title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"How can cows just eat grass when we need a balanced diet?"
] | [
false
] | null | [
"Well not all fermentation produces ethanol. Fermentation essentially refers to metabolism that occurs without oxygen. Not all species produce ethanol when they do this. According to Wikipedia the microbe community inside a rumen produces mostly volatile fatty acids which are absorbed as a source of nutrients, as ... | [
"Could you then tell what is a proper diet for a dairy cow? Or a good source on that?"
] | [
"Could you then tell what is a proper diet for a dairy cow? Or a good source on that?"
] |
[
"When observing an isotope over it's half-life, what determines which half deteriorates? Is it always exact? How?"
] | [
false
] | Isotopes have always evaded me as far as understanding. How do we understand this half-life concept so definitively that we can use it for so much? | [
"Atoms of a radioactive substance decay at ",
". There is no way to predict when any particular atom will decay.",
"That being said, there are some things you can say. If you have an atom you might expect it to take \"a long time\" to decay or maybe \"just a few seconds\". This is an informal way of expressing ... | [
"Exactly. The secret lies in the great numbers. Most people fail to grasp the sheer amount of atoms in a tiny portion of matter. It makes understanding and more so handling nuclear physics really difficult."
] | [
"Its not that it breaks down, as the smaller numbers means that instead of measuring number to a good approximation, it just shows the underlying physics that it's the expectation value that an atom will still exist after some time. The quantum nature of the nucleus transitioning to another state is where the rando... |
[
"Why do many humans have involuntary physical reactions to being tickled?"
] | [
false
] | Is the response to being tickled something that was evolved for a reason? My best guess is that it could alert us to creatures touching our skin or something like that. | [
"wiki on tickling",
" does a good job with this, stating that one of the 2 types of \"tickling\" called Knismesis (the irritating kind that doesn't make you laugh) is often elicited by insects..",
"My favorite line from it: \"Heinz Heger, a homosexual man persecuted in the Flossenburg concentration camp during ... | [
"He contributed a perfectly valid idea and admitted that he wasn't sure if it was true. I don't understand why that deserves to be downvoted so much. "
] | [
"He contributed a perfectly valid idea and admitted that he wasn't sure if it was true. I don't understand why that deserves to be downvoted so much. "
] |
[
"Some nightmares feel so real they leave you feeling traumatized, why would a brain traumatize itself?"
] | [
false
] | null | [
"What I've always been fascinated with, and had a hard time wrapping my head around, is similar to the question posted. How is the brain able to create an environment where it is both the actor and the creator, and yet devoid of that knowledge. That is to say, in a dream, you are creating the environment, but also ... | [
"How does the evidence stack up for dreams as training simulator for possible situations, vs dreams as random noise being interpreted as images and sensations? Claims like this always strike me as \"ad hoc\" or \"just so\" claims. Its possible dreams have little or no impact on genetic selection and it's really jus... | [
"How does the evidence stack up for dreams as training simulator for possible situations, vs dreams as random noise being interpreted as images and sensations? Claims like this always strike me as \"ad hoc\" or \"just so\" claims. Its possible dreams have little or no impact on genetic selection and it's really jus... |
[
"Is it possible to define electric charge in an absolute (non relative) sense?"
] | [
false
] | A positive charge is the opposite of a negative charge. But is it possible to define one without referring to the other, or they solely relative terms? A book I am reading claims it is not possible, and as a consequence the two charges could in theory swap throughout the entire universe, and nothing would be observed as different. It sounds very odd and i was wondering if the basis is true. | [
"For most purposes, you could swap the charges and everything will be the same. This is known as ",
"C-symmetry",
". But it's not perfect. The weak force violates C-symmetry. In order to get it to work right, you also have to mirror everything and swap the direction of time. This is known as ",
"CPT-symmetry"... | [
"This is the correct answer, just to clarify a bit some possible confusions. ",
"Which charge you decide to call negative and which you decide to call positive is completely a matter of convention.",
"But, once you have made the choice you cannot freely swap them arbitrarily because our universe is not entirely... | [
"The definition of one charge as negative and the other is positive is completely arbitrary. We could just as easily have defined the electron as having a positive charge and still be able to describe the same physics with the same math.",
"The swapping of positive and negative particles is definitely possible wi... |
[
"Why does the sunset appear blue on Mars?"
] | [
false
] | null | [
"I think that he was talking about real (not white balanced) Martian sunsets from Curiosity. Examples include ",
"this",
" and ",
"this",
".",
"There's an explanation in the page.",
"Mark Lemmon, of Texas A&M University, College Station, the Curiosity science-team member who planned the observations, sa... | [
"You have a picture? It might be color manipulation and not true color. For instance, here's Curiosity's view of Mount Sharp: ",
"Raw color: ",
"http://photojournal.jpl.nasa.gov/jpeg/PIA16769.jpg",
" ",
"White balanced: ",
"http://photojournal.jpl.nasa.gov/jpeg/PIA16768.jpg",
" ",
"The second image... | [
"You appear to have linked to the same picture (same URL) for both the raw colour and white balanced images."
] |
[
"What does it mean to be tidal locked to something?"
] | [
false
] | I am under the understanding that the moon is tidaly locked to earth, what does that mean and why has this arisen? | [
"Tidal locking means that the same face of the Moon always points toward Earth.",
"This occurs because tidal forces--the difference in gravitational tug from the Earth between different parts of the Moon-- cause small distortions and stretches in the shape of the Moon. These distortions dissipate the moon's rotat... | [
"Longer than the Sun's lifetime. We'll be toasted to a crisp before that has time to happen."
] | [
"Earth's day used to be about 6 hours. Wouldn't the moon be more responsible for this than the sun though? "
] |
[
"What is the geographical causes for long, thin stretches of land offshore from mainland areas? For example, Outerbanks, NC, Longboat Key, FL, or Pensacola Beach, FL?"
] | [
false
] | null | [
"These are barrier islands, basically a large sandbar. A number of theories for their formation can be found in Wikipedia. A combination of tides, wave action and the effects of glaciers are the main mechanisms forming barrier islands"
] | [
"Waves, tides, and storms deposit sand and silt near shore that eventually builds up into these barrier islands, that then get colonized by plants, birds, and other life, which increases their physical stability. Not they do routinely get wiped out by particularly heavy storms; responsible governments pay dredging ... | [
"The outer banks (and similar islands up to coast to Cape Cod) are barrier islands. Waves act to push coastal sediment coming out of river estuaries into berms along the beach, and then storms have flooded and eroded out the flat plains behind these berms.",
"The Florida Keys are formed from barrier reefs. A coas... |
[
"How does the renal HCO3- reabsorption increase blood pH?"
] | [
false
] | Hello, this thing is completely destroying my brain. HCO3- in renal tubules is "reabsorved" into the circulatory system through a bunch of reactions involving the carbonic anhydrase. Basically: - It combines with H+ forming CO2 + H2O, that can enter the tubular cells; - The reverse reaction happens inside these cells: forming HCO3- + H+. The HCO3- is reabsorved into the blood, and the H+ goes back to the renal tubules to restart the cycle with another HCO3-. I dont get how this is supposed to eliminate H+. Isn't the H+ net equal to 0 ? Also, how does this make the pH higher? If it reabsorbs the HCO3-, then the H+ used wont be eliminated and vice versa, so I don't see how any of these actions (one or another) could make the pH higher. Sorry if it is confusing and thank you. | [
"Your body secretes H+ and HCO3- through the kidneys. They combine to form H2CO3 (carbonic acid). An enzyme, carbonic anhydrase, splits the carbonic acid into H2O and CO2 in the renal tubular lumen and this water and carbon dioxide enter the renal tubular cell passively. This is because carbon dioxide is lipid solu... | [
"This",
" picture can be helpful"
] | [
"It doesn't directly eliminate H",
" from the body. As you said, there is net zero transport of H",
" Instead, a base (bicarbonate) is reabsorbed into the body.",
"You should not believe that every bicarbonate ion actually reacts with an H",
" ion -- there is a complex buffered equilibrium. But each reabsor... |
[
"Where does the logic of DNA codons come from?"
] | [
false
] | I was talking to a friend recently who is studying to be a microbiology major. She was showing me some of her material regarding genetic code. Her homework was to explain a line of genetic proteins. The page looked like a series of ATCG in what looked to me to be totally random order. She showed me how she broke down the code into blocks of 3 which corresponded to 64 codons. My understanding was that the codons form some sort of "letters" to be used in genetic code. I understand the basics of the proteins that make up DNA, but the codons baffle me. My question is, where did the underlying logic behind these codons come from? I somewhat understand how the codons form letters, but how do those letters create something such as skin or hair color? I tried Google and most of the explanations were religious or attempting to disprove evolution. I'm not interested in that, but I have to admit I'm at a total loss to explain how series of proteins form letters which then become a sort of language of life. Forgive me if my terminology or understanding is off. I'm definitely a layman when it comes to biology, but I like to learn. Just curious about life. Thanks for taking the time to read this. | [
"Lets say there is a stretch of DNA that is 306 bases long, Those 306 bases can me read over into a 306 base-length strand of mRNA, made up of 1 'start' codon, 100 'letter' codons, and 1 'stop' codon. As you correctly stated, each 'letter; codon corresponds to a specific ",
". Amino acids are the building blocks ... | [
"You have things slightly backwards. DNA is made up of nucleotides (the A, T, C, G) which are the letters you see when you read DNA. A codon is simply 3 of these letters grouped together. This is because the RNA polymerase reads in blocks of 3, and each block of three codes for an amino acid that will be added next... | [
"To add to baloo's answer:",
"Codons are read as sets of 3 nucleotides by the ribosome through the use of tRNAs. The ribosome doesn't read DNA, just mRNA (messenger RNA). A tRNA is a specific family of RNA molecule that has an amino acid attached at one end of the RNA. It stands for \"transfer\" RNA because it ge... |
[
"Can undersea cables undergo creep rupture?"
] | [
false
] | The pressure down there must be quite high. Is there any proof that undersea cables have undergone creep? | [
"Submarine cables used to fail for lots of reasons. Modern ones fail for three reasons: manufacturing defects at joints, dragging anchors close to shore, and deliberate interference.",
"In modern material terms the pressures involved are not that impressive. Transocean cables are laid at around 3-4km depths, whic... | [
"This is my new favorite qualifier, \"as an engineer completely unqualified in this area\" definitely going to use this someday"
] | [
"This is my new favorite qualifier, \"as an engineer completely unqualified in this area\" definitely going to use this someday"
] |
[
"Why does COVID-19 seem to have so many more variants than other pandemic-inducing pathogens?"
] | [
false
] | To clarify, the title is merely my perception of the situation, not an assertion of fact! Basically it feels like compared to other pandemics in history, such as Spanish flu, the pandemic resulting from this particular coronavirus has included many more variants and possibly is more long lasting. My guess is that compared to former pandemics, we are simply a lot better at identifying new variants, so prior similar episodes were lumped into one single pathogen? As for the longevity, it may be because we're actually a lot better at preventing death and spread than in previous pandemics, there are more uninfected people for a longer period of time leaving them open to infection for longer? These are just some of my guesses, but i'm curious if my perception is just simply incorrect or if not, what the actual reasons are behind these phenomena. | [
"Because this is the first pandemic in the era of rapid genome sequencing. Previous pandemics had lots of variants as well, but even during the most recent pandemic, 2009/10, rapid genome sequencing was just getting started."
] | [
"This is really the correct answer. It’s not just that the technology exists, but it’s also relatively inexpensive, widely available, and automated.",
"This is the first pandemic where we could identify strains precisely at their genetic level and observe the movement and evolution of virus in real time."
] | [
"Also because there are so many cases, this virus is gettig more play than most viruses, it's a numbers game on the mutations.",
"But covid actually has a double proof reading function and is less liable to mutate than other viruses like influenza, but if you get tens of millions of cases, hundreds of millions, a... |
[
"Does soap/detergent \"clean\" or does it just lower the surface tension of water?"
