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How do headphones actually work?
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Sound is composed of a time-varying pressure in the air. Your eardrums transmit vibrations from the pressure changes into your inner ear, where it is sent to your brain to be interpreted as noise, or music, or whatever. Most speakers replicate this change in pressure by driving a speaker cone with a magnet and wire. A current running through the wire will push or pull on the magnet, which moves the cone and induces a change in air pressure. By sending an electrical current that corresponds to the pressure changes in the music, you drive the speaker and induce pressure changes in the air, which you hear as music.
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Assuming you already understand the ELI5 answer for 'how does an audio cassette tape work?': Then the cassette adapter basically transmits the electronic signals from the headphone port through the wires into the fake cassette. Instead of being actual magnetic tape inside the cassette, there's just another magnetic tape head. However, instead of this tape head reading the signals off the magnetic tape, it's used to generate magnetic signals instead, just like if you were recording to a magnetic tape. The 'recording' tape head in the adapter aligns with the existing 'reading' tape head in the cassette player, so the audio signals can get across.
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What causes those "floaters" to appear in your eyes?
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They are just cell fragments floating around in the jelly in your eyeball.
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Assuming they're not sick it's like the stuff we get in our tear ducts in the morning. The fluid in the eye leaks at certain points, evaporates, and leaves behind a crust of everything that was dissolved in it. It's harmless.
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If I scratch a diamond with my fingernail, am I removing any atoms from the diamond?
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Yes, you'll be removing some atoms from the diamond. Far more material will be removed from your fingernail, but the diamond will lose atoms as well.
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A diamond can only be scratch with another diamond. You can still break it, actually diamonds can be somewhat fragile (I'm using a veeeery broad definition here) and can be broken with a hammer if you hit them in the correct place. If you grind diamonds with diamonds you'll get diamond dust that can be added to metal tools in order to cut and polish other diamonds.
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Is there any research being done to filter ash out of the atmosphere? Particularly in the case of cataclysmic volcanic events?
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Ash filters out of the atmosphere fairly rapidly, what causes climatic impact from volcano eruptions is typically the sulfur dioxide gas that remains in the stratosphere for years (where it converts into sulfuric acid and condense into aerosols that slightly increase the albedo of the upper atmosphere).
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No, it wouldn't have been. As described in [this paper](_URL_0_) from the year, the winds were predominantly westerlies so most of the ash fell over the northern US. You can see this more clearly in this [isopach diagram](_URL_1_) showing variation in the depth of ash deposited from the eruption. From the 1981 paper, there was a reversal in the wind direction at altitude, but it wasn't enough to shift the bulk of the ploom. As /u/2point0cat says, the USGS has written that ash fallout was found "around the globe within two weeks" - however, I assume the quantity of ash would have been trace and there certainly would not have been a visible plume or ash cloud. I've not been able to find a paper elaborating on what the USGS has written there, but I imagine this would have been light fallout from ash that made its way into the stratosphere where it can travel rapidly and stably around the world.
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How have Child Protective Serivices not intervened with the Westboro Baptist Church?
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Because there's nothing illegal about what they do. The first amendment protects everybody, including hateful assholes like them, and religious freedom allows them to teach that crap to their kids.
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It has been said that high up politicians have been abusing children for 30 years, using their status as a way to get away with it. The children didn't go to the police out of fear, and when they did, the police didn't believe them. In fact, if the Jimmy Savile scandal didn't bring child abuse into the mainstream media, they may of gotten away with it for longer. tl;dr: The reason its a huge problem is because of how high ranking the MP's were and how long they went undiscovered.
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Why are rowing machines not as popular as ellipticals or tread mills?
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I can only judge from my personal experience: An elliptical is intuitive; I can step on and basically "walk" with more resistance than usual, that's it. But rowing, oh... should I bend my knees, or my back, and when exactly? It seems like I would need some coaching to row correctly so not to hurt myself.. *and* here's the thing. Every time I ask any staff member anything (like just yesterday: "can I realign that seat to point straight"), they suggest I sign up for personal training lessons! Honestly I'm avoiding the staff.
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If you're looking at it purely from the perspective of cardiovascular fitness (in other words, heart health), the only thing that really matters is how fast your heart is beating, and for how long. So anything you do that can get your heart rate beating quickly for an extended period of time will be "comparable to running" if you're looking at it purely for cardiovascular fitness. I'd imagine rowing would be fine (though I understand that proper use of lower torso and legs are a part of "good" rowing form).
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Was any of the New Testament found in the DSS?
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No. The NT was composed between 55-120 CE while the DSS were composed between the 4th-1st centuries BCE. There is absolutely no overlap between the Qumran community and the composition of the NT. You might want to take a look at the Anchor Bible Dictionary entries on the various books of the NT as well as the entry on the Dead Sea Scrolls. The work of John Collins, Geza Vermes, Jodi Magness, and Bart Ehrman will be helpful as well.
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A sumerian hymn written 3400 years ago - the notes were deciphered by Prof. Anne Draffkorn Kilmer from cuneiform tablets. _URL_3_ Listen on youtube: _URL_2_
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How is Dr. Phil not a form of public humiliation?
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I was on dr Phil with my mother and completely regret it. She wrote in to dr Phil for a few weeks until she got a phone call from one of the producers and we flew to LA did the show and he never gave us the counseling he promised and even said it on show he would help us but he didn't. Anyways it's real and he cakes on a shit load of makeup too. Edit:spelling
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He isn't pretending to be a medical doctor. It's not like he has a clinic or writes prescriptions. Everyone pretty much gets that he isn't a real doctor, in the same vein as "Dr. Dre". He doesn't consider himself a doctor doctor. It's just a title.
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Why do toxicology reports for drugs take such a long time after death whereas if you're tested in the ER for drugs the results come within minutes/hours?
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It depends on what they are looking for and concentrations. Drug tests are exclusive, meaning you run a test and look if a specific compound is there. The how much of it. In the ER the are most likely only looking for a few things. If you come in looking like a heroin addict they'll test you for it and prob some other street drugs. For an autopsy, they don't know whet they are looking for so they look fr everything. They prob won't test the addict for arsenic or cyanide (etc) but they might for a autopsy. These things all take time so its a while before they can release the results.
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Two reasons: First, much of the substance is excreted out of your body. They are testing for what small amounts are left over. The concentrations in your body are very very small, and not enough to make you feel any effects, but can still be detected. Second, depending on the drug, they are not always testing directly for that drug, but its byproducts. You're body will break down the chemicals in the drug, but the byproducts of that process can hang out in your system for a long time.
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Is "text-speak" an aberration or has something similar ever happened in another country?
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Text speak isn't all that new. Abbreviations have been popular in other media where characters are limited. Take the telegraph- many shorthands were used to cut down on the time taken to communicate and [the earliest recorded use of "OMG" is a reference to a telegraph message in a letter sent to Winston Churchill in 1917](_URL_0_) Calling this a lack of proper grammar is a bit much, but to imply that text-speak is due to or the cause of a drastic drop in literacy is plain wrong. In the US at least, [there has been no significant change in literacy between 1992 and 2003](_URL_1_). In this time period, [US mobile phone ownership rose from 4% to 55%](_URL_2_).
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I don't know where it originated, but I've seen it since the 90's, Back in chat rooms and instant messaging. I didn't see it in text message until long after. So I at least know it may have originated there and not via text messaging. Hopefully someone with more knowledge can elaborate.
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A paper published in the Journal of Non-Equilibrium Thermodynamics makes a novel argument against global warming. Can anyone tell me if & why this is wrong?
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This isn't an argument against global warming. This is an argument that it's not statistically or methodologically kosher to take the entire library of the world's temperature data and shoehorn it into one number that supposedly represents a meaningful average of the data. Whether or not this argument is valid, or whatever, I'll leave to the climate scientists. (And hopefully they will be here soon to comment on this.) But, as far as I know, their field has been shying away from "global warming" and trying to use "climate change" more because it much more accurately describes what is going on. Some regions will get warmer, some regions will get colder, and some regions will see a marked change in climate, precipitation, etc.
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Global warming is what the planet is undergoing as a whole. The increase of average global temperature. Climate change is what could be observed in a specific region. A region could be hotter, cooler, wetter, drier, etc. The worry is that the ecosystems in a region could change too quickly for organisms to adapt and upset the balances each have. Also, this is why the "it's so cold outside, where's the global warming everyone's talking about?" argument doesn't get the gist of it.
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How could you become a target for someone to spy on you through your webcam, and how do they even do it?
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In addition to the other comments, attackers can also sometimes replace the drivers for the camera. Most cameras have a glowing LED the lights up when they are being used, but if an attacker can replace the camera driver then they could use the camera without the LED turning on.
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Basically, someone finds an address through whatever means necessary. With Yellowpages, IP lookups, and Facebook, it's really not that hard to track someone down. Keep in mind, most people are SWATted by a "friend". They then call in a terrorist threat of some sort that is time-sensitive. Bomb making and blowing up a school tomorrow, holding hostages etc. Immediately escalated past cops. Generally, they do this as if they are in the house in question. What can you do to prevent it? Nothing. What can cops do? Nothing. They have to act, can't just ignore threats of that severity. As a disclaimer, calling a SWATing is highly illegal. They will track you down, try you, and put you in jail, while levying heavy penalties (against your parents, since only kids are dumb enough to do this). Heck, they'll even [try a 15 year old as an adult and give them 25 to life](_URL_0_) for doing it.
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Why don't politicians get charged with libel when many of them knowingly lie or misrepresent facts?
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For a start, lying isn't necessarily libellous. You can say all sorts of untruths without defaming anyone. Second...if you sued a politician for lying, just thing of the exposure you'd be giving their arguments? Money couldn't buy that sort of airtime (well, OK, in the US it probably can). Third - some countries like the UK specifically exclude party manifestos from breach-of-promise rules. IIRC in the UK this came as a result of someone doing what you suggested. So - apart from not working, being counterproductive and they'd just move the goalposts anyway, no reason at all!
