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Monday, January 16, 2017

If elephants had gone extinct before humans came about, and we had never found mammoth remains with soft tissue intact, would we have known that they had trunks through their skeletons alone?

If elephants had gone extinct before humans came about, and we had never found mammoth remains with soft tissue intact, would we have known that they had trunks through their skeletons alone?

If elephants had gone extinct before humans came about, and we had never found mammoth remains with soft tissue intact, would we have known that they had trunks through their skeletons alone?

Posted: 15 Jan 2017 06:36 PM PST

Is it possible that many of the extinct animals we know of only through fossils could have had bizarre appendages?

submitted by /u/Kombaticus
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If we could use the Large Hadron Collider as a cannon pointed towards space, would the particle make it into orbit?

Posted: 15 Jan 2017 07:14 AM PST

How can TSA/Airport security workers stand next to X and T ray machines all day everyday without any ill effects?

Posted: 16 Jan 2017 07:08 AM PST

I know the people walking through the machines have nothing to worry about, but are there any precautions in place to stop the workers absorbing these rays? Do the machines focus the radiation into one area? Thanks in advance.

submitted by /u/DexterTheMoss
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Where does the energy in core-fusion come from?

Posted: 16 Jan 2017 04:39 AM PST

So the process in the sun is the following (as far as i know): a deterium- and a tritium-atom fuse into a helium-atom and one neutron. So where does this huge amount of energy come from? We have the same mass as before and there are no other energy-sources, as far as i can tell. Can someone please explain?

submitted by /u/Laternenpfahl
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How long will Voyager I last in space?

Posted: 15 Jan 2017 10:54 AM PST

I understand that Voyager is about to run out of power. My question is asking how long (in terms of millions or billions of years) will Voyager last? I heard that all elements radioactively decay so will the metal on voyager eventually decay?

submitted by /u/Big_G_Dog
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How do you measure the amount of molecules in a vacuum?

Posted: 16 Jan 2017 12:28 AM PST

How are Cosmologists Able to Estimate the Size of the Total Universe?

Posted: 16 Jan 2017 02:33 AM PST

Note the language in the title is 'the total universe,' so not just the observable universe.

From this article at Livescience

Mack noted that assuming inflation happened, the universe is actually 1023 times bigger than the 46 billion light-years humans can see.

How did this cosmologist, and apparently others, come to that conclusion? In other words, what clues are available about that which lies beyond the bounds of what can be observed by laws of nature?

submitted by /u/toomuchdota
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If I stood on Saturn and looked up would I see the rings?

Posted: 15 Jan 2017 12:50 PM PST

Why is it that we see a lot of Resistor-Capacitor (RC) circuits in electronic designs but not a lot of Resistor-Inductor (RL) circuits?

Posted: 15 Jan 2017 05:11 PM PST

I am reviewing RC and RL circuits and in my textbook they state that you rarely will see RL circuits used because of the inductor's inability to have a precise value as opposed to the capacitor.

If this actually true, why is it so? Is it because the inductor is comprised of a magnetic field whereas the capacitor is comprised of an electric field? Is working with a B field more difficult to have precise and expected values as opposed to working with an E field?

submitted by /u/agent_engineer
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Why does polarization and electric field have conjugate complex exponentials?

Posted: 15 Jan 2017 09:36 PM PST

I was going through a paper where the electric field and polarization have a particular shown here. It appears fairly familiar but one thing I don't quite understand is: why are the complex exponentials of E and P the conjugate of one another? As far as I'm aware, this is not necessary for Maxwell's equations. Is it simply specific to the authors' model?

submitted by /u/CallMeDoc24
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If you travel towards an object at very-close-to-c, will the object have aged once you arrive?

Posted: 16 Jan 2017 03:15 AM PST

If the answer is yes -- why? I thought time dilation was symmetric -- on board this spaceship moving at close-to-c it would seem as though the object is moving towards you and barely aging, and that the distance between you and the object would appear minimal so you'd arrive nearly instantly.

If the answer is no -- this seems impossible. You could start at A, go to B, pick up a package, return to A, and see neither A nor B have aged at all. From the perspective of someone on A, you'd have made a roundtrip in hardly any time and gone FTL. (edit: ok, this part is the twin paradox. Nevermind the round trip. If the answer is "no" please just explain why not. I thought that traveling towards something at close-to-c would make it appear as though that object's "clock" runs slower)

So, what am I missing?

submitted by /u/options_questioner
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If it is impossible to project a sphere onto a 2D plane without distortion, does that mean that every camera lens and telescope must have distortion because light is hitting it on different parts of a curved surface but we get a 2D image out of it?