] | [
false
] | I read that warm water cleans better because it has a lower surface tension. Essentially making it a better "wetting agent" allowing water to get into the pours and fissures more easily. I went on to read that detergents lower the surface tension of water. Wondering if soap/detergent actually does anything in the way of cleaning besides lowering the surface tension, or if it's just all the act of the water? | [
"Detergents are a type of molecule that is amphiphilic, meaning it is partly hydrophilic (water seeking and polar) and partly hydrophobic (water repelling and non-polar). This allows polar and non-polar substances like oil and water to mix. From a practical standpoint, using detergent in water just allows that mixt... | [
"To add to this: effectively, one end of the molecule will be attracted to the food, and the other end to the water. So it sort of pulls some molecules of the food away from the bulk and into the water."
] | [
"In most cases you're not speeding up any kind of dissolution with soap; it basically just enables two things to mix that normally will not. If you have oil stuck on a dish, you can blast some off with water, but this is really just a physical process. Soap will allow the oil to dissolve (well, emulsify) in the wat... |
[
"Angular Momentum vs. Linear Momentum"
] | [
false
] | Say I am flipping a coin, from all the energy and force input into the coin from my finger, what determines how much energy goes into linear motion and how much goes into rotational motion. To simplify, here's an example problem: Say I have a rod of length L, and has a mass of M (that is evenly distributed along the rod). Say at a distance D from the end of the rod, I apply a force F on the rod at an angle of 90 degrees (so perpendicular to the rod pushing at the rod), for a time of T. Now I have the change in momentum (impulse) from F*T, at the point on the rod. But how can I tell how much of the momentum is angular and how much is linear? | [
" change momentum, ",
" change angular momentum. Just because the contact between your finger and the coin is applying both does not mean it somehow has to distribute between the two: they are different things.",
"EDIT: I think that the problem is that your intuition that you have to divide what you're doing in... | [
"And yet, his is perfectly legit."
] | [
"Awesome! I understood that. I'll have to look into the math myself to work it out a bit, but I think I get it."
] |
[
"We toss and turn in our sleep. Why don't we fall out of bed (more often)?"
] | [
false
] | [deleted] | [
"Knowing where you are is as much a subconscious process as it is a conscious process. The brain stops you from falling out of bed the same way it prevents you from falling out of a chair when you stop paying attention. ",
"Here's a deeper explanation from a sleep expert \n",
"https://m.youtube.com/watch?v=FIZA... | [
"During sleep, the brain cycles between deep sleep and relatively shallow REM-sleep states during whoch we dream, and sometimes even form memories we can recall later. We are only physically active “tossing and turning” during shallow sleep phases and lie quite still during deep sleep. Also, never mind the movemen... | [
"So does this mean we never rest fully and deeply as part of us is always awake and on guard!?"
] |
[
"How does the body deal with ingested protein?"
] | [
false
] | [deleted] | [
"You are correct in your guess that it breaks them down into amino acids. Some are essential and must be part of our diet and the rest we can synthesize ourselves. The number of essential vs. nonessential keeps changing, but I believe we are up to 11 nonessential and 11 essential. "
] | [
"So I guess my secondary question is: Could we just drink a solution of amino acids? Or even just short polypeptide chains? I mean I feel like the answer is yes, but maybe I'm overlooking something."
] | [
"Or does it keep them intact and direct them where they need to go? ",
"This has two problems: ",
"There is a tight barrier of epthelial cells between the contents of the gut and the body proper. Otherwise the body would be awash in bacteria.",
"The foreign proteins would cause all sorts of trouble. Foreign... |
[
"How do children who haven't learned to speak yet think? How do animals and small children think without language?"
] | [
false
] | null | [
"In reading \"the dragons of eden\" by the late great Carl Sagan he said that it may be fairly similar to the way you think in a dream state. While dreaming, though you may not have noticed, you usually can't read or do math. Even though you may recognise a stop sign, you probably will not be able to read the word.... | [
"I think they think in impulses. ",
"it's hard to wrap your head around now, but imagine this scenario: have you ever done anything without thinking about it? Some kind of task that you've done enough, you could almost do it in your sleep? What is your thought process during those moments? Mostly empty, right? Wi... | [
"Think of it like getting bored with Reddit, and then opening up another tab of Reddit. You do that without thinking, and then you're like \"wtf\". You opened it because you're so used to getting bored on something else and going to Reddit that you do it in this instance."
] |
[
"How can hospitals check to see that operating rooms are sterile?"
] | [
false
] | Alternatively, how do we check to see how sterile a room is? | [
"As someone who works in the OR, I just wanted to mention this is the only correct answer in this thread."
] | [
"As someone who works in the OR, I just wanted to mention this is the only correct answer in this thread."
] | [
"They gas hospital rooms to sterilize them? Do you know what gas is used? "
] |
[
"Has the Earth always rotated on a 24 hour cycle and revolved around the Sun in 1 year?"
] | [
false
] | was there a time when it rotated/revolved faster/slower? | [
"I stand corrected. Thank you for the information, and I withdraw my previous comment."
] | [
"There are tidal rhythmites in Utah that show that the Earth used to have ",
" an 18 hour day, 750 million years ago"
] | [
"Tidal Acceleration",
" and geologic history beg to differ"
] |
[
"Roughly speaking, is salt evenly distributed in ocean water?"
] | [
false
] | Disregarding things like salt stuck in rocks at the bottom of the ocean. Thank you for replying. | [
"I would disagree with the previous two posters. The salinity of the ocean at the surface, shown ",
"here",
", is not uniformly distributed. The average salinity is 35 PSU (which means that each 1000 grams of water contains 35 grams of salt). The variation is about from 31 PSU to 39 PSU, which is a percentage v... | [
", salt is uniformly distributed in the world's ocean. ",
"/u/grapheneman",
"'s answer is basically correct but they were unfortunately downvoted. Yes there are also variations in salt but they are relatively small. Mean salinity is 35‰ and probably about 98% of the ocean by volume is between 34‰ - 36‰. Ther... | [
"Yes! Sound waves are just pressure waves, and pressure is a function (mostly) of the local density, which can be changed by changing the temperature or salinity."
] |
[
"How much heat (if any) reaches the surface of the Earth from the mantle?"
] | [
false
] | Besides volcanoes and vents, is there any heat reaching the Earth's surface through conduction? | [
"You bet it does. Not at lot, but yes.",
"Heat flows outward from the earth's core and mantle, ultimately to radiate out to space, in exactly the same way heat flows out of a bowl of hot oatmeal. ",
"This effect was used in the Apollo program",
" to assess the rate of heat flow out of the moon's core, as a wa... | [
"Wouldn't ",
" of the heat reach the surface? If the Earth's temperature is stable the heat must be flowing out as fast as it is produced, no?"
] | [
"Wouldn't all of the heat reach the surface?",
"Yes, but not all at once. The surface can radiate its heat away to space pretty easily, but is supplied with more heat from below. Still, eventually all of that heat will dissipate, at which point the earth will freeze solid, we'll lose our magnetic field, solar win... |
[
"Psychologists! If someone were assigned to periodically check-in on the progress of a chronic procrastinator's task, would it help them toward accomplishing their task?"
] | [
false
] | This idea came from a conversation between my wife, who is a very motivated/on-task person, and myself, a lifelong procrastinator. I hypothesized that if I informed someone of my desired task and the time/date to accomplish it, and I instructed them to occasionally check in on me for any measurable progress, this might act as a motivator for me to stay focused on said task. Initially I thought this wouldn't work based on the experience of living with my parents. Growing up, they'd often remind me of all the things I didn't want to do ("Have you done your homework?", "Have you cleaned your room?", "When are going to mow the lawn?"). However, the scenario I am presenting assumes the procrastinator to accomplish the task, and to be reminded and account for his/her progress. Would this work? Would it be sustainable? | [
"Checking up on progress is only one part of a reasonable solution... The next step is positive reinforcement any and all progress. Procrastination can be conceptualized as a negatively reinforced cycle. First, you start working on a task, or just think about starting, which leads to some sort of negative emotion -... | [
"Wow! I was not expecting a response to this, so thank you very much for doing so. I appreciate the detail you've gone into as well. From what it sounds like, positive reinforcement is absolutely key here in order to make any changes.",
"I did have one other factor to throw into this scenario that may or may not ... | [
"I think the effect from a previously unknown person would be much less than someone you know and expect to see again."
] |
[
"How would a helium balloon behave in a pressurized zero G environment?"
] | [
false
] | my guesses are it would either float towards the middle of the room or behave like a generic rock would in zero g. Also, if a spaceship were to accelerate and cause artificial gravity, would the balloon move contra the direction of gravity? | [
"Helium balloons float on Earth's surface because they are less dense than the air that would be occupying that space. Earth's gravity pulls all objects (including air and balloons) downward, but since the air weighs more, it fills that space and pushes the balloon upwards.",
"In zero G, zero net acceleration en... | [
"the second scenario highlights the equivalence principle, doesn't it? Stuff that happens in gravity based reference frames also happens in reference frames that are under any other type of acceleration"
] | [
"This is accurate, and is a classic example of the principle. The only caveat is that the rocket must be accelerating at a constant rate, such that the inertial effects are consistent."
] |
[
"Can the extraction of raw materials significantly influence the rotation and circulation of the Earth?"
] | [
false
] | null | [
"I think so, because the distribution of Earth's mass is changing. In addition, the Earth loses fractions of mass percentages by sending satellites / rockets."
] | [
"Hello,",
"Open-ended or hypothetical questions are more appropriate for ",
"/r/AskScienceDiscussion",
".",
"Cheers."
] | [
"ok thanks, I will ask it there because I'm curious."
] |
[
"/r/AskScience Vaccines Megathread"
] | [
false
] | Here at we would like to do our part to offer accurate information and answer questions about vaccines. How vaccines work The epidemics of an outbreak How vaccines are made Please remember that Do not post any personal health information here; it will be removed. Likewise, we do not allow anecdotal answers or commentary. This thread has been marked with the "Sources Required" flair, which means that answers to questions contain citations. Information on our source policy is . Please report comments that violate the guidelines. Thank you for your help in keeping the conversation scientific! | [
"There was a chance (",
"1/750,000",
") of contracting \"vaccine-associated paralytic poliomyelitis (VAPP)\" from the live, oral form of the polio vaccine. When polio was rampant, the risk of contracting the disease \"out in the wild\" was considered worse than than the risk of contracting it from the vaccine. ... | [
"There was a chance (",
"1/750,000",
") of contracting \"vaccine-associated paralytic poliomyelitis (VAPP)\" from the live, oral form of the polio vaccine. When polio was rampant, the risk of contracting the disease \"out in the wild\" was considered worse than than the risk of contracting it from the vaccine. ... | [
"As nearly any drug, vaccines can have several different side effects and can cause allergical reactions.",
"http://www.cdc.gov/vaccines/vac-gen/side-effects.htm"
] |
[
"If a blade such as a knife were to be completely sharpened, down to the molecular and atomic level, could it theoretically cut through ANYTHING? If so, what metal would the knife have to be made of?"
] | [
false
] | null | [
"No, the bonds at the very edge of the knife would have to be stronger than the bonds of the object you were trying to cut, and significantly strong, since you are putting more energy into the knife bonds by breaking more other bonds. The knife would blunt almost immediately anyway."
] | [
"Yes, if it was indestructible and provided with enough force it could cut through anything. Unfortunately that kind of bond does not exist."
] | [
"The knife would also have to be rigid enough for the bit not to fold over"
] |
[
"What's the deal with the squiggly lines when I mix alcohol and water/pop?"
] | [
false
] | [deleted] | [
"Your hypothesis is correct. Alcohol and water bend light differently, and having an incomplete mixture of the two causes certain areas to refract light one way and other areas in another. The result is the borders between areas become very apparent. "
] | [
"You aren't making your drinks strong enough. Seriously. I can't see it with a shot of alcohol in a big cup of coke but if I see the squiggles I know I'm in for a good night."