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I don't understand the intent of the question. Are you asking why politicians historically have lied about stuff? Or are you thinking about this as a particularly special case that might have an interesting motivation?
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Why do we have to buy domain names from companies instead of just claiming it ourselves for free?
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Back in the day, before everyone and his uncle wanted a domain name, before the world wide web, before google, you *could* just ask for a domain name and get it for free. Who did you ask? The National Science Foundation, of all things. When domains started getting more popular, the National Science Foundation got tired of doing it, and farmed the process out to anyone who wanted to be a "domain registrar." Turns out it's quite a bit of work.
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All domains are actually registered by ICANN which maintains a list that basically says who owns what. These services, like GoDaddy, are acting as a middle-man by just taking down the information you give them and registering them with ICANN itself. This is because ICANN is a very small organization for what it does and does not want to deal with costumers itself. I imagine you can not buy a domain forever as they wish to make sure domains do not eventually all get used up. ICANN was established by the US government to do this. Previously the US government controlled the internet as they primarily created it. Once they opened it up to the public did ICANN, a non-profit take over.
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We have first and third world countries but is there such a thing as a second world country?
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The term first, second, and third worlds refer to the cold war. The '1st' world was the NATO countries, the '2nd' was the Communist nations (mostly USSR, but China, Cuba, and some of Latin America), and '3rd' was everyone else. After the Cold War ended, the 2nd world concept lost meaning and 1st/3rd evolved to mean rich & poor.
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This term is a heritage from the Cold War. There were the NATO-aligned first world, the Soviet Bloc-aligned second world, and the third world were the remaining non-aligned countries.
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Why are computers always slow after you initially boot them up?
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There's a lot of shit that needs to be done when you first turn on a computer - starting up background services, pre-loading programs, checking for updates, etc. OS developers realized that most people only really recognize how long it takes to get the machine to the desktop, rather than how long it takes for the machine to fully become usable. As a result, they've prioritized getting the user logged in & showing the desktop - leaving you with a machine that's still sluggish as it does all the crap it **used to do** before you could log in.
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Mostly it has to do with how much software you have installed on your device. The more stuff you have running the more computing power each application takes. When you first open your phone it has very few things running in the background. But, after you install Facebook, Instagram, Twitter, WhatsApp, etc. those programs are all running in the background making your phone a little slower. If you want to get some of the speed back you can do a factory reset. This will make the phone much closer to the speed it was when new. But then it will slow down again as you reinstall apps.
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How can 'artists' put out cover versions of songs yet not fall foul of copyright?
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Because there's something called a mandatory license that basically says that anyone can make a cover song by paying a legally set rate to the copyright owner. The copyright owner doesn't have the ability to prevent it as long as they pay the license fee. This only applies once the song has been published by someone.
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> How is covering a song less of a legal problem than sampling a song? In the US music industry, there is something called mechanical royalties. You can cover any song you want, but you have to pay the original artist a portion of what you make on it. > Also, if they don't have final say on their intellectual property when it comes to others re-making their works, why am I not allowed to do whatever I'd like with my media? Because it is not your work anymore. Typically you sell the rights to your work to a publisher, who depending on the terms of the contract, gets to decide what to do with it going forward.
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Why does really hot water rinse food off of dishes so much faster than cool water?
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it cleans grease and congealed fat off of dishes faster because it melts it back to liquid form. Fun Fact though: the temperature of the water doesn't matter as far as sterilization. hot and cold water kills just as many germs with soap. To get to sterilization level of hotness with the water it would have to be well beyond the tolerable levels of your hands I.E. 2nd degree burns. thats what the dish washer takes care of for you.
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It can. When washing anything, the majority of the bacteria will be removed through the mechanical act of scrubbing. Temperature also helps though. Specifically with dishes, hotter temperatures cause certain fats and oils to liquify, allowing them to be cleaned off more easily. Warmer water also tends to be a bit faster and more effective as a solvent, allowing it to get rid of caked/dried on debris more easily. Finally, heat kills bacteria, while cold just slows their metabolism down and makes them go dormant. If you use hot water, you're more likely to kill any bacteria that the soap and scrubbing missed.
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If you went closer toward the center of the earth, would there be less gravity or more gravity?
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Think about it like this. Gravity doesn't pull from the center of some celestial being (like the Earth). It pulls from every single particle of that celestial being. Literally every single atom in the universe has a gravitational pull -- it's just so utterly microscopic that you don't notice it until a lot of those gravitational pulls add up together. When you're on the surface of the Earth, or far away from the Earth, it's convenient to identify the center as where gravity is attracting you too. But in the messy reality, it's attracting from every single atom that makes up what we call Earth. So as you move towards the center of Earth... the center would still be pulling on you, but so would all the other atoms. Which are now pulling you *away* from the center.
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Yes, the core. The [shell theorem](_URL_0_) means that if you are inside the Earth, you only feel the gravity of the sphere below you. The gravity of the shell above you all cancels out. When you are at the exact centre, the entire Earth is above you and nothing is below, so you feel no gravitational force.
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What is happening in the body when a drug like diphenhydramine (Benadryl) makes you drowsy?
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There are a few possible reasons for drowsiness from first generation antihistamines (it does not happen with second generation as often). Your brain has H1 receptors (to histamine) in the cortex. H1 receptors are used to block potassium channels, allowing depolarization of the cells in the cortex. H1 antagonists (antihistamines) essentially prevent this from happening, which is believed to cause drowsiness. Essentially, antihistamines in the brain lower the excitation potential of your neurons. Wikipedia also notes that the hypothalamus has a specific frequency of release of histamine during waking hours. This release lowers as you go into sleep and stops as you enter REM. It could have something to do with that as well.
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Most over the counter sleeping pills contain diphenhydramine, which is an allergy medication that lists sedation as a side effect. Prescription sleeping pills work by depressing the central nervous system. They work by binding GABA receptors in the brain, thus stimulating drowsiness. GABA receptors respond to the amino acid GABA, which is the main compound that inhibits nerve activity and causes sleepiness.
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Why can cows live on grass, while humans require such a complex balance of nutrition?
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Cows have an insane digestive system that's capable of deriving a *lot* more nutrients out of grass. You may have heard that cows have four stomachs, for example. We don't have that (:
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Because it's not just grass like what grows on your lawn. Think more of a field left to its own devices. Also to answer more specifically cows ruminate, that is they have four stomachs that ferment and break down their food. I would also point out most breeds don't live off of grass alone, should not live off of grass alone, and are more domestic than you would believe. For example, a dairy cow could not live off of graising alone and would die very quickly without a proper diet.
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Why not use the oxford comma?
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In some cases, the extra comma can make a sentence less clear. Like many "rules" of English, it's really a style choice. Pick a way, and stick to it; rewrite for clarity where needed whichever you choose.
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I've found that it helps me to imagine reading what I'm writing out loud. If you notice yourself making a slight pause, use a comma. If you end up with a sentence, that just keeps dragging on, and you're using lots of commas, not knowing if it's wrong, you should probably try and split it up into a few sentences. Another reason to use a comma is if you're making a list of one, two, three, four or even more items.
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Is sleeping in a fetal position (curled-up back) as bad for your posture as slouching for 8 hrs a day?
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I would assume that it is *not as bad* simply because you don't have the same downward pressure on the arch when you are lying down as when you are slouching in a seated position. That said, it probably isn't great for your posture to sleep in a fetal position (I do the same thing, and slouch, and have horrible posture myself).
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The first SPECIFIC example that comes to mind is that people with [sleep apnea](_URL_0_) are advised NOT to sleep on their back. Sleeping on your back can cause the tongue/palate to block the airway. Another well-known example of sleep position having an effect on health is [sudden infant death syndrome (SIDS)](_URL_1_). Babies who sleep on their stomachs are a greater risk. I would be wary of articles saying this or that is THE BEST way to sleep, unless they can provide some SPECIFIC mechanism for the reason (the arm-waving "it like, throws your spine out of whack this way or that way" doesn't count), OR a study that correlates sleep position with the disease/problem in question (but remember that correlation does not necessarily equal causation). The "fetal position" is the most common position, so a reasonable hypothesis might be that there is some advantage to it, but I'm not sure how far this has been scientifically explored (not my field, maybe some sleep expert will chime in).
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Why does frying food create bubbles?
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The oil used in frying is hotter than the boiling point of water. So when food touches it, the water contained in the food quickly boils, creating bubbles.
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Oil is active as a heat stabilizer and heat transfer fluid. As the oil heats various components begin to break down or evaporate (boiling does this rapidly). This takes energy and holds the temperature relatively even as the oil evaporates or smokes. This means that your food is cooked at a relatively stable high temperature evenly across the entire surface, which is what gives it the "fried" consistency (coupled with the residual oil). The bubbles are steam. Usually.
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Why do animals naturally interact with other animals they do not know while humans generally keep to themselves in a public setting?
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I'd say this is a matter of culture, not species. There are many human cultures where people actually interact with strangers.
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Most likely because the strangers it meets that it acts in a friendly manner to are either on what it figures is neutral territory or their territory and the strangers it acts nervously to or aggressively to are on what it thinks of as its territory. Also, your dog may well be picking up on body language and smells from yourself and other people that you're not even aware of.
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How certain colors affect our mood (i.e. red causes anger)
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Colors are associated with certain moods. It must be noted, however, that this is a cultural thing; some cultures may have colors that represent different moods than for me or you. How exactly do they affect your mood, though? Do you get angry when you see red?
