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Sunday, April 15, 2018

How did we first find out there was no oxygen in space?

How did we first find out there was no oxygen in space?

How did we first find out there was no oxygen in space?

Posted: 15 Apr 2018 03:55 AM PDT

Is the great attractor actually a real thing or is there just a lot of stuff there?

Posted: 15 Apr 2018 04:02 AM PDT

If you look at the shape of the matter in the universe, it's a web of clusters. I don't really think it's a black hole or anything, but it's more like so much stuff in these clusters that it's bending space and causing galaxies like ours which is like rural hick zone to fall in and eventually join into these dense areas or something.

submitted by /u/feelmysoul01
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Why does water damage electronics?

Posted: 14 Apr 2018 07:56 PM PDT

Is there a physical limit to how fast a human being can run?

Posted: 14 Apr 2018 10:53 AM PDT

According to a source in 2004; "No prehistoric remains have been found of people older than 50 years". Is this still true?

Posted: 14 Apr 2018 08:06 AM PDT

According to

Hayflick L. "Anti-aging" is an oxymoron. J Gerontol A Biol Sci Med Sci. 2004 Jun;59(6):B573-8.

No prehistoric remains have been found of people older than 50 years.

Question a) is this true and b) if yes, is it still true in 2018?

submitted by /u/netgeogates
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What is the significance of kB*T (Boltzmann constant multiplied by temperature) in physics / quantum mechanics?

Posted: 15 Apr 2018 04:45 AM PDT

Learning basic quantum mechanics for chemistry, I have read that only energy levels with energies "less than or comparable to kB*T" are only populated significantly at temperature T. Why is this? As kB*T is such a low value (~4.12E-21 J), does it follow that, at 298 K, only in translational wavefunctions is there a significant population of excited states, whereas only the zero point energy is significantly populated in rotational/vibrational wavefunctions?

submitted by /u/Fuckminsterfullerene
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Why does the strong force work keeping protons and neutrons when the electrostatic force would push them apart?

Posted: 14 Apr 2018 06:40 PM PDT

Why does the strong force work keeping protons and neutrons when the electrostatic force would push them apart?

For example, a proton and neutron would go together fine with the strong force, but a proton and another proton won't fit in together because of the electrostatic force.

I'm not an expert, but I feel this is a simple scenario that a high school student could fit in together.

submitted by /u/Isatis_tinctoria
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What is that feeling we get when we want to sneeze but can't. What exactly is going on in our noses at that time?

Posted: 14 Apr 2018 10:17 AM PDT

How do sperm find eggs?

Posted: 14 Apr 2018 04:51 PM PDT

What's the difference between the "heat death" and "Big Rip" models of the ultimate fate of the universe?

Posted: 14 Apr 2018 01:05 PM PDT

(Prefacing this with: I'm not a professional science person, I just love me a bitta space. I'm working on a prose-poem-y thing about anonymous sex and end-of-universe scenarios and I like to think I know a reasonable amount about both, but I only really have first hand experience of one of them and want to be as accurate as I can in the other.)

I thought I understood the idea pretty well: flat curvature, accellerated expansion, increased ratio of dark energy to regular matter and dark matter, things getting further away from each other, galaxies and solar systems and individual objects split apart, shit burns out, shit Hawking radiates away, atoms split apart, individual particles are on their own and to far away from each other to possible have any further causal relation to each other, everything is cold and boring and sad, no more pizza, yadda yadda yadda.

But I keep seeing them listed as two distinct models. Is it that they're kind of similar or overlap? Or are they mutually incompatible in some way that's gone over my head?

submitted by /u/lacanimalistic
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Is the electroweak force mediated by a carrier other than a photon, W, or Z boson, or does it simply not matter which of the three is mediating a particular interaction?

Posted: 14 Apr 2018 12:52 PM PDT

If it is a new boson, then does that mean that a photon, W, or Z boson could transform into this new boson by gaining energy, and turn back into any of the 3--not necessarily the same as before--if it lost energy?

submitted by /u/Unoriginal0000000000
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Why doesn’t kangaroo blood clot?