] | [
"Awesome, thanks!"
] |
[
"Is it true that marine iguanas boil the algae they consume before digesting them?"
] | [
false
] | Hi. I'm reading Kurt Vonnegut's Galapagos and at one point it says that marine iguanas dive underwater, scoop a large amount of algae and then bask in the sun to increase their body temperature until the algae have been boil and cooked, at which point they are soft enough to be digested. It even says that the digestive system forms a kind of pressure boiler. I've found this fascinating, but I haven't been able to confirm it. I've seen many pictures of iguanas basking in the sun and information about how much and which kinds of algae they eat, but I find no mention of the boiling part. Can anyone confirm it/debunk it? Edit: yeah, I know they can't literally boilt it or they would boil themselves in the process and die. My question is if they do use the heat and maybe, somehow, pressure in order to make algae more digestible. | [
"Vonnegut is taking artistic license here. Marine iguanas do not and cannot boil anything within their stomachs. The only thing I can think of is he is assuming they are basking after their dives in order to \"cook\" their food, but in reality they need to increase their lowered body temperature after losing energy... | [
"Theres no way an animal can \"pressure boil\" food inside them so nah. The point of the pressure in pressure cooking is to raise the steam temp since waters temp can't exceed boiling so you're saying it goes beyond 212f/100c Inside an animal lol. Maybe this animal does spit up seaweed and let it cook in the sun an... | [
"Vonnegut was being hyperbolical here. That is, a rhetorical statement that is deliberately exaggerated as a metaphor, which is not meant to be taken literally.",
"The water around the Galapagos is normally quite cool, around 15-20°C. This compared to the temperature on land which can reach 30°C in the summer. ",... |
[
"AskScience AMA Series: I am /u/pengdrew, a physiologist that studies Penguins! I study the physiology of aging in wild penguin species and am here to any questions you have about penguins, aging and physiology/ecology! AMA!"
] | [
false
] | Hi Reddit! I am a PhD physiologist and ecologist studying the physiology of aging in wild penguins! I am currently in the second year of my PostDoc studying stress hormones, aging, and ecology in Spheniscus penguins. Specifically my work explores the relationship between stress hormones, telomeres and life-history decisions (reproduction, mating, growth, etc) in a very long-lived seabird! I'm excited to talk about: A few other notes on me: I will be here from 12:00pm - 2:00pm PST (15 ET,20 UTC) to answer your questions… ! | [
"I've heard penguins can get a bit...rapey. There was even a paper that got published, and then was retracted by its author because he was so shocked by penguins sexual behaviors. ",
"What makes it so shocking ?",
"Is there a way that paper will ever be republished?",
"Thanks!"
] | [
"Are you referencing the observations from the Scott Expedition? I'm not aware of any retraction of a specific paper, the observation and notes from that expedition are on display at the British Antarctic Survey IIRC.",
"Edit: While I have not personally witnessed any similar observations in my field study. I hav... | [
"I've never been so excited for an AMA before! I hope you dont find my questions too silly or simple since I just love penguins and don't really have a science background:",
"1) emperor penguins get the most recognition (Happy Feet & March of the Penguins) but do any other species go through the same trials? ",
... |
[
"Would it be possible to get a good parallax view of the stars by taking one image from earth and then another image in the same direction near the edge of the solar system?"
] | [
false
] | I mean, enough of a parallax that if viewed together side by side or on a 3dtv, that we'd be able to see a clear 3d view of most of the stars in the image? If not, how far would we have to travel before such a view would be possible? | [
"astronomers actually do use parallax more easily than that - two pictures from earth 6 months apart to use the size of earth's rotation.",
"http://en.wikipedia.org/wiki/Stellar_parallax",
"the differences are very small though, and even with computers, this is only useful for stars that are pretty close to us ... | [
"For many stars, the parallax of the Earth around the sun is too tiny for even computers to measure. Parallax is measured in arc-seconds, or 3600ths of a degree. For objects farther than about a hundred or so parsecs, it is basically infeasible to measure their distance using this parallax (according to Wikipedia t... | [
"At distances on the order of the size of the solar system, you could probably determine some parallaxes by hand, a larger number by computer, but still most would not be observable at all. Maybe you could get most of the stars in the galaxy, but for other galaxies, the parallax would still be far too small."
] |
[
"Are linear polarizers conductive perpendicular to the plane of polarization?"
] | [
false
] | From my understanding, and please correct me if I'm wrong, linear polarizers such as the ones in old 3d IMAX glasses (before they started being also circularly polarized), polarize light going through it by selectively absorbing the light whose electric field is lined up to induce little currents in the material. The polarizing material, of the sort that i'm talking about, not of the reflective type (with brewster's angle and the such), contains parallel conductive pathways so that electrons are only really free to move in one direction in the material - hence the selective absorption. Shouldn't this mean that polarizers are conductive along these conductive pathways? Is this true only in the ideal case? What I mean is...in actual linear polarizers, are the conductive pathways not necessarily connected - they are just all aligned? | [
"Some linear polarizers are made by etching gold into tiny wires (called a wire grid polarizer); these will definitely conduct. Other designs use long strands of conjugated polymers; though these are conductive locally, they aren't much better than a plastic at macroscopic scales."
] | [
"That's what I thought. Do you know what the first type you mentioned is called or where I would possibly get it?"
] | [
"They're pretty common in infrared spectroscopy, but expensive and unnecessary for visible light. In any case, here are some carried by ",
"Edmund Optics",
". The other optics guys also carried similar stuff at similar prices."
] |
[
"Why do rockets and other space probes spin/roll?"
] | [
false
] | Like for example take the Perseverance rover. In the animation that NASA uses, it shows the entry capsule to be spinning through space, and once they hit the Martian atmosphere, reverse thrusters stabilize it. Is spinning your way through space somehow important or beneficial? PS. First time posting anything on Reddit, please forgive and tell me if I did something wrong XD | [
"It's called spin stabilisation. A spinning object will tend to keep its spin axis pointing in the same direction. Many spacecraft have used it.",
"It's actually less common nowadays. Three axis stabilisation, using electronics to measure the spacecraft orientation and thrusters to keep it that way, is the altern... | [
"On top of spin stabilization as ",
"/u/cantab314",
" said it can also help with thermal control depending on the spacecraft design. In that case it's often call the \"BBQ roll\". You spin slowly so that there is not one face facing the sun all the time getting too hot. It makes sure that all external surfaces ... | [
"I believe so, yes.",
"The page below mentions course correction burns by New Horizons. It mentions that for some corrections the spacecraft was in fact spun up for the burn, presumably having been non-spinning or spinning in a different orientation previously. Then spun down again after. The propellant used to s... |
[
"Is it true that COVID can make you lose memories?"
] | [
false
] | I’ve heard someone talk about it in the school, a girl might not be able to take the final exam at the end of the year, because she had corona. She lost significant amount of her memory, and doctors don’t know if she will recover. Is it true? | [
"Memory problems and other neurological symptoms do seem to be fairly common after recovering from COVID-19. For example, New York Times, Oct. 11: ",
"‘I Feel Like I Have Dementia’: Brain Fog Plagues Covid Survivors. The condition is affecting thousands of patients, impeding their ability to work and function i... | [
"It's important to qualify what we mean by \"memory loss.\" Colloquially, when we casually refer to \"memory loss,\" what we're usually talking about is ",
"retrograde amnesia",
", which is roughly \"something making you forget things you used to remember.\" This is usually associated with something significant... | [
"https://www.healthimaging.com/topics/advanced-visualization/covid-19-brain-abnormalities-mri",
"Simplifying it a lot, some have lesions in brain tissue after recovering. A general inflammation may be recoverable, but some of these complications will stay with you forever."
] |
[
"If the earth was not spinning around itself, would the apparent gravitational force be different?"
] | [
false
] | [deleted] | [
"Yes, but very slightly. The acceleration due to gravity you feel due to earth's gravity is ~10m/s",
" The acceleration you feel on the equator is about 0.03m/s",
" less than at the poles due to the rotation of the Earth."
] | [
"Oh, I thought that the 0.03 difference was due to the earth being a little \"fatter\" on the equator compared to the poles and not due to the tangential speed."
] | [
"the effect of the earth's rotation on gravity is called \"Coriolis Force\". It's pretty small, compared to \"regular\" gravity, but its impact is huge on the climate, shaping the path winds take.",
"here is a cool video to demostrate what the coriolis force and its associated effect is:\n",
"http://www.youtube... |
[
"How much lead would be equivalent to Earth's atmosphere when it comes to stopping radiation."
] | [
false
] | Does this even make sense? | [
"There's no hard and fast answer to this question - lead has an atomic number of 82, while the atmosphere has a very low average atomic number (in the range of ~7). Depending on what type of radiation (photons, protons, etc) or the energy of those particles, the effectiveness of shielding can vary wildly with Z. ... | [
"Keep in mind that Earth's atmosphere is not the only radiation stopping tool. In fact the magnetic field set up by its rotating core acts as a barrier as well, redirecting most of the cosmic rays that would otherwise strike the surface."
] | [
"Since you can't assume that the atmosphere has the same density at all the altitudes, I don't think you can calculate the answer to my question with only those values."
] |
[
"What do neutron stars really look like?"
] | [
false
] | Neutron stars are almost always depicted faint with surface features readily visible, spinning rapidly on its magnetic axis. However, pulsars such as the crab pulsar do not certainly look like this. Before you answer, just know I already l know what hotspots and the precessing astrophysical jets are, so you don't need need to explain it. What I'm curious about is the atmosphere (Corona) of the star and how the magnetosphere and gravitational lensing affects it. Also how bright would the jet be in comparison to the neutron star? | [
"Accretion jets are black holes. They're completely different than the energy jets from pulsars. The glow from the jets and the gas in the nebula is a reaction with the light rather than the original light itself. That's why there are a variety of colors. Its because of the variety of materials the light is reactin... | [
"The jets and the neuteon star probably wouldn't be very bright at all from your perspective as far as stars are concerned. The star would likely be a faint bluish white. This is because most of the light would be emited in the ultra violet+ range, so you would only be able to see the bluish white on the visible en... | [
"A hot blackbody IIRC doesn't stop or reduce emission at lower frequencies as it heats up, but rather increases emission across the whole spectrum. So a hot neutron star would appear blindingly blue-white at any visible distance."
] |
[
"What is a plausible scientific explanation for \"glory clouds\" in church services?"
] | [
false
] | I read a NYT article about a runner that relied on his faith. He mentioned something about "glory clouds" during his church service. Being the skeptical citizen I am I was curious and googled it. I found a few youtube videos of the phenomenon occurring in their church (Bethel Church in Redding, CA). I googled around to see if there was a debunking and I found nothing more than some suggestions that it was either a malfunctioning in their ventilation system, or a good old fashioned glitter dump. Are there any reasonable explanations here? Or is trickery at work? Thanks! NYT article: Youtube video (one of many similar): | [
"Edit: Probably ",
"This.",
"It is most likely due to the condensation of water from evaporated sweat and breath. Supposedly if one of Hitler's buildings had been created the amount of people within the room's combined water generation would cause rain. ",
"Most likely in the video the air conditioning system... | [
"That's dust. Definitely dust, you can tell by the straight line it makes coming from the light. "
] | [
"Hitler's buildings",
"what?"
] |
[
"How do erasable pens work?"
] | [
false
] | How does the ink and eraser of an erasable pen work? I've been curious for a while. | [
"Thermochromatic eraseable pens are a recent innovation. The first eraseable pens, and the ones that most people are familiar with, use a rubber cement ink that comes off the paper through mechanical force."
] | [
"This is true, but you can recover the document by popping it in the freezer. The ink is thermochromatic. You can cycle it from pigmented to colorless more times than I care to test."
] | [
"This is true, but you can recover the document by popping it in the freezer. The ink is thermochromatic. You can cycle it from pigmented to colorless more times than I care to test."