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Different colors have different affects on your mood. Light green as well as blue is more calming, which is why the insides of many hospitals are light green. While red is more intense. I remember my psychology professor mentioned once that there was a study where 2 kids were in different rooms, one red and one blue. The kid in the red room became very aggressive and angry while the kid in the blue remained calm.
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Why are we unable to make gold artificially?
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We *can* produce gold artificially. However, the costs to do so are significantly higher than the gold itself is worth.
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It's been [done](_URL_0_) by way of Nuclear Transmutation. Basically you use a particle accelerator to knock loose protons and neutrons until you have gold left. That said, it would never be an economical way to make gold. The energetic costs far outweigh the increase in value going from lead to gold. You also might have a hard time getting someone to buy your radioactive gold. Though Goldfinger might be interested.
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Why do we use "Baby" to indicate someone like our boy/girlfriend, or people close to us?
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A baby is something more or less universally cared for and considered valuable. By saying "baby" people communicate "my feelings toward you are similar to those people experience toward a small child". It's a pretty clear way of communicating a complex concept, except for using a distinctly negative tone. "I care about you" "I like that you are here" "You are something I want to protect" "I feel emotionally close to you" "You are an integral part of my life" All in one word, and pretty difficult to missunderstand.
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They mean just what you'd think--a reference to a literal baby. That's something cute that people usually care a lot about, so it works as a term of endearment.
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Is it (theoretically) possible to wire a person so that they can see more colors than normal? [Relevant to Neuroscience, Biology, and possibly Medicine]
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Check out this RadioLab episode: [The Perfect Yellow](_URL_0_) They talk about [Jay Neitz](_URL_1_) (professor of ophthalmology & color vision researcher @ U of Washington, Seattle) injecting the human gene(s?) for red cones into the eyes of squirrel monkeys, and the possibility of doing something similar for colorblind people, and even expanding typical human color perception. Worth a listen. According to Jay Neitz, “If the neural circuits for color vision are sufficiently plastic, it may be possible to use gene therapy to replace missing photopigments in the eyes of color blind humans." Neitz further states that since apparently "the neural circuits can handle even higher dimensions of color vision that could come from artificially adding a fourth cone type, it is possible that gene therapy could also be used to extend normal human color vision", making human trichromats into tetrachromats.
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They extracted the proteins from the retina of the Mantis Shrimp. We have three types of cone cells in our eyes that are activated when differing wavelengths of light hit them. The mantis shrimp is the same, except they found up to 12 different types of detectors; each for a slightly different wavelength. The real question is: with a visual cortex so small, can the Shrimp really perceive all the beauty he could see? Or is he limited by the small size and power of his brain and able to only really see one or two wavelengths at a time?
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Why do tasers not affect the heart?
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Tasers can affect the heart, and there are cases where people have died from being tased. It's usually considered safe because, while high voltage will make your muscles twitch, high amperage is what will kill you. Tasers give off 60-100 thousand volts, but have tiny amperage, and are thus deemed "safe."
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There is a difference between "not being in pain from x" and "being immune to x." Pain tolerance is one thing, but a taser works by using electricity to create physical convulsions. This is direct stimulation of the muscles we're talking about. Adapting to THAT would require evolution to provide us with electrical insulation to sheath our skins/muscles/organs. Just get a heavy jacket with metallic filaments in it attached to a capacitor. Put that electricity to USE. :-)
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How do popular social media apps become popular when they start out with 0 users?
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usually an app will be tested by a group of people who the app is targeted at and the developers will see how they use it and then try to cater it towards that market of users. once they know exactly what people want from the app/social media its entirely about marketing. getting the word out there, tell your friends about the app, they tell their friends, the userbase grows.
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They don't. Their main goal is to get as many users as possible in hopes that FB or Twitter will acquire them. Then FB or Twitter will figure out how to make money from them.
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Do you sweat while you swim?
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As a swim instructor and swim team member, I am an expert on this issue. My expertise is known across the world (don't look me up its classified). Anyway, yes you do sweat, and a lot. Just as you would when playing football or soccer, you sweat while swimming. Lots of people think they aren't sweating because they constantly feel wet, which creates issues where people don't hydrate enough while swimming. Hope this helps!
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Yes, but less so than when on land. The function of sweating is to cool the body down. Being immersed in water reduces the need for sweating, but during intense activity (most notably, swimming), people still do sweat. The Australian Institute of Sport did a detailed study of the Australian Swimming Team in Atlanta in 1995 to arrive at this conclusion, measuring an average of 125 ml of sweat lost per kilometer swum. Additional findings: male swimmers sweated more than female swimmers, and sweat loss increased with anaerobic threshold training. Reference _URL_0_
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Is toffee a non-Newtonian solid?
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Solids are not described as "Newtonian" (though they may be described as "Hookean"). Almost all food materials display a mixture of elastic, plastic, and viscous behaviors. This means they don't fit nicely into particular bins like a lot of traditional engineering materials. In addition, the properties of a particular class of foods (like toffee) can vary considerably between individual samples based on the exact ingredients and cooking methods.
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Just saying 'non-Newtonian' is really too broad of a term, as there are many different behaviors that fluids can have in response to shear that are not Newtonian. When you say 'non-Newtonian fluids solidify on application of pressure', that actually doesn't really make sense. Whether a fluid is non-Newtonian or not depends upon its response to the application of *shear*, not pressure. Since liquids are all essentially incompressible, applying static pressure to a container of fluid won't tell you anything about its rheology. As explained in the [wikipedia article](_URL_1_), there are 7 different classes of behaviors that a fluid can have when stress is applied, only one of those is a Newtonian behavior. If you are referring to a shear-thickening or dilatant fluid, then application of s-waves would most likely cause the fluid to increase its viscosity, causing weird effects like [this](_URL_0_).
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Why if the distance between two objects can always be halved, do they ever touch other?
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Two answers: 1. You can't keep cutting matter in half. There are particles which are indivisible. 2. Your idea of what it means to "touch" something only applies at the macro scale. On the quantum level, "touching" isn't a binary state in which two atoms are either touching or they're not. What's actually happening is that the closer two atoms get, the stronger the electromagnetic forces between the electrons and the protons in the atoms are felt. It's like trying to push together two repelling magnets that can never be touched together.
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Exactly right. The strong and weak atomic forces (as you'd expect) are dominant *inside* the atom. Gravity is extremely weak and thus is only powerful on astronomical scales (from planetary scales to galactic clusters and beyond). When two bodies "touch" (as we see it), it is due to interactions involving photons -- hence, due to the electromagnetic force.
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Why do so few people choose a modern nomadic life in developed areas such as the USA or Britain?
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* There is a huge stigma attached to homelessness, which technically, is what you are describing. * A genuinely nomadic lifestyle is one in which a people (not just a person) are consistently moving to wherever the resources lead them. The resources in first world countries are mostly fixed in place, therefore the people are as well. * The weather in a country like the USA would limit one's movements, especially in the winter months. If resources (work) were plentiful in Chicago in January it would be a difficult situation for a nomad to endure moving there in there tent. * Chances are that there are more nomads than you may realize in the USA, but their culture is stigmatized and the people tend to stay out of sight for fear of garnering the attention of law enforcement (not that cops in the US would ever be dicks to innocent nomads) * You might enjoy this episode of Vice [Thumbs Up!]( _URL_0_)
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I think it's particularly because Gypsies were a nomadic kind of people who didn't pay tax and took up space.
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I've seen a few gifs/videos from Japan here over the past few days. Why are some of them wearing what appears to be dust masks?
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If you are sick it's good manners to wear a mask and not breath germy air all over everyone. It's a pretty cool thing and cuts down on spread of things like colds and flus. It doesn't cut it to zero and it's imperfect of course but it is more than the West does when people are sick and at work or out and about.
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The contamination here is referring to the miasma theory. They thought that the air contained particles that caused disease, most commonly by upsetting the balance of the four humors. Contagion as we understand it wasn't fully accepted until Jenner, Koch, and Pasteur. Source: lecture series on epidemics in western culture by Dr.Frank Snowden available free through YouTube. Edit: the break is for containing herbs that overwhelm the stench of the miasma keeping you safe (!), the wax coverings is so that the vapors can't hang on to your clothes (!), and the other common item you see on these depictions: a stick for hitting people so that they stayed away (I'm sure this one actually worked to some degree.)
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If space is a vacuum, does the space station just need to be sturdy enough for the pressure difference plus 50% or so for safety, or is it capable of enduring massive pressure differences?
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As Professor Farnsworth points out in a Futurama episode when asked how much pressure a spaceship can withstand: "well, it's a spaceship, so anywhere between zero and one." There's no reason to build it to be capable of withstanding immense pressure differences. It will never be highly pressurized, nor exposed to heavy external pressure (except at the very end, when they de-orbit it.)
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> Wouldn't a space with no material in it have a much lower density? It would! The problem is the materials we have that could support such a vacuum chamber without it crushing are too heavy for the displacement of the vacuum. If we somehow had a magical material which wouldn't collapse under the pressure but was light enough for it to support then it would work, but we don't have anything like that.
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a difficult high school physics forces question
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I'm in AP Physics and we have never had a single question like this, nor do I think such a question even appears on the exam. This is nuts.
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From experiments. F=ma is a definition of force, but you can observe that forces always come in pairs: If body A exerts a force X on B, then B also exerts a force X on A in the opposite direction. You can test this with thousands of different objects and mechanisms for transmitting the force until you are reasonable sure that this is always the case. To find G, measure the force between two masses in the lab. F=G m1 m2 / r^2, or G = F r^2 / (m1 m2). Repeat this with as many objects as possible to verify that it always works.
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Where did the 60's get their smoking habit from?
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Do you have any sources citing that tobacco use was more prevalent during the 60s than previous decades?
