwtMMhg is immediately after. | Specific keys and modes carry emotional cues independent of culture. The brain just reads them as jubilant, sad, angry, tense/scared, etc innately. Now these are then reinforced by culture in the way the people around us react and what we choose to play the music with as well and at a point this cultural component may be larger that the base, but the base is still there. Your child is likely picking up on these base cues as well as your reactions to it. | 179 | 332 |
ELI5: Why do some programs crash/become unresponsive when minimized? | Skyrim is a huge example for many people. Why can't some programs do this? | Let's say your computer is a line of students (programs) in primary school waiting to be served lunch (processing resources).
Skyrim, the school bully, has the notorious reputation of beating other kids up to get the Fullscreen pass which allows him to cut in front of the lunch line so he gets the highest priority for the food.
A new teacher, Mrs. Minimize, notices the bullying and forces Skyrim to the back of the line. Since Skyrim is always used to getting the highest priority for food, he gets extremely upset. If he isn't first in line, then no one should be! He charges through the cafeteria, crashes the table of food to the ground, and stomps his way out.
Summary: Some programs are used to getting high priority for processing power. When minimized, they switch to low priority which could cause processing issues, causing them to crash or become unresponsive. | 26 | 28 |
ELI5: Spider silk was, until recently, the strongest known natural material known to man. How is it that spider silk is stronger than something like a turtle's shell or a ram's horns? | Strong is relative. Cement is strong, unless you pull on it; steel is strong, when being pulled on, but isn't so great when force is applied in certain axis. Cement has incredible *compressive* strength, steel has great *tensile* strength.
When they discuss spider silk as being "strong", what they are really saying is that it's the strongest naturally occurring tensile material (at the time), meaning that it can support many times more weight than something like a steel cable of the same mass and length. A turtle shell or ram's horns have better sheer and compressive strength - they resist being compressed and are rigid, and don't break under specific levels of force.
But don't confuse hardness with strength - a turtle's shell may be hard, in that it has little give, but not be very strong, while steel is relatively soft (in that it deforms easily, but has great tensile strength when under load. | 419 | 450 |
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Having Python script run without having to install packages | I have an assignment where I must submit a Python program that my professor will then run on his computer. It is a web crawler that outputs data to a CSV. It requires a few packages such as Requests. Is there a way that I can submit a working assignment that does not require the professor to install the packages in order for the program to run? I have just started looking at Docker and think it could be a solution. I would be very grateful if anyone could point me in the right direction. | I would see what your professor recommends. This seems strange that they would expect this from you but not have their own plan.
Typically with something like this you should ‘pip freeze’ into a requirements.txt file, double check that the file only contains packages required for your code and include this file with your code.
Your professor can then use this to recreate the environment needed to run your code.
Aside: If you are starting to look at Docker, start to look at virtual environments first. Virtual environment tools are built into python three and are amazing. | 20 | 23 |
To all Computer Engineering/Science students & graduates, what sorts of projects did you do during college and what do you recommend for the students currently in CS program? | I am not sure what field to enter after completing my undergraduates. I want to get a taste of all the options before considering something to do all my life.
I am a Computer Engineering student in my 5th semester. I wanna know what sorts of projects or things are my fellow CS students learning and doing in their university? Even the graduates can share their experiences and projects. Mentioning languages, tools and the benefits from those projects would be highly appreciated.
Any tips regarding how to figure out the topic for me would be great as well.
I am sure it is just not me confused with the mushrooming fields around CS to choose a career from. So, any help/suggestions from fellow students, graduates or even professors would be appreciated by a whole lot of us.
Thanking you all in advance! | There are a number of things you can try to do, I'll just list some that come to mind:
Build an application that lets users upload an image, and it says whether that image contains a flower or a dog. Architecture this app as a web app with React/Vue/Angular on the frontend and Python/C# on the backend. Use a neural network to do the image classification to try your hand at deep learning. Make a CI/CD pipeline which runs tests and publishes your app as a Docker image to a Docker registry. Deploy your app to a cloud platform like AWS/Google Cloud/Azure using your Docker image. Bonus points if you try your hand at Kubernetes.
If you do something like that, you'll get a cross-section view of a bunch of software fields: frontend, backend, ML, CI/CD, cloud. You can decide for yourself which parts you enjoyed the most, and enhance your project in those areas.
Enjoy ML? Improve the accuracy of the model or give the users an option to add new classes of images (like boats).
Enjoy backend/frontend? Add more features like batch asynchronous processing, multithreading etc.
You can make a mobile client app for this.
If you enjoy the cloud aspect, you can configure GitOps, or improve your deployment by adding rolling deployments or redundancy. Learn about Kubernetes and Helm.
That's just an idea, you can take it anywhere you want. | 10 | 20 |
How harmful are microplastics to human babies? | Studies show that babies' feces contain as much as 10x the amount of microplastics found in adult ones. And since babies are more fragile, microplastics must harm them more than they harm us. But by what margin? | The effects of widespread microplastics are simply not known, and research funding towards the area is fairly recent. Our lab is one of many aiming at this problem, but it will take some time to build a confident body of evidence.
Some hurdles include:
* The huge variety of different microplastics generated, which vary by region collected
* The many coexposures of additives in the plastics and other chemicals
* The complex weathering processes
* Difficulty in isolating and analyzing nanoplastics
* Difficulty in obtaining information from industry
* Intrinsic limitations of in vitro and in vivo models
* Poor understanding of mechanistic pathways involved | 93 | 72 |
ELI5: Why does a computer playing chess make different moves against a player making the same moves in different games if the computer's moves are all calculated? | A ) computers may utilize randomization to alter their plays: especially in the opening moves.
B ) computers might not get quite as far in their calculations each round in each game, so they might not always arrive at the same results. | 37 | 32 |
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ELI5: Why do internet-based voice calls have lag but standard phone calls don't? | I've got some family in Australia and it's always amazed me how a WhatsApp call, despite both having very fast internet speeds, will have a bit of lag (normally around a second or two) but a standard landline phone call the same distance will have none at all. And the same even applies to local calls.
Essentially, what is it about standard phone communication (landline or mobile) which allows it to transfer data thousands of miles absolutely instantaneously? Will we ever hit internet speeds which allow the same thing? | Standard lines don’t really transmit data as much as transmitting signals.
Voice over IP works by sending data in packets over the internet. Internet protocols work differently than standard phone lines. Standard phone line calls basically happen at the speed of electricity. VOIP data is sent in packets that get routed through the internet along with all other kinds of data. The time it takes for this processing is called latency. When your device sends of the stream of voice data in these packets it doesn’t care how they get there and they may take different routes and arrive out of order and have to be out back together, that’s called jitter. Together, latency and jitter are what you experience as lag. There’s also another concept called buffering, which basically is a way to compensate for the time all the above takes. All of this happens and rehappens throughout the call and is constantly changing. Both clients basically measure the time it takes to send and receive packets and try to compensate. | 61 | 81 |
Advice from the other side - industry | Hi everyone. Hearing from those in academia themselves could really help a fellow redditor who’s currently having a life crisis :)
I work in corporate America, been doing it for several years, make 6 figures and am unhappy. Prior to pursuing the field I am in now, I was considering a PhD. I am finding myself regretting not taking that path to begin with realizing it was probably better suited for my personality to be in academia. I also read books relating to what I was thinking about studying in my personal time, 8 years later, making me realize that it truly is an intrinsic motivation vs. my current career that doesn’t intellectually stimulate me but gave great perks early career such as the money and travel.
Some general questions I have for you is:
- Is the phd worth it? Particularly in a field that wouldhave no choice but to stay in academia afterwards?
- would you recommend someone close to entering their 30s to go for the phd?
- as a women, would it be wise to embark on this journey knowing you will be in school during your prime years of child bearing (currently have no plans to have a child, would like to at some point in life)
- what could the biggest challenges be?
If you read this far, thank you.
EDIT: thank you everyone for such thoughtful advice. I really appreciate it. To clarify, my research interests could lie in marketing/org behavior/ business management disciplines | Your age isn't an issue, not is your gender. Plenty of people get their PhD when they're in their 30s, and plenty start a family during the process.
What is an issue is the academic job market. Any student entering a PhD program at this point needs multiple alt-academic backup plans. The idea that your program of study would leave you no choice but an academic job is problematic. | 59 | 39 |
ELI5: Why does chewing sound louder with headphones on? | For example, when crunching chips, it sounds louder than eating them without headphones. Why does this happen? | several reasons
a few of the main reasons:
sound travels faster through plastics/metals than through air, so distinct sound reaches your eardrums more quickly than you're used to hearing
the headphones block external sounds which normally make up a part of the sound you usually hear. the sounds that normally travel through the air, bounces off of nearby objects, etc. are blocked.
with headphones on you are also able to more distinctly hear the sounds being transmitted through your own flesh, bones, etc. - normally these are mixed in with echoes, ambient noise etc
with cup type headphones, the chamber between your ears and the headphones has its own echoic properties and changes how you'll perceive the sound | 138 | 361 |
[WH40K] Just how powerful is a Living Saint? | They certainly *look* like they're the holy equivalent of a Daemon Prince, but how strong are they?
Could they go toe-to-toe with a Daemon Prince, a Primarch, a Daemon Primarch? | Despite them being divine beings, their powers vary as it is determined by how much of The Emperor's essence is bestowed upon them. Often they are only given enough power for the mission that The Emperor has chosen them for.
For the most part, they are comparable in power to daemon princes and greater chaos champions, but it is unlikely they could go toe to toe with a primarch.
| 40 | 74 |
ELI5: Why are camera lenses round, but the photos that they produce are square/rectangular? | Making round lenses is easier than square or other shapes.
The thing that actually captures the image (whether its the CMOS/CCD in a digitial camera or a piece of film) is still square or rectangular - the size of the optics are chosen to be just larger than the extents of the film frame/sensor - thats why on some viewfinders you actually have a rectangle (especially if you see a movie camera) - thats showing the cameraman/photographer what part of his view he will be capturing on fim/digital. | 29 | 48 |
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ELI5: How does depth perception work? Do you need two eyes to have depth perception? | Depth perception is our ability to judge distances.
This can be done approximately based on how much our eyes have to focus, how big something is, how much ground there is between us and it based on our height, etc... All of these are monocular cues, and are relatively unreliable compared to parallax. They are sufficient for many animals, but predators especially tend to prefer something more precise as it makes catching prey easier.
This is where binocular vision comes in. While many creatures have two eyes, having two eyes that both face forward is much rarer. This allows both eyes to look at something. The difference in the angle that both eyes must face gives us a much more reliable method of depth perception. | 22 | 23 |
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[Batman Begins] What was the official story behind Bruce coming back to Gotham after being presumed dead for 7 years? | What possible reason would there be for a spoiled, self-absorbed billionaire playboy living off his parents' inheritance to just disappear from the public eye for several years?
And wouldn't people find it suspicious that Bruce Wayne's return strangely coincided with the Batman's first sightings? | Public answer to the first question: he was tired of the fame, media attention, and expectations put upon him as the sole heir to the Wayne family fortune. So he spent a few years traveling the world, laying low, and figuring out himself. | 68 | 63 |
CMV: The United States should not drill any oil | The United State's policy of increasing oil drilling is misguided. In all practicality, it is counter productive. First of all, the environmental consequences of drilling are intense, ranging from devastating the area to pollutants, to causing geologic instability with fracking techniques. Second, increasing oil production is both functionally and ideologically counter to the renewable energy movement. Third, it provides minimal economic benefit to the US. The most common rationale for expansion of drilling is that it will lower oil prices, but that is a misconception. Oil companies will always sell their oil on the world market, at world prices. We cannot force them to sell their oil at lower US specific costs for obvious reasons.
sources and examples will be provided on request.
EDIT:
In order to develop this case further, I offer the following. In the long run, the world will run out of fossil fuels. Honestly, this is a matter of when. This should not be our goal, as a world that is not ready to switch is not a pretty picture. I offer two advantages to stopping US production.
First, it is not making as large a positive impact than stopping it. See point #3 here http://www.reddit.com/r/changemyview/comments/23svx5/cmv_the_united_states_should_not_drill_any_oil/ch0aqak
any resulting price increase will create an incentive to innovate in renewable technology.
Second, in a fatalistic world view, we will probably fail at the switch anyways. That means that the price of oil will skyrocket. If everyone else has run dry, we set the price, and become insanely rich. This could give us the resources to make the switch at the last possible second, a hallmark of US politics. That is, if we can keep the wealth in the economy and out of CEO's bank accounts.
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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!* | 1) There *can* be significant environmental consequences with some forms of drilling. Those can be managed on the one hand and must be measured against prospective benefit on the other.