Posted: 14 Apr 2018 09:45 AM PDT

I was watching a nature documentary and they were doing surgery on a kangaroo, and mentioned that kangaroo blood doesn't clot. They didn't say why this was, and google turned up no results. It seems like clotting blood is a critical thing, since a small cut could lead to a kangaroo bleeding to death. Why doesn't this happen?

submitted by /u/USAisAok
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How do great white sharks mate?

Posted: 14 Apr 2018 05:16 PM PDT

Why are elevators placed at the rear of planes, and not at the front?

Posted: 14 Apr 2018 12:50 PM PDT

Does space equipment get dirty in space ?

Posted: 14 Apr 2018 09:57 AM PDT

All kinds of equipment needs regular cleaning from things that get deposited on them, specific to which environment its in. Does the same go for the space station or the the canadarm? Would the effect of these objects in the vacuum of space be strong enough to attract dust and other things? Is there even enough stuff in space to deposit on the equipment for it to matter?

submitted by /u/the_walls_have_noses
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How are carbon nanotubes made? And are there ways for them to be made commercially?

Posted: 14 Apr 2018 10:09 PM PDT

How did the transition to an amniotic egg happen?

Posted: 14 Apr 2018 10:22 AM PDT

I can't seem to understand the logistics of how egg hatching can evolve. It's not like one generation is born in water, then evolved to lay an egg on land. What was the transition like from water egg to land egg? was there an in between that I don't know about?

submitted by /u/SquawSquaw
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Is there a statistically significant difference in any variable depending on the season of the year you were born?

Posted: 14 Apr 2018 09:02 AM PDT

Like a stronger immune system? A higher likelihood of having certain traits?

submitted by /u/oh_hullo_there
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What has the biggest effect on the nutrition of a fruit/vegetable?

Posted: 14 Apr 2018 09:34 AM PDT

I've seen some people stating that our food has become less nutritiously dense over time. Is this true? I believe they specifically are talking about the vitamins and minerals, not just calories. 2004 Article 2009 Article

Is it because food is now picked weeks before consumption (to be shipped to stores) and loses nutrition over time?

or

Does a crop grown in "dead" soil that is fertilized with "traditional" chemical fertilizers have the same nutrition as a crop grown in a biologically active soil with high percentage of organic matter? Where does hydroponics fit in?

or

Have modern crop varieties been breed for appearance and not nutrition?

or

Something else entirely?

Thank you for your time.

submitted by /u/danieldoesnt
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How are some plants able to survive without direct sunlight, or little to no sunlight at all?

Posted: 14 Apr 2018 08:51 AM PDT

Why are 2D hexagonal arrays more stable than square or triangular arrays?

Posted: 14 Apr 2018 09:19 AM PDT

I was just reading the following passage in this article:

...surface tension explains the patterns of bubble rafts and foams. The foam will seek to find the structure that has the lowest total surface tension, which means the least area of soap-film wall. But the configuration of bubble walls also has to be mechanically stable: The tugs in different directions at a junction have to balance perfectly, just as the forces must be balanced in the walls of a cathedral if the building is going to stand up. The three-way junction in a bubble raft, and the four-way junctions in foam, are the configurations that achieve this balance.

It's the last sentence I want to understand better. Why do the three-way junctions of the hexagonal grid "balance the forces" better? Is there a visual that will help me understand?

submitted by /u/El_Poopo
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When an airlock gets opened and the contents of a ship or station rush out into space, what happens to the air?

Posted: 14 Apr 2018 08:46 AM PDT

At which point was Van der Waals' equation necessary for Onnes' work in liquefying helium?

Posted: 14 Apr 2018 01:42 PM PDT

I read that he wanted to prove/disprove his friends theory. What did he wanted to prove? It surely wasn't the quantifiable capability of VdW's equation when a gas is in its phase transition below the critical temperature, because carbon dioxide would be way better for that.

So what do the people mean, when they are writing, that he wanted to prove his friends theory.

And what does he mean, when he is saying, that he was led by VdW's theory?

(His nobel prize was awarded in 1913 and I just tried to read his lecture which one can read for free on the nobelprize site)

Thank you in advance

submitted by /u/MaesterHiccup
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Saturday, April 14, 2018

How common is lightning on other planets?

How common is lightning on other planets?

How common is lightning on other planets?

Posted: 14 Apr 2018 02:01 AM PDT

How common is it to find lighting storms on other planets? And how are they different from the ones on Earth?

submitted by /u/Tonroz
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If we weren't counting, would there be a way to tell how old we were?