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Invention of smoking is prehistory, not history. No one will give you a definitive answer, that's like asking why people started drinking fermented juice. People have burnt countless grasses and woods over the millenia of fire use. They could've used cannabis as tinder, they could've burned it to clear fields for crops or they could've experimented with aromatic grasses to keep insects away or improve the air quality of their dwelling.
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War of the Roses armour: black?
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Black armor was actually very prevalent in European history. For example, the "Black Prince of Wales" was allegedly thus named for his black armor, although this is only one explanation and the name only came up after his death. In any way, that it is one possible explanation for the name already shows that black armor was indeed used and worn and is no artistic license. Blackening is actually fairly easy and is done by oxidizing the steel, mostly by means of applying oil (a commonly available oil for this would have been linseed oil for example) to the armor and then heating it. This did not need a very intense heat to start an oxidizing process, about 300°C are enough. With the right oil and technique, even a "cast iron" look (so really dark black) was achievable.
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So the unanswered question remains... how would he have made black armor and was black armor common or is this just fiction making things more interesting?
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What is the patch worn just above hitlers arm in this .gif?
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The badge on his arm represents the Italian fascist party, he is wearing it because he is visiting his fascist ally Mussolini.
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That's the Belgian War Cross. It was given to soldiers and civilians for showing bravery in actions against the enemy. On second sight: some things are off. The cross is not exactly the same (_URL_0_) and the middle figure should be a rampant lion or the Kings sigil (two stylised L's with a roman numeral 3). So it's likely a prop based on the War Cross.
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How does an snes game get converted into a ROM and played on a pc?
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Through a process called ROM dumping. A special adapter called a ROM dumping device is used to copy the full contents of the read-only memory (ROM) chip found in the game cartridge onto a computer. An example of this device can be found [here](_URL_0_).
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Ingenuity and technical prowess. SNES in particular had specially designed chips that actually went into the cartridges after the SNES core system was developed that were able to boost the overall capabilites of the system itself and render items that would appear to be 3D even. Games that truly accomplished this and improved upon the system were like Donkey Kong, Yoshi's Island and Starfox, where the abilities created for use were amplified by use of specialized chips and software. The SNES and PS1 were technological behemoths in their own right, and even though the Sega models had more power, the developers did less with them and were not using the system to its fullest extent.
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Why, if you yawn while you’re humming softly, does the sound of your own voice become so amplified?
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When you yawn, your Eustachian tubes open briefly, allowing the sound from your throat to travel up into your ear canal more easily. Thus amplifying the sound.
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When you yawn you tighten your canal muscles, which move the blood vessels to a position where the noise inside those blood vessels can be conducted into the inner ear producing that particular sound.
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Why are ranks not standardized throughout the US Military branches? If put in mixed-units, do higher ranks of one branch have command over lower ranks of another branch?
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Ranks are standardized throughout the US Military. Enlisted ranks go from E1-E9, officer ranks go from O1-O10. It's just each branch calls each one differently. In the Army an O3 is a captain and an E7 is a Sergeant First Class, while in the Navy those two ranks would be Lieutenant and Chief Petty Officer. There's no real need to change the names. There would be very little to gain. Plus, a lot of the nanes are tradition and based on history of those armed services.
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In the US and Canadian Navy, Commander is junior to Captain. In NASA, the Commander *is* the captain. In the US Army, there is no rank of 'commander' (though there is a Captain) but like with NASA commander can be a term for 'guy in charge.' As far as 'more accurate,' different organizations have different terms for their ranks. Since these are fictional organizations, they can structure as they want.
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What are penny stocks and are they worth investing into?
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A "penny stock" is a security that trades below $5 per share, is not listed on a national exchange, and some other stuff too. The advantage of such a stock is that you can buy a larger number of shares and (since the prices are so low) any fluctuation in the price is going to be a larger by percentage. If you buy 20 shares of a $1 stock, and the price increases by $1, you have a 100% return on investment (+ $20). If you buy 1 share of a $20 stock, and the price increases $1, you have a 5% ROI (+$1). The disadvantage is that companies that trade at such low prices do so because they are not highly valued, and there's a good chance that most of those stocks go nowhere as the small companies fail and fold. Like any stock, they are a risky investment. You should never buy (any) stock with money you cannot afford to simply light a match to, since that could very well be what you end up doing.
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[Penny stocks](_URL_1_) are very cheap stocks that are not listed on a major stock exchange, but rather are traded "over the counter"(_URL_0_). They may be companies that haven't started turning a profit yet, or aren't "ready" to be traded on an exchange. They are extremely risky investments because usually the probability that the company will actually "make it" and increase in value is very low, and the price tends to be very volatile. In addition, the lack of a stock exchange to supervise trades results in less transparency and more susceptibility for the investor to end up getting tricked or scammed in some way.
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Can Euros who sing English songs speak fluent English and why do they sing English songs in the first place?
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1. Usually. The level of fluency depends on how much they tried to learn, but most will know at least some English. 2. Because it's the *lingua franca*, meaning that it's the common language used worldwide for groups of people to communicate when they speak different native languages.
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maybe because it's such a distinct sound you cant really ignore it. If someone is talking in English you can completely understand them, you'll only listen to them if they have something that catches your interest. When someone from a foreign language speaks, you do not know what they are saying and just hearing pronunciations you do not usually hear will catch your interest. Thats my guess. Foreigners also talk very loud too so that could be part of it
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What is the difference between Christian and an evangelical Christian?
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As a Christian, I've heard the term used in a few ways: 1. To denote a Christian more active in *evangelism*, or spreading Christianity through preaching. 2. To denote a Christian more culturally/politically active; that is, one who tries to align their surrounding culture with the precepts of Christianity (to varying degrees). 3. To distinguish more-loosely-organized protestant groups (e.g. Baptists, Methodists) from more-ecclesiastical protestant groups (e.g. Lutherans, Anglicans) and Catholic/Orthodox groups.
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They are conflicting today, but there was no Christianity until it was invented. To be Christian is to believe that Jesus was the prophesied Messiah of the Jewish religion. So then there were the Jews who disbelieved and the Jews who believed what Jesus was saying is true (now called Christians). To use a more modern example, Joseph Smith was a Christian. Then he started the Mormon religion and became a Mormon. Think of these as branches on a tree and the instigator of each religion being the point where the branch starts.
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Why does alcohol make me awake and nicotine make me sleepy even though alcohol is a depressant and nicotine is a stimulant?
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Alcohol although a depressant, spikes your blood sugar which gives you energy. Consuming nicotine reduces anxiety making it easier to fall asleep.
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Talking about drugs as stimulants & depressants isn't the most helpful way of understanding what effects they have on people's behaviors. A stimulant makes *something* in your body act up & a depressant makes *something* in your body slow down but that doesn't mean they make *everything* change. Alcohol slows down the part of your brain that stops you from doing stupid things in public. Normally you wouldn't take your pants off & run across a football field or call your ex-GF at 3am because you think of the consequences of those actions. When you're drunk, you're not longer inhibited. Similarly, nicotine stimulates the part of your brain that says "good job boy, you just finished doing something good" which releases chemicals into your brain that make you feel good & lets you relax.
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When sound waves interfere in air, they create beat frequencies. Does this also happen when electromagnetic waves interfere in space?
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Usually when people talk about the "beat frequency" from sound waves interfering, they are usually just talking about the apparent amplitude modulation that occurs when two slightly different frequencies drift in and out of phase, rather than the nonlinear interaction that produces new frequency components in the resultant signal. For electromagnetic waves, the linear interaction type of beat frequency will still of course occur in vacuum (or resonant cavity or waveguide). But nonlinear distortion effects will not occur. Note that in a nonlinear medium, distortion products are also produced even when the excitation is just one pure sine wave. In that case they are harmonics of the original frequency. Also note that the sum and difference frequencies are only two of the many frequencies that can be produced when intermodulation distortion occurs. For more on the linear "beat frequency" phenomenon in acoustics, see _URL_0_ For more on nonlinear intermodulation distortion, see _URL_1_
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All sounds are waves in a material. The wave is formed by compressing and expanding the material at some rate. If 2 things try to expand and compress the same piece of material then they will interfere. & nbsp; Imagine someone is pushing and pulling on you. You will shake around. If a second person pushes and pulls on you then you will only shake in 1 pattern that is the result of both people pushing and pulling on you. So interference of sound waves results in a new sound wave. So if you record all the pieces of a band and all their sound waves, you can combine them into 1 new sound wave that when played back sounds like all the instruments playing together.
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What happens to plants, seeds and bulbs when they begin germinating, sprouting, budding and flowering in February?
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It's a series of thermo-regulated systems, this regulation system is called **vernalization**, and some plant species strictly depend on it The plant embryo, contained within the seed, doesn't grow unless triggered to do so, since the nutrients contained within the seed's endosperm are just enough for the bud to develop enough until photosynthesis can supply it's needs. Thus, the embryo is held in stasis until there's an increase in temperature, to ensure that the nutrients in the seed will be used to grow in optimal conditions. As most seedlings will die if exposed to the winter conditions. The problem is when there's a heat spike in winter, which triggers those pathways, and prompts the seed to start developing, if a new cold wave strikes, the newly developed bud will freeze to death, kill a significant number of the crops, and lead to a poor harvest, thus, less money for the farmer, and less food for the people.
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Hormones. Abscisic acid and gibberellins to be precise. The first one promotes seed inhibition and keeps them dormant while the other one promotes seed growth. As long as the ratio is high enough the seeds won't start sprouting. Source: Myself, 6 years biology education.
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The difference between decriminalisation and legalisation
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you can still be fined for things that are decriminalized. You won't be sent to jail though.
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Yes. _URL_0_ To 'decriminalize' means to remove the criminal penalty for - it can still be a civil offense (like a traffic ticket) where you pay a fine, rather than facing a stiffer criminal penalty. Basically, Obama wants to make it so that it's not something you can be sent to prison for, but it's still not OK.
