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How much does the moon affect the gravitational constant "g"?
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As an aside from the other answers, it's worth pointing out that "gravitational constant" normally refers to "big G", the universal gravitational constant that describes how fundamentally strong the force of gravity is. The value of 9.81 m s^-1 just describes the accelaration on Earth' surface, nowhere else. And even then, it's just the average value; it can vary surprisingly much! So be wary of calling it a "constant"! Edit: Yes yes, I mis-spelled gravity.
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In [Newtonian gravity](_URL_1_), and indeed in most every situation you'll ever encounter, the gravitational forces of two objects can just be added—so the gravitational force of a large object is the sum of the gravitational forces of its constituents. However, on very large scales, or in extreme gravity, it's necessary to use [general relativity](_URL_2_) instead. The equations of general relativity look pretty different from those of Newtonian gravity, and one of the consequences is that you can't just sum up the contributions of two objects. This isn't very relevant if you want to find the total gravity of the earth-moon system as seen by someone far away, but it's quite relevant if you want to predict what will happen if two black holes spiral to a collision. You may enjoy [this very accessible discussion](_URL_0_) of how all this works.
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why is 3G and lesser cellular reception often completely unusable, when it used to be a perfectly functional signal strength for using data?
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In addition to the relative data usage already described, the 3G network *is* actually worse than it was previously. The 3g networks are being cannibalized to increase lte coverage.
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Strong signal means you are close to the cell tower - so there's one/some in the subway. Slow data means either lots of people are all trying to use the data at once or the cell tower(s) have a slow connection to the providers Internet. It's likely that lots of people are using the data as most smart phones keep data connections open for push communications/notifications.
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How come people die when strangled, but are only knocked unconscious when put in a sleeper hold?
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Because if you do not release the sleeper hold you will kill them. Both actions restrict blood flow to the brain strangulation can occour with a sleeper hold.
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Choking someone by compressing their trachea (like a strong headlock) would result in inability to oxygenate blood which would affect all organs. One might lose consciousness, but the lack of oxygen would also affect the heart and could result in deadly arrhyhthmias. On the other hand, choking a person by compressing their carotid arteries (ie. grabbing with two hands) could result in lack of blood flow to the brain and possibly lead to unconsciousness, but blood could still be oxygenated and other organs including the heart would not be affected. Therefore you could cause a person to become unconscious without necessarily leading to death (although brain death could certainly occur). Obviously this is a very broad generalization and choking people is a bad idea regardless.
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Did the advent of cooking food correlate with an increased longer lifespan, and/or have an obvious impact on early human evolution?
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My thought is that it definitely has an impact on human lifespan. The heat used to cook food kills many microorganisms present in the food that could possibly cause diseases in humans. Also. Because cooking food breaks down the molecules in food to form simpler substances, this would also mean our bodies expend less energy to completely digest the food consumed and absorb nutrients from the food. As such, naturally, less food is required to provide enough energy for a human to function.
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Although an exact answer isn't known it is believed that cooking meat first started by accident. Leaving food too close to a heat source would slowly cook it, which releases aromas and flavors. These accidents would soon lead to humans trying to recreate the desirable smells and tastes. This practice would catch on because cooking foods generally makes them better tasting, but also safer and more nutritious to consume. So primitives that cook their food would survive and thrive better than those that didn't. From there its just trial and error over several hundred millennia to get to where we are with cooking today. A good read, and the source of where I got this info: Food in History, Reay Tannahill
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why we sell gas by the volume but not mass, unlike in avionics and auto racing?
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Planes and race cars care about how much weight they're moving around as it has a significant impact on performance. A plane needs more power to get more weight off the ground so extra mass is a problem for it if you happen to fuel it on a cold day Passenger cars don't care as much about added mass, and people know they have a 10 or 12 or 15 gallon fuel tank, not a 64, 96, or 128 pound fuel tank. We generally measure liquids by volume not mass, you can see this with baking instructions too We also don't meticulously temperature control gasoline. Put it in a big underground tank and it'll stay around the same temperature all year long. Even if it does go through temperature swings, it doesn't change in density that much. At 0C gasoline is 1.8% denser than at 15C, and at 30C it is 2% less dense than at 15C, that's not a huge swing
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Since this is /r/askscience you've gotten the chemical answers to your question but I'll add something about the market too. Gasoline is what's known as a fungible commodity, like non-organic whole milk. When one supplier has too much, it sells it as a generic product to another buyer. For example, if Exxon cooks too much gasoline then they will sell the "leftovers" to a different company. You might ask why they would give their competitors a supply, but the process of making gasoline is expensive, long, and complicated, and disposal so difficult, that they really only need to make pennies on the dollar to justify the sale.
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How is/was Scientology able to get major celebrities on board?
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Scientology specifically target celebrities, particularly actors, and put in a lot of effort to recruit them. Celebrities may seem like superhumans to us but in reality they are human beings who are more vulnerable than people realize; the top celebrities do a ton of work, become the center of the universe and yet constantly lives under the fear of falling from the top and losing their popularity; plus they have to deal with haters, paparazzi, and they are all artists and creators who constantly struggle to reach new heights. This makes them easy targets for a cult that can promise them a super-secret revelation that'll solve all their problems. Source: [this article](_URL_0_)
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Because to get higher up in the ranks of Scientology requires lots of $$$$$$. Celebrities (actors specifically) tend to have lots of money, and we know them best as scientologists because they are the only scientologists who the world knows are in that cult. I'm sure there are plenty of other rich people who are scientologists but just aren't tabloided up
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On Cops, you always hear the officers talk about the offender leaving a well known "Drug House". If a house is that well known why hasn't an attempt already been made to obtain a warrant and shut the operation down?
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if you shut down the house quick, you haven't caught the supplier feeding the drug house. if you monitor it, you can figure out who is delivering to it, follow him, and find out what place is supplying this house and other houses. work your way up the chain and bust the production house eventually. Basically, cut the head off the serpent and the rest of it dies too.
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[Maryland v. Pringle](_URL_0_) SCOTUS ruling found that officer finding drugs in a car may arrest and charge all occupants. "We think it an entirely reasonable inference from these facts that any or all three of the occupants had knowledge of, and exercised dominion and control over, the cocaine," Chief Justice William Rehnquist wrote for the court. "Thus a reasonable officer could conclude that there was probable cause to believe Pringle committed the crime of possession of cocaine, either solely or jointly." **Basically, unless one person owns up to the drugs or the others roll on the owner of the drugs, they all go down for it.**
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How did ISIS come to be ISIS? How are they different from Al Qaeda and where is Al Qaeda now?
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ISIS's leader is Baghdadi. They believe that they are a special sect of Muslims who will be chosen by allah (god) because of their very strict following of the Koran (think bible). They are following this because of a special set of circumstances that have made Baghdadi seem like a messiah or prophet (He's got the right ancestors, controls land and a few other things) This is called a caliphate. Many of the members were a part of Al Qaeda or just extremists around the world but since they have a caliphate now they will do everything that the Koran or their leader says even if its 1000 years out of date. [source]( _URL_8_)
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The Taliban are an organization primarily interested in the politics and power structure of Afghanistan. Al Qaeda is a loose-organization primarily interested in global politics and the furthering of islamic fundamentalism. Al Qaeda's interest in the Taliban is that they need a power-center and the Taliban's similar ideology makes the possibility of having that power-center be Afghanistan (where...indeed....Al Qaeda was able to operate alongside the Taliban for many years).
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How much tuna is OK per week/month?
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Here are the [EPA/FDA recommendations](_URL_0_) for women who are pregnant, may become pregnant, or are nursing, as well as children: > Eat up to 12 ounces (2 average meals) a week of a variety of fish and shellfish that are lower in mercury. > > Five of the most commonly eaten fish that are low in mercury are shrimp, canned light tuna, salmon, pollock, and catfish. > Another commonly eaten fish, albacore ("white") tuna has more mercury than canned light tuna. So, when choosing your two meals of fish and shellfish, you may eat up to 6 ounces (one average meal) of albacore tuna per week.
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There are different kinds of tuna, and different grades within each kind. The huge prices are primarily for a very small number of fish each year. The stuff that goes for ten grand is not the same stuff you get in a can.
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With modern encryption, is it possible to decode a fragment of a container if you have the key?
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It depends on what you decided before you encrypted. On the one hand, it is often desirable to be able to read any part of the hard disk without having to hold the entire disk in memory or having to decrypt every part before that; so most standard hard disk encryption operates in [modes](_URL_0_) which behave like this. On the other hand, we know how to do something called an [all-or-nothing transform](_URL_1_), which makes it impossible (well, infeasible) to decrypt only a part of the data.
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Modern cryptography is built upon public key encryption. There is one key to encrypt, and one to decrypt, and having one doesn't help you with the other. The transmission goes like this: Alice: here my encryption key, which I don't care if everyone knows Bob: got it, here is a message encrypted with that key Alice: got it, I am now decrypting it my private key, which I keep secret If Eve is listening on the line, she can get Alice's encryption get and the message Alice sent to Bob, but that does her no good in decrypting the message.
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if the universe is expanding from one point, does that mean there's an edge to the universe?
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The universe isn't expanding from one point. The current consensus is that the universe was probably infinitely large at the Big Bang, so there isn't an edge. Even if it's not infinitely big, there still isn't an edge, it'd be curved in such a way that if you kept going in the same direction long enough, you'd end up where you started, like walking around the globe.
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There is no edge. Metric expansion isn't about objects traveling outward from a central point, it's a homogeneous and isotropic stretching of space. The amount of space between two distant points is simply increasing. You could go to the edge of the observable universe, and you'd see much the same thing that you see from here: galaxies, largely in groups and clusters and superclusters, stretching for billions of light years, and then eventually the cosmic microwave background. The universe is most likely either infinite or *finite but unbounded*--the latter case meaning that you could travel far enough in one direction to come back to your starting point. See the FAQ in the sidebar for more discussions of expansion.
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Why do we picture the cliché bomb as a "cannonball" with a fuse?