Posted: 13 Apr 2018 05:16 PM PDT

How do lakes maintain any depth overtime?

Posted: 13 Apr 2018 04:11 PM PDT

It seems like the amount of organic matter being added to a lake would always outstrip its ability to shift sediment out through any draining creeks, even more so for those that don't have major out flows.

submitted by /u/Solmeaus
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The closer you get to a massive body, the faster you need to go to orbit. For earth, air resistance limits closeness you can achieve orbit at, but is there a theoretical limit for how close your orbit can be, on bodies without an atmosphere?

Posted: 13 Apr 2018 04:15 PM PDT

For example, on the moon, could you orbit at 500 ft, if you were going fast enough? 50 ft? 5?

submitted by /u/non-troll_account
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Do plants near highways or busy roads have different cell structure, due to emissions, compared to plants in a forest?

Posted: 13 Apr 2018 02:26 PM PDT

Do adopted children take on personality traits in favour of their biological or adopted parents?

Posted: 13 Apr 2018 04:07 PM PDT

What happens when a turtle ends up upside down in the wild? Does it just lay upside down till it dies?

Posted: 13 Apr 2018 05:39 PM PDT

How are heat sink compounds both graded, and selected for use? Whose prime area of expertise is this?

Posted: 13 Apr 2018 06:38 PM PDT

On the whole, when an end user buys heat sink compound there's no great need for in-depth decisions. A 1.5g tube for $5-10 will probably be fine. But my Mac, I discovered, has at least two quite distinct grades of compound in use. There's a higher-performance paste between the GPU and its heat sink, and a much thicker paste plastered on to all the VRAM chips on the graphics card. It looks like tile grout, to be honest, and it has to be plastered on about 3mm deep in order to give thermal contact between the very low-profile VRAM chips and the graphics card heat sink they lie under.

This got me wondering. How do engineers decide what grades of heat sink compound to use? How much does it matter? How many different grades are there in common use? Is selecting the right compound taught in Electrical Engineering these days, and if not, which discipline does consider it? My £5 tube specified its viscosity, thermal conductivity, operating temperature range and maybe 1-2 other things as well I don't remember. But I didn't understand the significance of any of those numbers, so all I could do was assume the numbers were reasonable for my use case and glop it on. If, as an engineer, you calculate that you do need some specialised compound, where can you obtain it from? What use cases require special formulas??

I did know heat sink selection could be a serious business, but I hadn't appreciated that choosing the right heat sink compound could be equally finicky.

submitted by /u/Simons_Mith
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How do Lasers burn objects? Do the stream of photons actually impart energy in the form of heat upon absorption, or does the act of hitting a surface create some sort of friction-based heat?

Posted: 13 Apr 2018 04:21 PM PDT

I'd imagine it's not friction-based or else glass would heat up as light passed through it, plus, someone once told me that light cannot generate friction because it lacks the mass, although I have no idea whether that's true or not. It doesn't sound right, but I'm far from being an expert.

Also, I know that dark surfaces are meant to get hotter in the sun than lighter surfaces because they reflect less light and absorb more - I'm guessing this would be the same for a laser beam, the absorption of light generating the heat?

submitted by /u/gjs628
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Are Astronauts on the ISS required to speak multiple languages?

Posted: 13 Apr 2018 03:41 PM PDT

For example, are the Cosmonauts required to speak English? And the Astronauts required to speak Russian?

Edit: not really astronomy but I feel as though it's the most relevant flair

submitted by /u/sammiali04
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Do starchier plants deteriorate slower than plants with higher sugar content?

Posted: 13 Apr 2018 04:25 PM PDT

Why does administering IV Dexamethasone too quickly cause a burning/itching sensation in the recipient's groin?

Posted: 13 Apr 2018 09:14 PM PDT

We call it "ants in the pants" or "ring of fire." Pushing the med slowly helps but some patients are ultra sensitive & some days unfortunately I can't spend that much time on it. This is a question that obviously comes up from patients on an almost daily basis. I'd be remiss not to attempt to find out why.

submitted by /u/mid_1990s_death_doom
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What affect does pollution have on flight?