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Question on the use of armored trains during the Russian civil war
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Did somebody say "armoured train"? It's not often that we get an excuse to resurrect this classic post by /u/Georgy_K_Zhukov * [What is the point of Armored Trains?](_URL_2_) Also, here's a follow-up post [What was the tactical purpose of the armoured train?](_URL_0_), and an older comment by /u/LaoBa [How effective were armoured trains as a fighting force?](_URL_1_) Unfortunately, none of the threads seem to address the issue of track wear & tear and maintenance (aside from destroying them on purpose), so hopefully someone can chip in here with some info on that aspect.
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Saboteurs certainly could attempt to derail the train. There's the famous incident that occurred when Boers derailed part of Winston Churchill's armored train during the Boer War with a boulder placed on the rails. Enough people with enough brute strength can rip up a railroad (e.g. "Sherman's neckties" during the American Civil War). But it's not easy to do and you need time and large numbers of people. That not something every commander has. Nor do they necessarily have the explosives to do the job. So armored trains had a certain utility for internal security against lightly-armed partisan forces or small groups of enemy troops. Plus, if you control the railroad the train will be moving on (say, in the case of a fighting retreat), an armored train can be a mobile, heavily-armed, and well-protected means of fighting a rearguard action. The Poles used armored trains for this during the 1920s against the Russians *Winston Churchill "My Early Life" *Steven Zaloga, "Armored Trains"
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What did people with bad vision (pre invention of corrective lenses) do to survive? How were their lives? Did they die younger?
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Just to add another question, how were glasses discovered? How did people figure out that using glass would fix your eyesight? And how accessible were glasses? Could a farmer get a pair?
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Not necessarily. People with poor eyesight could have had a functioning role in most organized societies even back in the caveman days. Rather than go out and try to spot wild creatures to hunt, even a functionally blind person could help to skin and stretch and dry pelts for leather, or later on to operate a loom. And once we got to agrarian societies, making beer or threshing grain were ways you could earn your keep. And those poor-eyesight people would have wanted kids too. One other point: ~~a lot of our bad eyesight is caused by our habits, not by our genes.~~ As we age, our eyes change shape, and *that increases the odds we'll need glasses and have lower quality vision. More of us are living longer and there are more older people around, so eyeglasses are becoming more prevalent* ~~we can accelerate it if we spend all of our time staring at a computer screen a foot or two away.~~ *Edited for accuracy.*
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When you are fingering a girl, why do some vaginas feel pretty smooth inside while others feel quite rough? [NSFW]
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The vagina is mostly muscular tissue that can stretch enough to accommodate childbirth. All that extra tissue has to go somewhere, so when the vagina isn't stretched out (most of the time) it sort of folds up into wrinkles. The folded wrinkles on an organ are called rugae (other organs have them too, most notably the stomach. Scrotums as well - wrinkled up when cold, let it all loose when warm). The amount of ridging and where it occurs varies from person to person. The vagina will be roughest/most textured when not aroused and will be smoothest when aroused or in childbirth. Not every woman will be totally smooth when aroused, though. Women whose vaginas feel more smooth are either more aroused at the moment or don't have as pronounced rugae for whatever reason. The g-spot may also have a slightly different feel to it.
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Yes, it's normal. Females produce variable amounts of liquid from both the lining of the vagina (the bit inside, not the vulva which is the proper name for the outside parts). Also there are glands near the outside of the vagina which produce varying amounts of liquid. The function of this is lubrication when intercourse is taking place. Health risks, not really.
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How do internet searches work with non-Roman characters?
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> How does a search engine interpret these characters and find relevant results? A search engine doesn't care what the string of characters are that it is matching. It could be matching real words or nonsense strings, and as long as it recognizes the kanji as characters then it will work just fine. More complicated would be for the engine to draw connections between the English version of the kanji sequence and return similar results for either one.
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It uses Unicode modifiers to add all these crazy accent marks and stuff to normal characters. In other words it's actual text.
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How far behind a semi-truck would I have to drive to take full advantage of the wind-drag shadow it creates?
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Just to build off this idea, while it seems that driving that close to a truck is too dangerous to do in practice, it has become an idea that may allow early integration of robotic driving cars. The truck starts a convoy of cars behind it that are all networked and computer controlled to minimize air resistance and maximize speed. The computer controls are supposed to make up for the dangers of letting humans drive that close together that quickly. I believe it's this [SARTRE](_URL_0_) project.
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No - the main reason would be less air resistance, because the car is in the truck's [slipstream](_URL_0_). I'm tempted to say there might be less friction due to fewer tyres on the road (if the car is on the truck, rather than being towed), but there would be increased friction on the truck's wheels due to more weight being put on them, so the net effect is probably zero for that.
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What is up with bath salts and why they make people go absolutely fucking crazy
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Bath salts is simply a euphemism for recreational drugs, often research chemicals. They operate in a sketchy legal area as it is so they call them 'bath salts' or 'plant food' to emphasise that they're 'not' for human consumption to attempt to avoid legal issues. Bath salts in general are typically chemical analogues of more well-known illegal drugs like MDMA. The daft part is despite being legal, they're often more dangerous than their illegal counterparts because there has been far less research conducted on them and less people have taken them.
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Selection bias? As far as hallucinations from 'bath salts' go, it is a blanket phrase for dozens of research chemicals, mostly stimulants. With any stimulant you can reach something called "stimulant psychosis" after being awake for days. It would happen to someone sober (albeit less intense) if they were awake for a few days too. It causes paranoid delusions and hallucinations...and this is why the 'bath salts' are being called hallucinogens (not to say there couldn't be some random chemical in one brand). And guy who ate the face, we'll have to wait for a toxicology report to see what he was on, but he could have easily been insane already and just pushed over the edge.
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Do black holes have an escape velocity?
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> Or is this a nonsensical question? Bingo. I know you mentioned "what if + time travel," but entertaining these miss the point of physics because they disregard physics entirely. In any case, as long as you kept outside the horizon you would have an escape velocity. Once inside, well shucks.
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Sure. In fact, it cannot "not travel". There is no absolute velocity in space. Everything moves in most reference frames. > And if so, could we detect its motion by measuring the change in radiation from the accretion disc? It doesn't change. the position of the accretion disk is at rest relative to the black hole. The position of the black hole in the sky can change over time. There can be some red- or blueshift from radial motion.
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How does lung function vary between a daily smoker who is very physically active, and a daily smoker who lives a sedentary lifestyle?
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There's surprisingly little solid info at my hands about this at the moment. [Basically,](_URL_0_) as expected, active smokers have lower heart rates than sedentary smokers. This isn't quite the answer to your question but it's a start. I have some more literature, just going to take some time to find, if I'm recalling the right things. That said, I recall one about [grain workers](_URL_1_) and shows that the sedentary workers have poorer lung function than the active ones across all measures. There's a high degree of individual variability though, and this will be more pronounced in smokers I think. Occupation can play a huge role in our lung function.
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This depends on far too many factors to be truly answerable, IMO. How obese? How much smoking? How do you compare the two? How many pack-years correlate to each extra pound of weight (or whatever)? What other conditions are in play? What about interaction of the two? I'm a lung guy that spent a decade working on COPD, so my bias says smoking is worse. But that's wildly speculative bias...and about as good of an answer as you can really get, I think. And it's a shitty useless answer.
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I'm the 3rd son of the 3rd son of the 3rd son of an earl in 16th century England. Am I still a member of the gentry, or would I be a farmer or tradesmen living hand to mouth like any other commoner?
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I'm afraid you are simply out on your keister. Even if you were the first son of the third son you'd be out of luck. Your grandfather as the son of an earl would be referred to as "the honorable" when addressed in the third person but he wouldn't actually have any special rights or privileges otherwise. I found a wonderful website where you can read up on [courtesy titles](_URL_0_)
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In Sweden from the late medieval era to 1866 (when the estates parliament was abolished), the peasant estate was represented by the self-owning farmers (which owned between 1/3 and 1/2 of the arable land of Sweden depending on when you take a look). To be a self-owning farmer meant that you owned something valuable to pass on to your children. You were middle class. Tradesmen in the towns were represented as burghers in the estates parliament and owned the right to have a trade in the town and trade with foreign countries, a right which was also inherited. A tradesman on the countryside were often a crofter (who did not own his land) with some skills. He could not pass anything on to his family and would be considered lower class.
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How are military systems like fighter planes protected from backdooring or other neutralization against their original country of origin?
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These days a backdoor would almost certainly be implemented in software and at least some buyers are able to negotiate access to source code as part of the purchase agreement. I believe that the F35 falls in this category because the other countries are considered to be co-developers rather than just buyers and in some cases have unique capabilities built just for them. I suspect that this applies to a fairly small number of contracts but when it does it gives the buyer an extra layer of protection.
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I'm not sure about all these people claiming there was no security at all pre-9/11, there most certainly was (there wouldn't be scenes spoofing it in the Airplane! movies if there was no security...). Hijackings and bombings were certainly a thing before 2001. I recall a school trip in 1989 when one of my classmates made a joke about having a gun when going through security and getting a very stern talking to from the Airport Security person. There was little in the way of centralized authority, however, most airports contracted out their own security force, so details would be different from airport to airport, and would often be not too much above Mall Cops. Typically there would be a metal detector you would go through, possibly an x-ray for carryons. However, there was no checking to see if you had a valid boarding pass. If I was dropping someone off or picking someone up, I could go right to the gate myself, even though I wasn't flying that day.
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Why a humidifier doesn't use as much energy as an electric kettle?