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That's because early explosive bombs did physically resemble the popular image of the bomb. Just take a look at this [illustration of a fragmentation bomb](_URL_0_) from the *Huolongjing*, a text from the Chinese Ming dynasty. It shares the same shape as drawings of bombs commonly seen in popular culture. Primitive gunpowder bombs first appeared during the Song dynasty. Soldiers lit the fuse of round cast iron or ceramic shells filled with gunpowder, which were then fired using catapults. For more on the early history of bombs, I would recommend reading *Military Technology: The Gunpowder Epic*, volume 5 part 7 of Needham's *Science and Civilization in China*, published in 1987.
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That's what old-timey artillery shells and grenades looked like. Black iron sphere with a fuse in one end. Light, launch, and hope it explodes near where you want it to explode.
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Who decides what is fake news?
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You got exactly the right question. In the original meaning of the term, nobody decides. There is objective truth and there is untruth. If the latter is reported as if it were truth, that is fake news. Problem: everyone and their mother is adopting the term "fake news" to mean "anything that goes against my personal belief".
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- people (like President Trump famously did) declaring news stories they don't agree with as "fake news" is just them being/acting dumb. - there are lots of fake stories, many posted prior to the US election (US) or regarding refugees commiting crimes or getting special treatments (Eu) they are often shared on facebook with people not realizing they're not comming from legitimate news sources - sites like Breitbart, Infowars or Natural News thrive on posting news stories that have some sort of factual basis onto which they add incorrect additions which twist that basis into something far away from the basis they used, to further their political agenda. If you generally follow bigger media organizations then you will have little direct contact with fake news.
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Why the Republicans want to impeach Obama, and do they have a case?
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Typical bi-partisan bickering with no substance. My guess is the number of republicans who are really serious about impeachment are a very, very small minority, but certain news organizations which will not be named will pick up the story and make it sound like that's what everyone in the party is pushing for.
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Justices can be impeached for whatever reasons the Senate cares to impeach them for. In the 60s it was fashionable among the GOP to demand Chief Justice Earl Warren be impeached for . . . reasons . . . you know, good reasons of some kind because he was a liberal.
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In a siege battle, did the attackers generally concentrate siege engines on one section to either capture or breach the walls, or did they try to overwhelm the defenders by closing in on multiple points simultaneously?
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Mehmet II of the Ottoman Empire sieged cities and castles by surrounding the entirety of it, capturing any other nearby forts, and then focusing artillery on a weak point in order to force a breach. This was the norm before star forts replaced more traditional castles as the most effective means of defensively multiplying limited manpower - ie the strength of the garrison. Typically, once it looked like a breach would be made, the defenders would surrender.
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hi! not that this is even begin to answer all your questions, but while you're waiting for responses to roll in, you may find some relevant info in this section of the FAQ [Life under siege](_URL_0_)
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Why has Arizona's sb1062 bill turned into a christian versus gay debate when that is one of hundreds of scenarios that the bill would address?
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I strongly suspect that the bill was primarily intended to address the christian versus gay debate. It's based on no small part on other lawsuits from other states in which a homosexual couple has sued a business owner who refused them service based on their religious beliefs.
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There are two cases in front of the supreme court this week to hear arguments. The first is a case around California's Prop. 8 ban on gay marriage. The second is at the federal level, the "Defense of Marriage Act", which dictates that the federal government will not recognize gay marriage, and also says that no state is forced to recognize a gay marriage that was made in another state. I believe only the first part is being challenged in SCOTUS.
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why is the Mona Lisa so famous?
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because it was stolen from the Louvre. Probably went viral when it was rediscovered
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(My answer when this question came up in a [previous thread](_URL_2_)) Most people say it's because of her "enigmatic smile", where her smile seems to disappear the longer you look at the painting. I read an article that suggested this is because Leonardo shaded her face so it looks like she's smiling from a distance, but the facial features show a neutral expression. Kind of like how [this image looks like Einstein when viewed normally and Monroe when you squint at it](_URL_3_)
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Why are they just getting around to researching marijuana's medicinal potential now?
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Here are a few I'm aware of: - The DEA lists marijuana as a schedule 1 substance (**no accepted medical use**; high potential for abuse) and a lot of researchers in the US were under the impression the DEA based that on sound scientific data, which it did not. - The most definitive research showing the benefits of marijuana derivatives have come from small, foreign laboratories, so their publications didn't receive a lot of publicity. Academic snobbery can be a big problem in general. - The assumption that people who seek medical marijuana just wanted to get high. And because of this, they lie about its efficacy just to ensure a steady supply of the drug. This also leads people to dismiss marijuana's legitimate medical use.
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We don't know. All we have currently are educated guesses. Because of cannabis/marijuana history and restrictions (schedule 1, "war on drugs", primary research funding sources controlled by governments), research has been tightly controlled. It is easier for biomedical researchers to acquire and investigate cocaine (schedule 2). Sources for cannabis to use in research are tightly controlled (you can't grow your own or buy it from a local dealer) and requests for cannabis are often denied. If cannabis is removed from schedule 1 status and/or more states/governments approve recreational use and/or decriminalise, expect more research to be produced.
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What's the difference between garbage and trash?
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It sounds like a joke, as those two words are synonyms (they mean the same thing). The word *garbage* possibly came from Anglo-French/French and *trash* probably came from a Scandinavian language, but that's basically the only difference.
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Yer not alone in askin', and kind strangers have explained: 1. [ELI5: Why does garbage always smell the same? ](_URL_0_) 1. [Why does all garbage have the same overall smell? ](_URL_3_) 1. [ELI5: Why does garbage have that distinct "garbage smell", seemingly regardless of what's in it? ](_URL_4_) 1. [ELI5: Why does garbage have a distinct smell when it's such a large variety of waste items? ](_URL_2_) 1. [ELI5: Why every garbage dumpster smells the same? ](_URL_1_)
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Were Roman gladiators used as prostitutes for wealthy Roman women the way they are in Spartacus?
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I'm sorry, but after an extensive search I haven't found anything. The only notable information I've found revolves around female gladiators. _URL_0_
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It did vary a lot, depending on the time (see the Lex Iulia and papia) but prostitution was mostly well accepted in ancient Rome. Although it's true that most prostitutes were slaves who were forced by their masters, there were also freedmen and foreigners. Free-born Roman women had to register with the authorities on a trade. In 40CE Caligula introduced a tax on prostitution to the amount of "the payment for one intercourse a day". There were courtesans, some extremely rich and famous. For a very detailed answer, I recommand Prostitution, Sexuality, and the Law in Ancient Rome by Thomas A. J. McGinn _URL_0_ For a shorter read : Grand Valley Journal of History Volume 3 | Issue 2 Article 4 12-1-2014 The Social Effect the Law had on Prostitutes in Ancient Rome _URL_1_
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Was there ever a serious attempt to domesticate rhinos?
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Historically, no one ever has. But some people have recently been talking about farming them for their horns, the idea being that a rhino farm could undercut poacher prices. The problem with domesticating rhinos without modern technology is that to domesticate an animal you have to be able to selectively breed it. To selectively breed an animal, you have to control who is around who....basically, you usually have to fence them in. Building a fence that can stop an amorous rhino from going where it wants is a massive undertaking for anyone. Not to mention that it takes a long time for rhinos to grow up and mature, which makes the whole endeavor less cost effective. So yeah, it never really got done.
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It's likely to be easier to kill the rhinos rather than to subdue then and remove their horns.
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How do keygens (Key Generators) for cracked games and software work?
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That is how keygens DO work generally. The developer makes a bunch of keys they generate themselves. Then someone on the internet figures out how they generated them and releases a program that generates them too.
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The cracking community is quite competitive. Getting your hands on something new and providing a keygen for it first is what gains you status. These guys are talented. They get their hands on the program ASAP and start digging, using programs that help you understand the structure of the software. They're looking for parts of the program that have to do with verifying keys. They can develop a patch that removes that behavior, or, if the key actually decrypts the program for install, they'll try to crack it as a password. They either look at how the key gets analyzed, or they'll try to figure out how they're generated.
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what do motion detectors actually detect?
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There's a few types of motion detector, but the most common is the Passive Infra-Red sensor (PIR). They spot sudden changes in the amount of infrared (heat) radiation in front of it - if a person suddenly appears in front of it, then things will suddenly get warmer, and that'll trigger the sensor.
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Pretty much nothing. It's a pretty purely physics thing. Electrical and materials and computer engineering might rejoice at being able to make such an impressive detector.
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why does the cold air make my nose run?
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Cold air is usually much drier than warm air - this dries out your nasal passages - they react by putting out more mucous to keep things moisturised, but over-do it sometimes which makes it run out your nose.
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From NPR, January 2009 "Dr. LANE: Well, it's really a combination of two things. It's part respiratory biology and part of it is physics, or thermodynamics. One of the main functions of the nose is to warm and humidify the air that we breathe so that when it reaches your lungs, it's nice and conditioned. And in order to do this, the nose has to add some moisture to it. When it's very cold out, the air is usually dry as well, and the nose is really working overtime to add some fluid. And there are reflexes that are in place that allow the nose to increase its fluid production. And if it really makes a lot of fluid, then it starts to run out of the end of your nose. "
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Statistically speaking, if I were to generate a number from 1 to infinity, what could that number be?
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There is no way to randomly pick a number between 1 and infinity. There has to be some kind of bias to make something like that work.
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Infinity is a mathematical concept, not a practical one, so it really depends on how you define any particular infinity. For example, you might say that there is an infinite amount of decimal places between the numbers 1 and 2, and you would be right. You can move halfway between 1 and 2 an infinite number of times without ever reaching 2 (1.5, 1.75, 1.875 etc), but then have a second infinity that contains the number 3, making it bigger than the first infinity.
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Why have they never launched two shuttles at the same time?
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The largest reasons are due to all the tertiary support required for a launch. The United Space Alliance company is only staffed to process one mission at a time, the Vehicle Assembly Building is set up to only handle one orbiter at a time, Kennedy Space center is only set up to control one launch at a time, the Mission Control Center in Houston is only really set up to manage one shuttle mission at a time, etc. You'd end up with one Shuttle sitting on the pad waiting while the other was being prepared for launch. Other than "it'd be super awesome cool looking", there is no reason to do that.