2) The "renewable energy movement" is a nice idea, but it isn't going to readily provide us with gasoline for cars or natural gas for heating and cooking in the near future. Until they can do that, we need energy we can use. Oddly enough, fracking tends to offer a high yield of natural gas, which is cleaner than oil and could help us transition to more stable energy sources.
3) It provides considerable economic benefit to the US. When the US produces a resource, it produces value. Whether we sell it or use it domestically, we make money that stays in or enters the US. That's a good thing. And while domestic production wouldn't affect per barrel price very much, cuts in transportation overhead could reduce prices at the pump or on the utility bill. | 17 | 23 |
ELI5: Why do we still have court stenographers? Why don't they just record all the audio in the room? | The purpose of the transcripts is that the lawyers and judges can review what was said at a later date, and then reference it in motions and briefs.
You might have a court hearing, then later file a motion saying something like, "As Officer Johnson said, 'The accused was nowhere near the scene of the crime at the time the offense was committed.'" Then you would cite to the page of the physical transcript where that was said. Since you cited to it, the judge and the opposing counsel can open their copy of the transcript to the correct page.
It also comes in handy in the case of appeals. When a case is appealed, the court of appeals gets a copy of everything that was said in court. It makes it easier for them to review everything.
Some courts do record sessions rather than have a stenographer, but it is not as smooth a process for referring to what was said. Think about if you were telling a friend about a song, and a particular set of lyrics. You could give them an mp3 file of the song, and say, "Check the lyrics from 1:24 to 1:58, they are really good!" Or, you could just send them the lyrics that have been written down. | 18 | 18 |
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ELI5 the meaning behind "turtles all the way down" | >A well-known scientist (some say it was Bertrand Russell) once gave a public lecture on astronomy. He described how the earth orbits around the sun and how the sun, in turn, orbits around the center of a vast collection of stars called our galaxy. At the end of the lecture, a little old lady at the back of the room got up and said: "What you have told us is rubbish. The world is really a flat plate supported on the back of a giant tortoise." The scientist gave a superior smile before replying, "What is the tortoise standing on?" "You're very clever, young man, very clever," said the old lady. "But it's turtles all the way down!" | 61 | 73 |
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What is your team's practice for new coding standards? | I'm on a small team that has been struggling with communication and formal processes for the last few months while we grow and get more pressure from a growing startup.
We need a formal code standard process to be able to 1) introduce code standard proposals, 2) decide on whether to implement, 3) make sure the team knows what the code standards are.
My thinking is to have just that: a form of some kind where people can propose them, and every period of time we get together as a team and discuss them (maybe every week or before we start the next sprint). But I was curious if there are any other processes out there that people have liked on their teams.
Edit: for clarity I'm not really asking for "use linting" - we already do that, we also already test builds for PRs and all code goes through code review. I'm asking for if your team has a process or there's a process you've used in the past for code standards that aren't linting rules. E.g. "Single responsibility functions", UI layout, when to put an index on a table, naming conventions, etc. We also do use best practices for the stack when they're available, ie our naming conventions for Postgres come from Postgres best practices -- however, just because *I* know something is a Postgres best practice doesn't mean everyone on the team does, and we need to put that information somewhere. Currently we don't have a process to literally say "Hey this is the best practice for this, let's commit to it as a team" and agree on that and put it in a place everyone can easily find it. | Use a code formatter. Use a common format across the entire team.
Use some kind of static analysis tool if the language you work with has one.
Use types addition if you are working with a dynamic language and find yourself fighting types often.
Establish a naming convention for common actions. When do you use get vs fetch vs retrieve? When do you use set or make or build?
Hold sprint post-mortems. What worked well, what didn't. What can stay, what needs changing.
Setup what rough boundaries that is allowed by individuals devs without discussions. A new language feature? New lib? New service? How much refactoring is too much? Write that line in the sand so you don't have devs introducing too much new stuff in code reviews, blindsiding reviewers.
Reduce your API surface. Expose as few functions as possible and make it known that certain functions are called only by internals. Make it easy for other devs to how and where to extend existing functions. | 23 | 33 |
How does Cancer cross the blood brain barrier? | The blood brain barrier prevents chemicals from crossing from the blood stream into neurons. Circulating Cancer cells will just edge themselves in a capillary and start driving there forming a ball of tissue .
It is like you putting a fence to prevent rabbits from entering your backyard and eating your plants, but then you get a bunch of squatters sitting up camp on the fence, eventually braking it. | 91 | 131 |
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ELI5:When people are lined up for black Friday sales days in advance, how do they do normal "life" stuff? | Here is an example:
http://www.huffingtonpost.com/2013/11/21/black-friday-shoppers-lining-up-best-buy-2013_n_4316397.html
Now be it folks lining up 12 days or 5 days or 2 days early for Black Friday Sales, how do these folks shower, shave, eat, work, take care of the kids, pay their bills, go to the bathroom-especially at night when the store is closed and most of all, how is this not seen as loitering or trespassing when at other times of the year it would be seen as such? | Frequently they're students or others with a low opportunity cost of being there (meaning they may live with parents or others who pay bills and work infrequently or jobs that are rather more flexible than most or offer liberal leave policies).
Stores love this because it means there will be a news story that basically says look how low the prices will be on the biggest shopping day of the year, you can't buy that sort of advertising. | 23 | 39 |
If someone was standing on an asteroid in the asteroid belt, would you be able to see other asteroids? | The average distance between asteroids in the asteroid belt is about 100,000 km. The radium of larger asteroids is about 1km. Using those numbers an asteroid would be 1 arcsecond big (about 300 times smaller than the moon). If you did see anything it wouldn't be more than a faint twinkle. | 21 | 27 |
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ELI5: What does it even mean for the fundamental forces to be “unified” just after the Big Bang? | This concept simply doesn’t make sense to me. The idea that they could be unified. How does that even make sense, and how would it manifest in the world at the time? | What scientists have been able to prove is that once you add a certain amount of energy to a system, certain forces start behaving the same way. Going up in energy you first have Electromagnetism and the Weakforce merging into the Electroweak force, then the Electroweak force and Strong force merge and finally, that new frankenforce will merge with gravity once we hit a certain energy level.
Problem is, the last time the universe was at that energy level was right after the big bang. Scientists really want to know what happened there because if they're able to describe how the forces split off one another, it should be considerably easier to come up with one unified model for how forces work. This is particularly important because at the moment we have to irreconcilable branches of physics to govern small and large systems (quantum mech. And gravity) but figuring this out might merge the two together. | 21 | 22 |
[SCP Foundation/Dead Space] How would the foundation deal with the Marker? | The Marker from Dead Space is unearthed in a remote part of Southeastern Europe and the foundation sets out to do its job. How do they deal with the Marker and the Necromorphs it creates? | After the Foundation would most likely be first made aware of the Marker's location after a researcher in some facility realizes the specific area in Europe has a few too many local superstitions and legends, especially of monsters that attack people that get too close to its location.
The first agents on the scene would just scout the immediate area and try to interview locals as much as they can. It's doubtful they will get much information this way, just whispered fears, prayers and repeats of the same legends they already know. Perhaps one interviewee offers to lead the advance agents to the location of the Marker. For a price, of course. The foundation would cover those expenses.
Once the initial agents arrive at the Marker, which lies in a shallow cave in the middle of a very ancient meteor crater, they call in cargo helecopters and a full fledged security detail. Amnesiatics would be dispersed among the local population to cover the extraction and the Foundation would try to be in and out within the same day. Only one researcher on scene notices the complete lack of life within a two hundred meter radius circle around the marker and the cave.
Darkness falls as the giant cargo helecopter begins to liftoff with the Black Marker in tow. The security team has grown tired of the desolate landscape and the babble of workers and scientists. They don't respond fast enough to the shrieks and cries that emanate from deep in the cave. Before they know it, a dozen twisted and mangled creatures emerge from behind the Marker and begin slaughtering everyone in sight. The commotion is enough to drive the security guards out of their stupor and they respond to the threat with lethal efficiency. It doesn't take long for them to realize standard head and body shots do little to stop the horrors, but they are trained to handle emergencies such as these. After twenty more deaths, the survivors learn the benefits of full dismemberment on their targets and the last of the monsters are put down. (Not long after returning home and giving full reports and video recordings of the incident, the surviving security officers are also put down.)
The Marker is transported to the nearest facility and placed in a sealed room. A new research team looks over the findings from the site as well as the local legends and come to the conclusion that... the Marker is wonderful. The monsters are of no consequence when you really look at it. It's providing limitless free energy! All they need to do is study it day and night and before long, humans can replicate the Markers any number of times, thus ending Earth's growing energy crisis in one fell swoop! Later, many of the researchers begin to show signs of severe depression or mania, leading to three cases of suicide and one case of serial murder before the Foundation sends in a cleanup crew.
The next research team is given orders to only study the Marker remotely. No one is allowed to stand within one hundred meters of the object, save a small group of Class-D personnel specifically chosen to have a wide variety of psychological profiles. The next team does not show the same fervor or dementia as the first, but most of the Class-Ds do. Many begin babbling pseudo-religious nonsense while others report hallucinations of deceased loved ones or friends. One out of a hundred Class-Ds show no effect at all. The 99 others are humanely dealt with, the survivors are taken to another facility.
Eventually, the Marker storage facility becomes devoted solely to the study of the Marker. Too many other artifacts in need of further study are placed within the dangerous circle of "dead space" (as coined by a researcher) and are slowly removed by expendable recruits and other Class-Ds. Eventually, the entire compound is empty, save for the Marker and a small cadre of researchers and doctors. Their lab is one of the quieter ones in the Foundation, but they provide results when asked.
The only oddity worth reporting is the strange wording in the center of each document from the facility. No matter what the document is, from food requisition to data specifically about the Marker, the words "Make us whole again." appear within. Usually without context. | 28 | 15 |
If evolution involves subtle changes in DNA structure, why aren't there more "transitional" species (e.g. more birds that can't really fly, or half-fish/half-land-creatures) alive today? | It seems like there would be an abundance of these transitional creatures, and the "end result" (species as we know them today) would be much smaller in comparison.
Notwithstanding fossils that may exist but we have not yet found, shouldn't we see many of these creatures living in the wild right now? It seems like there should be *some* transitional species that, while their numbers are dwindling since they are at some sort of disadvantage, are nevertheless still around. | All the species are transitional. The word "transitional" only works retrospectively, as we normally do not know in which direction a species is evolving, and with several species to compare.
edit:
Let's take you, and next to you your mother, and her mother and so on. If you take enough mothers, you will eventually reach a mother that looks like a small, furry animal you have never seen before. But you can see all the mothers/daughters lined up. Some have more than one child that will turn out to be different animals. Monkeys are standing closer to you, and manatees further away.
Mind that it was of course not the same individual that gave birth to different species. Imagine painting with watercolors, and from a central red you go with one brush to green and with another to blue. If the steps inbetween are as small as in evolution, you won't be able to tell them apart for a very long time.
To come back to the transitional species: each of them is - retrospectively - a transitional state. But evolution has no goal to reach, and thus no end of the transition. Yes, you are the end at the moment, but with your children, it will continue. | 42 | 15 |
Can someone explain the holographic theory of the universe to me in an easy to understand manner? | I really can't quite grasp the concept from what I've read on Wiki, and I've yet to find an explanation that "clicks." | Intuitively, you would expect the amount of information you can store in a ball of space to be proportional to the volume of that ball. But it isn't; it's actually proportional to the surface area of the ball.
There's an associated sci-fi concept, which claims all the information contained in a ball actually *is* stored on the surface. This is not scientifically meaningful, so don't worry about not being able to grasp it. | 19 | 52 |
I believe high schools should use a multi-tier system to stream teenagers into appropriate programs based on intelligence, regardless of the stigma this may cause. CMV | Myself and a few of my friends have recently been discussing the merits of our current educational system in Canada (and possibly North America, I dont know how the US public school system works) and I am an avid supporter of a tiered system, similar to the on used in the UK and other European countries. Schools are abandoning their most promising students by forcing them to spend four years in classes far below the level they should be on with students who are not peers. Our nations brightest are left to coast because of the prevailing mentality that everyone is "good" and failure isnt possible. How much potential is lost..? Can you change my view?
Edit: To clarify, I should have used the word capability or style of learning rather than intelligence in the title, as many of you have pointed out that intelligence is very difficult to measure and not strongly indicative of future performance. | Success is more often based on hard work, not some innate natural talent. Those so called 'brightest' students who coast along not working hard are not worth more investment than a person with less natural talent but works their ass off. | 139 | 385 |
You can't form an "ought" from an "is"? | This phrase comes up a lot in internet debates and it always seems to end the debate, which seems wrong to me. What can you say in reply? What *can* you form an "ought" from? The trouble is that most statements you can make seem like "is" statements, even those about values, which would seem to be where the answer should come from. Is it just a debating trick?