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A kettle's job is to boil a whole lot of water very fast. A humidifer's job is basically boil a small amounts of water slowly. The amount of energy used to boil 1L of water in a kettle dry is the same as the amount used by a humidifer to use up 1L, however a kettle will use all that energy in like a minute, whereas the humidifier will take hours. So working it out as energy / hour (which is what we call "power") the kettle use much more.
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Taking the question further, how about an electric kettle?
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Why does getting a massage make you feel good?
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A few reasons. Firstly because massage relaxes the muscles, reduces discomfort/ pain (by pain gating mechanism through the spine), promotes blood flow and helps to strengthen the muscles and joints. It's beneficial effects also include endorphin release in the brain, which is similar to morphine (= relaxation, well being, bliss) Secondly, massage has evolutionary roots. Grooming is part of our ape + developmental past and it clearly *still* helps with personal/ group bonding and the additional psychological benefits.
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The muscles have worked themselves into remaining tense. A massage forces the muscles to relax and untense. This relaxation reduces following fatigue and allows the muscle to recover.
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Why did the French never emigrate en masse to their colonies like Britons, Spaniards and Irish did?
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As a starting point, you might consider my earlier answer to "[Why did so few French (comparatively) move to America in the 19th century?](_URL_0_)"
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On a related note, why are many former French colonies so fucked up? Vietnam...Haiti...Louisiana...
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How did we know that the moon had weaker gravity than earth before visiting it?
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Scientists had a working theory of gravity well before humans travelled to the moon. Sir Isaac Newton pioneered the theory of gravity in the 1600s, and the equation used to model gravitational force, F*_g_* = GMm / r^2 , was known far before the moon landing. The fact that observations made by astronauts on the moon matched the predictions made by scientists using this theory strengthened the theory's credibility.
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It's the other way around. When you're on the part of the Moon that is closest to the Earth, the gravity of the Earth pulls you in the opposite direction as the gravity of the Moon, so it partially cancels out the gravity of the Moon. When you're on the other side of the Moon, far away from Earth, both sources of gravity work in the same direction and add up. The effect is very small though, on the surface of the Moon the gravity exerted by the Moon is about 500 times stronger than the gravity exerted by the Earth. You could measure the difference with a reasonably accurate scale, but you won't notice it otherwise.
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Do we know who built the Chinese pyramids?
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Yes, the Chinese did. In all seriousness, the Chinese pyramids are elite burial mounds, quite a few of which have been investigated archaeologically. As a burial practice it had a fair amount of staying power--the earliest ones date from the late Zhou Period, while for the emperors (for whom tradition was very important) tumuli continued to be built into the Ming Dynasty. Does this prove a connection with Egypt? No. If nothing else, there is a fair amount of chronological difficulty, with the Egyptians having stopped pyramid constriction roughly one thousand years earlier. But also keep in mind that we have an enormous and varied literary record from China, and so this isn't some "mysterious" civilization. Had there been a bunch of Egyptians wandering around, we would have heard of it.
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You're right on with the skyscraper comment. When people say we don't know how they built the pyramids, it's not because we're dumbfounded as to how they did it. It's not a free response question we're staring at blankly, it's a multiple choice question with three possible responses and research supporting each. There's no secret about it- it's just something people stopped doing, so no one needed to know the exact construction method. Pyramids went out of style ~2400 BC, though there was bit of a revival 400 years after that. The underground tombs, such as those in the Valley of the Kings, were secluded and more protected.
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when i light up a stove, why doesn't the flame follow the pipe to the source?
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When you ignite a flammable gas the flame front can only travel at a certain maximum velocity for that specific mixture. If you look closely at gas burners the outlet of the pipe is always pinched. As gas flows through this pinch point its velocity increases such that it is moving faster than the velocity of the flame front. As the gas slows down combustion is allowed to take place. This holds true even if you mix oxygen with the flammable gas prior to ejection out of the burner, as long as the velocity of the gas at the burner outlet exceeds the speed of the flame front then combustion cannot move inwards toward the source.
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The heat coming off the flame distorts the air thus affecting the path of light between you and that object. _URL_0_
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Online shoppers in the US, how does sales tax work since each state has a different rate?
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The states vary of course, but the general rule nationally is that online retailers have to collect sales tax from a purchaser in a state where the retailer has a physical presence. That might be a brick and mortar store or just a distribution center. There are companies that specialize in providing up-to-date sales tax rate info for all 50 states and countless localities so this is not difficult, just a matter of accounting. Many states have, and have had for ages, laws about interstate purchases and a requirement for self-reporting, but they are pretty much completely ignored by private individuals. It should go without saying that most all states want in on all that cash they are missing out on.
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Tax is the main one i think. In U.S. you are supposed to be responsible on paying the tax for the stuff you buy online. You are supposed to pay the sale tax for your state on the item. Few people do. Hopefully someone from US can answer more accurately than me.
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Confused - 'Slices' of spacetime based on relative motion, and the relativity of simultaneity.
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This is one of the astounding consequences of the theory of relativity. Simultaneity is not something that is valid valid in all frames of reference. Contrary to everyday experience two things do not either happen simultaneously or not, it depends on the frame of reference of the observer. I just saw that there is even a Wiki article on this with the same example (minus the Simpsons characters) _URL_0_
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You are always moving at the speed of light in 4 dimensional spacetime. Your speed in the 3 space directions plus your speed in the time direction always add up to c. Normally all of that speed is in the time direction, but if you move really really fast you take some speed from the time direction to go in one of the space directions so you slow down in the time direction.
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Government Encouraging Marriage
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It's not so much marriage that they're encouraging as being a stay-at-home spouse. There's only really a tax benefit if one person is making most of the money. If the two people make even close to the same amount of money, they pay less in taxes by filling separately.
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Marriage is not just religious, also lawful. By not allowing people with certain sexual preferences to get married, it is a form of descrimination and thus an equality issue.
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If a test for prostate cancer has 75% false positives, would it be more accurate to just flip a coin?
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Ok, so let's say that a group of 10 men get a regular prostate exam, and 4 of them test positive. You now have 6 people who you know don't have prostate cancer, and 4 people who might have it, and need more testing to be sure. Now let's say you just flip a coin. Half the men get heads, half the men get tails. So now you have 10 men who have no idea if they have prostate cancer or not, and they all need more testing done.
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There is always a false-positive rate with a test, and these false positives can cause more problems than the test solves. A good test like this might pick up 90% of persons with the cancer, but also trigger on 10% of people who do not. If the cancer only shows up in 0.1% of the population, then for every person that you detect with cancer, you'll also misdiagnose 111 persons without it.
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Are daily vitamins really that necessary to take?
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Some vitamins are not water soluble. For instance, you can take a great deal of vitamin C. You’ll just pee it out. (Extreme doses can cause some discomfort.) However, vitamins A,D,E and K along with others can be very dangerous when misused. Overdose can occur and can have issues from skin discoloration to death. The MOST anyone should need, unless recommended by a doctor, should be ONE multivitamin per day. Chances are you’re getting enough from 3 meals, but if you have bad eating habits, 1 per day is plenty. EDIT: Some replies below mentioned some mild discomforts from too much vitamin C, so I’ve changed it from “as much vitamin C as you like”, to a “great deal of vitamin C”.
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If you're otherwise healthy, [vitamin supplements may not do much for you](_URL_1_). The vitamins contained in a pill may [differ from those in food](_URL_0_) based on type and bioavailability. The other reasons that vitamin supplements are not ideal is that they are not controlled the way medication is. That means that the content of a pill may vary wildly from what is specified on the bottle.
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The difference between a police officer and a sheriff?
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A police officer is usually districted to a certain town/city. For example, RPD - Raleigh Police Department. A sheriff is usually districted to a certain county. They serve the same purpose, but their jurisdictions, or areas they're in charge of, are different. Not every part of the county is fully controlled by a town/city, and the county has control there. Also, if a crime crosses outside a police district's jurisdiction, it falls onto the sheriff's plate. If it crosses county lines, it falls onto the state trooper's plate. If it crosses state lines, it falls onto the FBI's plate.
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Sheriffs are elected law enforcement officers (LEOs), often under the jurisdiction of the courts. Police are LEOs under the jurisdiction of the local executives -- county board, governors, etc. Their jurisdiction is a function of where they're located and who they answer to. Highway patrol LEOs are usually state police, with jurisdiction through an entire state. Every type of LEO has a different boss and a different goal. They work together, but their objective and reason for being is different.
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Why can’t you use steroid cream for more than two weeks at a time? Surely it wouldn’t dry out your skin, because it’s in a lotion?
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Your skin thins out while you use steroids making it easier to cut and get infected. Your body can also become addicted to steroids causing 1+ year of painful withdrawal (see Red Skin Syndrome)
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Lotion actually creates a layer on your skin which stops water from leaving the body, so instead of a continual "leak" of water it accumulates and makes your skin appear fuller. Try YouTube I've seen some good videos on this for school projects.
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why is the "no-smoking" sign still fitted on new aeroplanes?
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I imagine it's to prevent the inevitable lawsuit of someone smoking on a plane "because no one said I couldnt." The same reason there are warnings to not put plastic bags on your head.
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Who told you that smoking affected aircraft instruments? Maybe you are talking about electronics? I was an Aviation Electronics tech and I've never heard this.
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What exactly are Jewish settlements and why do the people of Palestine hate them so much?
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They are communities of Jewish residents built on land that is part of Palestine. In many cases they have displaced Palestinians in order to take the land. The goal is to make the land part of Israel, the reality is that it is fragmenting the land that should be Palestine into tiny islands that will be unmanageable. They are doing this in direct violation of previous peace agreements and UN resolution. Both sides have elements that are doing everything they can to insure the continued violence and needless deaths, in the US we focus on the violence of the Palestinians while ignoring if not outright supporting tha of the Israelis.