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Because the shuttle itself was expensive, unreliable and overall a boondoggle. Reusable reentry vehicles are prone to wear and tear that single use vehicles are not. There are a number of factors, but safety and cost are primary among them.
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Why can a resistor be put on either side of an LED?
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It's been 20 years since my network analysis class, and I wasn't that great a student then anyway. But as I understand it, the second resistor (between D1 and GND) is establishing a voltage above ground on the ground side of the diode, which makes the voltage flowing through D1 less. Remember that voltage is a difference in charge between two points. So if you've got 5V on your output line, and the LED can only handle 1.2V, the resistors serve to reduce that 5V difference to 1.2V across the LED.
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I see others are using analogies here, I'll just keep it simple. :) Voltage is measured between two points. In the case of your two parallel resistors, the ends of each resistor are effectively shorted together, just one big piece of low resistance metal. As such, they must both have the same voltage on either end.
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Why aren't pieces written only in A minor/C major for easy playing if music sounds more or less the same across different keys?
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Music does not sound the same across different keys. Particularly for piano. Pianos are "tempered" which means the notes are not at their true pitches. Instead they are tuned slightly off so that they sound good in all keys but are not perfect in any. This gives different keys different sound qualities and characteristics. Additionally you need to write the piano music in keys that the instrument or singer can perform in. Certain instruments and voice ranges require different keys for the person to perform the music.
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Somebody correct me if I'm wrong, but from what I remember, back when these conventions were being made the minor scale was actually more predominant than the major scale in music. So when music gradually shifted to being major dominant the "default key" shifted from A minor to C major.
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Is every particle gravitationally acting on every other particle? Is there a point distance-wise after which a atom will stop acting on other nearby atoms?
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The "point of insignificance" will occur when the distance between the particles becomes so great that the resulting gravitational force will be cancelled out by other forces. The mass of each particle (relative to the other) will determine the size of that distance. So yes, always real and > 0, but usually difficult to determine for a real world system. For example, if you hold out a toothpick at arms length and drop it, both your body and the earth will exert gravitational forces on the toothpick. However, since the earth has much much more mass than your body, the force acting on the tooth pick from your body will be insignificant, and the toothpick will fall to the ground.
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In addition to cyhky's answer, there is [electron capture](_URL_0_) as well. However, the fundamental point really is that "bumping into each other" is not too meaningful at the quantum scale of things, as the particles cannot be treated classically (i.e., the electron is not a ball that orbits a proton).
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Does any amount of CO2 leak out into empty space, or is every molecule of fossil fuels that we've ever burnt still in our atmosphere?
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No to both. Carbon dioxide won't escape the atmosphere into outer space because gravity holds it back. However, CO2 also won't just stay in the air once it's introduced to it via burning of fuels. Plants do a very fine job of filtering out the CO2 and using it to produce O2 in a process called photosynthesis. In fact, the amount of CO2 in the air that you breath is less than half a percent.
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Yes. We produce roughly 26.4 Gt (gigatons) of CO2 alone per year. Additionally, recent more-rapid warming began roughly around the start of the industrial revolution.
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Why are prion diseases so difficult to cure?
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As I understand it (BS in Biochem, plus some independent study into the subject), it's because there's no mechanism for the body (or us) to selectively remove the misfolded PrP (Prion Protein). Whereas viruses, bacteria, and the like are incredibly distinct from our own cells and proteins (usually), PrP is expressed endogenously in human cells. That means that many natural defense mechanisms will ignore it. Furthermore, we don't actually know a whole lot about PrP - we don't even have a good structure of the pathological form - which makes it next to impossible to purposefully design drugs against it, even if they could be delivered to the relevant areas within the body. Obviously, no natural product has been used to address the issue either, and to my knowledge, no promising candidates have been found. TLDR; prions are completely different than the diseases that we're used to dealing with, so our usual strategies mean nothing, and we don't know enough about them to have come up with anything novel yet.
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A prion is a protein that has "gone rogue." So if we're talking about mad cow disease, there are certain proteins in the brain. proteins are strings of amino acids that are folded up into a certain shape to accomplish a particular task. well, a prion is the same string, but folded in a different way; it not only fails to do what it's intended, but also has the ability to interact with healthy proteins and deform them, too. Prion disease is not very well understood, but that's our best guess right now
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How can median household incomes in an area be ~$50k but average home price be $5M?
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If you read that page, you will see that the $5M home price was for a specific *part* of that area, and the average income was for the city. So, basically, that area is a very upscale part of town that also has other, less affluent neighborhoods.
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I'll also point out that median is not average. If you considered five guys who made $10K, $20K, $30K, $40K and $1M, you could say, "we made $1,100,000 last year amongst the five of us (or $220,000 per person) but out median wage is only $30,000. Where'd all the rest of it go?"
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Did Erwin Rommel have the capabilities to reach the Iraqi oil fields in WW2?
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> How true are these claims? They are very true! The British had three Armies in the Middle East, 8th Army in Egypt, 9th Army in the Levant and Iraq, and 10th Army in Iran. Against this, the Germans and the Italians could muster at best the equivalent of an Army. Logistics were also precarious, with only some supplies capable of being brought in to closer ports like Tobruk, so the bulk of Axis fuel and ammunition had to be transported from Tripoli, all the way into Egypt by truck. It's extremely doubtful that Rommel's forces could have made it to the Suez Canal, let along Iraq, as reinforcements began to reach the British and the 8th Army recovered it's strength at El Alamein.
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I am not trying to discourage any new answers coming in, but you can find a lot of questions and answers about Rommel if you search around the sub. I'd suggest definitely reading [this](_URL_0_) brilliant post by /u/Georgy_K_Zhukov from the FAQ.
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how blisters are formed.
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Disclaimer: I am not a doctor. Most of this explanation comes to you via what I remember about the nature of bleeding and blood-clotting from Beakman's World about 20 years ago - they used balloons to demonstrate. It was super-effective; I never forgot. The liquid is plasma, basically a bath of white blood cells and proteins. Red blood cells are larger and tend to stick to each other, forming a net, but the water, white blood cells, and proteins are smaller and basically slip through easily. This is good, because it helps both naturally clean a wound as well as pack it in rich proteins for regrowth and white blood cells to help fight off infection. When you get a blister, the friction (or burn, or chemical, etc) irritated the skin enough to separate layers of dermis, but not puncture it, so the larger red blood cells don't escape, but all the rest does.
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Burn blisters occur when the second layer of the skin is damaged, they occur to protect the underlying skin layers from more damage and infection. You could see it as the bodys/skins natural bandage, so never pop them. The skin remain warm because of the increased blood in the area to repair and replace the damaged skin.
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How do filmmakers make this effect?
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[Here is exactly how that scene was made.](_URL_0_) They film them standing still, since its hard to be completely still, they edit it to make it stabilize their bodies, and then they add in effects such as popcorn frozen in mid-air and muzzle flashes.
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Film guy here. Movies were edited by watching different reels on a machine that looks like this: _URL_0_ which lets you play and listen to different clips and/or the whole assembled movie. Film Footage was cut apart and taped together with blades and special tape with a device that looks something like this: _URL_1_ Certain VFX were done by carefully planning out two matching shots them photographing two reels of film into one with a machine called an "optical printer": _URL_2_ Often this meant creating additional black areas on one piece of film or both so you didn't have a double image.
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Why does Greenland have more Ice than Iceland and vice-versa? [Other]
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Oh i know why Greenland is called Greenland! Erik the Red was exiled there from Iceland. He wanted to develop the Island more with communities and people and such. But it was a rather barren icy place, so he called it Greenland in order to attract more people there.
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Greenland isn't an independent country, for starters. It's still part of Denmark. Considering that it has a population of 60,000 people, using the same data as for Denmark proper wouldn't be an accurate representation.
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Semicolons, when to use them and how?
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Generally speaking, use a semicolon only where you would use a period. If a comma belongs there, a semicolon does not. Use a semicolon instead of a period if two sentences seem like they go together more so than usual. One example would be a sentence that shows one side of an argument coupled with another sentence that shows the other side. *Ex. "I like butter on my toast; however, my wife likes jam." Semicolons are never necessary (you can always use a conjunction or a period). The only time (off the top of my head) that a semicolon will replace a comma is in a list which begins with a colon and in which the elements are long and may themselves involve commas. *Ex. The company proposes some new rules: no more food outside the break room; employees must leave cell phones, laptops, and tablets at home; and children are no longer allowed in restricted areas."
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An independent clause can stand on its own as a complete sentence; a dependent clause can't. Semicolons are used to link two independent clauses that are somehow related to one another, as I did in the previous sentence. There are some other uses too, but that's the main one.
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How do bird lungs work?
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Here, try [this](_URL_0_) diagram instead of the one on the wikipedia page. The bird breathes in air, which goes to the farthest air sacs. It breathes out, and air travels through the lungs. It breathes in again, filling that rear set of air sacs once more while the first breath enters the air sacs nearest the mouth, and then the bird breathes out again, and the old air from the first breath exits, while the second "batch" of air enters the lungs. Does that help? Edit: to clarify the exact statement on the wikipedia diagram, I believe they mean that the bird collects fresh air when it breathes in, and actually extracts oxygen from the still-fresh air when it breathes out. It isn't as if the bird is literally taking in fresh air from its environment during both inhalation and exhalation.
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There's an event called "pipping", just before hatching, when the bird breaks through a membrane into an air cell just under the shell. This is when the lungs start working, and it's also when you sometimes start to hear the chick (still in the shell) start to vocalize.
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how does a private prison operate differently from a state or a federally funded prisons?
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Private prisons have an incentive to cut corners in order to pass the savings on to their investors. This often means less experienced, less-well-trained security personnel, worse food, higher prisoner to guard ratios, less ability to accommodate special needs of prisoners, less maintenance, less investment in prisoner reform programs, less ability to investigate and address crimes committed within prison, etc.. Prisons are already a system which encourages dehumanization and the pressures of doing more with less make it even easier to treat prisoners less humanely. This results in greater harm to people serving time, greater risk to those supervising them, and greater risk of ex-prisoners committing new crimes when they leave.
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**Jails** are correctional facilities run by counties(smaller areas) - usually inmates serve up to one year there. **Prisons** are run by the state or federal government. Anyone serving sentences of a year and a day or more, go to prison.