Posted: 15 Jan 2017 06:26 PM PST

If a computer is mining Bitcoin in a room, is all of the power supplied to it eventually available as heat, or does some of the power go into the "information" the calculations produced?

Posted: 15 Jan 2017 06:44 PM PST

This occurred to me a while ago: heat generation is done, essentially, by using what for every other application is considered waste. So would it be possible to get the waste heat from computer calculations to function as a space heater, while getting a useful result out of the process beyond just the heat?

submitted by /u/neaanopri
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What causes a razor blade to lose its sharpness?

Posted: 15 Jan 2017 02:28 PM PST

What would happen if a neutrino interacted with one of the photoreceptor cells in someones eye? What would they see?

Posted: 15 Jan 2017 06:11 PM PST

What are the odds of this happening to anyone? Are there any documented cases of this happening?

submitted by /u/PM_ME_LECTURE_NOTES
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How would an atmosphere twice as dense as that of Earth affect the transmission of sound? Would it be noisier? Quieter?

Posted: 15 Jan 2017 12:09 PM PST

If two bodies in space were orbiting each other at say 1 light minute apart and one disappeared would the remaining body be instantaneously affected or would it take one minute to react to the lack of gravity?

Posted: 15 Jan 2017 03:01 PM PST

If the Universe is an outdoor pool, is the CMB the pool walls or simply the edge of a sphere within the pool corresponding to our 13.8 bn years eye sight? Could there be many such spheres in the pool, none of them seeing the actual pool walls?

Posted: 15 Jan 2017 01:54 PM PST

The heart of my question is the cosmic microwave background (CMB). I know what it is (thank you Internet), but what does it represent? Is it the end of what we see, or an actual border (but then: a border of what?).

If it's just the end of lightspeed vision, could there be a number of universes happily dangling around in a greater area (the "pool")?

Then comes the (I think) unanswered question: what is all this composed of? The Universe sphere we know well. What about the space between the spheres? What about the pool walls?Beyond the pool walls?

I apologize for the semantics, these are hard concepts for me to grasp. Thank you!

submitted by /u/Bucksan
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If we stuck one end of a tube in the ocean and the other end in space, would the vacuum be strong enough to pull up the water column?

Posted: 15 Jan 2017 09:42 AM PST

I assume the answer to this depends on the diameter of the tube, so alternatively, what size tube would be needed to get the vacuum of space to draw the water up?

submitted by /u/finemustard
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Why doesn't gargling Listerine immediately end Strep throat?

Posted: 15 Jan 2017 04:52 PM PST

Is the mean free path affected by the speed of the particle?

Posted: 15 Jan 2017 08:12 PM PST

To be clear, i'm asking if a slow moving particle and a fast moving particle will have a different mean free path(through the atmosphere)? Assuming that everything else is kept the same.

submitted by /u/juke_lord
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How is addiction measured?

Posted: 15 Jan 2017 03:59 PM PST

Do babies in utero recognize language differences in multi-lingual mothers?

Posted: 15 Jan 2017 09:32 AM PST

In addition, does in vitro exposure to multiple languages have long term cognitive benefits in the same way post-birth exposure does? Does it matter whether the mother is a native speaker of the spoken languages? Thank you.

submitted by /u/Traulinger
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If astronauts had a gun fight in space, how far apart could they be while maintaining lethality?

Posted: 15 Jan 2017 02:24 PM PST
vào lúc No comments:

Sunday, January 15, 2017

How does the physical concept of entropy relates to the information theory concept of entropy?

How does the physical concept of entropy relates to the information theory concept of entropy?

How does the physical concept of entropy relates to the information theory concept of entropy?

Posted: 14 Jan 2017 11:18 AM PST

Differences in electric and magnetic dipole transitions?

