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Friday, November 15, 2019

How do meteorologists calculate wind chill or “feels like” temperatures?

How do meteorologists calculate wind chill or “feels like” temperatures?

How do meteorologists calculate wind chill or “feels like” temperatures?

Posted: 14 Nov 2019 03:07 PM PST

Did Huygens potentially contaminate Titan?

Posted: 15 Nov 2019 06:51 AM PST

As I understand it Cassini was deliberately directed into the atmosphere of Saturn to avoid an accidental crash landing on one of the system's moons and a potential contamination of the environment with earthly bacteria. How come there was no such concerns about landing Huygens on Titan? Was this as reckless as it seems considering the views of, among others, Chris McKay ( I know he was involved in the hydrogen tests during the decent) regarding the possibility of life on Titan? How did the scientific community justify the risks?

submitted by /u/demojunky73
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If contact between matter and its antimatter counterpart causes annihilation that is extremely energetic, how is antimatter creation at the LHC safe?

Posted: 14 Nov 2019 11:08 PM PST

If insects can grow larger by being raised in an oxygen-rich environment, can animals like crabs and lobsters also grow larger in oxygen-richer water?

Posted: 15 Nov 2019 05:24 AM PST

There have been experiments showing that insects grow a bit larger when raised in a high-oxygen container. Does that carry over to sea arthropods too? What would the other limitting factors be? How could an experiment be designed and performed in order to test this hypothesis?

submitted by /u/rosenbergstein
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Is it possible for a modern ship to go Canada-West Russia (Moscow) through the Artic?

Posted: 15 Nov 2019 04:52 AM PST

Weird permanent thing in the sky?

Posted: 14 Nov 2019 07:58 PM PST

A few months ago, my dad and I were camping in the middle of nowhere in Queensland, Australia. There was no major light pollution for at least 60 kilometres, so we could see a lot of the stars and astronomical stuff. Around 9 pm, we were sitting there looking at it all, and I noticed a cloud; nothing strange, so I took no notice of it. It was a moderately windy night, so when I looked back at it 20 minutes later and it hasn't moved, I was naturally curious. I asked him if it was one of those huge masses of gas in space, and he said it probably wasn't, and he wasn't exactly sure what it was. He did a lot of science and mathematics in university, so I trusted him. I am also relatively knowledgeable in physics (brag), but I couldn't think of what it could be. I forgot about it, and then we went to bed (tent?) at 11 pm-ish. At 3 am, I got up to go pee, and it was in the exact same spot as when I saw it hours ago, even though the rest of the starts and gas masses had shifted around. At that point I realised that it had to be in our atmosphere, or spinning with the earth at least, because it hadn't moved. It also definitely couldn't have been a cloud or anything physically light because at that time it was insanely windy at sea level, so I couldn't imagine what it would be like that far up. Still now, months later, I have no idea what it could have been. Does anyone in the entire r/science community have an idea? It's been killing me ever since I saw it.

submitted by /u/decmh_
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What evolved first, Limbs or Digits?

Posted: 15 Nov 2019 02:29 AM PST

Did we have at some point in our evolution history we're we creatures with limbs which then started to split into digits or did we have clusters of digits that started to extend away from the body on limbs? Or did both limbs and digits evolve pretty much simultaneously?

submitted by /u/Dave-the-Flamingo
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How does the Aristotle's lantern (the jaw apparatus found in a sea urchin) work?

Posted: 15 Nov 2019 07:17 AM PST

Hello! I'm a non-scientist (obviously!) who is currently working on a design project. While doing my research, I came across the structure of the mouth of the sea urchin (known as Aristotle's lantern) and I'm really fascinated. I tried to read more about it on the internet, but due to my non-science background, I have trouble understanding it. Can somebody please explain to me how does the mouth of a sea urchin work? How is it formed structurally? What is the mechanism behind the movement? How is it held together?

Thank you very much :))

submitted by /u/babybananacake
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How did the spread of the Black Plague die down?