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How common is it in the US to "have a therapist"?
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The taboo of seeing a therapist in the US has been slowly receding. Reality is, life is a complicated thing and most people could benefit from some therapy. Despite that, I would say that most people do not regularly see a therapist. It seems likely to me that you're frequenting places on reddit where people are more likely to than in your normal life. Alternatively, some people "have a therapist" in the same way you might "have a dermatologist", meaning they don't go regularly but when they do they go to the same person. For whatever it's worth, I was spending about 60$ a session which is pretty expensive when you may have weekly or bi-weekly sessions, but after reaching a max deductible with my insurance it goes down to about 6$.
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My opinion on this is that it is as common nowadays as it was two or three decades ago. But now its more accepted to speak about it. There is no stigma with going to the psychiatrist. Just my opinion.
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Chemically, why does salt make food taste better?
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Humans need a certain amount of salt to survive, which has caused our taste buds to evolve over time to make salty foods taste better to us. I know this answer is more biology than chemistry, but it's the best I could think of :)
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I just took a Vertebrate Sensory Systems course, and the reason that salt enhances taste is this: Each taste in the mouth uses different mechanisms to signal that particular taste, most of which involve the opening of sodium channels that cause signaling to the brain. Since salt itself (NaCl) increases the amount of sodium outside of the taste receptor cell, the gradient is stronger, and thus more sodium enters open sodium channels, causing more signaling for any particular taste.
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does adding soap and lathering before adding water to your hands increase the effectiveness of ridding bacteria?
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The point of soap is to cling to and loosen up stuff that won't rinse off your hands with water alone (like oils). Water interferes with this action a bit because you're not applying the soap directly to the stuff you're washing off: there's a layer of water in between. I lather up dry like that when I'm trying to get something really greasy off my hands, like if I had been working on a car and had motor oil and gunk on them. It *is* a more effective way of using soap, but it's not necessary for your average hand-washing session.
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Because soap bonds with both fats and water. Normally you can't just rinse off fats and oils since they are hydrophobic - they don't like water and won't stick to it or dissolve in it. So you just get water running over your oily skin, and all the bacteria living in the oil or just under the oil remain. Soap, however, has molecules with an interesting property. One side of the molecule bonds with oils and fats, but the other side is hydrophilic - it really *likes* water and tries to stick to water when it can. So if you lather up with soap, the soap will bond with the oils and the vigorous rubbing will dislodge the oils and soaps while the water pulls them away, leaving your skin free of most germs and other gunk! The germs that end up on the soap itself get washed away due to the water, or die after a time anyway since soap is not particularly well-suited for bacterial growth, at least compared to oily human skin.
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Was there a point in time where sound could travel through space?
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The large-scale structure of the universe is actually covered in the relics of sound waves in the very early universe, called [Baryon Acoustic Oscillations](_URL_0_).
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What we perceive as sound via our sense of hearing is really pressure waves in the air causing our ear drums to vibrate. That tells you immediately that sound requires air (or some other medium) to reach your ear. Sound can propagate through compressible media such as air, water and solids as longitudinal waves and also as a transverse waves in solids. However, there is no air in space, so there is no sound.
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Is Joan of Arc an historical anomaly? Are there other examples of young women in roles of military leadership?
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[Gustavus_Adolphus](_URL_0_) led the Swedish Army when he inherited the crown at age 16. Edward, Prince of Wales (known as The Black Prince) commanded the English vanguard at Crecy, being 16 years old. Alexander the Great led the left wing at the battle of Chaeronea aged 18 and was in overall command of the Macedonian army at age 20. Cyrus the Younger was 23 or younger when he led the rebellion against his older brother described in the Anabasis. George Custer was a (brigadier) general at age 23 during the American Civil War.
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Sure. Ancient * Sex scandals under Emperor Domitan (Cornelia, Julia Flavia) * Ton of other Roman scandals (the classical guys will show up soon, I'm sure). Medieval * Tour de Nesle Affair (1314) * Henry VIII's wives / "Great Matter" (1527-35) Early modern * The Sally Hemings/Thomas Jefferson affair (1790s/1800s) * The sensational Mordaunt divorce trial (1869-70) * Colonel Valentine Baker attempted rape case (1875) * Grover Cleveland's love child, Oscar Folsom Halpin (1888)
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Sometimes my rings feel more loose on my fingers then other times, why?
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Finger tissue swelling/shrinkage. Rings will allwsys be looser in cold conditions. Somebody else wanna take the "it must be cold in here" dick joke??
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Metal does expand when warm and contract when cold. However, in this case, the more important part is that your fingers also expand and contract - and fingers grow/shrink much more than the ring will. edit: A couple of people have posted comments about the ring expanding inwards. This is actually [not the case](_URL_0_).
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How can banks be 'too big to fail'?
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"Too big to fail" means the economic fallout would be too dramatic if one of them collapsed. All of those people and companies that keep their money with one of those would need to be reimbursed by the government (UK has deposit insurance, right?), which would be to the tune of billions of dollars. It would also lead to a loss in investor confidence and most certainly drop the country into a recession, so its in everybody's best interest to keep those banks afloat. This means the government will step him and keep them in business by giving them interest free loans or erasing their debt so that they can recover.
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Some companies (e.g. banks, car manufacturers etc.) may be considered 'too big to fail' because so many hundreds of thousands of people (e.g. employees) fully depend on these companies operating that it would arguably do more harm than good to the greater society to let the company fail as opposed to provide bail-outs to get them back on track. In other words, letting some of these companies fail may be seen as more disastrous and disruptive to the economy than the expense of providing financial assistance to prevent the company from failing.
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Did people ever buy slaves to set them free?
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A woman named Frances Wright did something like what you are asking in 1824. In Memphis, TN she bought two thousand acres of land from Andrew Jackson and would buy slaves. On this land she set up a co-operative labor system where they could basically work off their price of purchase and then they would be set free. EDIT: Forgot to mention that the name of this place was Nashoba. Nashoba is the Chickasaw word for "wolf." Source: Gerald M. Capers Jr.'s *The Biography of a River Town*
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I know that Seneca did it, in his Epistulae ad Lucilium. Letter 47 deals with this, and though he does not directly denounce slavery, he does argue that all men are slaves to fortune/fate, that slaves are treated horribly by their masters and are serving decadence, that examples exist of people becoming slaves or ex-slaves becoming masters, and that both slaves and their masters are human beings. His conclusion is that you should treat your slaves as you would want to be treated. And that even if you are currently a free man, that can always change (famous examples being Hecuba, queen of Troy, Croesus, king of Lydia, the mother of king Darius of Persia, Plato and Diogenes).
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Why does a shaken carbonated drink explode?
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In ELI5 terms, carbonated drinks have gas under pressure and bubbles. When the drink is shaken the big bubbles that are normally near the top of the bottle can now be found anywhere in the bottle. When the drink is opened, some of the gas escapes and the bubbles reach the opening of the bottle or can, this stirs up more of the gas dissolved in the soda making them want to escape the drink causing a chain reaction and a big burst of foam and liquid. I hope this explanation is clear, if not I can try to rephrase it.
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Machines in the factory put carbon dioxide into carbonated drinks which makes them fizzy. The carbon dioxide constantly wants to escape and while it sits on a shelf waiting to be bought, the carbon dioxide moves towards the top of the bottle because it is a gas that is not actually mixed into the drink, which is why there is a hiss when you open the bottle or can. If you shake the bottle or can before you let the carbon dioxide waiting at the top to release, the carbon dioxide gets remixed with the soda. Since the gas is now dispersed throughout the bottle, when it releases it brings the liquid that is surrounding the carbon dioxide with it, which is why it causes an explosion of the drink.
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Why does taking a deep breath calm you down?
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A simple answer is that deep breathing increases the amount of oxygen in your body and slows your heart rate, helping you feel more relaxed. Another reason is that it activates the parasympathetic part of the autonomic nervous system (ANS), which is responsible for controlling our rest and relaxation. The other half of the ANS is called the sympathetic nervous system and deals with the fight-or-flight response, and is associated with fast, short breaths. Also by focussing on taking deep breaths, you take your mind off of whatever is making you stressed.
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We tend to start breathing faster/hyperventilating when we're faced with stress or danger. This helps oxygenate our bodies for the fight or flight response, but since it can also be triggered by general anxiety, it can be more inconveniencing than helpful in an everyday situation. Lightheadedness, sweatiness, and trembling abound. Breathing deeply and mindfully slows your heartrate down and manually halts this process if there is no need to fight or run.
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In the past, what was done about acne? How was being spotty perceived in society and were there any treatments?
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In an attempt to answer a question about how spicy Aztec food was, I discovered that chilis were used to clear "roughness of the face" which I think might be acne. You may find the post [interesting](_URL_8_).
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Acne is caused by bacteria that gets in our oily pores and hair follicles, and our immune system reacts to fight it. That bacteria has been out there a long time. And because it doesn't prevent us from procreating, there's no environmental pressure to select genes that could reduce its effects.
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Is a linearly polarized laser made up of equal parts spin up and spin down photons?
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Photons do not carry transverse spin. Circularly polarized light has clockwise and/or counterclockwise spin. So linearly polarized (perpendicular to direction of motion) is an equal mix of those two spin states.
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In short, yes. At a fundamental level, the polarization of light waves is an artifact of the spin of the photons, so a beam of photons in the same spin state will be a beam with a specific polarization. Thus, if we take a collection of electrons and get them all in the same spin state will be polarized.
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Why do most running shoes have more padding in the heel than in the front?
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Those shoes are more properly called "jogging" shoes. Jogging is a strange activity, because it's not natural. Yes, yes, there's such a thing as running slowly. But if you were in the middle of nowhere and wanted to get from point A to point B as quick as possible, you wouldn't jog at a comfy pace. You'd run as far as you could, then walk until you caught your breath, then run again, then walk again, etc. And it would be faster than jogging the whole way. You might jog a little bit, but long-distance jogging is really a much more odd activity than we realize nowadays. Jogging is hard on the feet because you're not moving fast enough to get your feet in the right place to land (if you were, you'd be running), so what you tend to do is heel-strike. Heels are made for standing, not impact (that's what toes and the ball of your foot are for). Thus, the need for extra heel cushioning.