] |
[
"Why do these droplets spread out into star-like patterns as they freeze?"
] | [
false
] | We're currently in a cold stretch - roughly 0°F, swinging a little above during the day and a little below at night. Every day, the sun hits these ice crystals on our window and melts them into round water droplets, but it's too cold for them to evaporate. So every night, they refreeze in these sort of star patterns. Why do they change shape as they freeze, rather than freeze as droplets? I've been thinking about it myself - I assume they start freezing on the outer surface, and water of course expands as it freezes. I'm tempted to think that the glass might be slightly warm under the droplet since it's close to the house, but this phenomenon happens on a screen as well, and in that case both sides are exposed to the cold air. I've tagged this as physics, but I suspect that a materials scientist could help as well. The pattern reminds me of dendritic crystals that I've seen in additive manufacturing papers. | [
"In general you see dendrites as a growth mechanism when you have a diffusion-limited transformation process. In this case, it's likely the rejection of the heat of fusion from the liquid/solid phase transformation. As you transform into ice, you have an exothermic event. This will lead to locally warmer central ar... | [
"Oh, sure. When you change from one phase to another (say, from ice to water when you're melting), it will happen at a single temperature for a pure substance. However, it takes a significant amount of energy to do this. This is the reason we put ice cubes into drinks. It'll cool your drink down to 32 °C for a long... | [
"In my example in the second paragraph, the ice is colder than 32 F. If it's colder than 32 F it has to be heated before it can begin to melt. So, if your freezer is set to 20 F you get 12 degrees of sensible heating prior to latent heat transfer."
] |
[
"Should I finish my PhD in Cancer Biology if I Want to Go into Biotech/Pharma Consulting or Even Business Strategy Consulting"
] | [
false
] | Right, I already have a Master's and I will be completing my last qualifying exam for the PhD in about 2 months which will make me a PhD candidate. After that I will only have to successfully defend my disseration to obtain the degree. But the problem is that it will likely happen no earlier than the end of 2012/beginning of 2013. I'm 34 now and will likely graduate at 36-37 years of age. I'd very much like to leave lab bench science and am attracted to Biotech/Pharma consulting but would even consider business strategy consulting at BCG, for example. I know that these consulting firms "say" that they don't really require that their consultants have PhDs so I wonder if that's bullshit and that a terminal (which a Master's is not) advanced degree is required a PhD is still valuable enough in this down-turned economy to be worth the extra years that it would take to complete it with respect to the consulting market, keeping in mind that I'll be ~37 when I make myself available for the job market a Master's degree would be enough for consulting firms to take on a 34 year old with no experience (or is age something I shouldn't consider?). Certainly I plan on trying to get internship prior to my graduation but even then it will likely only be during my last year as a PhD student because of the time demands placed on the student. I'd appreciate any input anyone (especially those already in biotech/pharma or business strategy consulting field) would have. Cheerz! I graduated with a BS in '99 and entered industry doing rote tasks til 2002 when I reentered academia as technician (sadly with only 1 publication (middle author) and various poster abstracts) and later entered into the Master's program and earned my Master's 2009 and just finished my second year of my PhD. The average number of years to complete the PhD in my field is 4-5 total years. 2011 is the beginning of my 3rd year. (xpost from and ) | [
"Finish your Ph.D., the two or three additional years are very much worth it.",
"Credibility in biotech/pharma consulting is very important! Your Ph.D. candidacy is not going to get you that. It may be different in business consulting, but if you want to keep other options open (e.g. application scientist or some... | [
"Do you have connections or any experience with the industry you're trying to get into? I don't really know, but it seems to me that a combination of you'll have a PhD and the job market will be a lot more friendly makes waiting to graduate a much more attractive option.",
"Of course, you could just apply and see... | [
"The consulting firms that I know of (like McKinsey) are extremely competitive. I've heard that they pretty much won't even consider you without a PhD, but I don't know about other firms or if there are specific types of jobs that cater towards those with a Masters. You can always consider contacting someone at wha... |
[
"When I heat up a metal where do photons come from?"
] | [
false
] | So I heat up any given metal to the point it starts giving off light, just like in a light bulb or foundry/ironworks. Where do photons come from and assuming I do so in a vacuum would such metal lose it's weight after some time? | [
"A photon is an electromagnetic wave. You make one by \"shaking\" an electron (any charged particle actually, but electron is most common). When you shake an electron you cause a momentary electrical wave, which then self induces a magnetic component and that's what a photon is.",
"No nothing is lost from the ele... | [
"As Nune said it does lose the mass-energy of the photon, but it had just gained that much mass-energy from the heat input. There is no net loss of mass over time: it can emit photons forever as long as heat keeps getting dumped in."
] | [
"In blackbody radiation the electrons are not in excited states. If they were, the light would be mono-chromatic. Instead you have wide-band light because the atoms are vibrating randomly and directly generating light.",
"You do have peaks in the light, which do reflect excited states, but they are a small compon... |
[
"What are the differences between Methimazole for humans and Methimazole for cats?"
] | [
false
] | Long story short, one of my cats needs Methimazole to treat his Hyperthyroidism. Doing preliminary search on only Google results, there is a form of Methimazole that can be used for humans. I was curious about the differences between the Methimazole that is used for humans and the Methimazole used for cats? Thank you. | [
"The majority of medicines prescribed to pets are actually drugs made to treat humans. This is true for most chronic or acute conditions. Most \"pet only\" drugs that are developed are preventative medications like flea, tick, and heartworm. This is why you should always price shop for your pet's meds. If the vet i... | [
"Typically drugs for human use are subject to more (or possibly different) testing, and more control of quality systems. The active ingredient can be chemically identical, but the control around the manufacturing can be different. I have no special knowledge of this drug though. "
] | [
"The dosage of the drug can also vary between humans and animals. Eg if a human needs, say, 10mg/kg and they weigh 70kg, they need a dose of 700 mg. If a cat needed the same dose it'd need like 50 mg. So human drugs might be packaged in pills of 100 mg where cat pills would only have 20mg.\nAs well as this, the cat... |
[
"How does dark energy relate to vacuum energy?"
] | [
false
] | null | [
"Vacuum energy must contribute to dark energy. However, dark energy can also include other contributions. Quite literally:",
"Dark energy = vacuum energy + ..."
] | [
"Yes, and the point is that ... is negative and equally big. ",
"In particular ... includes a renormalization counterterm that should cancel the vacuum energy to get a zero or very very small result for dark energy. The counterterm is arbitrary at the level of the standard model, though. A theory of everything sh... | [
"Yes. That's why it really cannot be a coincidence and there's an explanation behind. In fact at the very simple level at which I understand this, I would argue vacuum energy + counterterm sum to exactly zero because of ToE reasons, and our current value of DE is due to another contribution of different origin. ",
... |
[
"Why does Boiling Point of a substance change on change in pressure in surroundings?"
] | [
false
] | Lately, I had been watching a documentary on Terra-forming mars, in which it was said that, The only problem water was not to be found on the surface is that the atmospheric pressure in the surroundings is too low for water to stay there in liquid form. My question is, According to the Ideal gas equation, PV = nRT, If pressure decreases, Temperature also decreases, but how is it possible that Boiling point and Melting point also decreases? | [
"Ideal gas law only deals with the ",
" of a ",
". If you have a steel box full of air, and you heat it to double its temperature, it would double the pressure of the gas inside. But that is simply the state of the gas in the box. If I did the same thing with a gallon of a gas in a ten gallon hefty bag, the bag... | [
"I wrote an explanation of that yesterday"
] | [
"The boiling point is the easier concept to think about. When you have a liquid (in 1 atmosphere of air pressure) we define its boiling point when its vapor pressure is equal to atmospheric pressure. The vapor pressure of a substance is related to temperature, so increasing the temperature increases the vapor press... |
[
"Why do blurry objects become clearer when we squint our eyes?"
] | [
false
] | [deleted] | [
"First of all, realize that this only works for people who have vision problems due to incorrect focusing of the light. For our eyes to work properly, incoming light must be focused down to the retina. When this does not happen, either because light is focused in front of the retina (a condition called myopia or ne... | [
"I drew you a picture. Basically it blocks all light that isn't coming in straight so there's less dispersion. The picture will explain it. Also, unless you have a 100% perfect cornea and eye muscles, this will help. ",
"http://i.imgur.com/b7tQ7D6.jpg",
"Try the pinhole trick. Close one eye and unfocus the othe... | [
"This image",
" can help understand the two effects.",
"The increase in field of fiew correspond to the first 2 pictures. ",
"The change of focal plane correspond to the last 2 pictures. When the hole is small, the light is diffracted and does not travel in a straight line anymore. This will help short sighte... |
[
"Will quantum computation kill crypto?"
] | [
false
] | null | [
"Thank you for your submission! Unfortunately, your submission has been removed for the following reason(s):",
"It is hypothetical or speculative in nature. We do not allow hypothetical questions because questions that cannot be confidently answered with any available data often invite non-scientific speculation.... | [
"It’s not really speculation. An expert can easily answer this without speculating. Please reconsider."
] | [
"You are asking about a situation which has not yet come to pass, which requires speculation. Please consider posting in ",
"/r/AskScienceDiscussion",
" "
] |
[
"What is the catch on this machine. Why is it not flourishing?"
] | [
false
] | This machine turns plastic waste into oil. Is there an ecological catch which is preventing this machine from spreading across the world? Why is this not spreading like wildfire? | [
"He is taking polymers (presumably mostly simple stuff, like polyethylene) with molecular weights of probably 80,000 - a few hundred kilodaltons, and supposedly breaking them down in a controlled fashion to oils of a couple hundred g/mol. Supposedly. There is also effluent gas that is not accounted for. While th... | [
"My semantics were off. I meant oil that you burn to cook stuff (as is common in India for example) not oil used to fry food. ",
"I guess this is still considered \"heating oil\" "
] | [
"My semantics were off. I meant oil that you burn to cook stuff (as is common in India for example) not oil used to fry food. ",
"I guess this is still considered \"heating oil\" "
] |
[
"People say that a nuclear bomb is equivalent to X tons of TNT. Well, if X tons of TNT were actually there instead of a nuclear bomb, will it have the same effect?"
] | [
false
] | Perhaps without the radiation. But I'm talking more about the shockwave, destructive force, etc. And assuming you can blow them up at the exact same time. | [
"According to a 2010 report by the National Confectioner's Association (First result of ",
"this",
" Google search because I couldn't find a direct link-PDF warning), Americans ate chocolate 107 times in 2010. If we assume that averages out to about a ",
"50g Snickers bar",
" that comes out to 5.35 kg per c... | [
"It's an equivalency of energy ",
"They could also equate it too calories or joules but tnt they think is more relatable",
"To answer your question directly no it would not explode the same simply because a nuclear bombs volume is smaller than that many tons of tnt and many other factors "
] | [
"So how many fat man's worth of nukes does America consume in candy bars every day?"
] |
[
"How are the repeated segments in a centipede developed?"
] | [
false
] | null | [
"In short, it’s basically due to a wave of transcription and following non-transcription of specific developmental genes throughout the body plan of the embryonic centipede. Waves of transcription/non-transcription are key for development and signalling in other organisms too, like the muscular system developing fr... | [
"Also, this is a good paper to read about your question specifically: \n",
"https://scholar.google.ca/scholar?q=segmentation+development+chilopoda&hl=en&as_sdt=0&as_vis=1&oi=scholart#d=gs_qabs&u=%23p%3DHkmBh2FaEZoJ",
" "
] | [
"Thank you!"
] |
[
"How come teeth move back to their original positions if you stop wearing braces?"
] | [
false
] | null | [
"Dentist here. There are many different factors affecting movement of a tooth. If your treatment with braces is incomplete, then as commented above, one factor causing relapse is that the soft tissue fibres attached to that tooth will be under tension to a greater or lesser degree in certain directions and will pul... | [
"That's really interesting!! Thanks for such an in depth reply I'll definitely remember this haha"
] | [
"Well aligned teeth are definitely much easier to keep clean than crowded ones. They function more efficiently when chewing as there are minimal gaps between upper and lower teeth when closed. Being properly aligned can allow them to work together better and prevent excessive forces and wearing of a few teeth, inst... |
[
"Why do wet dogs have a stronger smell than dry dogs?"