I understand the phrase arises from Hume's philosophy but I can't find anything about it on his Wikipedia page. | It can be a little confusing to think about in the terms in which it's couched, since even obviously normative propositions like "it's wrong to cause unnecessary pain to others" are framed as "is" statements. But all Hume is saying here is that you can't get from purely descriptive facts to normative ones. So like:
P1) Infidelity causes harm
C) Therefore, infidelity is wrong
is an example of an argument that would fall afoul of Hume's guillotine, and, as it happens, it's invalid. But something like:
P1) Infidelity causes harm
P2) Causing harm is wrong
C) therefore, infidelity is wrong
would not. It's really more about descriptive versus normative/evaluative than the literal words ought versus is. (Plus, any normative "is" statement could be rephrased in "ought" terms to avoid the semantic confusion). Did this help at all? | 22 | 19 |
This is a stupid question, but are human cells roughly flat/planar or spherical in shape? | I was under the assumption that the lipid bi-layer of the plasma membrane was roughly planar due to the roughly cylindrical shape of the double-tail phospholipid molecule (as opposed to the spherical shape formed by lipid micelles due to the single layer of conical single-tail lipid molecules). But are cells with plasma membrane bi-layers still spherical? Are pictures like [these](http://missinglink.ucsf.edu/lm/IDS_101_histo_resource/images/cell_structure_lab_micrograph_B-labelled.jpg) simply a cross-section of the cell using EM? | Cell morphology depends on its function. Red blood cells are shaped like a closed torus, lymphocytes are mostly spherical. Epithelial cells are mostly flat unless they are columnar epithelial cells - guess what shape those are!
To address your other question about imaging - even the flattest cells have a certain depth to them. The depth of field of a microscope at high magnification is rather thin, thinner usually than a cell, so yes you are looking at a cross section of the cell in every case. Sometimes a microscope can take a z-stack - a series of images at every focal plane at whatever increments - and those can be either used to make a 3D model of the cell of compressed into a single 2D image of all the planes. | 25 | 34 |
ELI5: What makes a "Special Agent" so special? Does the FBI/etc have Un-special agents? | An Agent is simply a representative of the government who can conduct investigations. They do not possess the special power to also arrest people. FBI agents are “Special Agents” because they are able to both conduct investigations and they possess the special power to make arrests.
They have agents and they have special agents. | 11,273 | 9,175 |
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ELI5: What do artists mean when they talk about rendering? | I hear the term "rendering" thrown around in both traditional and digital art communities like it's some sort of buzzword, but I've never gotten a clear explanation as to what it means. | Think of the work you do in the software like a pencil sketch of an idea
You get everything where it needs to be and laid out,
but then you need to ink the sketch, do coloring and shading. Thats rendering.
If you render a low res work....say a southpark episode. The computer has almost no shading to do, the colors are simple fills, and shadows rarely exist. The rendering speed can approach real time.
If you want to render a photorealistic world, with photorealstic people every object is coated in a high resolution skin, the computer needs to create all the shadows and highlights the sources of light demand...and you want 23fps?..and your rendering times stretch out into YEARS of processing time on your weaksauce laptop.
So you pay to have rendering done at a server farm where hundreds of computers will each chip away at seconds of your footage, returning results....well just about as fast as your wallet allows.
In olden days, animation shops would send their work to cheap foreign sweat shops for dozens of low paid third world artists to "render their ideas a reality in ink and paint" For computer graphics those sweat shops are render farms. | 31 | 33 |
How can Leibniz' God (as a monad Himself) cause other monads if he admits that substances are not intercausal? | This is specifically in reference to his *Discourse On Metaphysics* in which in paragraph XIV says "A particular substance never acts on another particular substance" and in paragraph XVI says "...God being the true cause of substances."
If God Himself is a substance, how can Leibniz take all of these to be true? | "Created substances depend on God, who conserves them and even produces them continually by a kind of emanation as we produce our thoughts” (Discourse on Metaphysics). God is the ultimate source of substances, so this doesn't contradict substances not acting on other substances. | 18 | 22 |
ELI5:Rather than have two separate sexes, why are not all species hermaphroditic? | Organisms that exchange genes change more per generation than organisms that don't.
As such, sexual organisms tend to evolve a lot faster relative to generation length than asexual ones.
Not only does this allow them to more rapidly exploit ecological niches and adapt to change (thus standing a better chance of avoiding extinction), but it allows them to be *more different* than their peers - which means that a lot of the biological diversity out there *is the result of* sex-driven evolution.
As with most evolutionary concepts, you kind of need to look at these things in hindsight. Species that haven't changed much over the eons... are the weird primitive things you find under rocks in ponds, because that's where they started, and they just haven't moved on.
Any species that turns hermaphroditic (there are even some lizards that have) is retiring from the rat-race, because it lives in an environment so stable that mutations allowing self-fertilization provide less disadvantage than the cost of maintaining males. This doesn't tend to happen very often - and even when it does, it doesn't tend to spread, because a stable species doesn't split into new species. | 15 | 39 |
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ELI5:the caucuses, and why only 3 states "matter", why exactly do those states matter do much? | Iowa, new Hampshire, etc | There are two main reasons:
- Those states are the first ones to vote for the primaries, they therefore set the tone of the entire election. If you win all the states that vote first, chances are that you'll win the rest of the country and get your party's nomination for the presidential election.
- Those states are also low populated states, which means that individual votes are more important than votes in other states, the vote of an Iowan will count more than the vote of a Californian in the presidential election. It's a consequence of the system and the existence of the electoral college. Some find it anti-democratic, some find it fair. The debate is strong. | 17 | 24 |
ELI5: Is there a reason that concert stages are raised above the audience but sport fields are lowered? Shouldn't they both be easily visible? | For example, the Coliseum floor (where the action is) is below all of the spectators so they can easily see what's happening, but almost all concert stages are raised above the audience. Is there a particular reason or is it just the way it is? | For sporting events, you want to be able to see the entire playing field, because the action might be anywhere on it. The "bowl" design, with the field at the bottom, makes the most sense for this - everyone is above the action, and everyone can see any portion of the playing field.
For performances (music, theatre), you don't need to see the ENTIRE stage, just the front, where the action is happening. Also, the performers can only face one direction at a time. Consequently, the simplest design for a stage that the largest number of people can see is just constructing a raised platform. | 33 | 51 |
Why do gravitational lenses sometimes result in Einstein-crosses rather than full circles? | In what way can the light be "bent" by a gravitational lense so that an observer sees two (or more) copies of the object rather than seeing a full circle? E.g. in Einstein-crosses you see 4 copies spaced evenly around the center. What about the spaces between those 4 copies? Why does the light not take these ways?
(Btw I asked this several times in different places now and never got an answer, sometimes I just got downvoted - I hope this sub is the right place) | Not all gravitational lensing happens around objects that can be approximated as spheres. Some objects that can lens, like galaxies, can be quite elongated. Additionally, you would only expect to see a ring in the object being "lensed" was very close to directly behind the object. If it is off center, you would not see a ring but two images(in the simplest case). As you pointed out with the Einstein cross, this is an example where both of these factors are in play. The object lensing is an oblong shape, and the object being lensed is not directly behind it from our vantage point. | 26 | 41 |
How to begin a career as an economic researcher | Hi, I'm an undergraduate rising sophomore and I'm interested in doing research as a career. I've read online that private sector/public sector research internships as well as research with professors is important. However, the only economics knowledge I have are my intro micro and macro classes. I have no previous experience with any kind of research or relevant work experience. How can I set myself up for a sophomore summer internship with this kind of minimal experience? Any wisdom is appreciated! | 1. Take intermediate micro, intermediate macro, economic statistics, and econometrics.
2. Talk to your econ department's Director of Undergraduate Studies. Ask about grad school. Ask about undergrad research opportunities. Ask about potential departmental or university-wide funding for summer research assistantships.
3. Look for internships at research-oriented firms (AIR, Westat, RTI) and public institutions (maybe the BLS/BEA/Census, maybe the Fed banks).
4. Talk to professors. Ask if they have any projects that they need help on. Express a willingness to learn statistics and programming, because those are likely to be your areas of comparative advantage. | 17 | 25 |
ELI5:What are doctors looking for when they check your ears? | Just got a physical and it got me thinking. What are doctors looking for in your ear? Please help.
Edit: Thank you guys. Some really informative explanations. Reddit never fails me. | Doctors look for fluid in the ears, what the tympanic membrane (ear drum) looks like to look for inflammation, and overall condition of the skin inside to make sure there aren't cuts or full of cerumen (ear wax) | 21 | 22 |
ELI5: All the stages of starvation up to death. | The first stage would be the conversion of any stored glycogen (form of stored excess glucose) into glucose. The second stage would be the breaking down of any stored fats in your body to provide for energy. The third and final stage would be the rapid muscle wasting once you do not have any fats left for breaking down. By this point of time, you may undergo cardiac arrest or simply die from diseases due to a weakened immune system. You're pretty much screwed at this point. | 29 | 77 |
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Eli5: What is the Simpson’s paradox in statistics? | Can someone explain its significance and maybe a simple example as well? | Say we want to see whether a medicine is effective at preventing heart attack in elderly populations. We see that among those taking the medicine, 5% suffer heart attacks compared to 3% of those who don’t. Seems like the medicine is counterproductive right?
Say you look deeper in the data and find that among those with high risk factors, 20% of those without the medicine suffer heart attacks compared with 6% that do take the medicine. Meanwhile, among those without high risk factors, 2% who don’t take the medicine suffer heart attacks, while 0.2% who take the medicine do. That means the medicine reduced the rate of heart attacks for both high risk and low risk people! However, an overwhelming majority of high risk people take the medicine, compared with maybe half or so of the low risk people. And since high risk people have such a higher baseline of risk, this means that those taking medicine are more likely to get heart attacks than those who don’t even though the medicine itself makes them less likely.
Tldr: Simpson’s paradox is when a correlation reverses itself once you control for another variable. | 7,984 | 5,954 |
ELI5: Which transmission gives more mileage and why? | I drive a manual transmission car and I find my mileage to be comparable if not lower to an automatic transmission car. While activating cruise control, my mileage rises by a few kms because of this I have always wondered which transmission for my next car would be the best, considering mileage to be an important factor. | The blunt truth: Driver skill/style is 10x more important than transmission.
If fuel consumption is a priority:
1) Drive at the speed limit. EVERY car (other than sports cars perhaps) will be a LOT more fuel efficient at 65mph or less. This can easily save 10-15% on fuel consumption on highways.
2) Accelerate gently and anticipate slowing down and coasting to more gentle stops. In stop and start traffic, this again easily saves 5-10% on fuel consumption.
3) Maintain tire pressures, tire alignment and maintenance of engine.
The differences in fuel consumption between a modern automatic transmission and a manual are small, if any, if a driver practices the above.
This is a very easy thing to test. Drive slower and less aggressively and monitor mileage. Do the comparison. | 132 | 48 |
ELI5: What was it about Navajo Code talkers that made their signals so hard to decrypt in WWII? | I hear about how cool these guys were and how much of a help they were in WWII, but what is it about the Navajo language that makes it such a good code? | English is related to German, Italian, and most European languages that were relevant in WWII, and plenty of them knew English anyway.
Navajo, on the other hand, has been separated from other world languages for so long that any sort of pattern that could be derived from being a related language wasn't present. Even most other Native American languages are so distantly related that they aren't a great guide. It also wasn't well documented, so there were no resources for the enemy to turn to, even if they suspected Navajo. On top of that, the code talkers didn't use plain Navajo, but a code based on Navajo, so that it'd still be difficult to decipher if a random Navajo speaker were captured. So it was basically a difficult code on top of a difficult code. | 109 | 91 |
Is there any way a Non-Scientist can contribute to /AskScience? | I absolutely LOVE this subreddit, its facinating, friendly and professional.
I've found out countless bits of great info here and I'm looking for a way to give back.