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Part of the Israeli perspective is not just about that specific piece of a land, but some kind of land at all. After the Inquisition, crusades, Holocaust, scapegoats during the Plague, ghettos, etc. Jews didn't feel safe anywhere. The Holocaust was the final turning point. Over the last thousand years, they've never had a real home, just lived in European ghetto districts or scattered throughout other countries. A lot of Jews are told that no matter what, you are always welcome in Israel (look at French Jews right now fleeing to Israel). With the large amount of Muslim States in the world, and the relatively small size of Israel, Jews feel strongly that it needs to be a Jewish State so that Jews always have a place to go. Arabs/muslims, Christians, etc. can live there too, but it has a be a Jewish state for the reasons above.
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The biological and physical process that things like fire flies make light?
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It's called bioluminescence. Fireflies have an enzyme named luciferase which reacts with luciferin in the presence of magnesium ions, oxygen and ATP (Adenosine Triphosphate) to emit light. Its helpful in keeping the predators away as the chemical has a terrible taste. Also, the male fireflies glow to attract the female fireflies, and sometimes the female glows to call a male, and eat it. Other than that they glow to lure other insects, and they become the prey.
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It gives of light for the same reason any object does. It isn't special. Light is emitted when an electron gets bumped. In a light bulb flowing electricity (which is electrons) bump and hostile the electrons of the material that compared the light filament +or gas) Fire is created when a chemical reaction involving oxygen combustion occurs. When these reactions happen the molecules are violently ripped apart by the oxygen, and snap apart as other oxygen comes barreling in to laugh onto the atoms that used to make up the molecules. This violent set of collisions bounce around the electrons in those atoms, and nearby ones. This released light photons.
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How can mothers and babies have different blood types?
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There actually isn't blood transfer directly from the mother to the fetus. Blood vessels from maternal circulation are arranged very close to the fetal circulation within the placenta which allows oxygen, nutrients, waste products, etc to cross between the two by crossing venous/arterial walls but they are not connected. See more with diagrams: _URL_0_
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The genetics of your blood type cannot change. But in some situations it's possible for the expressed antigens to change, which means the measured type will show up different on a test. For instance, if you ever had a bone marrow transplant, your blood would change to match the donor's because blood is made in the bone marrow. It's also possible for the antigens to change in some kinds of autoimmune disease, or other very rare situations. However it's much more likely that one or the other result was a lab mistake. Clearly there is something unusual going on, because it is normally not possible for a type O parent to have a type AB child.
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Why do amnesia patients lose their identity, but not motor functions? Such as their ability to walk, talk, ect..
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We have many different types of memory. In this case the important distinction is between episodic and procedural memory. The first is the memory of stuff we personally experienced, the later is on how you do stuff. This division is rather handy as it allows you to ride a bike without thinking about all the times you fell down as a kid, learning how to ride a bike. Anyhow these types of memories are independent and can be damaged separately. One interesting case is patients with anterograde amnesia, that is they remember everything up to the accident but they can't form new long term episodic memories, just like in Memento. They can still acquire new skills. There has been a case there as an experiment a patient like this learned to play chess, and developed a certain level of skill in it, but still had no memory of actually playing.
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Like when a diner has a lot yellow and red throughout... It reminds you of mustard and kept hip then suddenly your craving a tasty hamburger or a nice juicy hot dog... Lucky for you this diner makes those. Or hospitals are mostly white and light blue... Calming and clean colors. To promote a calm environment. If you work nights you may want to paint your room dark colors to help mellow you out for sleep during the day. Colors play a lot in our mind. Red can make a person angry... A lot of kitchens get that sunshine yellow. Colors can help jar a person's memory too like smells and tastes. These things get used when dealing with amnesiac patients too. Using the senses psychology to grab a memory.
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Why do dogs feel the need to obey their masters?
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Dogs are a bit like marines. They don't question orders, they just carry them out to the best of their ability.
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It's actually learned by them. Haven't you ever seen dogs who prefer not to be touched? Well, if you have, it's because human contact was never associated with something good early in their lives. For dogs who like to be petted, human contact usually meant playing or cuddling or treats. For dogs who do not like human touch, they were either not socialized, abused, neglected, etc. Dogs learn through classical conditioning. They associate one thing with another. If a dog associates people and petting with good things, they will learn to enjoy it. If it associates petting with bad things, they will shy away from it. Edit:Classical Conditioning _URL_0_
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How often do new stars appear in our observable sky?
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These processes are so slow that human history hasn't been long enough - nowhere near - to notice new stars forming, or older ones disappearing. The exceptions are novae and supernovae. Those explosions happen very quickly, and many are seen every year, although it's been a long time (centuries) since one happened nearby enough to be a big naked-eye-visible event.
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No, most stars that we can see with the naked eye are within a few thousand light-years of us, and stars last billions of years.
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How do tire balancing beads work to balance a tire?
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Well, They don't actually balance it the same way that weights balance it. The beads spread out as the tire rotates, drive by the tire's rotation. When the heavy spot on the tire moves the wheel in one direction, momentum carries the beads the other way, until they spread out in a "balanced" layer. that's a layer such that spinning the tire doesn't cause vibration - aka balanced. This works great on tires with tall aspect ration like tires on semi trucks. Car tires are often low profile, and then the up and down effect is smaller than the lateral (tilt from side to side) balance. Cars and low profile tires still need computer balanced static weights.
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The tire bead makes an air tight seal where the tire contacts the wheel. The tire bead is made of a strong braided steel cable loop that is covered in rubber. The rubber makes it air tight, the steel makes it strong enough to not blow off of the rim.
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Why is the "Croatoan" mystery so heavily talked about?
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It's a good ghost story, in the typical version - "Settlement vanishes, the only clue is the mysterious word CROATOAN carved into a fencepost". It's not much of a mystery to people who have done research on the area, though. The Roanoke colony was friendly with the local Indians, who had a settlement on the nearby island called Croatoan. Nobody ever got around to checking if they moved there, but reports from other settlers in the area mentions that tribe of indians had white members, built two-story stone houses, and spent the next hundred years telling people they had white ancestors, and showing off their European eye colors. And archaeological digs on the island have found European artifacts. "They moved" is just a much less interesting story than "they mysteriously vanished ooOOOooooOOO".
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It's one of those things that really isn't that much of a mystery unless you try to describe it with imprecise wording.
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Why do schools still insist on standardized tests even though all the teachers and students find them to be dumb?
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Pretty simple. Because they are easy to grade and organize students based on a score. There are much better ways to gauge learning, but they require a lot more time and effort than filling in bubbles and running them through a machine.
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> What's the point of having a class so difficult that 50% becomes a passing grade? It allows the professor to accurately judge the performance of top students in relation to each other. If two students both get 100%, then all you know is that both of them are more proficient than everyone else, but you have no idea how they compare to each other. Making an exam so difficult that no one can get 100% allows a better understanding of how *all* of the students are performing.
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Why do physicists say that a photon has zero rest mass instead of saying that a photon doesn't exist at rest?
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A better term than "rest mass" is "invariant mass", or just "mass" (since "relativistic mass" is an outdated concept). You may have seen the equation for the relativistic energy of a particle, E^(2)=m^(2)c^(4)+p^(2)c^(2). If we re-express this equation as E^(2)-p^(2)c^(2)=m^(2)c^(4), we find that we can express the mass of a particle as a function of the particle's energy and momentum. The important point is that, even though the Energy and momentum will be different in different frames, this calculated mass will always be the same, hence "invariant mass". For photons, the energy is always E=pc, so their invariant mass is zero.
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If you're at all familiar with Einstein's theory of Special Relativity, you're probably used to seeing the equation E=mc^(2). That's not actually the full equation, which is 𝐸^(2)=(𝑚0𝑐^(2))^(2)\+𝑝^(2)𝑐^(2) where p is momentum, and m0 is it's rest mass. Since photons have no mass, it can be reduced to E=pc. Since photons have energy, and the speed of light is constant, we can confirm that photons do have momentum, even without mass.
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Why don't we find fossils everywhere?
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There need to be special conditions so fossils get formed. The fossilization process has to happen before the body gets eaten by bacteria and such which usually take care of dead bodies.
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Because early human populations were small and they lived in regions that were not physically conducive to fossilization.
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What would happen if the owner of a major company such as Mc Donald or Wal-Mart just decided to shut down the franchise one morning?
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If it were privately owned by one person or a small group of people, sure. For example, White Castle, it's a burger chain that is owned by a small family. If they decided to shut everything down, they totally could. Walmart, McDonalds, and most other companies that you interact with on a daily basis are *not* privately owned. They are publicly owned. There are hundreds of thousands, probably millions of people who own the company. If you want, you can become an owner of McDonalds or WalMart, all you've got to do is shell out a few hundred bucks for a share. If you're lucky and buy the right share, you'll even get some of their profits. Even if you don't, and the company does well, your share will go up in value and you can sell it for profit.
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From what I recall from economics class, the entire economy would essentially collapse and the country would shut down if many of those large corporations were left to die at the same time, due to multiple dependencies of the underlying economic infrastructure and critical systems which those corporations contribute to. When one large corporation closes its doors unexpectedly, thousands of jobs are lost and the economy is impacted. I will let someone a little more familiar with the specific details chime in on exactly how that type of scenario would unfold. Edit: Looks like the post got yanked. Oh well. Thanks for all the contributions to the thread, lots of good info here.
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What are the physics behind urinal design?
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May I direct you to 'The Bathroom' by Alexander Kira - the definitive work.
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It's called the latchkey incontinence. The brain signals your body when it sees things that remind you to pee!
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Where is the addiction/reward system field headed? It's easy enough to find broad overviews of the pathways and neurotransmitters involved in addiction and reward, but what new questions is the field as a whole investigating now?