Posted: 14 Nov 2019 01:48 PM PST

So I know the plague was spread by rats but how did it get to such low rates and how long did it take to die down?

submitted by /u/ThatRanblingKid
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Are there any problems that classical computers are better at solving than quantum computers?

Posted: 14 Nov 2019 05:03 PM PST

If I have two stop watches and start a timer, leave one on earth, take the other one to mars and come back. Will they show the same time time counted?

Posted: 15 Nov 2019 01:58 AM PST

I've been trying to wrap my head around the concept of how time is slower/faster on other planets.

So if I have two stop watches and start them at the same time, then take one to Mars, stay there for a couple of days, then fly back. Will they still show the same time? Or will the one that I took to mars have counted faster? Because apparently time is faster on mars (I think).

I just clearly understood how speed is relative and I want to understand this as well.

submitted by /u/Bderken
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How does the quantum tunneling effect limit development of micro processors and how do we overcome that?

Posted: 15 Nov 2019 04:57 AM PST

Is it true that people are physiologically inclined to feel more awake at certain times?

Posted: 15 Nov 2019 04:37 AM PST

In other words, is the idea of a "morning person" and "night person" actually valid? I'm wondering if this is true because I've always felt extremely tired sleeping early and waking up at 6AM every day for work, but I felt perfectly fine whenever I slept late and woke up at 12PM during my university days. Is it because I'm actually, on a physiological level, a night person? Or am I just mentally convincing myself that I am and that I could just simply adjust to this early-morning lifestyle if I'd just accept it gung-ho?

submitted by /u/john_wildemire
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Rocketship going 51%c shoots out a second rocket ship going 51%c?

Posted: 14 Nov 2019 01:31 PM PST

I sometimes help tutor remedial introductory uni-physics, and someone asked this question and it honestly stumped me I couldn't figure out an intuitive way to answer this basic question.

The student asked something like: "If you had a rocket ship that was travelling through space at 51% of the speed of light relative to earth and it had a smaller rocket ship on board and it shot off the second spaceship from its docking bay and the smaller rocket ship also accelerated itself to 51% the speed of light relative to the first ship. Wouldn't the smaller rocket ship be travelling at 102% the speed of light relative to earth?"

I started talking about frames of reference but honestly, I can't for the life of me figure out an intuitive way of explaining that. Pleas help.

submitted by /u/coolyouone
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How is melanin produced in humans/how does tyrosinase produce melanin?

Posted: 15 Nov 2019 02:56 AM PST

I'm trying to find a good resource that can explain the enzymatic activity of tyrosinase.

submitted by /u/Alternative_Stand
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How does CERN/LHC deal with soil movement?

Posted: 14 Nov 2019 02:44 PM PST

I was watching a video on the LHC and this question popped into my mind that I couldn't find an answer to online.

Which is how the LHC in Geneva accounts for soil movement, expanding soils, and things like that, given that it's such a massive structure? Wouldn't it eventually throw their measurements off? I know they need a remarkable amount of precision to electromagnetically shoot particle beams into one another.

submitted by /u/Domorama
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Why is it often the case that invasive species outcompete native ones when native species have evolved specifically to be best suited to their environment?

Posted: 14 Nov 2019 01:13 PM PST

What keeps the galaxies intact?

Posted: 14 Nov 2019 02:58 PM PST

Trying to explain myself better, according to scientists, the matter that we can see, is not enough to hold the galaxies together, so there must be a matter that we don't see, that only interacts gravitationally with the "normal" matter. But as far as we know, do we have evidence that it is the dark matter that keeps the galaxies intact? Or could it be magic or the power of God or stuff like that, holding the galaxies together?

Sorry if my question seems stupid to you, and for my mistakes in writing English.

submitted by /u/TristoMietiTrebbia
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Is the Earth completely neutral or is more acidic or basic? Why?