I have great interest in science but little knowledge.
| If you find a question thats very interesting, do some research about it. Simple googling and a few tens of minutes can get answers to almost every question asked here in layman terms. Post what you found, with the links where you read them! There's no such thing as a "non-scientist", just people who have read stuff for too long and people who haven't :) | 27 | 20 |
ELI5: Why was plasma television technology discontinued? | I ask because it seemed premature to me. OLED has great promise in the next 5 years, but it's still not there yet and certainly not there in terms of value/price ratio. I've been told by a videophile that the best TV on the market is now discontinued, the Panasonic VT60. So what we're left with is mediocre offerings at the low to mid range (LCDs), and great offerings at only the very high end. | LCD technology is generally cheaper, easier to make, and provides benefits in a lot of places that plasma doesn't, especially as you continue to go up in resolution. LCDs are also brighter, which can be a plus here and there. | 38 | 183 |
ELI5: What is the difference in sight between having 2 eyes and having 1? | Or, what are the differences | Stereo vision gives you depth perception. hold 2 objects out in front of you, but with one further away from you than the other. When you close one eye, they can appear to be on the same plane. Having both eyes open lets you see that one is further away from you. | 21 | 43 |
ELI5: How is a diesel engine such as the VW TDI able to obtain better fuel economy than an unleaded engine? | One of the factors which affects the efficiency of an internal combustion engine is the degree to which the working fluid (the hot gases) are allowed to expand, which is related to the compression ratio.
Diesels use a much higher compression ratio, so they start off with a higher maximum efficiency.
Add to that diesel fuel itself is more dense and contains more energy, and you have your answer. | 20 | 25 |
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ELI5: What is Chemotherapy, and what happens during it? | it's chemical treatment to combat (usually) cancer growth. most are in liquid form and are administered intravenously (through a drip in your arm). a single treatment of chemo may involve receiving several different chemicals in one session, commonly over quite a while (an hour or more). usually you sit on the ward with others while receiving it or there are some you can receive at home. depending on the length of course this may be done weekly or fortnightly for several months. on ward most people chat / read / watch tv while receiving treatment. the combination of chemicals are designed to slow down cell reproduction in your body. others are designed to kill cancer cells or types of cell in your body. there are lots of different kinds of chemo for lots of different kinds of cancer. the side effects usually stem from the slowing cell growth and killing of certain cells : hair loss, nausea/vomiting, constipation, thirst and so on. it's common to have additional courses of medicine that combat the side effects specifically. | 15 | 24 |
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ELI5: the difference between a legal and an illegal war. | Yes, I know there are numerous treaties and conventions governing conduct in war but is war itself legal and is there a distinction between a legal and illegal war? | In just war theory we can distinguish between *jus ad bellum* (right to war) and *jus in bello* (right in war). The first concerns itself with what are justifications for going to war, and the second with proper conduct when in war. Together these can be seen as the law of war. Over time there has been a number of sources for
law of war, most famously the Geneva convention.
One of the biggest concepts in international politics is sovereignty. All states have sovereignty, which means that whatever happens within their borders is their own concern, and other states can't violate this sovereignty.
Currently, in international law there are two main reasons when going to war is seen as legal and thus acceptable to the international community. First is self-defense. Second is if the UN Security Council permits it. Since the 1990s there is also the introduction of the concept of Resonsibility to Protect, which means that the international community should intervene in gross human rights violations, even if those are happening within a country and thus intervention violates the sovereignty of that country. R2P however is not something that states can unilaterally invoke, it should go through the United Nations.
Because of this, any act of war that is started without Security Council clearance and that is not committed in self defence is illegal under international law. | 1,156 | 718 |
When the body loses a significant amount of blood, is the production of blood cells sped up to help replace the lost blood quickly, or are they produced at the same rate? | The short answer is yes, the production of red blood cells is increased. The process is called erythropoiesis and starts in the bone marrow. There is a hormone that stimulates blood cell production called erythropoietin which is produced mainly by the kidney and released into the circulation. When there are less red blood cells in the body, a condition called anemia, the kidneys make more erythropoietin which stimulates erythropoiesis in the bone marrow. The erythropoietin is then inactive. This creates a feedback loop in which the production of red blood cells is adjusted to meet the body's demand. So, if an otherwise healthy person suffers from acute blood loss (hemorrhage), then his or her red blood cell production will increase.
However, certain disease conditions can limit the amount of erythropoiesis. Diseased kidneys produce less erythropoietin, and people with this condition will have chronic anemia and may require exogenous, supplemental erythropoietin. Similarly, people with diseased bone marrow (e.g., leukemia) may overproduce or underproduce red blood cells regardless of their current amount of red blood cells.
Edit: clarity | 383 | 987 |
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CMV: The 2016 US presidential election is mainly as predicted and won't be views as particularly extraordinary by history | 1.5-2 years ago most political experts/analysts predicted that 2016 will be Hillary vs. Jeb Bush. Most predicted that Hillary certainly will be the Dem candidate and that she will most likely win because
1. She is more prepared than anyone else. She spend years, if not decades preparing for this and already tried to get the nomination in 2008. She has a large network of donors and an extensive ground game. Plus a lot of support from celebrities and influential people.
2. The US is changing from a mainly white Christian country to a more racially, religiously and sexually diverse country. The Republicans are mainly strong with whites, especially Christian men whereas the Democrats are strong with blacks, Hispanics, educated whites, women, other religions and LGBT. Therefore the odds are against any Republican, especially if their candidate fails to convince other/new demographics.
3. The Republicans have a large share of far right wingers that push their candidate towards the right and away from the center. That makes is hard to win the general election because the Republican candidate has to position himself relative far right to win the primaries and then either shift his position to the center, which means losing credibility and upsetting far right Republicans, or remain relatively far right, which means losing a lot of centrists/independents to the Dem candidate.
So the only thing that really changed is that instead of Jeb Bush being pushed to the right, it was actually a far right wing candidate (Trump) that won the primaries. Everything else happened exactly as predicted.
1. Hillary won the primaries not because she was extremely popular but because she prepared better than anyone else and basically had the party behind her after years of lobbying and she could mobilize the voters she needed. This advantage continues in the general election, her ground game is far better than Trump's and she can spend more money. She is also far better prepared for pretty much anything (e.g. debates, scandals...). It's basically the small differences that add up and give her a lead.
2. Hillary is also leading because she does well with all minorities and women and, as widely predicted, the Republican candidate is struggling and losing because he can't convince enough people outside the typical Republican voter groups.
3. The only real surprise is that instead of an establishment candidate (like Bush) this time the far right wing candidate won the primaries. However, I think even this victory is overrated. Trump didn't win a 1 on 1 vs. a main stream candidate but rather the rest of the party failed to unite behind one "anti Trump" candidate until it was too late. He basically won by "divide and conquer", not by popularity. He had the biggest minority, not really the majority. I think he is one of the most unpopular candidates within the Rep party. However, Trump isn't really different from what was predicted. It basically just shows that the far right wing drift of the Rep party is a bit strong than everyone thought, but the effect is the standard the "Rep candidate is being pushed too far to the right by his own party to win the GE" situation everyone predicted.
Overall, I don't think the outcome and process is much different from what everyone expected. Hillary will win, as predicted, and the Rep will lose for the predicted reasons. If anything the (likely) clear defeat of Trump proofs that the predictions were correct about the trends and their results. If anything the outcome was clearer than expected.
For other themes the media often states as extraordinary in the 2016 election I think they are mainly irrelevant or not that extraordinary. E.g. US politics is full of sex scandals. Ironically, Bill Clinton actually proofs that. And other presidential candidates lost because of sex scandals before. Also Trumps populism isn't that unusual either, it's similar to the European far right wing rhetoric. I guess you could claim that it's extraordinary that he behaves like a reality TV show clown but I don't think that's too relevant and there is a general trend towards sensationalism anyway. Also if you go back in history then other candidates actually did make crazy claims too (e.g. that elections were rigged, unfairly attacking the other candidate, over 1000 psychologists declared Berry Goldwater as mentally unfit for president...). Also everyone is ignoring that there we hardly heard any extremely religious rhetoric, which is actually one of the few things that I find pretty surprising about the 2016 election considering how deeply religious large parts of US are.
EDIT. Please no claims like "Trump isn't losing, this one poll/unscientific polls shows otherwise".
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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!* | Historical perceptions of events rarely have much to do with what the predictions were leading up to those events; there's a complete disconnect in the attitudes and understanding of the general public consciousness between the time in which such predictions are made and the later times in which they are evaluated.
You're looking at it from the perspective of an informed contemporary, but in a hundred years, how many people will have as much information as you about what the general feeling was about the 2016 election in 2014? Very few, and nobody will have that feeling internalized as you do.
Our historical perceptions, even if we're relatively knowledgeable, always get cut down to a relatively few critical, fascinating details. And on that level, this is absolutely an extraordinary election. If Hillary gets elected, that's the first female president - that alone will make this election stand out. And Trump is an objectively unusual presidential candidate in terms of his background, and he's generated some amazing footage for posterity. Video of Trump is going to stand out within the historical record of presidential elections long after the fuller context is forgotten. Come on, *The Apprentice*? That's a much more permanent, compelling historical quirk than anything Barry Goldwater ever generated.
The outcome may have been predictable, but the election will be viewed as extraordinary, no question. | 60 | 109 |
[General] Why do nearly all beings, from alien to robot to monster, store critical components in their topmost extremity? | It seems that battle robots, at least, would be built with a decoy 'head' that can be lost with almost no repercussions. The instincts of many creatures would misfire if the head was a non-vital component. | Physics plays a role.
Signals only propagate so fast, so it behooves a creature for its sensory organs/devices to be as close as possible to its central processing apparatus. It is also advantageous for sensory organs to be on extremities, particularly elevated ones.
Combine those two things, and you get 'brains' in 'heads' a lot, because they 'eyes' are also in the 'head'. | 54 | 30 |
How do we design new surgeries and decide who attempts it first? | Many surgeries are one of a kind processes, not every tumor grows in the same place, affects the same organs/vessels, not all organs have the same pathologies, etc. A good surgeon will design each surgery to the patient, and will have to possibly react on the fly to changes that occur during surgery.
There are everyday simple ones like appendix removal, setting broken limbs, removing a limb, things like that. Then there is trying to save a mans face while removing the cancer spreading from his neck, and having to get in there and do what needs done. Or a full reconstructive surgery to a severe burn victim. Or separating conjoined twins. These are all unique, one of a kind situations, every time.
Something radical, like replacing a heart with a machine, or other major transplants (even one day inter-species ones, like pig hearts) is usually tested on animals first. Then a human will allow it to be done, as it is the only possible way to save their life. As for which surgeon performs it, that is decided by the patient, hospital, and the surgeon. If he/she is qualified, understands the process, and feels confident based on past experience, they may suggest it to the patient as a last ditch effort. The surgeon may even be the one who did the research. The first ones aren't always long lived, but they help pave the road for others.
For instance, the first heart transplant was on a dog, before the first human transplant was done (patient died 18 days later, but the heart was healthy.)
So really, part of the training and expertise of a surgeon is "crafting" a surgery. The procedures are mechanical in nature, but the process is as much art as engineering. | 30 | 57 |
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How do we know the laws of physics don't change over time? | So much of what we know about the universe is based on our understanding of the laws of physics as we know them today. For example, the age of the universe and the rate of expansion are measured using this current understanding and application of the known laws since we cannot actually go back in time to do the measuring. Is it possible that throughout time, especially during periods of chaos like moments after the big bang, the equations and limits we know to be true and verifiable today could potentially be invalid? If so, what are some of the major implications, and how could we go about mitigating them? | As far back as we are able to acquire data, the same laws of physics appear to hold.
When we look at distant galaxies and stars, we are looking at objects from long ago. And we measure their spectra, for example, which tell us that the atoms and molecules a long time ago behave the same way as those on Earth do today. These spectra depend on the mass and charge of the electron, the nuclear physics that allows atomic nuclei to form, the nature of the electric force, and so on.
We can also look at the abundance of nuclei today, and we see the universe is about 3/4 hydrogen and 1/4 helium, and a tiny bit everything else. Then you take the laws we know, and you see nuclei would form in the first minutes after the Big Bang (5 to 20 minutes), and you calculate the amounts that would form, and you find that the nuclei formed would be 3/4 hydrogen and 1/4 helium.
Looking at things like supernovas or the cosmic microwave background radiation give us additional insights into the past.
Thus, there is concrete evidence that the laws of physics we see today here on Earth have applied throughout the history of the universe, as far back as we have been able to check. | 29 | 21 |
[General comics]Why do superheroes wear such ridiculous costumes? | In the comics world, it makes sense for your character to have a garish outfit, it means they're easily recognisable despite being drawn by different artists and it stands out on the newsstand (hence spideys red and blue) but in the world which these characters live, what's the thinking behind it?
There are a few where it's clear, like Batman (he's all about the theatre and imagery, he's deliberately trying to be strange) and Ironman (it's not a costume, it's armour) but what is it about the average person that when they discover they can run faster than sound or find themselves bulletproof and they decide "I will use these powers to fight/commit crime and rid the world of evil/make myself rich, but first, I must make a costume from pink spandex, with no pockets!"