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Re: addiction, [Karl Friston](_URL_4_) has a paper that's very cutting edge but requires a good amount of background knowledge to understand. See here: _URL_1_ For something on addiction that has more neurobiology talk, but uses more traditional theory, see this paper:_URL_3_ "Reward" is a fairly nebulous concept and is slowly being replaced by more precise terminology. Moreover, a lot of the popular science ideas about dopamine are probably wrong. For the most recent review of the field, see [this paper](_URL_2_). For cutting edge theory on dopamine and reward, see [this paper](_URL_0_).
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Short answer; Dopamine. I teach classes for a health organization and one is one addiction. I use this video to help illustrate what addiction is. It's kind of propaganda for the Wait21 group and has a message for kids/teens about substance use/abuse. Still, it's good info on the dopamine response and the formation of addictions. _URL_0_
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Why the TV show "How it's Made" censors some product names but not others
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Contracts. When the company that gave them permission to film makes products for several brands, the brand owners would have to give permission. Either it was too much trouble to ask or, more likely, they said no. When a company is filming manufacturing of its own products, the more free advertising the better.
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Two reasons: 1. Product placement. Companies pay good money for movies and TV shows to show their products, so the shows' producers wouldn't want to "give it away for free". They would also wish to avoid any possible legal and business complications if by any chance the company doesn't like its products appearing on a certain show or movie (even if it's legal). 2. [Viewer-Friend Interface](_URL_0_). Real life user interfaces are designed for people who sit closely in front of the monitor. They have lots of data. Showing something like that on a TV show would be confusing to the viewer - the display needs to be large and clear.
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If an airplane acts as a Faraday Cage, why can we still use 4G and GPS reasonably well inside (at low altitudes)?
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An airplane has windows which are large enough the 4G radio wave energy can pass through without being attenuated 'much'. & #x200B; Two things. & #x200B; Radio's can work 'fine' with extremely attenuated signals. In the big scheme of things being inside an airplane with windows doesn't effect the signal very much. One the other hand when you talk about a plane being hit by lightning. That's different. The aircraft skin being aluminum just shunts all the current around the passengers. Lightning isn't radio waves. It's direct current.
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It's a system designed to keep the phone as small and low power as possible. The FCC limits the amount of power a phone can radiate into your body. For GSM, a tower transmits at ~20 Watts (43 dBm), but your phone only transmits at 1-2 Watts (30-33 dBm). Since the tower and the phone have to talk to each other, the tower has to have a receive antenna that can hear signals that are 20 times weaker that your phone's receive antenna. The asymmetry increases the range of the communication while keeping the antennas in the phone small, cheap, and low power. The tower wants to be high in the air, that way it gets a clearer line of sight to the phone. If the antennas are up in the air people walking by will absorb less radiated power. Using the Friis transmission equation (which makes many simplifying assumptions), for a 1.8GHz signal at 20 feet, I get a loss of 53 dB. So your 20 watts of transmit power is ~ 0.1 mW at the ground.
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What is the difference between a migraine and a headache and what is the primary cause of them?
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A migraine feels like a hangover with a throbbing headache thrown in for good measure. When having one I have a lot of trouble focusing on anything and just want to shut myself in a dark room and sleep. It can last anywhere from a few hours to a few days and vary in intensity from a minor annoyance to truly debilitating. Excedrin migraine works moderately well.
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That's why it's called a headache, not brainache. There's plenty of receptors inside your skull.
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How much energy does it take to make an average LED indicator blink?
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Pulse forward current (pulsing 10% of the time with 1 ms pulses) is ~50 mA for a typical LED, forward voltage 2V. P = IV (kek) P = .05 A * 2 V = .1W But this is only 10% of the time, the rest of the time the LED is off... 100 pulses/s 100 pulses, each has .1 W going in at 1ms ~ .1 mJ of energy in each pulse. 1 mJ/s is 1 mW. Very efficient. To answer your question literally, it completely depends on how long it runs for. To run it for an infinite amount of time requires infinite energy.
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There's two things that use power for the flashing LED: The LED itself and the switching circuit. If the LED power is more than the power needed to drive the switching circuit it will of course require less power in total to flash the LED than have it constantly on. There can be many ways such a switching circuit can be made but in general they are not very complicated and do not consume a lot of power, thus for most LEDs in use it is more energy efficient to have it flashing. For instance, LED bike lights are typically reported to have double the battery life in flashing mode, e.g.: _URL_0_ (25 lumen constant: 1 hrs 40 min, 25 lumen flashing: 3 hrs)
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What is the oldest event we know the date of?
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The earliest event where we have a date which we can convert into the modern Calendar is the Battle of Megiddo which according to the Egyptians happened on the 21st day of the first month of the third season, of Year 23 of the reign of Thutmose III. Now converting that into the modern calendar we get the date of April 16th 1457 BCE. There are events that occurred earlier but the exact date is unknown.
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You may be interested in these questions from the past: [What is the earliest recorded date that we can determine accurately?](_URL_0_) [What is the oldest specific date we know?](_URL_2_) [What is the earliest reliable documented event in human history?](_URL_3_) Related: [Who is the earliest historical figure?](_URL_1_) in the AskHistorians wiki There's always room for more discussion, though, especially since these threads are quite old.
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Would a slow dripping tap be picked up on the water meter?
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> If there was very little pressure and the propeller inside the pipe was to stay open (-) not (|), would the dripping water be costing us any extra on our bills? A related question, isn't the water in your pipes always at full pressure? I thought that's why it comes out fast when you open the faucet.
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[This page](_URL_0_) has some data. For typical US tap water it seems to indicate a value of less than 100kΩcm.
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Does the body heat generated by humans affect the overall air temperature of the Earth?
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Heat generated by a human, about 100W. By 7 billion humans, 700GW. Heat from the Sun hitting Earth (which is over 99% of the heat energy affecting Earth) is about [173,000,000GW](_URL_0_) So humans are about 0.0004% of that. But we could also say that we get that heat energy from food, ultimately from plants, which got that energy from the Sun. The plants sucked up that energy, we eat them and expel it. Net effect is zero.
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Yes. Heat is not uniformly distributed throughout the human body. One's extremities tend to be cooler that our center of mass. Additionally, due to metabolism, attire, health and current activity, our bodies will vary in temperature over time. 98.6F is a baseline reference rather than a fixed state for body temperature.
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How come my allergy to cats makes me sneeze and my friend's allergy to peanuts can kill him?
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Both allergies are type one hypersensitivity reactions, which means that exposure to the allergen causes IgE antibodies to bind to mast cells and release histamine. The histamine then causes, among other things, the bronchioles to constrict, which cuts off breathing. The main difference in response is entirely caused by how much histamine is released, which is determined by how much of the allergen binds to IgE. The big difference between peanuts and cat dander is how you're exposed. You're only breathing tiny amounts of cat dander, while your friend is exposed to a lot more by eating peanuts. As far as i know no one has tried it, and i doubt it could be done without purifying it in a lab, but chances are you would have just as bad of a reaction if you somehow ate that much cat dander.
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Also want to know this. Used to be allergic to cats and fine around dogs. Now it's the opposite.
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What happens to the contaminated body fluids from Ebola patients? How do we dispose of it?
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Bleach kills the Ebola virus pretty quickly. It's also destructive to living human cells, which is why we can't douse contagious people with concentrated bleach, however once the fluids have left the body, bleach on. Heat, cold, and exposure to UV rays from sunlight also kill viruses, just not as quickly as bleach.
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It has a very high kill rate (above 70%?), but it's also pretty hard to spread (mostly just through bodily fluids). So it's far more containable. I wouldn't lose any sleep over it at the moment. I'm much more afraid of something airborn, like a 1918-esque strain of the flu. Ebola will kill a few Americans here and there before this outbreak gets snuffed out, but a 1918 flu could wreak havoc on even medically advanced nations.
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A book that explores the Balkan Wars and specifically the siege of Sarajevo
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Thread carefully. Being from Croatia I can tell you that most of the first hand stuff is still marred by a significant slant (for any side, regardless). And even things written by third parties are often politically charged and historically less then useful. If you are gonna study it, don't rely on any single text. I think Balkan breakup debacle is far too recent for serious historical discussion. If you need any direct first hand interpretation I may offer some insights, I'll try to be neutral about it but in the interest of full disclosure my stuff comes from a centre-left, anti-Communist, pro-US/EU position. However, I will recommend the movie "No man's land" (won an oscar for best Foreign Movie). Produced by a Bosnian team and featuring prominent Bosnian/Croatian/Serbian actors it is a surprisingly level headed look at the conflict which shares the sentiments of most people from ex-Yu; that our leaders fucked us over.
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Gavrilo Princip wrote a poem in his prison cell. There is a [link in Serbian](_URL_1_). Below is my impromptu translation of the poem Sarajevo 1914 Slowly the time is dragging And there is nothing new Today is same as yesterday Tomorrow will be too. And instead in war While battle trumpets are crying Here we are in a casamate Chains on us are rattling. Every day is the same life Trampled, stomped, crushed I am not an idiot This is death for me. The truth said [Žerajić](_URL_0_) before me Who wants to leave let him die Who want to die let him live.
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How does navigation in space work opposed to here on earth?
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In deep space, navigation is based on the location of highly visible stars. They become the "landmarks." There's no north or south, and no up or down.
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Well first, the magnetic field of the Earth extends far out into space, but that's just an aside. There are many more ways to navigate than just using a compass. Most spacecraft navigate using some combination of inertial guidance, star sighting, tracking from grounds stations, and or global positioning satellites like GPS. Astronauts also are almost never actually flying the spacecraft. It's not like driving a car. The entire launch and ascent is per-programmed and executed by the computer. Docking with the station can be done manually but it can also be performed automatically, and all other on-orbit and de-orbit maneuvers are done by the computer.
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