Posted: 14 Nov 2019 01:12 PM PST

At least in soils, it seems that the majority of Earth's soils are acidic. This makes me wonder if the Earth is majority acidic.

submitted by /u/Crawfish1997
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Is there any actual difference in battery technology or is it all marketing like "quantum" batteries from Duracell?

Posted: 14 Nov 2019 11:16 AM PST

How do bugs survive winter by hiding in tiny cracks, when big animals like us are so vulnerable to it?

Posted: 14 Nov 2019 10:17 AM PST

When light enters a black hole and then fails to exit it, would the black hole not cause the light to slow down below the speed of light which, should be impossible for light in a vacuum?

Posted: 14 Nov 2019 10:38 AM PST

Has there been any progress of pinning down the free parameters of generalizations of general relativity like Brans-Dicke or Kaluza-Klein so that we can actually calculate with them?

Posted: 14 Nov 2019 02:05 PM PST

I heard somewhere that at low energies superstring theory reduces to a version of Brans-Dicke, which is basically general relativity with an extra scalar field instead of the gravitational constant G. If this is true, then if we can determine a decent value of ω, won't that help narrow down the string theory landscape? I'm curious about this kind of approach because it sounds like we might not get any experimental evidence for string theory at the quantum scale any time soon, but perhaps there's a way at much larger scales?

submitted by /u/schottm
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Thursday, November 14, 2019

How did ancient people keep stored water supplies such as cisterns safe to drink?

How did ancient people keep stored water supplies such as cisterns safe to drink?

How did ancient people keep stored water supplies such as cisterns safe to drink?

Posted: 13 Nov 2019 07:38 PM PST

This has bothered me for quite some time. I get that a lot of people died of diseases and such. Standing, stagnant water allways looks so disgusting. Was the ones who lived immune systems so much better or were they able to keep the cistern free of diseases using plants or something?

submitted by /u/Jet-Streem
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Do citizen science programs like Zooniverse contribute to scientific research to a meaningful extent?

Posted: 13 Nov 2019 09:43 PM PST

Recently came across a program called Galaxy Zoo (hence the astronomy flair) and I am just wondering how useful are these types of things to scientists?

submitted by /u/UpsidedownEngineer
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Why does ions like iron or copper have “varying charge” so that there’s iron(3) and iron(2)?

Posted: 14 Nov 2019 01:08 AM PST

Can insects fly in the rain?

Posted: 13 Nov 2019 01:01 PM PST

Why is the average height of humans increasing over time?

Posted: 13 Nov 2019 12:22 AM PST

Napoleon, who was known for his short stature, was average height in his day. During the American Revolution, the average male height was 5'6.

Does this mean that taller people are "fitter" to survive?

submitted by /u/siraaris
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When you leave a carbonated drink to sit for a while after being shaken to avoid it fizzing over, what is actually happening here?

Posted: 12 Nov 2019 09:25 PM PST

How acutely aware are animals of mutations?

Posted: 12 Nov 2019 09:50 PM PST

So there was recently a picture on r/all of a dog with a small nonfunctional tail on its forehead.

So it got me wondering exactly how aware are animals of mutations like that? With the example above would the dog be shunned? Is it with as visceral a reaction as humans in the old days? Do they perhaps only care about mutations that affect ability or do they care about aesthetic mutations as well?

submitted by /u/ThisIsDark
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What makes things soluble?

Posted: 13 Nov 2019 12:52 AM PST

Is there any reason why the arctic is an ocean surrounded by continents and the antarctic is a continent surrounded by oceans, and both pretty much centered, other than coincidence?

Posted: 12 Nov 2019 07:41 PM PST

If Rheumatoid arthritis (or really any autoimmune disease) is caused by your immune system attacking specific tissues/cells, then why does doing things that would lower your immune system (such as overexertion, poor sleep, or stress) cause you to have a "flare up"?