Why do they end up in outfits like [this](http://img2.wikia.nocookie.net/__cb20100113195026/superfriends/images/2/2e/Titans.jpg), [this](http://upload.wikimedia.org/wikipedia/en/archive/a/a6/20140729104234!Psylocke_MvC2.png), [this](http://static.comicvine.com/uploads/scale_super/1/15388/1341133-wolverine_by_commanderlewis.jpg), or [this](http://static.comicvine.com/uploads/scale_super/0/8015/212453-28047-green-arrow.jpg) ?
On a related note, where do they get these outfits from? They can't all be expert with a needle and thread and you aren't getting those boots from the doc shop | Generally tight fitting clothing allows for much more easily executed acrobatics. The color combos are just their personal brand... usually some personal meaning behind the colors.
As for the Flash specifically, he's wearing a suit that reduces drag and can put up with the friction against the air... or else his close may catch on fire. | 37 | 21 |
ELI5: Why does water poured onto already moist potting soil soak in faster than water poured onto completely dry potting soil? | When the soil dries completely there are hydrophobic residues on the surface that prevent the water from being absorbed until the surface tension is broken.
ELI5-er:
When the soil dries completely, waxes and oils in the soil protect the surface.
Kind of like the way it is hard to wet a new towel.
Source: asked this exact question in hydrology class once. | 40 | 59 |
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ELI5: Why does water taste different at different temperatures? | Chilled water tastes different than warm or boiled water. What is the reason for this? | Assuming that it's the same water and not from different sources which may contain different salts.. there are 2-3 major factors
1. The temperature itself. When water touches our taste buds, the temperature sets off slightly different responses to the brain.
2. The material. Chilled water may be stored in any container- plastic/glass/metal. Warm/Hot water is almost always used with metal and sometimes glass. So this is also a small factor.
3. Gases. The most important factor is gases. If a liquid surface is kept in contact with a gas, the gas WILL dissolve in the liquid slowly. The colder the temperature, the faster the gas will dissolve in liquid and vice versa. Boiled water is thus absolutely devoid of gases ( bud-bud-bud-bud bubbles, remember? ). That's why bottled water tastes sweet while boiled water tastes bitter. Oxygen. | 36 | 56 |
ELI5 - How can oases exist in deserts? Where does the water come from? How come they don't just vaporize? And where do trees and plants there grow from? | Oases exist where groundwater comes to or near to the surface. This usually happens in low places, where all the underground water flows end up. The water itself comes ultimately from rains, which, however rare, occur in every desert. The water then seeps down through the ground until it reaches a barrier made of impermeable rock, and then flows down along that barrier towards an oasis, where it accumulates. This way the infrequent rainfall over many thousands of square kilometers of desert can support a single small oasis in the low place of the area. | 143 | 84 |
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Is the speed of gravity slower in a medium? | In the weak field limit, gravitational waves behave in a very similar fashion to electromagnetic waves. In fact the mathematics is nearly identical and if we consider a medium of point mass oscillators (say a thin gas because the math is easier) we can calculate what the "refractive index" of gravitational waves in a medium and the accompanying dispersion relation. Thus, while the the effect is small, gravitational waves can slow down in the same way light slows down in glass or water. | 19 | 128 |
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Can a person that has seen the source code of a product, implement a clean-room clone of it? | There's a program that is used in our company, which is a modified version of an open source program that is hosted on GitHub. The original developers at the company (they have since left the company) had lied and claimed that it is 100% written by them.
Anyway, it is a piece of crap, plagued with plenty of bugs and the management doesn't spend enough on it to fix the bugs as well as refactoring it.
The program is written in Python and I am thinking about implementing a new version of it at home using Java.
Even though the original code was/is open source and my company can't claim that I have stolen their IP, ideally I wanted to write a [clean room implementation](http://wiki.c2.com/?CleanRoomImplementation) of it after resigning from my company. But considering that I have already seen the source code of this program, can I ever claim that my implementation is clean room? | I'd say if you are changing languages, you are probably going to be mostly in the clear since python and Java are fairly different. Legally speaking, eh, grey area for sure.
When dealing with reverse engineering, this comes up all the time. Generally the safest route to proceed is for one person to look at the decompiled code and write wireframe algorithms and documentation, and another person that hasn't seen this code to take an implement these algorithms.
I certainly wouldn't go forth proclaiming that its a clean room implementation. Maybe make it clear what it has been written in. Quickly and directly address any inquiries regarding if it is using stolen code. | 11 | 15 |
ELI5: Why is cancer research so expensive? | Where is all the money from fundraisers and charities going? | Cancer is not one disease, it is a huge variety of different diseases. People who study cancer and develop treatments are doctors (MD and PhD) who require a lot of expensive education. They are assisted by technicians that also have expensive educations. The lab equipment they use is very expensive. Tests of new treatments and drugs take a long time and require extensive oversight and documentation. FDA approval of new treatments takes a long time. Equipment to synthesize and manufacture new drugs is expensive.
On top of that, millions may be spent pursuing new treatments that are ultimately determined to be failures, requiring researchers to abandon them and start over.
On top of that, many charities may not actually devote much of their earnings to research. Use charitynavigator.com to research charities to see how they spend their money. | 17 | 16 |
What are examples of "bland" or relatively non-regional accents/dialects in other languages? Which accents/dialects are most popular for news broadcasts, for example, in languages other than American English? | I remember reading this article about [General American](http://en.wikipedia.org/wiki/General_American), which is the dialect/accent most popular with national news broadcasts, and is based on how people speak in parts of the Midwest / Great Plains. I also remember a story on NPR (though I can't source it right now) that the most popular dialect/accent for Spanish-language programs in Latin America comes from Colombia.
I was curious - are there examples of dialects/accents from other large widespread languages like French or Arabic where one dialect/accent is considered dominant, as the "blandest" or "most normal", preferred for news broadcasts and other means of popular consumption? | The Arabic of officialdom and journalism is Modern Standard Arabic ("fus-ha"), a modernized adaptation of Classical or Qur'anic Arabic. Lawyers, newscasters, diplomats, politicians, professors, and clerics all speak in MSA on the job, but most will switch to colloquial forms with friends and family.
It's not just an accent, it's a higher "register" of Arabic that would seem kind of silly and inappropriate in a non-formal setting. Colloquial dialects of Arabic are not always mutually intelligible, though, so if an Iraqi wants to talk to an Algerian smoothly, they'll probably speak MSA.
Just about everyone in the Middle East can understand it (because people on TV use it), but not everyone can speak or write it correctly. It's a bit like how most English-speakers could read a King James Bible well enough, but if you asked them to imitate the grammar they'd probably bungle it here and there.
Loads of Western Arabic students learn MSA because it's universal, but it's like wearing a sign on your chest that says "I haven't been here very long". Arab friends will nudge you toward colloquial so you can quit sounding like a ponce.
**edit** Classical Arabic is also (of course) the language of the Qur'an and prayer, so the average Arab will be familiar with it that way as well. | 30 | 38 |
[Superheroes] I'm a misanthropic diver looking into super villany, what are some ocean crimes I can commit for fun and profit? | There are a lot of undersea cables crossing the oceans that are very important for global communication even in an age of satellites. If you invest in satellite communication/undersea cable construction and use your diving talents to plant timed explosives or otherwise sabotage the cables in a way that requires replacement you could get fabulously wealthy and have fun diving in new places all over the world! | 223 | 267 |
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ELI5:Why don't Americans have the lowest medical costs in the world... is it a failure of the free market or government intervention or something else? | Back during World War II some regulations were put in place regarding wages and salaries.
But the short version is that a lot of companies over time started offering health insurance as part of the benefits package, essentially to pay workers more without actually increasing wages or salaries.
Over time this became more and more the system, and now most people in the US get their healthcare from their job.
Now, this doesn't have all negative consequences. For instance, the reason people will still say: "The United States has the best health care in the world, if you have insurance" is because when you're on the company policy, in many cases when you get a heart-attack you're treated just the same as if your CEO had a heart attack. Flown to Seattle, put in a fancy hospital with top-rate doctors and surgeons. etc.
And while the "*if you have insurance* caveat seems like a real catch, it's actually not so horrible. The "chronically" uninsured in the country only constituted about 12 million people in the country (pre-Obamacare).
But anyway - one of the bad parts of this system is that it *separates payer of cost from receiver of services.* It's really not even this system specifically, but the *"full-coverage"* style of the insurance that's common to the system.
We now have an ingrained 3-party payment system for our Healthcare. It used to be that you go to the Dr. Office with a spranged ankle, and he says: *"That's a spranged ankle. Stay off it for 2 weeks."* You pay him $50 and you go on your way. But the Doctor is worried about being sued if it was something worse than a sprang, so he says: *"I think it's just a sprang, but I'd like to do an MRI."*
MRI's are covered by your insurance, so you say: "Sure!" and go get an MRI. It doesn't cost you any extra.
And then every doctor and every patient does this, and so insurance rates go up. Rinse, lather, repeat.
It doesn't change how much you pay if you get no medical treatment or open-heart surgery. Your doctor doesn't gain or lose customers for what he charges, because that's paid by the insurance company. Your insurance company just sees you as one part of a company, so it doesn't target or charge you specifically. The end result is that nobody has any direct incentive to be efficient about medical services, or demand lower rates.
It is very much worth noting that Lasik eye surgery, and cosmetic surgery, are not covered by most any form of insurance. And they're the only medical procedures to *drop* drastically in price over the last two decades.
If you want medical costs to go down in a free market, you need to make sure that the signals money sends out get received by the actors making the decisions. Higher deductibles and less-full coverage would make be cognizant, discriminating shoppers for the services, and you'd see prices drop as a result. At the moment there is no competition or incentive to reduce costs by anybody. | 66 | 137 |
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What is the role of the default constructor and why do we need more than one constructor? | I still dont understand the idea behind constructors. What does the one that doesnt take any value do? And why do some other constructors less say, one takes two parameters and the other might take two parameters of the first one plus a third one. | Say you have some default settings you want to apply for a given class. One way you can do that is create the class, then apply those settings in however many lines of code needed. For example:
Rectangle r = new Rectangle();
r.setWidth(2);
r.setHeight(4);
But what happens if you have that in multiple places? That's annoying! Better put it in the Rectangle class:
public class Rectangle {
// assume fields and setters are here
public void init() {
setWidth(2);
setHeight(4);
}
}
Then you can do this everywhere, and your values are in one convenient place!
Rectangle r = new Rectangle();
r.init();
But wait, that's still an extra line of code that you have to remember to do. Bummer. Let's do a constructor instead!
public class Rectangle {
// assume fields and setters are here
public Rectangle() {
setWidth(2);
setHeight(4);
}
}
Now you can create a rectangle with default values in one easy line.
Rectangle r = new Rectangle();
One more step: let's say you want flexible values on creation, but you want to be absolutely sure that those values are provided. Make your class look like this instead:
public class Rectangle {
// assume fields and setters are here
public Rectangle(int width, int height) {
setWidth(width);
setHeight(height);
}
}
That will work with this line of code:
Rectangle r = new Rectangle(2, 4);
But this old line will not compile, because no constructor matches that signature (input parameter types, in this case (int, int))
Rectangle r = new Rectangle();
If you have no constructor at all, the default is used at all times and you'll have all values set to null, 0, or 0.0 depending on the data type.
Hope that helps! | 27 | 17 |
[Mass Effect] If the Citadel is really a Mass Relay then how come it doesn't contain a massive deposit of Element zero in its core like the other Mass Relays have? | I know that the both made of the same material but other than the fact that they're both mass transit devices there are no similarities between the Mass Relays and the citadel.
| Relays work by creating a mass-free virtual 'corridor' through space between the outgoing relay and the receiving relay. Presumably only the outgoing relay has to have the eezo core to generate the corridor, with the receiving relay acting as just an anchor point on the other end.
When using the Citadel to enter from Dark Space, the Reapers could just use the relay that's at the other end of that connection, the one out in Dark Space, and jump in. It wouldn't be out of their capabilities to then attach a temporary eezo core to use when leaving the galaxy at the end of a Harvest and then have the Vanguard left behind remove it. Maybe the Vanguard even *is* the power supply.