Posted: 13 Apr 2018 08:26 PM PDT

Is there a difference between flying through clean air vs. flying through smog/pollution?

submitted by /u/inertiaWORKS
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The Large Hadron Collider is 27km long in order to stably accelerate particles, but is there any hope of miniaturization in the future?

Posted: 13 Apr 2018 11:37 AM PDT

Can the mass of a particle change?

Posted: 13 Apr 2018 09:20 AM PDT

Since almost all of the mass of a particle is from the binding energy it holds, Is it possible to reduce the amount of binding energy there is in the particle by making it cooler or hotter or other weird scenarios which could effectively change the binding energy and hence the mass?

submitted by /u/JackTalle
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Are there any "flighted" birds that opt not to fly?

Posted: 13 Apr 2018 12:58 PM PDT

I guess my questions is that we all know there are bird species that cannot fly, my guess is because they were able to survive without flying. Are there any species of birds that are in that transitional phase of being able to fly but able to thrive without flying very much or not at all?

submitted by /u/prick-in-the-wall
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Does Halley's comet get smaller after each orbit?

Posted: 13 Apr 2018 09:00 AM PDT

If the tail of the comet is all the melting ice and dirt then should it be getting smaller. Or does it gain more ice and dirt as it flies back into deep space?

Edit: I misspelled tail

submitted by /u/DrPotatoEsquire
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I have two pieces of wood. One is burnt by fire. The other is burnt by a lightning strike. Is there anyway to distinguish between the two?

Posted: 13 Apr 2018 05:14 PM PDT

Will Earthquakes and Volcanos Eventually Stop? If so, when?

Posted: 13 Apr 2018 08:20 AM PDT

As I understand it, Earth was once entirely molten, and then began cooling and the crust formed, and that's where we all live. We have earthquakes because forces under the crust push the pieces around, and we have volcanos because the crust isn't very thick in some places and/or that's where two crust pieces meet and the molten stuff underneath pushes out.

If cooling is still going on, shouldn't the crust still be getting thicker, and at some point won't the crust be so thick these things stop happening? Right now, the crust isn't even 100km thick. If it was 150km, or 200km, or 500km thick, would that be enough to stop tectonic movement, and thus bring an end to earthquakes, and also be too thick for volcanos to push out?

How thick would the crust have to be for earthquakes and volcanos to stop? How long will it take for the crust to get that thick?

submitted by /u/MyActualRealName
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Friday, April 13, 2018

If extra wings seen on biplanes add more lift and maneuverability, why don’t we add them to modern planes or jets and have them built into the airframe like we do today?

If extra wings seen on biplanes add more lift and maneuverability, why don’t we add them to modern planes or jets and have them built into the airframe like we do today?

If extra wings seen on biplanes add more lift and maneuverability, why don’t we add them to modern planes or jets and have them built into the airframe like we do today?

Posted: 13 Apr 2018 05:05 AM PDT

Does the moon or other planets have magnetic poles?

Posted: 12 Apr 2018 10:51 PM PDT

Would we be able to use a compass there like we do here?

submitted by /u/frickfrackcute
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Why are cooling towers shaped the way they are?

Posted: 13 Apr 2018 04:28 AM PDT

Power plants or large factorys all have the same shape of their cooling tower. The radius is smaller in the middle and widing up on top again. Whats the reason we dont use the same radius everywhere or it only gets smaller higher up.

submitted by /u/IntenSIEF
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Does body language have 'dialects' as such?

Posted: 13 Apr 2018 05:40 AM PDT

What exactly happens when Polyurethane foam is formed?

Posted: 13 Apr 2018 03:20 AM PDT

I am currently doing my mechanical engineering dissertation on making structures using polyurethane foam, I have no background in chemistry and reading through many papers on polyurethane I find them hard to follow sometimes. I have searched through many papers to try and find what is going on but I cannot. Basically I have seen studies whereby the PU foam is formed within a vacuum, however in my experiments I have tried to form PU foam within a bag and it does not expand anything like it does when open to the air. Can anyone explain what is going on and why air is needed? Or am I missing something ? I am using 2 part pour-able foam.

TL:DR Polyurethane 2 part foam is not expanding properly when not exposed to air, why?

submitted by /u/teegfit1
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Do birds have tastebuds?

Posted: 13 Apr 2018 05:32 AM PDT

What draws them to French fries, potato chips, and other "snacky" foods?

submitted by /u/meganzin
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Why doesnt AIDS burn itself out?