Posted: 15 Jan 2017 06:37 AM PST

To my knowledge, a magnetic moment and dipole moment are simply based on the distribution of charges/currents in the particular case. Thus the 21 cm line in Hydrogen for example is magnetic dipolar because it is caused by spin interactions of the proton and electron. Thus any transitions from the excited state here would be observed to be a magnetic field (although one would still observe an electric field due to Maxwell's equations). Similarly for the 18 cm line in OH (radical), since it is due to an electric dipole (i.e. the extra unpaired electron and the nucleus), the emission from the excited to the ground state would be electric dipolar. But then I also know the 18 cm line has hyperfine transition causes by spin interactions, and so the emitted wave would have both a magnetic and electric component, correct? I was also reading:

If during the switch the atom can behave like an oscillating electric dipole, then this is usually (for visible/IR/radio radiation at least) more efficient than the oscillating magnetic dipole or electric quadrupole etc. This would be termed an electric dipole transition. However, for certain changes of quantum state, the atom cannot behave like an oscillating electric dipole and the transition can only proceed (less efficiently - often called a "forbidden transition" in astrophysics) by the atom behaving like an oscillating magnetic dipole - i.e. a magnetic dipole transition.

and I was wondering why it's more efficient for it to be electric dipolar as opposed to magnetic dipolar? Are not electric and magnetic fields inherently the same, and as long as they have the right frequency, wouldn't an electric field be able to bring an electron to an excited state even if it's a magnetic dipolar transition?

I suppose I am beginning to confuse the two types of transitions and how one can experimentally distinguish the two as being inherently different.

submitted by /u/CallMeDoc24
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How are non-quantized wavelenghts of light produced? i.e. How can a continuum of wavelengths of light exist with seemingly finite possible electron energy levels from which electrons can drop?

Posted: 14 Jan 2017 09:08 AM PST

When electrons drop from one energy level to another, they emit a photon of a specific wavelength. With a finite number of energy levels, it seems the possible number of wavelengths produced would be finite. Not accounting for red-shifting or blue-shifting, how do we get a continuum of possible wavelengths? (I'm not referring to perceived color, here)

The idea which led me here is this -- I know that light can pass through glass, because visible light does not have sufficient energy to raise the energy level of electrons enough to be absorbed. When they DO get absorbed, is any excess energy absorbed as heat (explain?), or is some emitted/passed as lower energy wavelengths? All the material I've found so far stops as soon as the photon is absorbed -- without really explaining what happens if a HIGHER energy photon passes through... and what happens when the energy level is high? It seems that if the electrons in glass dropped to a lower energy level, the direction in which the new photon travels would be random.

I feel like I'm missing something fundamental which is glossed over because it seems intuitive or obvious...

submitted by /u/onwardknave
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With 95% of the oceans unexplored, is it feasible many prehistoric species still exist ?

Posted: 14 Jan 2017 10:17 AM PST

I don't believe lake monsters or the such, but in vast oceans, could dinosaur-type creatures still roam the seas? Is this where sea serpent tales truly came from?

submitted by /u/TupacSchwartzODoyle
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Could gravitational waves explain "dark" energy and/or matter?

Posted: 15 Jan 2017 01:04 AM PST

Gravitational waves can compress space-time while traveling at c and therefore have energy (even though it's a tiny tiny tiny amount of energy). If you take the energy generated by every gravitational wave produced by every system in every galaxy in the universe could it possibly explain all the missing energy and/or mass?

submitted by /u/ISNT_A_ROBOT
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Is it possible to create a black hole using energy instead of mass?

Posted: 14 Jan 2017 09:25 AM PST

Instead of compacting mass until it collapses under it's own gravity, is it possible to compact energy (for example, light) until it collapses?

submitted by /u/_telemarketing
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What property of an atom makes it reflective?

Posted: 14 Jan 2017 08:46 AM PST

I've been digging around for this answer for a while now, and all I've found is that a smooth surface (on a near atomic levrl) makes ie reflect light, but what is it about the properties of the atom that allow it to reflect light, since light has no mass how does it bounced off the surface etc. Thanks!!

submitted by /u/yungchocolatebar
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Why do electrons orbit protons and not just collide with them?

Posted: 14 Jan 2017 09:17 AM PST

Consider a proton and an electron in empty space separated by some reasonable distance (ie not an atom). They would be attracted and travel towards one another. Now I know that they would eventually come together and form a hydrogen atom. But why? Why don't they just collide one another?