] | [
false
] | I was lying next to my cat when I realized he smelled like a wet dog. Then I wondered why wet dogs have a specific smell. What causes this? | [
"It's essentially ",
"steam distillation"
] | [
"Hmm, aromatics' solubility in water vs. its volatility (in air)?"
] | [
"This is at least one side of the answer: An old chemistry teacher explained to us why the smell of a fart magnifies in a shower compared to any other environment. The answer was that the aromatics (smell molecules) are entrained in the water vapor, essentially attaching to it to make for a more efficient ride to y... |
[
"If plants are constantly exposed to the sun, why don't they develop cancer?"
] | [
false
] | Is there something special about plant cells that shields them radiation that is harmful to humans? It it possible for a plant to "develop cancer" or any sort of harmful mutation? | [
"Plants do develop cancer. But their lack of a circulatory system makes cancer not very harmful to plants. Note that, in humans, cancer is usually only deadly when it is able to spread through the bloodstream and start growing in many sensitive areas of the body at once (such as the brain). In plants, cancer jus... | [
"Woodworker here, they're also worth a shitload of money if they're properly dried. (Because they're beautiful)",
"Example 1",
" ",
"Example 2"
] | [
"Yup. Did you ever see those weird lumps on trees? They are called burls and are a sort of plant malignancy."
] |
[
"[x-post from ask reddit] question on human evolution"
] | [
false
] | Hello, it was suggested I post this here. I've since done a little searching on reddit and no previous threads seem to address what I'm driving at; Ok Reddit; You seem to know way more about science than me and I trust that a lot of you can answer this question to your own satisfaction but you may not manage to educate me if you assume that I have the same scientific education as you. My formal science education stopped 11 years ago when I was 16 years old. Since then it has been what I happened across and conversations with scientists. (I love learning through conversations). Please go slow explaining this... Here's my understanding of the principles of evolution theory; If you live to make babies who live, well done your genes are passed on. If you don't, sad times mr, your genes are no longer contributing anything. If a certain gene gives you an advantage over your competitors for a mate or for a dwelling or for surviving a winter etc then they will help you to survive and make a baby or two. This way the genes that are helpful slowly are preserved whilst the genes which do not help or even hinder slowly get weeded out. It's good it's logical and I'm happy. Until... I'm considering the final stages of human evolution; At some point we got quite ahead of the curve. We're much more intelligent and adaptable than our closest evolutionary relative right? We have developed technology like weapons and clothes. We can adapt much better. So at some point our competition stopped being with the other species I think and was only down to who got to sleep with yonder hottie and who survived that snow storm last winter. Perhaps it was also to do with fights over who get's to sleep in this part of the valley. My point is. There's a huge amount of lovely inhabitable fertile world out there. Once we beat the apes even by 25% of the advantage we have over them now, why did we continue to evolve so far in advance of them? Our competition with fellow humans is surely not fierce enough? Only now are we really in a place where the population is unsustainable. Why would we have evolved before now? I apologise if this is long and meandering. I wish I knew the short hand for explaining these ideas. TL DR; Oh man, how to succinctly ask? Why are humans so far in advance of other species? What was the evolutionary motivation or necessity after securing ourselves at the top of the pile? Thanks! EDIT 1; I aoplogise for oversimplifying the truth by saying we're at the top of the pile. My (now) more refined question is... I'm unaware of the timescales involved but let's talk about the half way point from the previous homo-species to the current homo-sapiens, how and why did we get there? And how and why did we get to be homo-sapiens? | [
"Stephen Jay Gould wrote about this. We evolved survival skills that apparently required our large brains, the ability to write symphonies and do quadratic equations was a byproduct of this large brain, not the purpose of it."
] | [
"As was said by KevZero, the driving force behind all evolution is genetic variation and to add to that, mutation. The traits we possess today are a result of fitness within the environment as driven by those mutations. As with every creature, the more offspring you have, the higher your evolutionary fitness. You m... | [
"Every [eukaryotic] organism alive today is descended from the same ancient, primitive ancestor. Therefore, every organism that is alive has survived and reproduced just as successfully as any other. Humans are ",
" ahead at all. We're not the most plentiful by number of individuals, nor by biomass. We ",
" alm... |
[
"How do injuries in the mouth heal themselves?"
] | [
false
] | null | [
"Just like other injuries to the body, platelets aggregate to the site and clot together, and prevent any additional bleeding from broken vessels of the injury. Leukocytes travel to the affected tissues, starting the inflammatory process, and then white blood cells kill bacteria and clean up dead cells.",
"Injuri... | [
"Essentially, yes. Rather than spitting, evolutionarily speaking, humans have an instinct to suck on their finger if they cut it; 'wound licking' is an instinctive response that is found in humans and many other animals. However, for humans, it is not really advised to spit or suck on major wounds because the bacte... | [
"Why is the bacteria safe in your mouth but dangerous in wounds. Is it the direct contact with your blood?"
] |
[
"Does the human heart really generate an electrical field?"
] | [
false
] | I've heard this come from self-help types and wondering how much merit it has. They say that every time you have a thought, a "pulse" of electro-magnetic energy is generated at the base of the heart. This smells of bullshit to me, but for all I know it could be true. | [
"... every time you have a thought, a \"pulse\" of electro-magnetic energy is generated at the base of the heart...",
"What!? The heart is not responsible for thinking! Whoever wrote or said that in whatever self-help book/seminar is spreading complete and utter balderdash.",
"However, the heart ",
" generate... | [
"Indeed! It doesn't make any sense for the body to evolve the kind of function that these people are proposing. Their tactics are transparent: Show videos with nice music and lovely images, pepper them with pseudo-science, get them to shell out thousands of dollars for books, CDs, seminars, camps, et cetera. It's s... | [
"I wonder how they explain Dick Cheney, who apparently no longer has a heart beat due to ",
"his heart being replaced with a continuous pump",
". "
] |
[
"How do credit card chips work?"
] | [
false
] | How do credit card chips work differently than the magnetic strips? Why can the credit card chip not be intercepted by a scammer and be reproduced while the magnetic strip can? | [
"Basically the chip is a computer. The magnetic stripe is a piece of data.",
"The terminal can ask the chip to perform a computation on a number, without the chip ever revealing the secret keys used to the terminal. This is called a cryptographic signature."
] | [
"The chip alone prevents usefully cloning the magnetic stripe, and magnetic stripe cloned card fraud is currently a much bigger problem than when the card itself is lost or stolen. So the chip alone is a large improvement. If you want to prevent lost or stolen cards from being used, that's when the PIN comes in but... | [
"Yes, and no. In your example, you're assuming a dynamic/secret algorithm or function. (your 5(x",
" What's actually going on is the card has a known algorithm, and the secret portion is a number that also factors into that algorithm. The mathematics behind cryptography are extremely complex, but the long and sho... |
[
"Has Folding@Home really accomplished anything?"
] | [
false
] | Folding@Home has been going on for quite a while now. They have almost 100 published papers at . I'm not knowledgeable enough to know whether these papers are BS or actual important findings. Could someone who does know what's going on shed some light on this? Thanks in advance! | [
"Unequivocally, yes.",
"I do drug discovery. One important part is knowing the molecular target, which requires precise knowledge of structural elements of complex proteins. ",
"Some of these are solved by x-ray crystallography, but Folding@Home has solved several knotty problems for proteins that are not ame... | [
"Alzheimer's. ",
"Here's",
" the reference. That's from J Med Chem, which is the workhorse journal in my field.",
"Drug development usually takes at least ten years from idea to clinic, and Folding@Home was only launched 12 years ago.",
"Edit: If you have questions about Alzheimer's drug discovery, I jus... | [
"So what are some drugs that have been developed or are being developed, thanks to F@H? Also, what are those drugs treating?"
] |
[
"What substance/element/thing has the highest melting point and how did we manage to find out what it was?"
] | [
false
] | Wouldn't it melt anything touching it first? Would it be done using magnets to keep it from touching something else (if magnetic) or possibly in space where there is no gravity? | [
"Tungsten is the element with the highest melting point -- more information here:",
"http://www.newton.dep.anl.gov/askasci/phy00/phy00914.htm"
] | [
"Carbon does melt under the right conditions. The melting point of a substance depends on both temperature and pressure. A phase diagram of carbon can be seen ",
"here",
". As you can see, at pressures above 100atm, carbon will melt from a solid to a liquid if the temperature is high enough. ",
"Perhaps the O... | [
"Carbon stays solid at higher temperatures",
":",
"Carbon sublimes in a carbon arc which has a temperature of about 5,800 K (5,530 °C; 9,980 °F). Thus, irrespective of its allotropic form, carbon remains solid at higher temperatures than the highest melting point metals such as tungsten or rhenium."
] |
[
"Why don't power plants store energy mechanically?"
] | [
false
] | A big problem with wind and solar energy is that they are not consistent. Why not store this energy mechanically? By say pumping water up vertically. Also, what are the best ways to store energy mechanically for personal home use with solar and wind? | [
"This technology is already in widespread use"
] | [
"The relatively low energy density of pumped storage systems requires either a very large body of water or a large variation in height.",
"I guess this is why it isnt more common. "
] | [
"Using any storage medium means introducing inefficiencies into the process. If you generate X amount of power, then store it mechanically, you can only get say 75% out of what you put in."
] |
[
"Length of a \"horizon to horizon\" jet airplane contrail?"
] | [
false
] | What is the length in miles of a jet aircraft's continuous contrail if it flies directly overhead at 30,000 ft altitude? | [
"2 * (radius of earth+30,000 ft)*arccos(radius of earth/(radius of earth+30,000 ft))"
] | [
"If you're 6 ft tall then it's about 6 miles longer."
] | [
"2 * (radius of earth+30,000 ft)*arccos(radius of earth/(radius of earth+30,000 ft))",
"Assuming the Earth is a perfect sphere and that you are 0 ft tall."
] |
[
"Do each of my chromosomes come from a specific grandparent or are they all a mix of genes from each?"
] | [
false
] | I know I have 23 chromosome pairs, 23 from my mother and 23 from my father. But is my 1st chromosome a match to one of my grandparents 1st chromosome or does it have a mix of genes from all of them? If it's matching chromosomes, does that mean I get ~12 Maternal Grandmother Chromosomes ~11 Maternal Grandfather Chromosome from my Mother and similarly from my Father? And then on back through them ~5-6 from each of my great-grandparents, ~2-3 from each great-great, ~1-2 from great-great-great, ~0-1 from my great-great-great-great, etc. So does that mean if I pick an ancestor 6 generations back, I probably don't share any chromosomes with them? Does that mean I wouldn't be any more genetically related to most of my 128 great-great-great-great-great-grandparents than I am to anyone else from that generation, since I only have 46 chromosomes only 46 of them could have contributed a chromosome to me? | [
"The chromosome 1 you got from your father (similarly mother) is a mix of the two versions your father has of that chromosome. Importantly, it's not a random mix, but a \"recombination\": if we represent your chromosome 1 as a vertical stick, the bottom segment would derive from one of your father's chromosome 1's,... | [
"Chromosomes are all shuffled and mixed during reproduction! It's called ",
"genetic recombination",
". So each of your chromosome is a mixed of the ones of all your ancestors combined!",
"With the exception of your Y chromosome if you're male, as you only get your Y from your father... so you have the same Y... | [
"This isn't totally accurate. Recombination happens during the production of gametes, not during actual reproduction. You receive maternal and paternal chromosomes separately, but these do not physically mix in your body except when you produce your own eggs or sperm. While it's correct to say that any given chr... |
[
"If light shines on an object, does the object reflect more light as the intensity increases?"