Alternatively it does have an eezo core, its just buried deep within the inner workings of the station and not immediately visible. It does have artificial gravity and barriers so there's definitely some form of mass effect field generators there already. | 27 | 25 |
If I'm in an environment with abnormally high humidity, would I require less water to keep myself hydrated, or what would happen? | It really depends on the temperature of the environment; in a hot environment you need more water, especially when the humidity is above the dew point. The heat and high humidity will a) make you sweat more since it's hotter. b) your sweat won't have as great a cooling effect since the water in your sweat won't evaporate fast enough in the high humidity to cool you down. c) since your still hot even after sweating, your body will continue producing sweat hoping that it will eventually cool itself off. So the net result is you're hot, you're sweaty, and if you don't drink enough water, dehydrated from sweating so much. | 42 | 133 |
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What is the second fastest thing in the universe after the speed of light? How big is the difference? | Whatever you want. In a suitable reference frame.
Relative to Earth: High energy neutrinos are *extremely* close to the speed of light. Some of them should be slower than light by significantly less than one part in 10^(30). After traveling 1000 light years (10 quadrillion km), they are just something like the diameter of a proton behind light in vacuum. | 24 | 24 |
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CMV: Parents should not be given special treatment by employers at the expense of their childless colleagues. | Note: This does not include legally required special treatment, such as the Family Medical Leave act in the US.
**Specific areas of debate:**
* **Parents getting special daily schedule considerations.**
I don't believe that an employee should be permitted to leave early on a regular basis simply because he or she has reproduced. Often that employee's workload spills over onto his or her co-workers.
There are plenty of people who have children who have other arrangements in place and are able to work their full shifts, so clearly there must be some kind of acceptable mechanism in place and there's no reason all working parents can't use it.
The excuse that one needs to leave early to save on childcare expenses is not valid. Childcare expenses are simply a reality for working parents and it's part of the deal that you accepted when you chose to reproduce.
Note that my argument here is only when this happens on a regular basis. I don't have a problem with parents using accrued leave in order to leave early for specific events or emergency situations, just like any childless employee would be able to do as well.
The problem is with parents being allowed to leave early (especially in salary situations, where their pay does not decrease by working fewer hours) and childless co-workers being expected to pick up the slack.
* **Parents are always "not it" when someone has to work a holiday.**
In the case of 24/7/365 operations, childless employees are much more likely to get stuck working holidays. Just because an employee is childless doesn't make their holiday plans any less important; they also have families and events that are important to them. These kinds of work assignments should be rotated fairly regardless of an employee's parental status.
* **Bringing your child to work as an alternative to childcare is not okay.**
I'm not talking about once or twice a year for "Bring your kid to work day" or to trick-or-treat at Halloween, I'm talking about bringing your kid to work and having them camp out in your workspace for hours at a time. Their presence is distracting. Again, paying for childcare is part of the burden you accepted when you chose to become a working parent.
Also, your kids are tiny friggin' germ factories and your co-workers won't appreciate catching the cold that's going around Mrs. Thompson's 2nd grade class.
* **Childless employees are not 'selfish' for demanding equal treatment.**
I would instead argue that the offending parents are selfish for expecting to be treated like special snowflakes because they have a child or children.
Being a childless person and having had to put up with entitled parents considering me to be less of a person than they simply because I haven't popped out a baby, I realize that my view here will be difficult to change, but I would like to have more information so I can form a more well-rounded opinion. Thanks!
**UPDATE:** /u/garnteller convinced me that for economic reasons, giving special treatment to parents is the right choice for employers to make. I am still not convinced that they morally SHOULD do this.
_____
> *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 just 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!* | The the employers who decide how employees are treated or what benefits they receive. Guess what - they have realized that they "should" give them special treatment.
* It doesn't generally cost them more
* Parents need the job more than non-parents. They are more likely to favor security over money or opportunity.
* They don't want to be at a competitive disadvantage in hiring and retaining workers if other companies have more liberal policies
* Generally, reasonable flexibility results in greater loyalty and engagement from the workers. If you feel you are being treated well, you work harder.
* You don't hear very often of childless workers asking HR about the company's family policy so they can avoid the ones with liberal policies
* The vast majority of workers will have kids at some point, so it evens out eventually.
It makes complete sense for the employer- that's why they do it. | 18 | 46 |
[Star Wars] What can the average Joe do to help the Rebellion? | I hate the Empire, but I'm not quite brave enough to lay down my life on the battlefield. Is there anything I can do to assist the Rebels, preferably from the comfort of my home? | If you you made contact with a cell, probably the there lots of stuff you can do with varying degrees of safety.
Simple stuff like dropping supplies, picking and dropping messages, acting as a safe house, lookout etc.
Edit:
Actually the rebellion needs a well regulated militia. As long as the population has access to blaster rifles, there's no way a tyrannical fascist coup could take over. All it needs is a few good men to stand against the AT-ATs! | 184 | 287 |
Why do prisons exist? | Today I remembered some middle-school philosophy teachings about John Locke, Thomas Hobbes, and Jean-Jacques Rousseau; and I've been wondering about the perspectives of each of these philosophers on various prison-related issue.
The first issue is that of prison as an institution. I was thinking Locke with his concept of a "blank slate" and Rousseau with his idea of society corrupting individuals would view prison as a rehabilitative measure--something that would encourage one to see the error in their ways, or provide them with time away from the corrupting influences of the outside world. Hobbes, who views people as inherently good or bad, would instead see prison as a permanent residence for evil folk, so that they can be prevented from committing any more heinous acts on innocents.
I was also thinking about how the justice system (in the US) currently works and which parts of it align with which of the three philosophers. I think the most extreme sentences--like the death penalty and life in prison--are most in alignment with Hobbes, as they assume the person is wholly bad and cannot possibly be recovered in any meaningful way. Lesser crimes with lighter sentence are more in alignment with Locke and Rousseau (in my opinion), as these are more temporary measures intended to bring about changes in behavior.
I have a couple of unanswered philosophical questions from these three perspectives:
What if a person in prison permanently loses all of their memories? Are they still liable for their previous but forgotten criminal actions?
What if a hacker loses their fingers while in prison? If their primary means to commit crimes is no longer available to them, should they remain in prison?
A common phrase that former convicts use is "I've paid my debt to society." This phrase suggests that a criminal act is like a loan that is to be paid off in the form of a prison sentence. How does this viewing of the prison system as a societal transaction agree/disagree with these three philosophers? | An accurate answer to the question of why prisons exist will have to take into account not only modern attempts to provide philosophical justifications for their existence, but also an account of the history of their formation and the ideological conditions that brought them into existence. Probably the most famous work of philosophy dealing this this question is Foucault's *Discipline and Punish*, but an even better place to start would probably be Angela Davis' *Are Prisons Obsolete,* which builds on Foucault while being more accessible and more US focused (you mentioned the US justice system). | 15 | 23 |
ELI5: How is a person able to sing 2 notes at the same time? | Found this post in r/interestingasfuck that linked to https://youtu.be/vC9Qh709gas?t=27s of a woman being able to do this.
Was wondering if there was a scientific explanation for allowing a person this ability or if it is based off of skill and can be learned. | > Was wondering if there was a scientific explanation for allowing a person this ability or if it is based off of skill and can be learned.
Both. There is a scientific explanation - using the shape of the mouth to enhance or suppress certain frequencies when singing a note (not actually singing 2 notes, but sounds like it) - *and* it is a skill that can be learned - overtone singing & throat singing utilise the same principles to "shape" different notes & amplify preferred harmonics to create what you hear.
A lot of it comes down to the tongue & jaw position, a lower jaw with the tongue flat makes a big hole inside your mouth which enhances the deeper frequencies. A closed/nearly closed jaw with the tongue raised a little makes a much smaller hole & the higher frequencies are more audible. | 85 | 412 |
How hot is the interstellar and intragalactic space in dense galaxy clusters? | It seems to me that the space within these galaxy clusters would be that much higher because of the energies involved. Could life as we know it exist there? | You're asking, broadly, about all the baryonic matter (ie nuclei (mostly H and He) and electrons) in the universe which aren't in compact bodies like stars and planets and black holes.
The interstellar and intergalactic media have many components, depending on their origin.
For example, between galaxy clusters is the warm-hot intergalactic medium (IGM). Here, the density is as low as one particle per cubic meter, but because there's just so much damn *space* out in space, it may contain half of the baryonic matter in the universe. This matter is at temperatures of about a million Kelvin, and is ionized, due to a number of processes such as shock heating and AGN feedback.
Within galaxy clusters, there is the intra-cluster medium (ICM). It's basically the part of the IGM that's within clusters. It's not a trivial detail either, there's about 10x as much baryonic matter in this gas as there is in stars. The ICM is similarly hot, like a million Kelvin, and glows in the X-ray part of the spectrum, making galaxy clusters have a sort of diffuse glow when viewed at these wavelengths. It's heated due to shocks, relativistic plasma outflows from galactic nuclei and other transients. Even plasma outflows generated by supernova remnants which is ejected from galaxies are retained at this scale.
These media are active areas of research interest because they couple the observational structure and evolution of galaxies to the structure of the clusters they live in. It's something we can study with simulations and with observations, allowing cosmologists to construct detailed models for how the contents of the universe evolve (and why things are they way that they are). | 30 | 29 |
ELI5: How do Bluetooth things work, more specifically Bluetooth earphones? | Wireless devices (basically everything, these days) communicate by sending electromagnetic waves over the air that get picked up by other devices and interpreted as data. But in order for two devices to talk, they need to be speaking the same language, like maybe the waves should all be a certain length. Bluetooth is simply a standard, or a set of guidelines, for what type of waves two devices should use to communicate. If your device follows the Bluetooth wave rules, your device can talk to other devices that follow the Bluetooth wave rules. | 45 | 52 |
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What makes some plates, containers, etc. "microwave safe"? | Microwaves create oscillating electromagnetic fields. These fields will create electrical currents in materials with free charge carriers, ie basically they act as an antenna. They will also cause polar molecules to rotate with the field which leads to heating. Polar molecules are common in food, most notably water, so this is how a microwave heats. The effect is called dielectric heating. If the material is neither conductive nor highly polar, it won't absorb or interact strongly with the microwaves. So what is unreactive to the microwaves? Most ceramics, glasses, plastics, paper.
If you have a metal, conductive materials due to a lot of free charge carriers, the electrons will move the with field. This leads to multiple undesirable and dangerous effects;
* Small air gaps between metal, like the wrinkles of tin foil or the prongs of a fork, will cause sparking. Sparking will ignite anything flammable.
* Any metal with current flowing through it is going to heat up. This is non-ideal because you want to heat the food, not the dish. Beyond wasting energy on the wrong thing, heating the dish can again lead to high temperatures igniting something or cause burns to the user when goes to remove it. Some things like microwave popcorn bags intentionally have small metal foil layers to get hot enough at the surface to cook the popcorn properly.
* Metals will also reflect the microwaves if oriented correctly. You'll note the walls of the microwave are metal. Reflecting the microwaves in unintended ways can damage the microwave by reflecting them back into the magnetron (microwave generator) and overheating it.
Containers with metal are not always obvious like a stainless steel bowl. Some ceramic dishes contains traces of metals, especially in any glazing or shinny accenting wires they have. This makes some ceramic containers/dishes not microwave safe. Some paper products may also have a metallic foil layer. Don't microwave your tatrapaks for example. If the food is in paper, be careful for any sort of metallic water insulating layer. Wax water insulated paper is fine.
While most plastics do not strongly react with microwaves, they will be heated in the microwave simply by contact with the food. Some plastics will melt at low temperatures, others will leach chemicals into the food even if they aren't melting. Whether a plastic is marked microwave safe depends on whether it will melt or leach. Most plastics that are microwave safe have a clause stating up to 100C or something, which is hard to avoid locally, especially with dryer food, and after time you will start to notice little white deformities where they slightly melted. Pretty much all plastic will leach slightly, but how much and how toxic it is depends on the plastic. Polycarbonate bottles with BPA were largely banded and discontinued a few years back as they were leaching even at room temperatures.
So what is safe? Glass always. Ceramics most of the time, though check if they are marked. If they aren't marked, be weary of glazes and shinny strips. Try them out and see if they get hot. Paper most of the time, though if may get flimsy from steam and don't put in any with a shinny metallic foil on it. Plastics (or styrofoams) if they are marked safe, but note they still might leach some stuff and avoid getting them too hot. | 85 | 81 |
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ELI5: When we say that solar power is not (yet) efficient, what exactly do we mean? | Does this imply that the amount of energy used to produce a single panel is greater than the total amount of energy that panel will be able to generate in its lifetime? This is the only way I can see it being inefficient. | Typically when using the word "efficiency" in a comparative fashion for energy production the measurement refers to the source-energy relative to the converted usable energy. E.G. if gasoline has X amount of energy in it, the combustion engine can only create about X*.3 of that to its usable energy (movement, in this case).