I could attempt a hand waves answer talking about s orbitals and the Pauli exclusion principles and allowed energy levels; but I feel like id be skirting around the issue.

submitted by /u/pseudonym1066
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When can we say normalcy ends and pathology begins?

Posted: 14 Jan 2017 09:55 AM PST
vào lúc No comments:

Saturday, January 14, 2017

How do odour sprays like Febreeze or Lysol eliminate odours in the air?

How do odour sprays like Febreeze or Lysol eliminate odours in the air?

How do odour sprays like Febreeze or Lysol eliminate odours in the air?

Posted: 13 Jan 2017 09:16 PM PST

I understand adding a good smell but is there chemicals in it that destroys the odours from whatever youre trying to rid the room of?

submitted by /u/laapse
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Why does a lack of oxygen cause cell death instead of the cell 'winding down' into some kind of stasis?

Posted: 13 Jan 2017 11:03 PM PST

What makes GPUs so much faster at some things than CPUs, what are those some things, and why not use GPUs for everything?

Posted: 13 Jan 2017 04:29 PM PST

I understand that GPUs can be exponentially faster at calculating certain things compared to CPUs. For instance, bitcoin mining, graphical games and some BOINC applications run much faster on GPUs.

Why not use GPUs for everything? What can a CPU do well that a GPU can't? CPUs usually have an instruction set, so which instructions can a CPU do than a GPU cannot?

Thanks!

submitted by /u/Stuck_In_the_Matrix
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Do surface imperfections significantly increase the surface area of an object?

Posted: 14 Jan 2017 04:27 AM PST

For instance, is there a significant difference between a 1x1x1 cube made out of wood vs a mathematically perfect 1x1x1 cube? What types of material or what manufacturing methods having an interesting effect on this phenomena?

submitted by /u/olafwillocx
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Why do I need an even number of triangles when creating a closed 3D figure out of triangles?

Posted: 14 Jan 2017 06:47 AM PST

While working on an assignment in class, I noticed something interesting. In order to create a 3D figure out of multiple triangles of the same size and shape I would always need an even number of triangles. Is this true and if so, is there a proof for it?

submitted by /u/HighOverlordSarfang
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Why do baryons have a half life?

Posted: 14 Jan 2017 04:41 AM PST

I noticed that the proton has a half life of 1032 years. A neutron seems to have a half life of 10.3 minutes when not near a proton. Why is this? How can the quarks, which are bound together so strongly, decay that quickly?

submitted by /u/olafwillocx
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Are quotidian events stored differently in memory?

Posted: 13 Jan 2017 09:04 AM PST

Every day I do very similar things: take shower, put contacts in, take medicine, fill water bottle in backpack, etc. Sometimes it's genuinely confusing to remember if I did or didn't do something, because I've done it hundreds or thousands of times before.

This seems to fall between long- and short-term memory. I know where my contact case is in a strange hotel, even though I put it down somewhere 12+ hours before. I can find it in the dark the next morning. But a day later, there's no particular trace of these daily events. I probably couldn't even describe the hotel room with accuracy.

Are these types of events creating long-term memories that are ruthlessly pruned because of no reinforcement, or are they stored differently?

submitted by /u/warm_kitchenette
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Given that asteroids from Mars are found of Earth, would asteroids from Earth be found on Mars?

Posted: 14 Jan 2017 04:10 AM PST

And, if we find life on Mars, how would we show it wasn't just seeded there from Earth from one of these asteroids?

I know that we have found chunks of Mars on Earth in the form of some very rare asteroids. The thought being that pieces of Mars could be thrown into space during large asteroid collisions. Could this happen in reverse?...maybe with some large impact like the Yucatán impact of 65-million years ago?

submitted by /u/Sunfest
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Does chemistry matter when synthesizing superheavy elements?

Posted: 13 Jan 2017 04:54 PM PST

Because these new, artificially-produced elements require much energy to be produced and decay rapidly, I wonder whether the electrons are able to rearrange themselves into increasingly complicated configurations, and if so, whether it is possible to study the new element's chemical properties in any useful capacity.

submitted by /u/iprobablydontknowyou
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Can someone give me an idea how big 6!!! is? I understand 6! = 720 and 6!! = 2.6012189435657951E+1746. What is 6!!!? Can it be written out or described in terms of atoms of the universe or moments since the Big Bang or something?