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Heels were originally introduced to prevent feet from sliding directly through the stirrups when riding horseback. For this reason riding boots to this day are still made with moderate heels. Eventually they grew in popularity and in height, used to make the wearer look taller, more powerful, and establish their place in society. Today, women (including myself) wear heels to elongate their legs, and also improve posture. They bring confidence to your stance and complete your outfit (the ultimate multitask-er!) My personal opinion on wearing heels: They aren't generally uncomfortable until you've been walking around in them for 3+ hrs but at that point most shoes not purpose-built for extended standing/walking get uncomfortable. All the same, its why I always bring a backup pair of flats in my car/bag.
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How come Poland is one of the most religious countries in Europe, and Czechia is one of the least religious, even though they are neighbors and have a similar history?
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There's been quite a few events in the history of the Czech Republic (please don't call us Czechia) that made us distrust the Catholic Church and religion in general, notably the [Hussite Wars](_URL_0_). It's worth noting, however, that while a lot of the Czechs hate organized religion and churches, quite a lot of us seem to believe in some higher power, we just don't like to call it God.
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Poland was officially Roman Catholic since 966 A.D. The Teutonic Knights were originally German crusaders. In 1226, they were invited into Prussia by a Polish duke, and quickly cemented their power in the region. Although they were originally fighting pagans in Prussia and Lithuania for the pope, they began to expand in a secular manner, attacking any territories (Christian or not) that they could conquer. In the Polish-Teutonic war of 1306-09 they took over Pomerania after the death of a Polish king. The conflicts between Poland and the Teutonic Knights were not based on religion, but on the Teutonic desire of expansion. Hope this helped.
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Does E=mc^2 imply we can create matter?
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Yes, it does. Put in enough energy, and you can create matter. For instance, a collision of two photons with a total energy of 2 x 0.511 MeV has a high probability of producing an electron-positron pair.
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Instead of looking at it as the speed that light travels, look at as the fundamental unit of speed in the universe. Things that don't have mass go at this speed, including light. You know that energy and mass are equivalent. The simplest way to express this is **E=m**. However, energy has different units than mass. For example, the kinetic energy of a moving massive object is 1/2 mv^2 . It has units of mass times velocity squared. So you can say that since mass and energy is equivalent, I just multiply by the square of the fundamental unit of velocity of the universe to get from mass to energy. E=mc^2 is how you express this relationship and have the units work out. In fact, if you use "natural units" where c=1, the equation is just E=m. Hope that made sense.
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How does the body keep itself warm? How does it raise it's own temperature when you're ill?
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The main mechanisms to conserve/produce heat are (1) vasoconstriction to decrease blood flow to extremities and skin surface, (2) shivering, (3) decreasing sweating and (4) increased energy production via metabolism. When you're ill, this normal homeostasis is dysregulated, and, as an example, you can have shivering even when you are already very hot (e.g. chills).
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Viruses and bacteria multiply best at 98.6 degrees F. By rising the environmental temperature, even by just a degree or two, the body can stop a virus's ability to grow. That's why we get fevers. When the brain increases the body's temperature set-point, the rest of the body gets confused and feels like it needs to meet that higher temperature. You feel cold because technically you are colder than your body's new set-point. In turn, the body works to generate heat to warm itself by contracting and relaxing muscles, hence the shivering.
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I was fed Tamago Kake Gohan (Egg Over Rice) a ton of times as a kid. Raw egg is used. I never got salmonella. Did I develop a tolerance or is it just safe to eat raw eggs?
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According to the CDC, 1 in 10,000 eggs are infected with Salmonella. Before the 70s, Salmonella basically never got into chicken eggs, and the inside of eggs were effectively sterile and safe to eat raw. It's not clear why salmonella can infect eggs now, but the theory given [here](_URL_0_) is that the eradication of two other strains of salmonella that make chickens sick resulted in chickens being less immune to salmonella overall; so the strain that can get into eggs (which incidentally, *doesn't* make the chicken sick) wouldn't necessarily be attacked by the chicken's immune system. If you want to eat raw eggs, you can find pasteurized eggs that are 100% safe to eat raw; or you can take your 1 in 10,000 chances.
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It's not dangerous to undercook eggs. People eat runny eggs all the time. Raw eggs have a small chance of containing salmonella. Unless you're part of an at-risk population (very young, very old, pregnant etc.) then having a salmonella infection will, in most cases, just give you 2-3 days of food poisoning (fever, diarrhea and such).
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Why are my hands staining the inside of nitrile gloves?
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Interesting question. Different sorts of gloves are suitable for use with different chemicals; some will be permeated by some things but not by others. What have you been working with?
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Your skin is dried out. This happens because we use our hands all the time and wash them constantly with harsh chemicals. Moisturize more often to prevent the flaking.
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Why is it that headache doesn't usually come back after the painkillers have stopped working?
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Probably because the headache would have stopped on its own with or without the painkiller. The painkiller didn't cure the cause of the headache. It simply masked the pain while your body recovered from the cause.
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Headaches are often the result of inflammation. Many types of painkillers reduce inflammation, so the pain is actually gone. However, this does not mean that the underlying cause of the inflammation has been resolved. So..in this regard your question may not quite make sense! For example, if you have a headache because you got hit in the head with a hammer the pain killer doesn't make you _not have been hit by a hammer_, but it does reduce swelling which is one of the things that is causing you to experience _pain_.
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How do high rise buildings filter outdoor air for circulation?
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Hi rises don't have just one giant air moving HVAC. In my building each unit has their own hvac, and then there are three big ones that cool all the hallways, one in the gym, maybe a few more scattered throughout.
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I'm going to say it makes more sense to blow air out, since that's the way air is going to flow, anyway. All multi-story buildings have a strong "chimney effect": the air in the building warms and rises, drawing air into the basement. Trying to draw air into the top floor isn't going to change that. Instead, you need to get air moving through your apartment. Open windows at either end. Keeping the air circulating is more important for comfort than which direction your fan is blowing. Also, don't let direct light into your place. When she sun is shining in through windows, close those blinds.
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Can water remain liquid below 0 Celsius as long as it is flowing?
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The liquid water will try to build crystals of ice if under 0°C. Motion will not effectively prevent this but it can be prevented by removing impurities or even microscopic roughness on the adjacent materials on which the crystals could start growing. Even if the water is flowing if there is something to build crystals on they will grow. Although if you put demineralized water into smooth plastic container you can cool it way below 0°C and it will stay liquid.
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Almost correct. The most dense water is water at 4 degrees C. Warmer water will float above water at 4 degrees, but so will water colder. In answer to your question, a cup of hot water will have very little gradient from top to bottom.
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How can a breathalyzer detect the amount of alcohol in your blood?
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When you breathe, all that air fills your lungs and touches your blood. The oxygen goes from the air into your blood and the carbon dioxide goes from your blood into your lungs. When you drink alcohol, some of that alcohol in your blood also goes into your lungs, just like the carbon dioxide. That's what the breathalyzer is detecting.
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The presumed route of alcohol in a breathalyzer sample is blood- > lungs- > breath- > breathalyzer. So, anything that increases your BAC would show up in a breathalyzer.
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Why do some murders and kidnappings get national attention, when people are murdered and kidnapped relatively often?
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This may sound rather cynical, but it boils down to what's good ratings, stories, and publicity for reporters and journalists. If someone young and attractive or famous is murdered or kidnapped, It is easy to play up the tragedy and humanity of the situation and promote national shock and outrage, which results in high profile cases and stories to follow for news reporters. See [Missing White Woman Syndrome](_URL_0_), a phenomenon where white-middle class women and girls are disproportionately represented in the news after being victims of violence.
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Because they actually don't know they are going to be killed. Most of the time these hostages are dragged out in front of cameras and made to read stuff or stand as a prop many, many, many times over the course of their imprisonment. Not only are they regularly beaten and threatened but they are also told that they will eventually be released as long as they do what they are told. So imagine you know you will be hurt if you disobey, you have been told you will be freed eventually if you behave - a ransom is met or whatever - and you have been sat in front of a camera to read a pre-written farewell note 20 times already over the last few months. . . it gets to the point that's it's business as usual for you as a captive. You have no idea that this particular day is the day everything goes as it always has, except this time instead of them cutting the filming and walking you back to the truck, they cut your throat.
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does the 'voice break' that occurs during a man's puberty time period make sense in evolutionary terms ? How does that benefit us humans and what happens in the the body that creates this change ?
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This is a common misconception, not every trait has to benefit the species. So long as it is detrimental it won't be selected against, even if it is detrimental it still might not be removed completely. Voice cracking is just a side effect of puberty, it has no benefit or much disadvantage, given its infrequent and temporary affect. You know how sometimes when you were growing up you'd get growing pains? It's the same thing, your body is doing something to develop into an adult and it has an unintended, and sometimes unwanted, side effect.
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It has to do with changes during puberty. Males produce a lot of testosterone, which thickens and lengthens the vocal cords, giving a deeper voice. Females obviously don't have as much testosterone, and estrogen doesn't give the effect. As a side note, this is also why kids have super high voices; not only do they lack the large levels of testosterone, but they don't have the age and therefore length of the vocal cords.
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How did the first Hawaiians arrive and what compelled them to go?
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hi! in addition to Tiako's comment and link, here are a few more previous discussions [How did ancient people find Hawaii?](_URL_4_) [How did the Austronesians cross the pacific to places like Hawaii?](_URL_5_) [How did humans first reach to the most remote islands of the Pacific Ocean so long ago with such primitive crafts?](_URL_3_)
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Or why the Maori or other Polynesians didn't.
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When FDR became wheelchair bound did he develop the physical upper body strength to get around and learn to live independently, or was he more dependent on others for mobility and personal care?