Posted: 13 Apr 2018 06:04 AM PDT

Shouldnt there be a point where AIDS kill all of the lymphocytes that are its host, therefore not being able to reproduce anymore and dying. I.e burning itself out.

submitted by /u/nanaro10
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Can current models accurately predict the temperature of super nova stars just before they explode and create a black hole?

Posted: 12 Apr 2018 10:37 PM PDT

can the temperature be predicted as a star implodes, is there evidence to support how accurate the predictions of those temperatures are?

submitted by /u/CajunKush
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If my weather app breaks down the probability of precipitation by hour, how do I determine the probability for the day?

Posted: 13 Apr 2018 05:38 AM PDT

Right now it says 40% chance for the next two hours, 50% for the next hour, 56% for the next two hours, and then 30% for the rest of the evening.

If each of these is independent, does that mean the probability for the whole day is very high? Or is the whole day probably still around the 50% range?

submitted by /u/pm_me_ur_demotape
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Why can't processors guarantee calculation of a known problem in constant length of time?

Posted: 13 Apr 2018 04:41 AM PDT

All commercial airplanes basically have the exact same design; is that by necessity or happenstance? Did it really have to be that one way?

Posted: 12 Apr 2018 10:25 PM PDT

How do animals without parental figures know what species to mate with?

Posted: 12 Apr 2018 01:19 PM PDT

Differing forces in different reference frames?

Posted: 13 Apr 2018 05:06 AM PDT

Posted the question in the r/Physics thread but haven't gotten any answers so figured I might try my luck here.

A question that has been confusing me for a while now:- Firstly, we consider the day-to-day frame of reference that we normally think about. We are pulled down by a gravitational force mg downwards, and pushed up by the normal force of same magnitude provided by the ground - hence we stay stationary on the ground with no acceleration. However, if we look at the entire Earth as a reference frame, the Earth is rotating on its axis and we are rotating on it with the same angular velocity. Then clearly we cannot have the normal force N=mg, since in that case we would have no net acceleration and will not rotate in a circle around the Earth's axis.

So this is the part where I get confused about what forces are in play here. I think the normal force by the Earth in that reference frame must not be opposite to the gravitational force, but rather their vector sum should point towards the Earth's rotational axis to provide us with the centripetal acceleration. However in that case, why does the same(?) normal force appear to be acting in different directions in different reference frames? I also might be wrong in my analyses of forces present and there is another (pseudo?)force that can help explain this problem.

submitted by /u/IFTClerk
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Why does the Pauli Exclusion Principle apply to fermions but not to bosons?

Posted: 12 Apr 2018 12:53 PM PDT

Can a x86_64 CPU be designed to run code meant for ARM_64?

Posted: 13 Apr 2018 12:43 AM PDT

Unless I got something wrong a x86_64 should be able to handle all the instructions that an ARM_64 can, just at reduced speeds.
Would this even worth doing?
Or would it be just as fast to emulate an ARM_64 CPU?

submitted by /u/Starf4rged
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Could you make a Silicon version of Graphene?

Posted: 12 Apr 2018 01:43 PM PDT

Would it be possible to have a silicon (or other element in that group/column) equivalent of graphene where the atoms are arranged in the same manner? I imagine this substance would have similar properties to the carbon version.

submitted by /u/TheWierderOne
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Why do some plants have colorful (not green) leaves in the spring and summer and not just in the fall?

Posted: 12 Apr 2018 11:33 AM PDT

Something like a japanese maple comes to mind

submitted by /u/Forestpotato
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If there is an absolute cold, is there an absolute hot?

Posted: 12 Apr 2018 04:43 PM PDT

Is development of muscle memory partially performed outside the brain?

Posted: 12 Apr 2018 09:01 AM PDT

I'm aware that many changes occur in the brain when developing muscle memory, but I do not know to what degree the part of the somatic nervous system outside the brain changes and whether or not those changes are largely significant to performing a particular motor function. If you were to learn to play the guitar but, after doing so, only retained the neural development done directly in your brain, would you still have the capacity to play? I understand this is a hypothetical question to a degree, but the information the answer provides is relevant to the more concrete question underneath.

submitted by /u/ZaxasT
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