A solar panel converts about 20ish percent of the suns energy. If we compare that to other forms of _electricity_ production (the most reasonable analogue for your not-well-defined statement) then we'd be saying that "compared to the efficiency of capture of energy from coal and conversion to electricity, solar panels are significantly less efficient".
The REASON we might emphasize this statement however is that increasing efficiency of the panel in this dimension is correlated with requiring less physical space, likely high return on investment of actual purchase of the panels and so on. Its perceived that improved efficiency - amongst other things - is the path towards more economic viability for widespread solar. | 30 | 97 |
How did we first estimate/calculate the size of and distance to the moon? | You are right that it is very difficult to measure the distance to and size of the Moon without knowing one of them. Is the Moon large and far away or small and close?
It is a common technique in astronomy to measure one distance and then the ratio of this distance to another one, we do this for pretty much every distance that we can't measure directly. For the Moon we can very easily work out the ratio of it's size to the distance, this is just the Moon's angular size.
What Aristotle (or some other greek) did is he worked out the ratio of the Moon and the Earth radii by being very clever.
Suppose the distance to the Moon is R then we know the circumference of it's orbit is 2\*pi\*R. We will call this time T but we know that T=28 days. The Moons speed would be 2\*pi\*R/T
Next we need a Lunar eclipse which is when the Earth comes between the Sun and the Earth. Since the Sun is very far away, the light rays from it are approximately parallel and so the shadow the Earth casts is approximately the same radius as the Earth. I'll call this distance r.
For the moon to cross the shadow will take the distance, r, divided by it's speed and we can measure this by watching when the Earth's shadow first falls on the Moon and when it first leaves the Moon on the other side. If we call the time this takes t then the moons speed will be 2\*r (the diameter of Earth's shadow) divided by t. This assumes that the Moon passes through the exact centre of the shadow but can be adjusted if it doesn't.
Since both speeds are the same then we know 2\*pi\*R/T = 2\*r/t therefore pi\*R/r = T/t. T/t is a number we know, we can time the orbit (28 days) and time the Lunar eclipse (about 2 hours). This gives us a value of R/r of about 60.
Remember this is the ratio of the distance to the Moon and the radius of the Earth.
When the measurement was first done we didn't actually know the radius of the Earth but it was worked out fairly soon after, once you know the radius of the Earth you just multiply it by 60 to get the distance to the Moon. Once you know the distance to the Moon you just measure it's angular size and you can work out it's radius.
The answer still holds up today, the Moon is roughly 60 Earth radii away from us so good job on them for working that out over 2000 years ago. | 68 | 85 |
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ELI5: Why is heartrate usually only measured in BPM? Doesn't the strength of the beats matter too? | Like your heart can be beating 110BPM with light beats, but wouldn't 90BPM with much harder beats be equivalent or stronger? | Blood pressure is an extremely important measure for health diagnosis and assessment, but it requires special equipment. Heart rate, on the other hand, gives some information, though much less important or useful compared to BP, but it can be measured very easily with only a timepiece. | 24 | 15 |
[Star Wars] It's said that Anakin could have been twice as strong as the emperor but after Mustafar he could only be as strong as 4/5ths of the emperor. Why is that? | Wholeness of body and of mind.
A body can be cloned, cybernetic parts can be made, and the extremities can be regenerated with enough bacta.
But it takes far more effort to repair the mind, and when the body is lacking the process is all the more complicated.
Anakin Skywalker died in the moment Darth Vader was born - there, on Mustafar, while his wounds were cauterized by the scalding rock and his skin began to ripple and boil, Anakin Skywalker died. He had, to his knowledge, killed his wife and unborn children. He'd collapsed the government he'd previously dedicated his life too. The only man in the galaxy left who might call him friend had just cut off all of his favorite limbs. He closes his eyes, and upon opening them again
He is in a casket. A moving, breathing, blast-proof casket. For all his efforts and pain, Anakin Skywalker had died and the resultant being was locked inside a durasteel shell, kept alive by machines, and kept in pain by man who'd led him down that path.
His body could never heal, and his mind could never find peace. | 253 | 133 |
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Question : decided to learn about Existentialism, what to read ? | Hello, I've decided to learn about Nihilism and Existentialism, what books should I read and in what order ?
Most answers I found just throw authors names - Kirkegaard, Nietzsche , Sartre , Frankel ...
I decided to start from Kirkegaard - Fear and Trembling, Is thats the right chose ?
Sorry if it's weird question, philosophy is very new realm for me. | The Ethics of Ambiguity by Simone de Beauvoir. She never got the same fame as Sartre and Camus but this is definitely a very approachable and understandable text compared to others. That and Sartre's Existentialism is a Humanism are a good quick pair and then if you feel like tackling Being and Nothingness and other massive tomes, go for it.
Also, for a great read which is about 50% philosophy 50% history/biography, check out Sarah Bakewell's "At the Existentialist Cafe" which is a great overview of existentialism and its major players. Draws a nice narrative line from Heidegger and Husserl through Sartre, Camus, de Beauvoir, Merleau-Ponty, and many others. | 30 | 41 |
CMV: "Radical Islam" is a harmful and inaccurate phrase. | Much of the worlds current political struggles are attributed to the catch-all term of "Radical Islam." I believe this term to be wildly over simplistic and it ignores the political and nationalism issues that play a larger role in the hostility that some have with the West. Attributing the actions of these groups to the whims of religious fanaticism is an easy way to convince the public that their motivations are not grounded in anything other than "they are just nuts." To write off these actions in such a way is to detract from the true motivations of these individuals, which are largely a reaction to unwanted Western influence on their immediate geographic area. To ignore these tangible political and nationalism motivations - while chalking it up to religious people who are just being crazy - is to drive us further away from conflict resolution in these areas.
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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!* | What makes you think that religion is not a large part of the motivation? Let's look back to al-Qaeda in the 90's, trying to blow up the World Trade Center. What had America done to the Middle East by that point? They'd helped Afghanistan fend of an invasion, and they'd gone to war to defend Kuwait from Iraq. That was pretty much the extent of US involvement in the Middle East. Meanwhile, they'd systematically installed and destroyed governments across all of Latin America, propping up dictators and narco-terrorists alike. Yet we've seen no Guatemalan attacks on New York. There is more to the story than simply "those crazy religious folk", but to deny that religion plays a part is simply absurd. | 29 | 26 |
Questions on physicalism | Just wanted to ask. Wouldn't what we know about contemporary physics and the epistemic limits involved in the creation of such knowledge put physicalism in a position open to criticism? Much of what we know beyond the subatomic depends on not-quite empirical knowledge and seem to be inferred by mathematical limits. And wouldn't said knowledge also suggest the idea of the "physical" actually emerges from relationships that are not what we understand to be physical l? | > Wouldn't what we know about contemporary physics and the epistemic limits involved in the creation of such knowledge put physicalism in a position open to criticism?
Physicalism is already and in any case a position open to criticism!
> Much of what we know beyond the subatomic depends on not-quite empirical knowledge and seem to be inferred by mathematical limits.
But physicalism needn't restrict its grounds to strictly empirical sources, so this worry is probably neither here nor there. | 14 | 20 |
What do psychiatrists aim for, when treating a patient? | As in, is there an equivalent of homeostasis for the mind? | It sounds like you're asking if the goal is to "make you normal". For a variety of reasons, the answer is technically no. The focus is on reducing discomfort and dysfunction (and in some cases reducing psychological disorder) and increasing function. There's really no "normal" to shoot for. The working definition of psychopathology is that it impacts your life negatively and decreases your ability to function effectively, so the goal is to reverse that to whatever degree possible. Abnormality alone is not a psychopathology until or if it impacts your life negatively. You're free to be a wierdo in life until your behavior puts you in a position where you can potentially hurt yourself or others - and even then it depends on the extent. This leads into a whole other conversation on normality and abnormality in general which isn't really germane to the point.
In the case of disorders like schizophrenia or bipolar disorder medication is used to control the symptoms and increase ability to function. Behavior therapy is or can also be used, but medication is usually needed to control the worst symptoms.
With disorders of emotional regulation, PTSD, anxiety, or phobias, medications may or may not be used depending on the specific disorder. The main treatment would be psychotherapy to help the person learn to moderate the symptoms, in some cases to return to full functionality. | 98 | 63 |
ELI5: Does it rain over all the Oceans and Seas? Are any areas over an Ocean or a Sea classified as deserts? | Well I was watching some documentary and they mentioned ancient dried up seas. This got me wondering why they dried up, the obvious answer was the geology changed. But then I thought to myself, so why didn't a giant lake form here instead and I realised that since the geology had changed, there had been so little rainfall that the water all evaporated.
Which means that a area over this Sea would not have gotten rain, making it a Desert, right?
Does that question even make sense? I am a bit high.. | There are definitely bodies of water which get rained on more or less depending on where they are. The amount of precipitation which falls in the arctic is very small compared to that which falls in a tropical region. Areas of ocean which are downwind from deserts also get very little direct precipitation.
Oceans and seas which can accept ocean water can maintain their water levels because the water will slosh around to roughly even things out. If a body of water gets cut off from oceans, then the area which it can draw water from becomes a lot smaller and this sea is now going to be much more affected by local weather than the larger oceans. All surface water bodies evaporate and most seep into groundwater as well and many lose water to creatures (particularly humans in recent timse), but if the water isn't being replenished fast enough, then the water level will drop and eventually disappear, but many water bodies surrounded by land are able to find a balance point for a long time where their levels stay within a particular range across the seasons. | 11 | 26 |
ELI5: atheletes and their lungs and hearts | What is the effect of regular exercise (athelete) on the
1.resting tidal volume
2. Ressting Breathing rate
3. Resting Ventilation rate (minute ventilation)
4. Resting Cardiac volume
5. Resting Heart rate
6. Resting Cardiac output
Please only reply if you know, dont post your predictions
Edit: please note im asking about the athelete that is resting and relaxed, not while exercising. I want to know how exercise will affect his body permanently not at the moment of exercise. | Athletes have had their heart pumping at greater speeds for longer periods of time than most people, and have thus worked harder to pump more blood than most. When you work out a muscle harder, the cells grow, which is called hypertrophy. Athletes hearts slightly hypertrophy and thus can pump more blood in one beat than before (higher stroke volume). However their resting heart rate will be lower since the heart no longer needs to beat as fast when it pumps more blood per beat. Overall cardiac output = (stroke volume x heart rate) so as heart rate increases the cardiac output increases during excercise, and although stroke volume decreases slightly it does not decrease enough to decrease cardiac output until you reach a very high heart rate as you no longer give the heart time to fill. As far as breathing goes, when you heavily excercise your metabolized Co2 goes up and oxygen goes down due to consumption for ATP, thus increases breathing is required to breathe off co2 and breathe in o2. To do this more efficiently you take deeper breaths rather than faster ones to give air time to get to the alveoli and for gas exchange to occur. Thus tidal volume is increased and resting ventilation is lower.
Source: Med student with the most basic/minimum understanding of physiology. | 124 | 413 |
[MCU] Does Tony have backups of his AIs? | After JARVIS is integrated into Vision, we never see it again, and FRIDAY takes it's place. Does Tony not have a backup of JARVIS, or even all his AIs somewhere in his computer/cloud?
Or is that not the case as we see Tony revives JARVIS only after he retrieves it's protocols in the Nexus? | Jarvis was designed to be able to learn and grow and adapt. Tony wrote the basic programme, switched him on, and then stepped back and let Jarvis develop his personality from there.
Tony could in theory boot up a new Jarvis, but it wouldn't be the same. And given that he treats Jarvis almost as a friend, he probably wouldn't *want* to do that. | 22 | 15 |
Eli5: how does Jupiter stay together? | It's a gas giant, how does it work? | Gravity.
This gas has mass. All mass can produce gravitational force attracting nearby matter to it.
There is enough mass for the gravitational force to become appreciable, and this force pulls surrounding gas inward to the planet.
The planet is large enough for the velocity of gas particles inside to not escape the escape velocity of matter under the gravitational forces of the rest of the matter inside the planet. Thus, Jupiter (and all similar gas giants, stars and other gaseous bodies in the Universe) is held together as a gaseous planet by gravity from its own mass.
Simply put, the gas in Jupiter is held together as a planet by its own mass.
cred. Nicholas Yoong | 507 | 483 |
ELI5: As humans we seem to have an instinctual desire to be entertained, with videogames, boardgames, TV, jokes, the internet, etc.. Is there a scientific explanation detailing the evolutionary value of entertainment with humans and possibly other animals? | Title.