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FDR was pretty thin as a[ young guy](_URL_1_), but developed a pretty [big chest and arms](_URL_0_) with exercise after becoming paraplegic. There are accounts of him sometimes simply flopping off his chair in his office and dragging himself to where he needed to go, if no help or wheelchair was available. But despite the exercise, he never gained any function in his legs and , in the days before anyone thought of such a thing as handicap accessibility, he tended to need and have assistance. Though, he did have one of the [first cars equipped with hand-only controls](_URL_2_) Doris Kearns Goodwin: *No Ordinary Time: Franklin and Eleanor Roosevelt :The Homefront in WWII*
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You maybe be interested in [this previous answer](_URL_1_) of mine to a similar question. The short version is that there was a lot of confusion over the extent of FDR's disability because the Democrats were afraid the Republicans would use it as a political attack. And they had reason for concern, because the Republicans did try to do that infrequently, so FDR's aides were careful to keep the public in the dark as much as they could. The full extent wasn't fully communicated to the public until after his death. During his lifetime, people knew he'd had some kind of polio-related issue, but by and large, they thought he had overcome whatever issues he'd had, leading to some odd depictions of FDR during his presidency, such as in the cartoon ["Confidence"](_URL_0_) from 1933 starring Oswald the Lucky Rabbit.
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How did Britain manage the logistics of fighting overseas in the 18-19th century?
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They contracted with merchants, for the most part, and offered convoy escorts and other protection to make sure ships and supplies made it to their destination. A formal Transport Board existed from 1690-1724 and again 1794-1817, and offered employment to officers who had little prospect of climbing the regular naval career ladder but were nonetheless skilled commanders. The Transport Board was responsible for transporting troops, baggage, ordnance, and naval and military stores. Regular merchants were used for victualling and supplies like slops (clothes) and such. When the Transport Board lapsed, a variety of ad hoc arrangements were used that proved unsatisfactory. Other navies had somewhat similar arrangements, and convoy was used when possible. Intercepting stores and convoys The Glorious First of June, for example, was a battle where the British navy was intending to intercept a French grain convoy coming from the Americas.
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This question is ridiculously broad. You're asking about a time period spanning an unfeasible period of time to make meaningful comment on. If you have questions about the British army, it's better to pick a time period rather than in general. The army of Edward longshanks and Wellington had nothing in common. You might enjoy the book Generals. Ten British commanders who shaped the world by Mark Urban for an interesting and wide range of time periods looked at in detail. But frankly, your question is unanswerable in its current form.
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Why does fusion produce so much more energy than fission?
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Although it's not a hard and fast rule that fusion produces more energy than fission, usually people are comparing hydrogen fusion to uranium fission. Fusion of light elements tends to produce more energy per mass of fuel used because the change in binding energy per nucleon tends to be greater for transitions from lighter elements to heavier elements (they start with fewer nucleons) than from heavier ones from lighter ones (because they have more nucleons). This is somewhat connected to the relatively short range of the strong nuclear force. _URL_0_
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The energy is not really created. Instead, a small part of the mass of the fusion ingredients is converted into energy. You know Einstein's famous E = mc^2 equation? It tells you how much energy you get for each bit of mass. It turns out if you were to convert 1kg of mass to energy, you would get 1kg*c^2 energy. That's 89875517900000000 Joules. That's like about 20 Megatons of tnt! That's why nuclear weapons are so powerful and why nuclear power is so attractive. Of course, to completely convert matter into energy is really difficult. Nuclear Fission and Fusion just combine a certain mass of ingredients into a slightly lighter end-product and a fair chunk of energy.
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With all these kinds of toothpastes offering different things: whitening, sugar protection, gum care etc. Why can't there just be one offering all the benefits?
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Tooth paste does. All those terms are marketing terms to appeal to different types of people. Some care about a brighter smile, some care about no cavities, etc. I'm sure they could put "fat free toothpaste" on one and people would buy it for that reason. Almost all toothpaste have the same ingredients.
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Toothpaste doesn't really kill bacteria. It's there to *take away the stuff that the bad bacteria eat*. Basically, the bacteria that cause cavities take sugar and turn it into acid, which eats through the enamel on your teeth. Toothpaste helps clean the sugar away, and may shift some bacteria out, but the main advantage of toothpaste over just brushing is fluoride. This helps strengthen your enamel.
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How can the president order media blackouts?
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The First Amendment prevents Congress from making *laws* abridging your freedom of speech; what it doesn't do is prevent the President from telling government agencies what information they should and shouldn't make public. After all, if the First Amendment protected them against that, the president could do nothing to prevent them from tweeting, say, porn. The president has the power to control it because these agencies are part of the executive, and not Congress. Basically, it is now simply government policy for government agencies not to tweet about climate change.
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The federal government only provides about 20% of the NPR and PBS budget. He's just pandering. Cutting it would do nothing except abandon its audience. Edit: The US Government spends $444 million a year on the Corporation for Public Broadcasting. The defense budget this year is over **$1 trillion**. That should give you an idea.
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How much electricity could a gym produce if it installed dynamos on all of it's machines?
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A reasonably fit person can sustain around 150W of output power on a bike or rowing machine for 30 minutes. For a top athlete it's around 400W. The rate of heat production during this activity is around 4 times greater, but there's no way to use that. Treadmill running has a similar energy use, but no way to extract the power. For comparison, the electricity use of a domestic house is around 1000W. So, given a group of around 10 exercise machines in permanent use you could generate a decent amount of electricity.
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I'm also interested in how much average power produced during the clean movement by certain weightlifter, for ex: _URL_1_ **Edit 1:** So I found this: > 4786 watts for a 110 kg lifter. _URL_0_ Now compare this to other type of movements.
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Why are 9mm bullets less dangerous than 7.62 or even 5.56 ones? Shouldn’t they deal more damage with bigger size?
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9mm bullets are dangerous. However they are a handgun round. They're less aerodynamic and have less power coming out of the barrel. They're not designed for long-distance flight. 7.62/.308 and 5.56/.223 are rifle rounds. They have more power out the barrel and are designed for long- distance, accurate engagement.
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The numbers that you are mentioning only refer to the caliber, aka the width of the bullet itself. But bullet size isn't everything when it comes to power. There's also the length of the bullet, the amount of gunpowder behind it, the length of the barrel, etc. The 9mm you are referring to is a very small round, usually shot out of a handgun. The AK47's 7.62 round (technically a 7.62x39, the second number refers to the length of the case without the bullet) is thinner, weighs slightly less, has much more powder behind it and is typically shot out of a long barreled rifle. All of this message that the 7.62 bullet travels faster and has less wind resistance than the 9mm meaning that it can put more energy into the target.
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Have cats changed at all since becoming house cats, like how dogs have, or have they always been exactly like the way they are now?
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Yes, though not quite to the same degree as dogs. House cats were domesticated from wildcats, specifically the [African wildcat](_URL_0_), which looks pretty much exactly like their domestic relatives. But that's only if you don't count longhaired cats, persian cats, siamese cats, or essentially any breed that has been selected to look different from wildcats (sometimes subtly, sometimes extremely). Humans have bred cats for physical and behavioral traits we like, but because they are not working animals like dogs (e.g. sheep dogs, hunting dogs, sled dogs), today's cats haven't been made to diverge as far from their wild ancestors as dogs have.
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Domestic house cats are descended from the [Near Eastern Wildcat](_URL_0_) in the Middle East. It is believed they were domesticated around 10-12,000 years ago. Cats are not as readily trainable as dogs are so there was less motive to press them into various service roles. Cats were best to have around farms and granaries and such as pest control and for that there was no particular need to breed them into varying sizes and such. They did that job quite well without messing with them. Domestication (probably) occurred as the wild cats figured out that their food (rodents and such) liked to be where humans grew/stored grains. This brought them into close contact with humans and humans noticed the cat was a benefit. That said there are a wide variety of domestic cats. Not as varied as dogs but the variation is there.
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How much fossil fuel usage do electric cars save (compared with gas engines) as the electricity they use is often generated from fossil fuels anyway?
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They don't really save that much in fossil fuels if they are powered by them originally, but you can't power a gasoline car with hydroelectric, or solar, or wind, or nuclear power. But another major benefit is that even if you ultimately use fossil fuels to power an electric car, those fuels can be burned in a power plant away from the center of the city and pollution scrubbed much better than a car that needs to carry around its exhaust system.
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A car engine turns about 30% of the energy from gas into motion. The other 70% is lost as heat. Power plants that use fossil fuels use the heat from burning fuel to heat water that turn a generator. This is a more efficient conversion of the energy. Add to that, that not all of the electricity is generated by fossil fuel. Some planets are hydroelectric, wind, or solar. So an electric car is also running of some carbon-zero energy sources as well.
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How does air horn generate such a loud noise?
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U/Blesshope is talking out of his ass ,he doesn’t know what he’s talking about. Sorry brother. The airhorn uses a diaphragm similar to reed in a wind instrument. The cone is there to amplify the sound/ direct it, but the sound is actually created by vibrations on the diaphragm. _URL_0_
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So usually cars have two horns in the front of the car, a high pitch and a low pitch. So a standard electric car horn does have a diaphragm just like a speaker. Inside there’s basically a plunger connected to the center of the diaphragm and on the other side of the plunger is an electromagnet. When you hit the horn button. The electromagnet forces the plunger to bounce off of it so fast the diaphragm produces a frequency, a loud one. The combination of the high and low frequency together makes the sound travel farther and through more surfaces.
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How some hairs know that when to stop?
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The trick is that they *don't* stop. Ever. Hairs grow forever, but have an internal timer that causes the cells generating the hair to stop the hair and "disconnect" it (causing it to fall out), and then start a new hair. That time limit dictates the maximum length of the hair, and the longer hairs tend to mask the shorter ones (the hairs are not all in sync), so it looks like they're all one length if you don't look closely.
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Each hair root will grow for a certain length of time, and then stop, shed its hair, and start over. If the length of time it grows for is just a few weeks, then the hairs have time to grow very long, like the hairs on most people's body. If it's a couple of months, the hairs have time to get a bit longer, like your eyebrows. If the hair root will grow for several years, then the hair can become extremely long, like the hair on your head. But even though the hair on your head becomes very long, it doesn't grow "indefinitely" - if you stop cutting it completely, it will eventually reach its (quite long) natural length, just like the other hairs on your body.
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If states like California and Texas existed during the Civil War, how come both capitals and most of the historic battles were all on the East coast?