] | [
false
] | Let's say we start out with a not very intense beam of light, the object then becomes brighter because of the light. If we were to increase the light intensity, would the object increasingly reflect more light due to it's increasing brightness? The whiter an object gets, the more reflective it becomes, so does that also apply with brightness? | [
"In general yes. For classical reflection of light off of an effectively planar chunk of homogeneous material, the amount of reflected light is given by the ",
"Fresnel equations",
". The reflection coefficient in these equations is defined as the reflected power over the incident power, which basically assumes... | [
"If I am interpreting your question correctly, the answer is no. The reflectivity of an object is in general not changed by the amount of light you're shining on it. Of course the object looks brighter to you, because the total intensity of the reflected light increases when you increase the incoming power, but tha... | [
"Unless you change it, an object always reflects the same fraction of incident light. E.g., for a fresh coat of silver, the fraction is around 95%, depending on the quality of the process.",
"The ",
" remains the same. But the ",
" of reflected light increases with the brightness of the source."
] |
[
"Ask Anything Wednesday - Physics, Astronomy, Earth and Planetary Science"
] | [
false
] | Welcome to our weekly feature, Ask Anything Wednesday - this week we are focusing on Do you have a question within these topics you weren't sure was worth submitting? Is something a bit too speculative for a typical post? No question is too big or small for AAW. In this thread you can ask any science-related question! Things like: "What would happen if...", "How will the future...", "If all the rules for 'X' were different...", "Why does my...". Please post your question as a top-level response to this, and our team of panellists will be here to answer and discuss your questions. The other topic areas will appear in future Ask Anything Wednesdays, so if you have other questions not covered by this weeks theme please either hold on to it until those topics come around, or go and post over in our sister subreddit , where every day is Ask Anything Wednesday! Off-theme questions in this post will be removed to try and keep the thread a manageable size for both our readers and panellists. Please only answer a posted question if you are an expert in the field. . In short, this is a moderated subreddit, and responses which do not meet our quality guidelines will be removed. Remember, peer reviewed sources are always appreciated, and anecdotes are absolutely not appropriate. In general if your answer begins with 'I think', or 'I've heard', then it's not suitable for . If you would like to become a member of the AskScience panel, . Past AskAnythingWednesday posts . Ask away! | [
"The effect of the pull will travel through the material with the speed of sound as well. On your end, you pull on molecules close to you that in turn will pull on the next molecules, etc... While the action is different from banging the rod, the effect is the same.",
"Since these actions all appear to instantly ... | [
"A student asked me this once, and I couldn't give a reply that really convinced me.",
"\"Suppose I manufacture a rod that's, I don't know, 5 light years long. If I bang it with a hammer, the signal will propagate with the speed of sound and reach the other end. But what happens if I just grab it and pull? Haven'... | [
"Asked this question in another thread but it got lost. If I'm looking through a telescope at an object thousands of light years away I understand that the scattering of protons means that my resolution of the image is going to be limited by the size of my lens and how many protons I can capture and focus. ",
"My... |
[
"What is the scientific consensus on free radicals?"
] | [
false
] | [deleted] | [
"Others have given an answer to your question, but I want to address the idea of \"scientific consensus.\" Please remember that science is not in the business of locating truth -- that territory is reserved for religion.",
"In science, ideas are always open to further investigation, and theories are always open t... | [
"http://www.cancer.gov/cancertopics/factsheet/prevention/antioxidants"
] | [
"Thanks. I'll give that a long read through."
] |
[
"Is there an evolutionary, biological, or other definitive reason why the left side of the brain controls the right side of the body, and vice versa?"
] | [
false
] | From what I understand, the medulla oblongota (brainstem) connects the spinal cord to the rest of the brain. Here, the nerve tracts cross from left to right, and right to left. So, nerves controlling the left side of the body are found in the right side of the brain, and nerves controlling the right side of the body are found in the left side of the brain. Is there any specific reason for this? Or is it "just because" (which in and of itself is a rarity in science). | [
"Contralateral central nervous control may be an evolutionary consequence of dependence on the image-forming eye, especially in large organisms. As a result of the topological transformation of the visual stimulus in the pupillary eye, the external environmental hemispace impinges directly upon the contralateral in... | [
"Yeah, I'm still pretty confused :/"
] | [
"So, basically what you said is that it has to do with how our eyes look at things upside down?"
] |
[
"What do Titan's liquid methane seas actually look like?"
] | [
false
] | I've been asked to visualise the oceans of Titan, one of Saturn's moons - but can mainly find others' sci-fi renderings, nothing based on how light actually behaves. Would the oceans also have ice-blocks etc? For example, is its refractive index as a liquid, would it be perfectly transparent etc? | [
"Liquid methane is colorless. Even more colorless than water, which is ever so slightly blue. Based on its gas phase absorption spectrum shown ",
"here",
", methane's electronic absorptions lie in the far-UV or in the infrared region. In the liquid phase, absorption peaks tend to broaden out, so you might se... | [
"\"We can't rule out some exotic type of life that doesn't need water, but it's unlikely based on what we know.\"",
"What do we know that makes it unlikely?"
] | [
"On the surface of Titan or in its methane/ethane lakes, probably not. Life as we know it requires liquid water, and Titan's surface is far too cold for that. We can't rule out some exotic type of life that doesn't need water, but it's unlikely based on what we know.",
"However Titan, like many other moons in the... |
[
"Is the sun soft or hard?"
] | [
false
] | To give an example; if I was flying a spaceship (let's assume it can withstand the extreme conditions), and I wanted to enter the sun, would the ship just sail through or would it crash on the surface? | [
"To use your terminology, the edge of the Sun is rather soft. Take a look at ",
"this graph of the matter density profile of the Sun",
". Close to what we usually take to be the edge of the Sun, the density is about 10",
" g/cm",
". This density is comparable to the density of our atmosphere on Earth at gro... | [
"If you read the Sci-fi series \"The Golden Age\" by John C Wright, they discover the \"Island of stability\" actually exists and create entirely new elements. They create a star ship to do exactly that, sail into the core of a star. It's a great series: ",
"http://www.amazon.com/The-Golden-Age-John-Wright/dp/076... | [
"The author of the website appears to be particularly motivated, but deluded. He seems to think the sun has a solid calcium ferrite surface, and spends many paragraphs pointing out why NASA is \"wrong\" about their interpretation of satellite images of the sun and the like.",
"While I don't have time to go into i... |
[
"Can someone plainly explain how claims that the Pfizer and Moderna mRNA vaccines can promote prions be refuted?"
] | [
false
] | null | [
"This is a paper written with the same layout as a \"real\" scientific publication but it's just not... real.",
"For one, just FYI, PubMed doesn't index this journal and it's listed among known predatory journals. A good thing that's happening in publishing is open access publishing. A lot of journals now make pa... | [
"Good questions.",
"Another poster addressed the prion question very well. As for the pathogenic priming/immune enhancement thing: the easiest answer is we would have seen that in clinical trials, and we did not. Both MRNA vaccines greatly reduced the number of symptomatic cases. Among those that had the vacci... | [
"Thank you for your reply. I suspected as much after looking at the method section, but thought maybe their reasoning or logic wasn't just solely theirs. I wasn't able to keep up with the topic in their cited sources myself so your explanation is reassuring (unfortunately all I know on RNA/DNA is from high school)"... |
[
"Evolution speeding up?"
] | [
false
] | How long does it take for a evolution to take place and for a mutation to select itself in a community? Kevin Kelly states in his 2010 book, What Technology Wants, "We are not the same folks who marched out of Africa. Our genes have co-evolved with our inventions. In the past 10,000 years alone, in fact, our genes have evolved 100 times faster than the average rate for the previous 6 million years." Source: | [
"The pace of evolution depends on evolutionary pressure. Creatures well adapted to a static environment can remain largely unchanged for millions of years. But when that environment is altered, evolution can occur much more quickly. It has to, because creatures who can't evolve perish.",
"I don't know about Ke... | [
"It may also depend on complexity. Complex organisms may very well respond differently to the environment.",
"http://en.wikipedia.org/wiki/Timeline_of_evolution",
"Single-cell organisms took their sweet time before they did anything different. Then multicellular life just exploded.",
"Within multicellular lif... | [
"Kurzweil wrote a book on this. Specifically that, among other things, evolution was essentially \"speeding up\", or more accurately that the time between salient events is directly related to the amount of chaos in a system. This certainly isn't well accepted science, and I'm almost regretting posting it in ",
"... |
[
"Why does my breathing dramatically change when I go from taking a hot to a cold shower?"
] | [
false
] | I usually take a cold shower for about 30 seconds when I'm done taking a hot shower (for about 10 minutes) and I've always wondered why my breathing always drastically changes when the water gets cold. Is it like a shock to the body? | [
"It's likely ",
"part",
" of the ",
"diving reflex",
". Basically, your body wants to conserve oxygen when it thinks you're going to be underwater for a while. It slows your heart and constricts your blood vessels."
] | [
"Maybe it has something to do with ",
"this?"
] | [
"More than you'll ever want to know:",
"http://www.jappl.org/content/100/6/2057.full"
] |
[
"Could technologies like CRISPR eventually be able to change a person's sex and/or turn a person into an entirely new species of human after the changes have propagated through the entire body?"
] | [
false
] | I've watched a few interviews, TED talks and debates about CRISPR and in them they've said that it can be used to change an organisms DNA while the organism is still alive and the changes are permanent and 100% hereditary ( ). CRISPR supposedly can alter several genes at once, is re-programmable and is easy to use. What are the limits of CRISPR-like technologies? | [
"Sounds like those TED talks oversimplified the situation.",
"However:"
] | [
"You seem very reactive for all thread concerning CRISPR",
"Yeah no kidding. People have been asking about it a lot recently, and it's probably better that someone try to give them real information on the topic than let imaginations potentially wander off into misconception-land.",
"is Cas9 able to access conde... | [
"Mostly no.",
"In scifi shows you'll see DNA changing and a dude will change into a lizard (ST TNG: Genesis) which is absurd.",
"Very much of what you are is driven by genetics, but those things happen as you grow from a sperm-and-egg into an adult. The genes that made those changes are ",
" as an adult and ... |
[
"Could we keep an isolated brain alive with modern technology?"
] | [
false
] | I have recently discovered the concept of an isolated brain and have read through the wikipedia article. There were a few experiments in Soviet Russia during the 1940s. Has technology advanced enough for this to be plausible? Provided we could, would the brain operate as normal or would it require the body to function? Could the "Brain in a Jar" be achieved? | [
"So if you provide it with both those things, would the person be conscious? Would they be in pain or would you just be stopping cell death but the brain would stop functioning?"
] | [
"A brain just needs oxygen and nutrition to my understanding.",
"If it's in a jar, there isn't really anything stopping you from giving those things, as long as the concentration is higher on your side so they diffuse in.",
"I don't know why you would want a brain in a jar though. I think they're much more usef... | [
"I don't know, this is a question I've never thought about before.",
"Since it's detached from most of the nerves it is normally attached to, there would likely be pain in the same way the people with missing limbs hallucinate pain.",
"I think they would be conscious. The brain in the body is just sitting in a ... |
[
"What does it mean by 'virtual' in QED explanations?"
] | [
false
] | I am researching quantum electrodynamics while I'm in my Quantum II class at University. I have been looking at Feynman Diagrams for a little while to understand how they work. There was a note that any line that starts and ends inside the diagram is a virtual particle, i.e. virtual photon in the electron-electron repulsive exchange force. I know we measure photons and their properties (optics, qm, e+m), are these measured photons different from the virtual photons or am I being mislead by the title of 'virtual'? Thanks for your help | [
"Virtual photons are just a calculational tool. They are not a real thing. One way to see this is that there are ways to formulate quantum field theory that do not use virtual particles at all (e.g., lattice gauge theory).",
"Here's another way to see this. Take any photon you can actually observe, measure its ... | [
"Since you're in a quantum 2 course, I can tell you exactly how they're a calculational tool. You've probably learned perturbation theory, and you've learned that the first order correction is just the expectation value of the perturbation, <H>. However, the second order correction to the nth energy level takes an ... | [
"Are they the same as virtual work in mechanical/civil engineering terms then? We pretend there's a virtual particle and see what it would do if it were there, and at the end it cancels itself out?"