Posted: 13 Jan 2017 08:30 PM PST

Does the momentum of light increase with intensity?

Posted: 14 Jan 2017 12:24 AM PST

If we think about a particle with mass and give it a velocity (v) it will have a momentum, expressed by the equation p = mv. If we have two of said particles moving at velocity v their total collective momentum will increase as the mass has increased. Light, however, does not have a mass as such but it has momentum. If the intensity of the light is increased such that there are many photons instead of one, will momentum increase? I can think of two possible answers however I'm not sure if either is correct. 1: We view the many photons as one system. As the number of photons increases mass does not increase (as photons have no mass) and neither does velocity (as c is constant), that means momentum will be the same as if there were one photon. 2: We must view each photon as an individual photon with individual momentum and never as 'combined photons' thus as the number of photons increase momentum will increase in a linearly. Thanks in advance for any answers.

submitted by /u/matej_latte
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Why are bats the reservoir for so many zoonotic diseases?

Posted: 13 Jan 2017 07:42 AM PST

I've been reading David Quammen's Spillover, and it seems that for a lot of deadly zoonotic diseases - Hendra, Ebola, SARS, etc. - the natural reservoir is bats. This is kind of surprising to me, given that humans are not particularly closely related to bats, and we don't spend all that much time in close proximity to them (unlike, say, rats or pigeons). Is it just a coincidence that these three diseases all came from bats, or is there something about bats' immune system or lifecycle that makes them particularly apt to act as reservoirs of this kind of disease?

submitted by /u/Doglatine
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How does an organism's body allow it to maintain the same amino acid composition in cells even when the diet of the organism is variable in different amino acid concentrations?

Posted: 13 Jan 2017 07:43 PM PST

How does your organism measure the time?

Posted: 13 Jan 2017 07:31 AM PST

I've always wondered how your body (or any living organism) knows when it's time to start processes like puberty or end others, like growing. We all hit puberty in a really close range of years, but how does the body keep track of time to know it's the moment to do it?

submitted by /u/skrotox
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Why do most chemical catalysts contain a second or third row transition metal, as opposed to a first row transition metal?

Posted: 13 Jan 2017 12:32 PM PST

As the title says, I am interested in understanding why elements such as palladium, iridium, ruthenium, etc are widely seen in chemical catalysts, but elements such as iron, copper, manganese, etc are not. I have seen a few chemical reactions involving titanium and nickel complexes used, but not nearly as frequently as second and third row transition metals. What about these elements make them more active? Why do we not see more first row transition metal based catalysts?

submitted by /u/Mikey5296
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What controls the height of cloud formations, why are some high up and some are low creating things like fog?

Posted: 13 Jan 2017 06:52 AM PST

Why do soft drinks and beers foam up a lot when you pour them into a glass but not soda water?

Posted: 13 Jan 2017 06:06 PM PST

Why is a detached, insulated but non-heated garage warmer than outside during winter?

Posted: 13 Jan 2017 09:27 AM PST

My garage will be -5C when it is my -25C outside.

submitted by /u/damancody
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What is it about brain death that precludes the possibility of a person from being awakened?

Posted: 13 Jan 2017 05:14 PM PST

I get that brain death takes place. But what is it, specifically, that precludes us from -- hypothetically, of course -- re-oxygenating the blood and reviving the brain? What takes place, on a biological/physical and medical level, that precludes the possibility of a person's consciousness from being revived?

Thanks science guys! :D

submitted by /u/e_d_a_m
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How do hashes work? Wouldn't there be one hash that could result in many, many input data possibilities?

Posted: 13 Jan 2017 01:16 PM PST

Let's say your input data is 1 million characters (alphabetic in nature) of data, and your resulting hash is a 16 digit string of hex values. Your input data would have 261000000 possible combinations of unique arrangements, correct? But your hash result would only have 1616 unique arrangements. So there would be many inputs that would result the same hash. Is it just such a low probability that when you change something that it would result in the same hash and therefore we can say it's secure enough (in the case of cryptography)?

submitted by /u/arzthaus
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Since there is no perfect vacuum in space, is it possible to move in space using similar techniques like in air or in water?

Posted: 13 Jan 2017 08:19 PM PST

Regarding the obliquity of planets in the solar system, why are Venus and Uranus so different?