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California wasn't the booming state it is now. There was population thanks to the gold rush, but it just wasn't on the same scale as today. The vast majority of the population and industry was on the east coast. Don't forget that by the mid war, the Union blockade and control of the Mississippi had effectively cut off Texas from the rest of the Confederacy. [However there was still military activity in the Trans-Mississippi region.](_URL_0_) However due to the limited amount of resources in that theatre, operations were, of course, much smaller in scale.
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The states on the east coast were populated first (European population that is...). State lines (colony lines initially) were devised in various ways, but all dependent on much of the east coast being populated very early. In other words, there were lots of people clumped up into various areas on the east coast and they divided themselves into colonies and then states. It took longer for Euro-Americans to go further west, and when they did the populations were very small at first. So the western territories were much larger areas, with very low populations, and many of those whole territories later became states. That's actually the way it remains to this day. If you rank the states by population density, California is the only western state in the top half, and it's only #11. Little Rhode Island has almost four times the population density as California.
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Ok, so how incompetent was the Italian military really in WW2?
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I don't think it was totally incompetent. The RMI (The Italian Navy), despite being vastly outnumbered and outgunned by the Royal Navy, put up a pretty good fight in the Mediterranean in the early years of the war. The rank and file, as well as the actual line officers of the navy were pretty competent, but it suffered from poor leadership at the highest levels, IE: Mussolini. They had good ships, too, especially their smaller ships such as destroyers. They tended to be fast, but lightly armored. Their big disadvantage was a real lack of naval air support, relying on air support from land bases. The Italian army also wasn't entirely incompetent. Several Italian regiments (The Ariete Regiment was one) fought in North Africa with Rommel. He seemed to have a good deal of respect for them, but they weren't mechanized which really put them at a disadvantage in the wide open spaces of the North Africa theater.
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There's a roundup of some previous answers regarding WW2 in [this thread](_URL_0_). I could swear I saw an even better response more recently, but haven't been able to find it. The short version, for WW2, is that the country lacked the industrial base to properly equip modern armed forces, and also suffered poor leadership, in part due to a poorly educated population. I haven't seen a discussion of Italy in WW1 on here - *did* they perform so badly compared to other belligerents? - but the country's low industrial base would undoubtedly have had an effect there as well.
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How do media sharing sites (like Reddit, Imgur, YouTube, etc.) manage constant data being added to their servers without filling up?
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They use cloud storage providers like Amazon S3 (google it). These are available programmatically and the site owner doesn't even need to know what's happening in the background, the cloud provider takes care of it all. (The cloud provider has thousands upon thousands of hard drives and computers, it's their business after all, and these are available programatically).
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They have maaaaaaassive servers in the petabyte range. (It's a major source of funding stress for them I think – getting more and more storage) edit: [9 PB + 20 TB/mo](_URL_0_) i was wrong They regularly crawl through the web (so your personal webserver won't be accessed unless you host a semi-popular forum or something) and store each of the results given. Given most pages are less than 1 MB and most are less than 300-500 kB, they can store many snapshots of a lot of pages almost indefinitely. They rarely delete anything i think, at least very rarely. They only take the snapshots of un-logged websites (ie if they took a snapshot of reddit, they would only take a snapshot of what everyone sees before logging in) so any personal information stored is kind of your problem.
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Is it possible to scan a genome and identify the organism that it came from? How specific can we get?
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We can identify an organism by its DNA because we've sequenced the DNA of that organism before. Once you've sequenced the genome of, say, a rabbit then later when presented with DNA you can compare it to the known DNA sequence of a rabbit to see if the DNA came from a rabbit.
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Yes. When we have a protein sequence and we want to find where within the genome that it is encoded, we make a mixture of all possible codon sequences that would make that protein and use that mixture as a PCR probe. The technique is called a [degenerate primer](_URL_0_) probe. Edit: *In silico* a PBLAST is a search of a genomic database for a sequence that would produce a given protein sequence.
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How much manpower was represented by a single ship in antiquity?
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A trireme had a rowing crew of 170, plus about 30 other sailors, officers and marines. In comparison, a Roman quinquereme might have had 300 crew and 120 marines. So, with a trireme you can probably field 1700 men for every ten ships, while a quinquereme would allow in excess of 3000 men for every ten ships. [Source](_URL_0_)
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So few? The Greeks had thousands with a fleet supporting them. They also needed to only defend thin fields of battle.
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What's the history of lawyer jokes and ridiculing lawyers?
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I've certainly found plenty of them when researching nineteenth-century jokes, so they go back at least this far. Here's one I remember from 1891: **Chicago Woman**: How much do you charge for a divorce? **Chicago Lawyer:** One hundred dollars, ma’am, or six for 500dols This joke is as much about the loose morals of women from Chicago, but it nicely captures the character of the money-grabbing, amoral lawyer too. It was initially published in an American newspaper, but found its way to Britain (this [transatlantic circulation of jokes](_URL_0_) is my main research interest) - this suggests that the stereotype of the shady lawyer was known in both countries at this time. I don't have any others to hand, but could soon dig out a few more from the 19th century if you're interested!
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Disrespect and low opinion of lawyers goes back to at least the colonial era for Americans, and I wouldn't be surprised if the origins go back to pre-colonial England.
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Physicists,why is 'rest' and inertial motion regarded as 'natural',while acceleration and gravitation(including singularities) are regarded as abnormal?
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Internal motion (and this includes gravitation in GR actually, free fall into a gravity well is actually inertial motion, disregarding some nuance involving tides) means that the laws of physics are non-unique to your frame of reference, the mathematics are expressed the same way for you as they are for all the other inertial frames. Non-inertial frames, undergoing proper acceleration however will not only be mathematically expressed differently, but that expression will be solely unique to you and not necessarily true for any other accelerating frame. The most famous example being the centrifugal force which pops up in your equations of motion if you insist on considering a rotating frame of reference, but that centrifugal force will only be relevant to you. This doesn't mean fundamentally that inertial frames are the "correct" laws of physics, but their ubiquitous nature makes them philosophically pleasing--they are the laws of physics seen in the most generic way.
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Because of the Equivalence Principle(s) in GR, gravitational forces are no different from inertial forces which arise in non-inertial frames. For these inertial forces though, we have to introduce an extra force to introduce deviation from linear motion. Gravity, on the other hand, needs to preserve free motion while allowing for linear deviations, so we need to make the theory incorporate the idea of the curvature of spacetime. A common phrase in GR is 'Spacetime tells matter how to move, matter tells spacetime how to curve'.
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In terms of strength, how does caterpillar silk compare to spider silk?
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I found an article discussing this, the link is here: _URL_0_ Technically the article is comparing spiders to silk worms, but as silk worms are a type of caterpillar (albeit one bred for better quality silk), the comparison should still hold up. The key points are that spider silk is significantly stronger per unit weight (estimated at least twice as strong), but is much thinner (the actual thickness can be regulated by the spider).
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Its based on scale. Weight for weight, spider silk is actually stronger than steel. The key is silk is that it is also very tough (ductile), meaning it can undergo tremendous strain and it will plasticity deform without fracture.
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Could a person see a radio wave if it were intense enough?
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I don't know if this answers your question, but there are limits to the amplitude of a radio wave that could plausibly be present where a person was also there to observe it. For example, if the radio wave amplitude is extremely high, the electric field strength could exceed the [breakdown voltage](_URL_0_) of the air. At some radio wavelengths, strong fields could also become hazardous due to, for example, microwave heating, before they became strong enough to excite the receptors of the eye. There are also wavelengths, particularly in the infrared, where the light will be absorbed in the fluids (vitreous humors) of the eye and cause the eye itself to boil before they are strong enough to be seen.
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Yes, radio waves are (or consist of) photons too, and they have lower frequency (lower energy) than photons you can see with your eye. The energy of a photon impacts its 'absorbability' by various substances, too.
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When you get a sunburn, why does your skin feel warm/hot for the first couple of days?
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You're right. Sunburn is similar to any other kind of burn; there is an inflammatory response associated with sunburn, whereby vascular and lymphatic activity increases to deal with the damage done. Increasing the vascular activity in the tiny capillaries near the skin means that there is a higher heat transfer from the blood to the surrounding tissues, and seeing as how those tissues are near the surface, the heat is lost to the open air. That heat is what you feel. Further, sunburn is red because of the increased vascular activity near the skin too, which is similar to the redness you see when people blush.
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A sunburn is your skin's reaction to ultraviolet radiation. There are chemicals in your skin that breakdown under high exposure to ultraviolet radiation - four kinds of nucleotides specifically. When you body senses this breakdown it rushes in with blood, inflammation and attempts to rid of this now foreign broken down substance (being broken down it doesn't appear to be native "you" anymore). That causes the sunburn you experience.
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What makes Clingwrap stick to itself so well?
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Some cling wrap contain adhesives. The ones that don't aren't really adhesive on their own, so the plastic that's used is doped with smaller polymers like PIB and EVA that interact with each other strongly.
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Static electricity. That's the cling in cling wrap. Remove all the electrons from it and it looses that magic. Learned this from Mr. Wizard. The OG science guy.
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How accurate are depictions of 1970s American 'pimp fashion' in movies like Dolomite, and how/why did the styles develop?
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The 2002 book "Pimpnosis" by Tracy Fuches and Robert Marriott is a slim 150 page book with plenty of photos. It should answer most of your questions. _URL_0_ In a review in the August 2002 issue of Playboy magazine, they said it was the best book about pimps since Iceberg Slim wrote his seminal book "Pimp: The Story of my Life" back in 1967. Iceberg Slim's book is longer and has far fewer photographs. Iceberg Slim teaches his readers about the nuts and bolts of being a pimp. Pimpnosis looks more at the style of being a pimp.
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Now I'm super interested to look at these trends. Does anyone know a good source (or several sources) that give a nice overview of fashion in the last few hundred years?
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What is the scientific difference between fainting/being unconscious and being in a coma?