] |
[
"Is there any sort of concept of a genomic efficiency, i.e., is there any benefit to having a higher ratio of coding DNA to junk DNA?"
] | [
false
] | Is there no sort of penalty for carrying around all that non-coding DNA? | [
"A lot of non-coding DNA is functional. There are classes of functional non-coding RNAs, such as micro RNAs, as well as regions of the genome that are never transcribed into RNA but still play a role in the regulation of transcription of other parts of the genome.",
"That being said, smaller genomes are selected ... | [
"This is certainly a consideration for small, quick-replicating organisms like viruses or bacteria. In both cases, their population growth (and thus their fitness) is limited in part by how fast they can replicate their DNA. Since longer genomes take longer to replicate, there's a strong pressure for short, efficie... | [
"Just to add about viruses. One of the strategies they use to keep their genome small is bu using a very small number of structural proteins. Most viruses have one main protein that makes up the capsid, and it is simply arranged in a repeated fashion that produces capsids with ",
"quasi-icosahedral symmetry",
"... |
[
"If many electron systems are unsolvable, how do we know the orbital shapes?"
] | [
false
] | I have not taken physical chem or differentials (does it show?) so some math concepts might be over my head. I know we have a good understanding of orbital geometries and orbital hybridization for valence electrons at least in organic chem. At the same time I have heard that for atomic systems of greater than 2 electrons certain equations that have to do with wave functions in quantum mechanics become unsolvable. Can someone explain how those can both be true. Also before those atomic resolution images, were molecular orbital geometries experimentally determined (if so how?) or just predicted by quantum? | [
"\"Analytically\" means solving an equation exactly, in terms of elementary functions, like you would by hand. This is as opposed to solving an equation numerically, which is using a computer to find an approximate solution.",
"The Schrodinger equation is a complicated equation in all but the very simplest circum... | [
"OP, I would just like to ad that most (all?) electron orbital shapes you see in textbooks are actually the shapes for the one electron problem, which, of course, is analytically solvable. ",
"That is to say, the 1s, 2s, 2p",
"{x,y,z,z",
", x",
"-y",
"}, etc etc are all the shapes they would be, ",
". "... | [
"Well, you can still solve the Schrodinger equation for your system numerically, if not analytically.",
"But of course, at some point this strategy fails terribly when your system is too complicated.",
"This is when you will need to use various approximations to help you simplify your system. Maybe you don't ne... |
[
"Are there any effects of brain hemisphere lateralization?"
] | [
false
] | I read this in my consumer behavior textbook. Is the information accurate? Does brain lateralization have any effects on behavior? I am weary to believe anything of brain lateralization after learning that left/right brain personality theory is not necessarily true. | [
"This is mostly a bunch of hooey. People have a mix of personality traits and abilities that are not so simplistically dependent on a hemispheric laterality."
] | [
"There is a lot of baloney on this subject, and I believe the whole 'dominant side' is unfounded. ",
"I went through some of my books to find the exact info on it:",
"The left hemisphere controls the right side of your body, the right hemisphere controls the left side of your body. Your trunk muscles and facia... | [
"Yes, because we are about 97% left brain hemisphere dominant for language/speech, we are right handed. using the right hand selectively for writing, shaking hands, eating, and many other tasks, which also makes us largely right visual field dominant, is probably the most important brain hemisphere characteristic d... |
[
"How efficient is chlorophyll at light absorption? And how does it compare to modern-day solar pane light absorption?"
] | [
false
] | I'm trying to wrap my head around how much light is actually utilized for energy by plants and if our solar panes can absorb more or less energy from incoming solar light. Not sure if this can be best described in percentages or along the lines of frequencies in the electromagnetic spectrum - but either will be very helpful! | [
"There is a complication in your question. Most energy efficiency comparisons don't look at raw energy absorption. They also remove overhead from operation. You'll see this for plants and solar cells. For solar cells, there is some overhead which costs power. If you have a pane with the capability of 100% absorptio... | [
"I can't comment on the math but I have a nitpick; it's typically D-glucose, not d-glucose, though you aren't strictly wrong. "
] | [
"And what difference does capitalization make in this case?"
] |
[
"If a breastfeeding human female eats an exclusively non carbohydrates diet will she still be able to produce milk?"
] | [
false
] | null | [
"Mmmm. Well, I would have to say that yes, a mammal can still produce milk. I'm sorry, I don't have any citations, but look at predator mammalian species who subsist on an almost exclusively protein diet. They have no problem nursing their young, and the physiological mechanisms behind neoglucogenesis remains the s... | [
"I'm pretty sure that carbohydrates (unlike fats and proteins) are not essential nutrients. As in a zero carbohydrate diet might be suboptimal, and might also have negative long term side effects, but it's not going to cause any sort of short term malnutrition. Do you have a cite?"
] | [
"The body produces milk from fat stored in the body; as long as caloric needs were met for the duration of the pregnancy (from fats or carbs) the mother should be able to produce milk. Now I'm not 100% sure if glucose is required for milk production, but if it were I'd believe that gluconeogenisis would cover thos... |
[
"Is there a difference between hurricanes, cyclones, typhoons, medicanes and tropical storms? If not, is there a reason other than the place where they form for the name difference?"
] | [
false
] | null | [
"Atlantic and pacific storms are called hurricanes.",
"Storms in the ",
" Pacific are called Hurricanes, while storms that form in the ",
" Pacific are known as Typhoons. Storms forming in the Indian Ocean as well as the ",
" Pacific are referred to as Cyclones."
] | [
"It’s just where they are formed. Atlantic and pacific storms are called hurricanes. Storms off the coasts of Asia are typhoons. And storms in the oceanic region are cyclones. Never heard of medicanes before. All of them will downgrade to a tropical storm though."
] | [
"I just learned about medicanes this week because one is hitting Greece today with 60-90 mph gusts. They're rare..\n ",
"https://m.accuweather.com/en/weather-news/medicane-to-bring-heavy-rain-strong-winds-to-southern-greece-western-turkey/70006195"
] |
[
"How does altitude and topography affect the gravitational constant on earth?"
] | [
false
] | I understand the inverse square law but I want to know more about what happens when we make no idealizations. This all started as an argument between me and my brother, me saying that is smaller at higher altitude simply because of the inverse square law and him saying that it's not the inverse square law that takes precedence but instead that gravitational anomalies take precedence (i.e which had the caption "Red shows the areas where gravity is stronger than the smooth, standard value, and blue reveals areas where gravity is weaker."). Looking at that gif leads me to believe I'm completely wrong and that the gravity on Everest would be greater than sea level but I'm having a really hard time with that because all I've read and been taught is that gravity decreases as the inverse square of the radius where we can model the Earth as a point at its centre of mass. Are we not able to make this assumption in this case? | [
"If you want to make no idealizations, it is not really correct to call g a \"constant\" because it varies with distance from masses. Gravitational forces between objects depends of 3 things 1) the mass of object 1 ,lets call this you. 2) the mass of object 2, lets call this earth, and the distance between them. Co... | [
"Yes, and on the scales of neutron stars and black holes you need to dip into general relativity to fully describe these gravitational interactions. But for less exotic objects like stars and planets Newtonian gravitation works just fine."
] | [
"There are two corrections that have to be made",
"First your correct for the altitude at which the measurement is made:\n",
"http://en.wikipedia.org/wiki/Free-air_gravity_anomaly",
"Then you correct for changes in topography:\n",
"http://en.wikipedia.org/wiki/Bouguer_anomaly",
"It seems to me that the GR... |
[
"In ISS time lapse video, It says \"aurora australis over Madagascar\". Can this be true?"
] | [
false
] | According to my knowledge about auroras, they are created by the magnetic fields forcing particles form solar winds down around the poles. Surely Madagascar is not south enough to have aurora australis? The video can be seen at 2.02 at this link: | [
"Doubt Nasa? I would think that it is perfectly okay to question to caption on a video when I find a dissonance between it and what I thought I knew. I was doubting myself more than NASA. But thanks for the answer anyway. I discussed it with a friend who said that the aurora can be seen further north (or south in b... | [
"I find it odd that your immediate reaction is to doubt NASA. Pretty ssure they know what they're about.",
"The most important bit of info you're missing is the existence of the \"South Atlantic Anomaly\", it's almost like a hole in the Earth's magnetic field, or another pole. At it spreads from South America all... | [
"It's actually quite common that during geomagnetic storms during which solar winds are more active than normal, that the auroras can extend to lower latitudes, going as far north as Australia, New Zealand and also Madagascar. So this particular footage shows a quite rare, but not unheard of kind of aurora."
] |
[
"What kind of protection do memory T cell stored in bone marrow provide, compared to neutralizing/sterilizing immunity?"
] | [
false
] | There’s lots of discussion around the vaccines providing the best source of sterilizing immunity, but what protection could be provided from these memory T cells from natural infection and the following convalescent immunity? And do vaccines also provide this same type of immunity, or only sterilizing immunity? | [
"Vaccines provide antigens, which are pieces of a bacteria or virus (pathogen) that your immune system can recognise and use to trigger an immune response. The main actors in this part of the immune response are the B cells and the T cells. ",
"B cells make antibodies which bind to the antigen, and depending on w... | [
"I think it would be difficult to tell whether the a T cell response on it own would be better than a B cell response on its own because it would be difficult to get an isolated T cell response in a living human. The T cell response is often involved in activating the B cell response, so the two systems feed into e... | [
"The symptoms are a combination of the damage the virus is doing to your body and your body engaging your primary immune system to fight it off. The primary immune system involves things like fever, coughing and sneezing which your body does to try and suppress the pathogen or expel it from your body while your cel... |
[
"Could we in theory create Saturn style rings around the Earth, for shits and giggles."
] | [
false
] | If I recall correctly the rings around Saturn are supposed to be caused by a moon or something that exploded and all the pieces and rocks and ice circling it and forming what appear to be rings. Would it be possible to do the same thing to Earth, intentionally, how would we go about this? And would there be any negative consequences (I'm pretty sure that there'd be enough of a gap between the surface and the rings for it to not interfere with satellites or planes or anything) | [
"By constantly do you mean every few hundred thousands years or so?"
] | [
"Could adding artificial rings to Venus be used to cool it and aid in terraforming, potentially anyway?"
] | [
"Could adding artificial rings to Venus be used to cool it and aid in terraforming, potentially anyway?"
] |
[
"When neutron stars collide do they immediately form a black hole or would the collision produce ejecta?"
] | [
false
] | null | [
"This would depend heavily on initial conditions. While models do predict that neutron stars can spin fast enough to deform their shape, I have read little about how much mass escapes a merger, however, one paper I read did propose a method for calculating this, you can find it ",
"here",
". Based on their ca... | [
"Neutron stars are made up of a form of degenerate matter, in this case, neutron degenerate matter, though it is expected that they have an iron crust on the surface. Ejected degenerate matter would quickly go through a series of violent reactions once free from the neutron stars gravity, resulting in a spray of d... | [
"Their state of matter is only stable with the intense pressure in a neutron star. Everything that is ejected leaves as regular matter (probably as extremely hot plasma based on the energies involved in these processes)."
] |
[
"How has the amount of water on Earth’s surface changed over geologic time?"
] | [
false
] | Is water being subducted into the mantle faster than it’s being out gassed back out? Has the Earth experienced any net loss of water to space? | [
"This is a major ongoing question in geology, that I hope to do a PhD project on. ",
"Korenaga et al., 2016",
" came up with a net decrease of water on earth's surface over time, with almost a quadrillion gallons of water going down into the mantle per year."