Posted: 13 Jan 2017 11:06 AM PST
vào lúc No comments:

Friday, January 13, 2017

How much radiation dose would you receive if you touched Chernobyl's Elephant's Foot?

How much radiation dose would you receive if you touched Chernobyl's Elephant's Foot?

How much radiation dose would you receive if you touched Chernobyl's Elephant's Foot?

Posted: 12 Jan 2017 07:04 AM PST

Why don't electrons traveling in the orbitals of atoms lose energy, although they are a mass traveling a narrow space which should require some kind of acceleration to stay close to the atom?

Posted: 13 Jan 2017 04:29 AM PST

As I learned in physics the acceleration of a mass (and the change of direction is an acceleration) results in a change of kinetic energy, so traveling in a narrow space like an electron around an atom requires acceleration to change the direction of the electron to stay around the atom, so then why are atoms stable at all and why don't electrons bounded to atoms lose energy all the time?

submitted by /u/arachnofan
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Is there an objective definition for entropy?

Posted: 12 Jan 2017 07:09 PM PST

My understanding is that the second law of thermodynamics implies that the total entropy of the universe only increases over time, at least up to random decreases from statistical fluctuations. How does one define the total entropy of the universe in an objective way?

The only definitions of entropy I'm aware of are all properties of a probability distribution rather than of a single state. In physics, this seems to necessitate a partition of the state of a system into a fixed known macrostate, and an associated probability distribution over microstates for which the entropy is defined. This seems like it would make the definition of entropy subjective, in that different observers might have different definitions as to the macrostate of a system, and have correspondingly (very slightly) different evaluations of its entropy.

When measuring the entropy of the entire universe, I don't understand how one can objectively partition its state into a macrostate and a microstate, since presumably everything is just part of one total state and there's no way to pick out just one piece and call it the macrostate.

So I guess I have two questions.

  1. Is there a truly objective way to define the entropy of a physical system? If not, is there a suitable related concept which is objective?
  2. What is actually meant by the "total entropy of the universe"? Or, if it's not strictly the "entropy" of the universe that always increases, what property is it?
submitted by /u/phlogistic
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Can someone explain how magnetism generates electricity?

Posted: 12 Jan 2017 08:57 PM PST

And how they are related to magnetic field, electric field etc. Thanks reddit community!

submitted by /u/pelurusesat
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What's our most sound theory of consciousness to date and why?

Posted: 13 Jan 2017 01:21 AM PST

Yes, for that one person out there, consciousness is what most would deem as metaphysical, but that doesn't stop neuroscienctists from slicing brains now does it?

submitted by /u/AnonymousSteam
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If a planet in our solar system was impacted by a huge asteroid tomorrow, how long would it take for us to discover that, and would we be affected in any way on Earth?

Posted: 12 Jan 2017 08:48 AM PST

Like, for example, if Mars were struck by something rock-like moving at high speed that was say 1/20th the diameter of the planet itself. Obviously the landscape and the atmosphere of the planet would be altered, but what else would happen? Would its orbit get messed up, and would that have any influence on life here on Earth? How does this change if the impacted planet was Venus or Mercury? or if the object was 1/100th the diameter? 1/2? Also, could we go for a long time without knowing about this sort of thing happening in our solar system?

Thanks!

submitted by /u/groggyMPLS
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If friction is not taken into account, do helium balloons accelerate upwards at 9.8m/s/s?

Posted: 13 Jan 2017 04:12 AM PST

Bonus question!

If there are two objects of identical shape, one weighs 10grams, the other has 10 grams of lift, are their terminal velocities the same?

submitted by /u/empire314
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What happens when something is cooled to below 0 degrees Kelvin?

Posted: 12 Jan 2017 11:40 AM PST

I saw this post in r/TIL: https://www.reddit.com/r/todayilearned/comments/5nl5cp/til_physicists_were_able_to_cool_atomic_gas_below/

I was wondering if anyone could elaborate on how this works, it was my understanding that things could not go below 0 degrees Kelvin.

submitted by /u/PotaTOESnMoleASSES
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Why does 16 Psyche have such a low density?

Posted: 12 Jan 2017 01:22 PM PST

I read that asteroid 16 Psyche was composed mostly of pure iron and nickel. However, it only has a density of around 3.3 grams per cubic centimeter.