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Fainting is suddenly falling unconscious, usually for a short while. It's usually caused by a sudden drop in blood pressure, or a lack of oxygen that may be caused for some other reason. A coma is usually defined as being unconscious for at least 6 hours, and being unable to be awakened by light, sound, or pain. A coma can be caused by lots of different things, including chemical intoxication (drugs/alcohol), diseases affecting the central nervous system, violent trauma, or a prolonged lack of oxygen, any of which can damage the brain and so cause the coma. [Would you like](_URL_1_) [to know more?](_URL_0_)
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You're not unconscious, you're just in a different state of consciousness. Unconscious is when you're "knocked out"
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What is the difference between asperger autism and psychopathy?
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Asperbergers is often coined as "high functioning" autism, but truth is autism is a spectrum, I've worked with some people who have autism that are non verbal, can't even get dressed themselves in the morning, and then some people who have no issues doing normal tasks but will have struggles in social situations, loud noises, bright lights etc. So asperbergers is autism but often deemed more sociologically functional. Psychopathy is a lack of empathy, narcissism and pathological lying for your own self gain and is a personality disorder, whereas autism is a neurodevelopmental disorder.
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I had a look on scholar and couldn't find any papers looking at the comorbidity of autism with antisocial personality disorder (the diagnosis that psychopathy falls under in the DSM). This probably reflects the diagnostic differences between these disorders. [This paper](_URL_0_) found that the lack of empathy observed in children with autism and children who exhibit psychopathic tendencies are actually quite different. The lack of empathy in autism comes down to the difficulty in understanding what others think (lack of [Theory of Mind](_URL_1_)). The psychopathic tendencies appeared to be underpinned by an inability to reason about others' emotions. The main conclusions of [this paper](_URL_2_) are the same.
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The California drought is leaving rivers and lakes with less and less water, where is that water going?
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> Is that evaporated water moving to other regions? Pretty much. Evaporation of water in California is continuing but persistent weather patterns are leading to not much rain falling over California. The net effect is that that water ends up elsewhere.
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It's been a long time coming. In the 1980s, the average well depth in California farms was around 10 feet. Today, it's closer on 600-800 feet. California's population has continued to grow for decades, even as it's had to seek more and more water supplies from out of state or upstate, building pipelines through the mountains. California's use keeps going up. It's water table has been slowly depleting, and now it's almost gone. At the same time, climate change has marginally decreased annual rainfall. The fact is that California is overpopulated and overcultivated for it's natural water supplies. We're going to start supplementing the civilian water supply with desalination, but there is nothing that anyone can do for the farms, which use well water. Both sides will blame each other, but neither side's use impacts the other. In the end, California will become much more expensive to live in, and some of our food crops like lettuce, almonds, and avocados will go up in price.
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Why putting a hot piece of metal (i.e. an iron) straightens out wrinkles on a piece of fabric?
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It excites the fiber molecules making them expand and move more easily. Then when it cools they are held in a flat shape. It also explains how you get a tighter crease with an iron. Water/Steam helps with evening the heat transfer and lubricating the movement. For starch, you are just putting heat activated glue on your clothes.
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Friction between the molecules making up the object, this is not unique to plastic, any material will warm up when being bent or stretched because you are causing movement and therefore friction
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can erradicated diseases and/or pandemics occur from the rediscovery of artifacts, buried treasures, etc?
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Im pretty sure. I heard one about smallpox, thankfully we have the vaccination for it now. If bacteria is trapped in an artifact, upon discovery it can infect people.
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Yes. There is a reason disposal of corpses is invaluable during epidemics. The disease remains until the body can no longer sustain it as a host.
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If a black hole is a single point in 3 dimensional space how can we measure spin?
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As a cloud of matter collapses to form a black hole, it's going to have some total angular momentum; for example, it might be a rotating star undergoing gravitational collapse. Angular momentum has to be conserved even as the black hole forms, so the spacetime that results from the collapse is going to be one which reflects that overall spin. It doesn't quite mean that the singularity itself is spinning - it's not even clear what that would mean - but is a statement on the spacetime. The rotation leads to effects like [frame dragging](_URL_1_) and the existence of an [ergosphere](_URL_0_) which aren't present in non-rotating black holes.
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You can describe any general black hole with three quantities: the mass M, the charge Q, and the spin J (see [wiki](_URL_0_) for more). You are correct, you can get some strange effects, such as an inner and outer horizon, which is true if either Q = 0 or J = 0 as well (but not both).
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the difference between inductive and deductive reasoning
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Deductive reasoning reaches a conclusion from previous knowledge: All dogs are brown. Jack is a dog. Therefore, Jack is brown. Deduction reaches correct conclusions as long as the knowledge it's based on is correct. When the knowledge is not correct (as in this case), wrong conclusions may be reached. Induction generalizes observations into rules: Jack, Spot, and Pluto are dogs and they are brown. Therefore, all dogs are brown. Induction in general is quite unreliable, as your sample may be inadequate and you may miss counterexamples. Abduction reaches conclusions by elliminating possibilities: If A or B, then C. If D, then C and E. (There are no other known causes of C) A and C are true, E is false. Therefore B is true. You came back home and you found the meat is missing. Who ate it? Jack or Spot could eat it. Burglars could break in and steal it. You were taking Jack to the vet, so Jack couldn't eat it. There are no signs of a break in. So Spot ate the meat.
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Both are examples of [inductive reasoning](_URL_1_) and you could very well say that pattern recognition is a simple model. Model usually suggests that there is more rigor and some [deductive reasoning](_URL_0_) behind what is happening but there is nothing inherent about it. As an example I recently had to model the error of stochastic system, after measuring the error a few series of data and observing the general shape of the error I modeled it as additive [Gaussian noise](_URL_2_). That is I created a model based on recognizing a pattern.
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What does it mean when i hear people saying that time only exists this universe?
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time is a measure of change in the universe.
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We don't know. Whoever tells you otherwise is wrong. People often say that time is a property of this universe, ie. there is no "before" the big bang. That may or may not be the case. Big bang wasn't really "something from nothing" type of thing. Literally everything was already there, and now it's just spread out more. It is entirely possible that time did exist before the big bang. Things were just different then. We just don't know.
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Can mobile phones actually interfere with a flights navigation equipment? How?
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Almost certainly not. The problem is that it takes time and money to go from "almost certainly" to "definitely". The European aviation authorities have relatively recently allowed the use of mobile devices on aircraft, subject to each individual airline demonstrating to a satisfactory standard that the procedures they have in place, on their own specific aircraft, means that it can be done safely. I'm not sure how many airlines have actually gone through this process. My experience is with light aircraft rather than airliners. I know that a mobile phone can often cause a beeping sound on the radio, similar to what you sometimes hear if your phone is near a set of speakers when you receive a call or a text, but I wouldn't say this affects the safety of the flight.
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Apparently the phones create a lot of "noise" for the plane's system and airplane mode "silences"your phone as it's not searching for a network and stuff
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Why did Eisenhower fire Patton?
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After several earlier incidents involving slapping traumatized soldiers. in the post-war era as military governor of Bavaria he allowed former Nazi party members to participate in its regional government. Patton told the USA press that their party membership was just a compulsory event and no idealogical issue. Eisenhower did not agree and after a row Patton was replaced. Patton was a real war horse and hated the fact there were no more wars for him to fight. With the world going more politically correct, there was less space for the opinions of a war horse.
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He wasn't Supreme Allied Commander over all allied forces, he was Supreme Allied Commander for the Allied Expeditionary Force, which was the forces in NorthWest Europe. Forces in other theaters, such as the Mediterranean , Pacific or the Soviets in Eastern Europe did not report to him. He wasn't too worried about the Soviets until the two sides started getting close, at which point he started to send messages to the Soviets as to what they were up to and how to avoid shooting at each other when the two sides finally met. These messages initially met with some consternation in Washington, but upon clarification that the communication was purely at the tactical co-ordination level and not political/strategic, they relented. (See "Crusade in Europe, Eisenhower)
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Has anyone ever vertically circumnavigated the earth?
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I don't know whether mods will allow this answer, as the events we are talking about are fairly recent. Sir Ranulph Fiennes managed to circumnavigate the globe going through both poles in an expedition from 1979 to 1982. He is credited by the [Guinness Book of Records](_URL_0_) as the first to circumnavigate earth via both poles. If you want to be incredibly specific and only accept a journey that used only a ship as means of transportation, then the achievement is actually very recent. Adrian Flanagan actually circumnavigated the earth vertically. [Report by The Daily Telegraph on the feat](_URL_1_)
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If you did this through the North Pole, you would come our feet first, ignoring air resistance. If you did this anywhere else, you would slam into the side of the hole because Coriolis effect.
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Why do the layers of a star that were being pulled inward suddenly change direction and begin being pushed outward during a supernova?
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> What I'm not understanding is how so much energy that was originally going one direction can suddenly go the complete opposite direction for what seems like no reason. The same thing happens in internal combustion engines with the pistons. So, as for the star: You have the core producing some amount of energy which creates pressure to keep the outer layers of the star from going closer to the core and compressing it. Once the regular fuel of fusion is spent, the core suddenly no longer produces enough pressure. Queue the outer layers falling down towards the core. That in turn compresses the core and the layers above the core so much that these layers suddenly start fusing themselves. Now you have a hole lot of pressure from these newly compressed and fusing regions which is so much that it simply *halts* the collapse of the outer layers and **shoves** them away from the core.
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The solar system didn't just form out of the ejecta of a supernova, but out of the Interstellar Medium (ISM) which had been heavily enriched by nearby supernovae. Additionally, a supernova just means that all the hydrogen in the core has been exhausted. Some stars that go supernova have hydrogen in their outer layers, and the rest of them have usually blown a great deal of hydrogen back into the ISM during their asymptotic giant branch (AGB) phase late in their life.
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Are insect cells smaller than the cells of larger mammals?
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As a general rule, animals that are smaller tend to have lower cell counts, rather than having smaller cells. There's a size limit on how small things can be before they get too small to be useful. Anyway, even within one organism there's a huge range in sizes. So generally, fewer cells, rather than smaller. I can't give exact details though.
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From my understanding, it was mainly insects that were larger because of higher oxygen concentrations. This is because they get oxygen by diffusion of air into their bodies throigh small holes on their exterior. Since larger bodies meant the oxygen outside the body was more distant from the inside, a higher concentration was needed to get the needed amount inside. The higher the concentration of oxygen in the air, the more oxygen that would ultimately make it into their larger bodies.
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