Posted: 12 Nov 2019 01:50 PM PST

Autoimmune diseases are caused by your immune system developing antibodies to specific tissue's in your body. So, how is it that in situations where your immune system is naturally lower, like during periods of high stress, lack of sleep, and excess exercise, your symptoms worsen? Is it simply a matter of interrupting some sort of war between regenerating cells and attacking antibodies?

submitted by /u/miking3939
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Wednesday, November 13, 2019

Can a planet exist with a sphere, like Saturn's rings but a sphere instead?

Can a planet exist with a sphere, like Saturn's rings but a sphere instead?

Can a planet exist with a sphere, like Saturn's rings but a sphere instead?

Posted: 13 Nov 2019 12:49 AM PST

How do we know the universe is infinite?

Posted: 12 Nov 2019 05:55 PM PST

We assume the universe expands on and on into space, but can how can we assume space is infinite? Why do we think their can't be an end to expansion? Space isn't anything but we occupy it. How can we assume that space is never ending?

submitted by /u/FutureThot
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How would a wild forest fire solve itself if humans arent here to intervene?

Posted: 12 Nov 2019 07:52 PM PST

What would be the outcome?

submitted by /u/MSDLF
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Is the determinant of a 1-by-1 matrix defined, and if so, why is it defined as such?

Posted: 12 Nov 2019 11:16 PM PST

I'm currently studying multivariable calculus, and lately I've been interested in the mechanism by how multiple integrals can sometimes be simplified by a change of variables; I've been particularly interested in the Jacobian matrix and it's determinant (when its square, of course). Reading about these topics, I found out that the concept of the Jacobian is also defined for scalar-valued functions of a single variable; it is simply a 1-by-1 matrix whose only entry is the derivative of the function. With this knowledge, I noticed somewhat of a beautiful parallel between a multivariate change of variables and u-substitution, namely that the act of making a substitution in a single integral can be thought of as defining a differentiable transformation that maps the interval of integration in the original integral into its image in the transformed integral, where the extra factor that appears in the transformed integral is the determinant of the Jacobian of the transformation. I acknowledge that this wording can be a bit ambiguous and unclear, so I'll elaborate below with an illustrative example.

Let's assume, for the sake of simplicity, that f is a function that is continuous on the interval [a, b]. Suppose we want to compute the integral of f from a to b, which I will represent symbolically as follows (the notation [a, b] is meant to denote the interval of integration, where a is the lower bound, and b is the upper bound):

∫f(x)dx [a, b]

For the sake of the illustration, let's assume that a differentiable "transformation" (really just a scalar-valued univariate function) g exists that maps the interval [a, b] to [g(a), g(b)], and somehow, for some crazy reason, the interval [g(a), g(b)] will make the integral easier to evaluate. By analogy with the multivariate case, I reasoned that, if you were to make a change of variables by defining a transformation x = g(u), you can compute the value of ∫f(x)dx [a, b] by evaluating the integral ∫f(g(u))det[g'(u)]du [g(a), g(b)]. This formula is remarkably similar to the Substitution Rule for definite integrals, up to the det[g'(u)] term, which is where my question stems from.

In the multivariable case, it is necessary to take the absolute value of the Jacobian determinant, presumably because of issues arising with orientation when defining a transformation. Not only do I feel would it be nonsensical to do this in the univariate (since some substitutions have negative derivatives), I'm also unsure if such a determinant even exists for any 1-by-1 matrix. I'd greatly appreciate your response!

submitted by /u/4w350m3guY
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Ask Anything Wednesday - Physics, Astronomy, Earth and Planetary Science

Posted: 13 Nov 2019 07:08 AM PST

Welcome to our weekly feature, Ask Anything Wednesday - this week we are focusing on Physics, Astronomy, Earth and Planetary Science

Do you have a question within these topics you weren't sure was worth submitting? Is something a bit too speculative for a typical /r/AskScience 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...".

Asking Questions:

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 /r/AskScienceDiscussion , 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.

Answering Questions:

Please only answer a posted question if you are an expert in the field. The full guidelines for posting responses in AskScience can be found here. 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 /r/AskScience.