Also are there any unique ways that animals entertain themselves? | Survival wise a huge amount of species play 'games' to hone skills that they will use. This is why so many animals play-fight (among other activities).
It would seem logical that the games we play perform a similar role of hones our intellect/reasoning/mental skills in a way that helps us be more effective at survival.
As for jokes - they are likely slightly separate and to do with forming close bonds with your group, given the tribal/group nature of humans (I think it's fair to say all human groups ever discovered had tribal / group hierarchies of some form). | 43 | 85 |
Are the steps one can take to get good at continental philosophy different than those one would take to get better at analytic philosophy? | If one wanted to "get good" at, or "improve" at philosophy (I put those words in scare quotes b/c im not entirely sure what it means to be "good" at philosophy, generally), would doing so look different if one wanted to become better at, say, continental philosophy, in particular?
What might one do to become better at continental philosophy? | Well, they're different in the sense that to get good at continental philosophy you should study continental philosophy and to get good at analytic philosophy you should study analytic philosophy. General competence at philosophy, in terms of understanding its problems, having strong reading and note-taking skills, having a competence in critical thinking, etc., would be helpful foundations in both cases.
So this is like "Are the steps one would take to get good at Aristotle different from the steps one would take to get good at Kant?" Well, to get good at Aristotle you should study Aristotle, while to get good at Kant you should study Kant, but general competence in philosophy... etc. | 28 | 29 |
Do the thousands of layoffs in the tech industry (ignoring twitter) point to an upcoming recession, existing poor economic conditions, or something else? | > Lyft let go of 13% of its workforce, Stripe cut 14%, Opendoor reduced its workforce by 18%, Chime parted ways with 12%, and more. Meanwhile, both Apple and Amazon have reportedly gone into hiring freezes.
https://techcrunch.com/2022/11/03/stripe-cuts-14-of-its-workforce-ceo-says-they-overhired-for-the-world-were-in/
And Meta announced layoffs today | They can be considered proxy measures. Here's all we really know: these major companies feel the need to drastically switch strategies from burning cash to grow fast, to battening the hatches and reducing costs as much as possible. That's all we really know by the layoff decisions.
The reason the companies are doing this is because we are already in a recession, and have super high inflation. The number one goal for the American economy right now is to reduce inflation, and how they'll do that, is by reducing spending power. That is the only real way forward.
So, federal reserve doing everything it can go lower total spending power, would be reasonable to infer there will be less aggregate demand in the near future. And so companies are focused on cutting costs and being capital efficient.
Another way to look at this, is the cost of capital is going from close to zero to 5 percent. This increases the default yield any business needs to produce to be more attractive than the risk free rate of return. Capital is becoming more scarce. And so must be managed more efficiently. And so, instead of huge RnD teams trying to break out into new market segments, companies are looking to preserve capital, allocate it for known rewards, focus on cash flow, and make less risky bets. | 98 | 123 |
ELI5: Why do some animals tilt their heads when they are confused or trying to figure something out? | By tilting the head, you can adjust how sound waves travel over the ear and possibly get a better understanding of the sound stimulus. But animals do this when they see something unusual too, even if there are no sound waves associated with the object in question. | 11 | 18 |
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Why are there no solid objects that aren’t visible to the human eye? | If humans are only able to perceive the visible spectrum of light, but we know there are other wavelengths such as UV that we can’t see, how come we don’t bump into ‘invisible’ walls or blocks that are only visible in ultraviolet or infrared etc? | Solid objects that pass basically all visible light are common, we call them transparent e.g. glass.
The reason we can distinguish these objects from their background is due to the difference in their *refractive index* which bends light that passes through them, allowing us to see them as distortions of their background. For an object to be 'invisible' it must be both transparent and have the same refractive index as its surrounding medium. Air has a much lower refractive index than all transparent solids, which is why even very transparent solid objects are still noticeable | 106 | 29 |
ELI5: Why are salt and pepper such ubiquitous ingredients in cooking? | Why do we put salt and pepper in EVERYTHING that we cook? Why not anything else?
I imagine it is something to do with availability? Or is it taste related?
Thanks
**Edit**: thanks for all the answers, very informative! | The human sense of taste has evolved to enjoy salt, because salt is important for your body to keep functioning. But that's not the only cool thing it does, it also seems to suppress our perception of bitter tastes, which lets other tastes like sweet or sour stand out more. Salt not only tastes pretty good on its own, it also makes other things taste better.
Black pepper adds some flavor and a little bit of spiciness, but usually doesn't overpower dishes unless you add too much.
Many other spices tend to be strong and distinct in flavor, and as such can "take over" a dish, instead of just enhancing it.
| 174 | 306 |
How does a spider make a line of silk taut from point A to point B? | They start by creating a horizontal anchor line between two points, by ejecting a type of light very sticky silk in the same direction as the wind. When this anchor line is attached to the other side, the orb weaver will cross reinforcing that first line with a different type of silk. | 11 | 18 |
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CMV: Universities that receive public funding should be responsible for placing their graduating students in relevant careers | We spend an absolutely ludicrous amount of public money on education, yet the government rarely demands a return on this investment. IMO this is an unconscionable use of public funds. In addition to the amount wasted on the universities themselves, government will just hand tens of thousands of dollars to young, naive and impressionable teens that will piss it away on "education" without realizing that they aren't acquiring any useful skills until it is too late. Universities responded to this by creating enormous humanities departments, passing any kid who has a pulse, handing them a piece of useless paper after 4 years and expecting them to fend for themselves with a huge debt and no marketable skills. This has created a generation of baristas with huge debts and nothing to show for it, making it way harder for them to get ahead in life than it would have been if they never went to university in the first place. This is a terrible waste of tax resources. Governments need to start demanding a certain percentage of students get placed, and if universities can't do that, they shouldn't receive any funding, their students should be barred from receiving government loans, and the schools should be forced to close as a result (or exist only to serve the very rich who can afford to piss away $100k without developing marketable skills). This will mean less graduates, but that isn't a bad thing. The world needs baristas and janitors and bus drivers. It just doesn't need people with advanced degrees in Medieval Literature or Women's Studies doing these jobs.
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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 an effort to summarize your view I've reduced it to three statements. Let me know if I've misrepresented them.
1. Spending public money without a guaranteed return on investment is wrong.
2. Giving loans to students who then fail to become gainfully employed is a waste of resources.
3. Therefore universities should be responsible for their graduates' employment status after college - with financial consequences if a significant number fail to find employment.
You seem to be missing the situations in which students receive financial assistance from the government and then become gainfully employed. These students represent a significant return on investment. The addition of educated citizen and consumer represents a benefit to the community as well as an increased tax revenues for the government.
What of students who - having used financial assistance to graduate then fail to find a job? There are plenty of student's whose goals are not employment. Some go for the social bonds developed there, or to enable them to find a better marital partner, or to further goals other than simply finding a career. Would you burden universities by tying their successful graduates with a narrow set of restrictive employment options?
This is outside the responsibility of a university. If the university's granting of a degree to an individual creates an obligation beyond the scope of academia, why not extend it to child rearing, or nutrition, or other desirable goals. Universities should be concerned with creating educated individuals and should not be concerned with subjects as whimsical and fluctuating as future employment options. That should be the realm of the students themselves and their own personal goals.
There are better solutions than what you propose if your aim is to reduce money spent on people who then get a job outside of their degree. Mandatory employment counseling for people seeking financial assistance. Decreased loan interest rates (or other incentives) for people pursuing fields with a large projected growth. | 10 | 22 |
ELI5: How pet ant colony produce queen? did they just appear randomly? | They develop from larvae.
Ants lay 2 types of eggs, fertilised and unfertilised:
Unfertilised eggs hatch into larvae that turn into winged males.
Fertilised hatch into larvae that generally turn into sterile wingless female workers.
However a female larva that is well fed will turn into a fertile winged princess ant and fly off to start a new colony.
If there's no queen in the colony she'll stick around, bite her wings off and become queen. | 83 | 36 |
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[General] Why is there gravity inside spaceships? | Why is there always gravity (or what appears to be gravity) inside spaceships. This is prevalent in Star Wars, Star Trek, pretty much every Sci-fi media, and it's always bugged me.
We never see any sign of artificial gravity while inside spaceships, and it seems the instant the characters step outside for a spacewalk they are in zero gravity. What gives? | Most kinds of "artificial gravity" rely on a conceit like Mass Effect fields or "gravity plating".
Newer sci-fi (the Martian, Red Mars, and Halo, for instance) have ships with rotating toruses intended to simulate gravity via centripetal force.
When you move between toruses you experience different levels of gravity. In Halo they use special "gravity gyms" to get buff, while in Red Mars they use it to adjust to what it will be on Mars (.3G). On military vessels these toruses would be hidden behind layers of armor; the UNSC Halcyon is a pretty good example.
Magnetism can also produce gravity fields, however, you need extreme cold to keep the magnets superconductive (which drains power). This was actually the underlying conflict in 2009's Avatar; the humans wanted "Unobtanium" (stupid name) because it was a room temperature super-conductor. Just recently a device was made to levitate a small mouse using magnetism, thereby producing a 1G field to cancel out the Earth's gravity, so it is possible.
String theory posits that gravity and electromagnetism unify in hidden dimensions, however, no one knows how to manipulate this.
| 25 | 16 |
ELI5: If fever is a defense mechanism of your body, why do we try to stop it? Shouldn't we let it do it's purpose? | Sometimes the body does certain things that it thinks are good for it but can be detrimental to another part. Too high a fever might destroy the infection but very badly effect the brain. The body will just focus on the problem at hand and not think of the bigger picture so to speak | 30 | 15 |
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ELI5:Why are normal downloads of .exe files (e.g. adobe flash player) replaced with small, 1MB exe files that then start and initialise the download? | Instead of letting me install the exe myself?? | The benefit of having a separate installer is twofold:
1. The installer can be universal, and then download and install the correct version for your particular computer architecture. For instance, it can install either the 32-bit or 64-bit version of the program depending on your CPU/OS combination, without you having to know which one you have.
2. It prevents having outdated versions of the program floating around on the Internet. There are lots of websites that re-host software downloads, and when the installer is separate from the program itself, then they can update the download picked up by the installer in the background, preventing installers hosted on 3rd party websites from becoming obsolete. | 144 | 178 |
Could one of the first ever Homo Sapiens learn the same amount and same quality of information as a modern Homo sapien? | Does one of the first Homo sapiens have the same cognitive ability of modern Homo sapiens? Is what we know now simply collective knowledge that has been added on to each other or have we as a species gained the ability to learn more than our Homo sapien ancestors from 20 to 30 thousand years ago? | This question is sort of confusing, but I'll give it a shot:
First of all, we would need to define what we mean by Homo sapiens. Some researchers consider Homo to have only one species (e.g. Milford Wolpoff, Alan Mann), because they don't see any evidence for any speciation events in the fossil record. A more mainstream view is that Homo sapiens arose about 200k years ago, but this is mostly based on the Omo skull, which looks basically (but not quite) modern and has been dated to 195k. Genetic coalescence times suggest that this time range could be accurate (however, there are good reasons to suppose that these data don't actually tell us what many researchers think they do).
Cladistically, the origin of a species is defined by an event in which a species branches into two. There is a great amount of disagreement regarding what our sister species was. Homo erectus, Homo heidelbergensis, and Homo neanderthalensis all have supporters. So, maybe there was a split from one of these 200k years ago (of course, we now know that humans later mated with neandertals after maybe a couple hundred thousand years of reproductive isolation from each other).
So, the question is whether the cognitive capabilities of those folks 200ka would have been similar to our own. That's a question that doesn't really have a great answer, but there's not necessarily any reason to suppose that their abilities would have been significantly different from our own. Their brains were similar in size, and near as we can tell, were similar in structure.
20 to 30 thousand years ago, it is basically certain that they were just as smart; note, however, that IQ is very fluid, and is very much something that can be improved through use. They didn't have written language back then, so it's unlikely they would have been "smart" in the same way today's humans can be; they only would have been perfectly capable given the same cultural environment.
Hopefully that helps. Also note that "sapiens" is both singular and plural. "sapien" is improper. | 220 | 406 |
Why did Acemoglu never win a Nobel Prize in economics? | I feel like almost every topic on development he is the leading name, and his works seem disruptive.
Are there some specific reasons? Is it probable that he is going to be laureate soon due to his contributions? | Laureates generally tend to be older and prizes tend to take their time. Card, one of last year's laureates, won the prize for work that in part goes back to the 90's. Not to mention that you of course always have to pick someone and at the same time forego picking everybody else who's also an excellent candidate.
That said, Acemoglu certainly contributes a lot and there's a good chance he gets one at some point. | 56 | 30 |
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