] | [
"The lightest elements (Hydrogen and Helium) can escape the Earth's atmosphere because they are light enough to get occasionally whisked away into space. So can some light molecules. ",
"On human timescales, there is a tendency to think of an atmosphere as being\nas immutable as a planet’s rocks, but over geologi... | [
"I thought it was now fairly well accepted that the Earth’s oceans are slowly being lost to the mantle over time? (Though not quick enough to mean an end to any life before the sun boils the oceans away mind) ",
"Are there any significant objections to this line of thought?"
] |
[
"A question regarding colors and wavelengths."
] | [
false
] | Do different shades of one color have different wavelengths? For instance, does light blue have a different wavelength than dark blue? or is the difference just the amount of light waves/particles hitting one's eyes? | [
"Short answer: yes, they'd have a different spectral response.",
"Long answer:",
"http://i.imgur.com/SNJXdOT.png",
"The above image is a conceptual plot of all the colours that can be rendered by the human eye. The triangle in the middle represents the colours that can be reproduced by a computer monitor (lik... | [
"It is a different wavelength. Dimness and brightness are the differences in intensity."
] | [
"The chart is a visual representation of what is known as CIE 1931 color space. Wikipedia has an interesting article about how it's defined and how to undergo various transformations to different color models such as RGB. ",
"Scientists have experimentally determined (to some extent) how the cones in our eyes dec... |
[
"How would a person standing on the North Pole feel the effects of the earth's rotation?"
] | [
false
] | [deleted] | [
"Standing on the equator, you are moving at a whopping 1670 km/h around the center of the Earth. You don't feel this. ",
"Standing on either pole, you are stationary relative to the center of the earth. You are merely rotating very very slowly (0.0007 rpm). You are absolutely guaranteed not to feel this."
] | [
"They wouldn't. ",
"There are two forces that appear in uniformly rotating frames - the Coriolis force and the centrifugal force. ",
"The Coriolis force depends on the direction you're moving - it's produces the apparent motion of 'the earth rotating under you' when you move. If you're standing still this force... | [
"That and the fact that gravity would be weaker near the Equator due to the equatorial bulge makes about a .5% difference in weight between the two.",
"Source: ",
"http://curious.astro.cornell.edu/about-us/42-our-solar-system/the-earth/gravity/94-does-your-weight-change-between-the-poles-and-the-equator-interme... |
[
"How do the particles not escape the HADRON collider?"
] | [
false
] | null | [
"Their paths are constrained by magnetic fields."
] | [
"Ion optics. Electromagnetic fields are used to steer and shape the beams how they desire."
] | [
"Much stronger than common toy magnets, but typical ion optical field strengths are around a few Tesla. The strongest man-made magnets in existence that I know of have max continuous field strengths of around 50 Tesla."
] |
[
"What happens if the beta decay of a diproton into deuterium is unsuccessful?"
] | [
false
] | Do the two protons go back to being sole protons? How do they get back the energy that they lost earlier through gamma radiation when fusing into a diproton ? Does the star's core have any way of giving it back to them? If not what happens then? | [
"The diproton almost always decays to two protons. The beta decay to a deuteron has a very small branching fraction.",
"How do they get back the energy that they lost earlier through gamma radiation when fusing into a diproton ? ",
"They don't."
] | [
"Can those protons fuse into diproton again? If not, what happens to them from there on?"
] | [
"From this point they're just protons like any other, they have no \"memory\" of their previous diproton state."
] |
[
"Do the bacteria in our stomach become resistant to antibiotics over time?"
] | [
false
] | If we are creating antibiotic resistant bacteria that can infect us, I was wondering whether our microbiome would also become resistant. | [
"There are no bacteria in your stomach (unless you are infected with ",
").",
"For the most part, there are no bacteria in your small intestine either, as the forward motion of the muscle lining (peristalsis) keeps them moving forward toward the large intestine.",
"There are colonies of bacteria in your large... | [
"You're looking to learn about \"horizontal gene transfer\". There are a lot of ways it can happen. Wikipedia, as usual, is a good place to start: ",
"https://en.wikipedia.org/wiki/Horizontal_gene_transfer#Mechanism"
] | [
"On antibiotics. You either take it all and more if that didnt do the trick or you take none at all. "
] |
[
"If I had a spherical glass vacuum in a zero-g environment containing some rubber balls, shook it, then left it free-floating, would the balls ever completely stop moving inside it?"
] | [
false
] | [deleted] | [
"Some of the energy is going to dissipate because the collisions are not perfectly elastic.\nEvery time the rubber balls strike each other or the glass container some small component of the momentum is going to be lost.\nThe loss of energy is going to be due to some inelastic process, like friction between each bal... | [
"Why would they stop because a gravitational force is acting on them?"
] | [
"Ok, step by step now:",
"Because they all will have a constant force pulling them in towards a singular point.",
"So far so good. Let's ignore for a moment that gravity is not actually a force in order to keep it simple. The ball in the container is accelerated towards the wall by the \"force\" of gravity. At ... |
[
"Is there a limit to how small black holes can get? Also, are singularities all the same size?"
] | [
false
] | I was browsing , when a thought occurred to me: Is there a physical limit to how small a black hole can be? I understand that the event horizon is no measure for the size of a singularity, but could a black hole exist with an event horizon on the scale of planck lengths? I know that really small amounts of matter have been used before to create black holes, such as LHC and [RHIC]( ), but how small can they get? I was also wondering, are all singularities the same size? Do we know about this? Would [NCG 1277] (mcdonaldobservatory.org/news/releases/2012/1128.html) have the same size singularity as the ones made at RHIC? If so, how big are they? Thanks for any answers. Posted from a phone, sorry of the hidden links are broken. | [
"I know that really small amounts of matter have been used before to create black holes ",
"This is not true. The link you give points to a discussion that explains RHIC cannot produce an actual black hole. See ",
"http://www.bnl.gov/rhic/blackHoles.asp",
". Neither LHC nor RHIC nor any other accelerator ha... | [
"If black holes emit Hawking radiation, then a black hole will emit more than it absorbs from the cosmic microwave background if it is smaller than about the mass of the moon. However, as far as we know black holes are formed from collapsing stars, and stars much be much larger than the sun for this to occur.",
"... | [
"Thank you for referring to the singularity as a mathematical issue rather than a physical object. Most descriptions I see treat them as if they are real physical objects and I think that causes a lot of misunderstandings."
] |
[
"If every person were to stand at equal distance apart from each other on earth, how far apart would we be?"
] | [
false
] | [deleted] | [
"Let's just take land area and neglect the polar icecap (additional area) and areas which would be hard to stand on like cliff terrain etc. (subtracted area)",
"The land area of the earth is ",
"~150 million km",
". The world population is just under 7 billion (google).\n",
"\nSo dividing the area by the po... | [
"It's actually impossible to stand on a sphere with more than 20 people with exactly equal distance to each other. ",
"I know this sounds counter intuitive, but if it were possible there would be more platonic solids. The ancient greeks figured this out already. "
] | [
"How much difference will it make to the distance between hexagonal packing and just putting them in the suboptimal squares I've described below? (Not criticizing, just wondering how large that effect is and since you brought it up, you're probably more apt at making that calculation than me.)"
] |
[
"Cocaine and tobacco residues found in Egyptian mummies, does this indicate trade with the Americas?"
] | [
false
] | null | [
"http://www.faculty.ucr.edu/~legneref/ethnic/mummy.htm"
] | [
"[Citation Needed]"
] | [
"You should update your post to post the findings that you are referring to so others can share :)"
] |
[
"Why do people die instantly of heart failure? Shouldn't there be some time you're still alive while your brain is suffocating from lack of fresh oxygenated blood?"
] | [
false
] | null | [
"They do not, many many people have been resuscitated after the heart stops beating. You will lose consciousness within a short time of the moment it stops beating (similar to losing consciousness from being choked - lack of oxygen to the brain), but you are not dead immediately thereafter.",
"That is just what h... | [
"That is just what happens in movies.",
"To add my two cents, a fact that they always insist on getting wrong in the movies is the use of a defibrillator. They show it as a way to resuscitate someone's stopped heart but that's not it's function at all; desfibrillators are used to return a dysrhythmia (ventricular... | [
"In fact, you could make the case that the defibrillator's role is not to start, but to ",
" the heart.",
"You use it in ventricular tachycardia and fibrillation, which are \"rhythms\" where an electrical pulse goes haywire or where every muscle cell fires more or less randomly. The defibrillator delivers a pow... |
[
"Why does my radio get beter reception when I have my hand on it?"
] | [
false
] | Am I acting as like a flesh antenna or something? | [
"Water does not conduct electricity very well. The minerals in it do. "
] | [
"Basically, yes. Here's a couple articles on it:",
"http://www.thenakedscientists.com/HTML/content/qotw/question/2448/",
"https://www.scientificamerican.com/article.cfm?id=why-does-moving-your-hand",
"And a similar question:",
"http://www.reddit.com/r/askscience/comments/se5et/when_i_tune_my_radio_it_sounds... | [
"Most of your body is water, water conducts electricity, boom, antenna."
] |
[
"Do brain training games actually improve your cognitive ability?"
] | [
false
] | [deleted] | [
"The closest I can come to commenting on \"brain games\" in general is some of the research around the Brain Age games: people don't necessarily get \"smarter,\" but they do get better at Brain Age.",
"\nI remember reading in Wired way back when (quick google search finds this:",
"link",
") which found that s... | [
"There's evidence that ",
"n-back tasks",
" can increase test scores on Raven's Progressive Matrices. Whether Raven tests are a good indicator of IQ is arguable, although schools and high IQ societies do use it to vet candidates."
] | [
"There is some evidence that the placebo effect can remain even if the subject knows its a placebo. But the placebo effect isn't truly understood."
] |
[
"What would happen if sea levels DROPPED?"
] | [
false
] | We always hear about the social/economic/environmental problems and side effects of worldwide rising sea levels, but out of curiosity, what would one expect if the opposite was true? How would things change if sea level dropped, say, 10-20 metres. More, if that's more interesting. Thanks in advance! Edit: thanks everyone for the thought out and informative comments, dnd setting inbound ;) | [
"Well ... it happened before, of course, and within the previous few hundred thousand years no less ... litterally within human memory, during the last ice age. The Lascaux paintings are documentary evidence from that time period.",
"Just as global warming leads to rising sea levels as the ice caps melt, global c... | [
"Putting aside the climate effects required for a sea level drop, every major harbor in the world would now be high and dry--or at least have problems working at anything close to their original capacity--so much of world trade would be interrupted, and you could see regional famines resulting."
] | [
"OTOH, wouldn't the Sahara be \"wet\" (i.e. grassland) again as it was during the neolithic subpluvial?",
"Edit: thanks to all the folks who dropped knowledge below--learned a lot!"
] |
[
"AskScience AMA: I'm a biologist who studies stress and reproduction in large whales, sea turtles and other species. I'm at the international marine mammal meeting right now in New Zealand. AMA"
] | [
false
] | [deleted] | [
"The most common is actually shipping noise, and the most common high-volume noise is seismic exploration. Those never seem to get as much press as military sonar. A lot of my funding is specifically to look at effects of military sonar and yet it's clearer with every study that shipping noise and seismic explorati... | [
"Thanks for the AMA! 2 questions:",
"What have your studies found to be the most common source of ocean noise? ",
"What is, in your opinion, to be the most threatening factor to the whales' habitat? "
] | [
"Funny you should bring this up because the N. Atlantic right whales, and all the right whales, are kind of famous for their reproductive organs and repro behavior. They don't seem to suffer any erectile dysfunction though - partly because the right whale penis works quite differently - (a) like a lot of mammals th... |
[
"Why is it impossible to have a correct 2D map of the earth?"
] | [
false
] | [deleted] | [
"Because a sphere has non-zero intrinsic curvature and the plane has zero intrinsic curvature. You can't isometrically (preserve angles and distances) move from one to the other because isometries preserve curvature."
] | [
"try to lay an orange peel flat on a table. it will have bumps or it will break. "
] | [
"No matter how much you break it it will still not be 2d."
] |
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