If you would like to become a member of the AskScience panel, please refer to the information provided here.

Past AskAnythingWednesday posts can be found here.

Ask away!

submitted by /u/AutoModerator
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If Black Holes and Supermassive Black Holes draw and condense matter in, how does the mechanism for ejecting/pushing away material (like a rogue star) work?

Posted: 12 Nov 2019 09:43 PM PST

Does a PCB printed meandered trace antenna perform worse than a wire antenna of the same length?

Posted: 12 Nov 2019 07:04 PM PST

Do nutrition labels in the US represent the total caloric content of the food, or the net caloric intake after accounting for things like digestive efficiency and the Thermic Effect of Food?

Posted: 12 Nov 2019 01:22 PM PST

Do humans permanently retain some portion of the water they consume or is all of the consumed water eventually lost/replaced?

Posted: 12 Nov 2019 11:23 AM PST

Flu, cold and other common illnesses were one of the factors why native americans lost their continent. How come the same thing - illnesses from America - did not spread so widely in Europe?

Posted: 12 Nov 2019 04:57 PM PST

[Biology]How does the oxygen produced by macroalgae, phytoplankton, and cyanobacteria get into the atmosphere?

Posted: 12 Nov 2019 05:38 PM PST

There is a common "fact" I see stating that 50%-80% of the world's oxygen is produced by primary producers in the ocean. I can't seem to find a primary source supporting that and I was curious about the mechanism behind the oxygen getting into the atmosphere. Is it as simple as oxygen reaching a saturation capacity in sea water so it outgases into the atmosphere?

submitted by /u/CapedBaldyman
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How does the STAR detector at the Brookhaven Lab detect?

Posted: 12 Nov 2019 03:41 PM PST

I'm not sure how specific to be, this is a fairly new concept to me. For instance, what exactly are they looking for with the experiment

submitted by /u/throwaway03994939
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How do we produce microprocessors with billions of transistors?

Posted: 12 Nov 2019 05:56 PM PST

How are transistors mass produced on a computer chip? If they were assembled individually it might take months to make a single chip so I assume there must be a method to do it in mass?

submitted by /u/RockasaurusRex
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In which direction is the Milky Way rotating?

Posted: 12 Nov 2019 01:33 PM PST

Were the question: in which direction is the core of the Milky Way? It could be answered In the direction of Sagittarius as using a constellation to orientate is fine. So which way is the galaxy rotating, from our perspective? Presumably towards some constellation at 90° from Sag., but which one? Of course terms like clockwise will convey no meaning, and a net search reveals many pages saying so, while adding how fast it rotates, how long a rotation takes, but ever omitting to say which way.

submitted by /u/Antimutt
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If mesons are made of quarks and antiquarks, then why don't they annihilate immediately?

Posted: 12 Nov 2019 08:26 AM PST

I know enough about the general idea behind particle physics to really confuse myself when I run into the actual complicated specifics. Up until today I'd thought that pions could exist because the quark and antiquark involved had different flavours and antiquarks only annihilated with quarks of their own flavour, but I am now realizing that π0 mesons are a thing and are composed of up and anti-up or down and anti-down quarks. Do quarks only annihilate with their own flavour, or was I completely incorrect?

submitted by /u/zanderkerbal
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What is an arctic blast? Is it normal? How will it affect our environment?

Posted: 12 Nov 2019 01:02 PM PST

How is the aquatic life of the Nile River affected by the changing salinity during certain seasons?

Posted: 12 Nov 2019 12:31 PM PST

How are the daily value of vitiamins and minerals determined?

Posted: 12 Nov 2019 01:00 PM PST

It seems like one would have to eat an inordinate amount to get the recommended DV% of vitiamins in minerals. Obviously some are easy to get like vitiman C and calcium. But others like folate, magnesium, zinc, phosphates, vitiman K, etc, are so difficult to eat enough to get the 100% recommended doses. How were those numbers determined?

submitted by /u/pancakelife
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