How is this possible? If it's really pure iron/nickel shouldn't its density be WAY higher, like at least double?

submitted by /u/DelfonicSonic
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How close could you get to the black hole at the centre of the Milky Way, Sagittarius A*, without being pulled in?

Posted: 12 Jan 2017 10:46 AM PST

What keeps the sun in place?

Posted: 12 Jan 2017 11:51 PM PST

Gonna sound stupid but since there's no gravity in space then why doesn't the solar system float away? I know the sun's gravitational pull is what's keeping the planets in place but what's keeping the sun?

submitted by /u/Gingeehd123
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Has a proton been observed being emitted in β^(-) decay?

Posted: 12 Jan 2017 11:33 PM PST

I just learned of the continuous distribution among the 3 particles produced in beta decay. Normally in β- decay, a proton, electron, and antineutrino are produced, with the electron having a 1/250,000 chance of not having enough energy to escape the nucleus. Does this mean there is a non-zero chance of enough of the proton getting enough energy to escape, and has this ever been observed?

submitted by /u/thebigredfiretruck
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What is the smallest body in space that can have or support an atmosphere?

Posted: 12 Jan 2017 10:51 AM PST

I'm curious to know just how small a planet or other celestial body can be in order to sustain an atmosphere. Mars for example is smaller than Earth and has an atmosphere. New Horizons has shown us that even Pluto, a dwarf planet, has a small atmosphere; and even Ceres is showing signs of a very faint water vapor atmosphere. Can anyone weigh in as to whether or not there are set rules on how small an object can be to have an atmosphere?

submitted by /u/buffmb
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[Linguistics] Are there any languages with different words for first person plural, differentiating whether second person is included?

Posted: 12 Jan 2017 08:43 AM PST

Like one word "WE" (me, you, and possibly others), and another "We" (me and others, but not you)?

submitted by /u/ironshadowspider
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Does Mars have tectonic activity?

Posted: 12 Jan 2017 07:50 AM PST

I was recently reading this article on the BBC (1) that stated Earth is the only planet we know of with techtonic activity. I felt skeptical and did some addictional reading that suggested plate tectonics indeed exist on Mars, but I'm unsure if they have been verified extensively.

In addition the article also claims no other bodies with the exception of Jovian moons have volcanic activity. I know Io is volcanically active, so what causes this? Is it just tidal gravity?

1: http://www.bbc.com/earth/story/20170111-the-unexpected-ingredient-necessary-for-life

2: https://www.spaceanswers.com/solar-system/does-mars-have-tectonic-plates/

3: http://www.iflscience.com/space/mars-may-have-continental-crust-similar-earths/

submitted by /u/Largedump
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If I had a compass in the middle of space, lightyears away from any matter, which way would the compass point?

Posted: 12 Jan 2017 07:59 AM PST

What man-made object holds the record for highest kinetic energy ever obtained?

Posted: 12 Jan 2017 07:13 AM PST

I was thinking it must be something like the space station that moves very quickly and is relatively massive, or maybe the saturn V. I know that the question could get confusing based on the frame of reference for velocity.

submitted by /u/Toke76
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What is the consensus on the validity of the Katamatsu and Hirai 1999 "Monks Serotonin" Study?

Posted: 12 Jan 2017 02:17 PM PST

I understand that this is a non-standard question and fully understand if it is removed.

 

Moreso, is there proof that the study ever took place? The study is often cited in International Baccalaureate Psychology textbooks and learning resources, but all attempts by my teacher, classmates, and I to track down the study or either of the alleged authors have been fruitless. I feel that someone with experiance in this field may be able to shed more light on this subject than my peers or I have.

 

The information I have on the phantom study is as follows.

 

AIM

  • Determine how the neurotransmitter serotonin can affect behavior

METHOD

  • Researchers studied a group of Buddhist monks which went on a 72-hour pilgrimage to a holy mountain in Japan

  • Monks did not consume food or water, did not speak, and were exposed to the cold in the late autumn weather

  • After about 48 hours, the monks began to experience hallucinations, often seeing ancient ancestors researchers took blood samples before the pilgrimage and immediately after the monks reported having hallucinations

RESULTS

  • Amount of serotonin had increased in the monk's brains

CONCLUSION

  • Sensory deprivation triggered the release of serotonin

 

Thank you for any assistiance you may be able to provide.

submitted by /u/RyanAHixon
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