AskScience AMA Series: I'm astronaut Leland Melvin, space shuttle traveler and explorer. Ask My Anything! |
- AskScience AMA Series: I'm astronaut Leland Melvin, space shuttle traveler and explorer. Ask My Anything!
- Drinking water from natural sources and it needing to be boiled?
- Can I get an educated guess on what the creature might be that was found on Google Earth new Deception Island?
- Why are emitted Photons in a Quantum Dot Laser coherent?
- During normal thought, does that "inner voice" actually create vibrations on your vocal cords?
- How can one prove the Laws of Conservation?
- Other than humans, are there any known species on Earth that have increased their natural lifespans?
- The paradox of calculus - zero but not zero: is there a good explanation?
- Anything Smaller Than a Sub-Atomic Particle?
- how carbon and gamma rays interact?
- Is the sheer size of the yellowstone magma chamber keeping it from erupting?
- Can we determine animal behavior solely from fossil records?
- What geological evidence do we have to prove that ice ages are cyclical??
- Is there a material that allows movement in one direction but stops it in the other depending on how it is applied?
- Can wind patterns cancel each other out?
- Is it theoretically possible to keep a heavy element stable by trapping it in graphene, and possibly within a geometric arrangement of other atoms whose proximity 'force it' into stability?
- Why do nuclear reactors need a steam turbine to generate electricity? Why can't we just directly convert the thermal energy into electricity?
- Is there a typical bond length cutoff for hydrogen bonding?
- How are the amplitude and frequency of gravitational waves related to the source of said waves?
- Are we 100% sure that there isnt a stronger degeneracy pressure that would prevent a singularity from forming?
- What happens to tectonic plates when continents move?
- Relativistic space travel thought experiment: Time dilation, how does it work?
- Why is the interstellar medium made of hydrogen atoms and not H2 gas?
- Do black holes move through space? [Physics]
| Posted: 20 Jun 2016 04:57 AM PDT Hi everyone. I'm Astronaut Leland Melvin, a space shuttle traveler, explorer and STEAM (Science, Technology, Engineering, Art, and Mathematics) education promoter. This summer I'm featured on Science Channel's new series, HOW TO BUILD...EVERYTHING premiering on Wednesday, June 22 at 10PM. I will be here starting around 2 PM ET to answer your questions. Ask Me Anything! [link] [comments]  |
| Drinking water from natural sources and it needing to be boiled? Posted: 20 Jun 2016 01:37 AM PDT I watch quite a lot of surviving in the wild type programs and one thing that constantly puzzles me is the idea humans can't drink from natural water sources unless the water is boiled. I find it hard to believe our ancestors did this when we were hunter gathers and it seems odd to me that all other animals seem to have no issues drinking from whatever water source they can find. So what's the explanation? Would we actually be fine in a lot of cases and people are just being over cautious? Is it a matter of us just not having the exposure to the various bugs that might be found in such water? If say we had been drinking it all our lives would we be fine with it? [link] [comments]  |
| Posted: 20 Jun 2016 06:50 AM PDT Video: https://www.youtube.com/watch?v=F-WZ7CCpsis Is this some sort of magical sea creature or something from the deep? Or is it most likely something completely explainable that was blown out of proportion by the internet? Detailed reasoning would be interesting and helpful. [link] [comments]  |
| Why are emitted Photons in a Quantum Dot Laser coherent? Posted: 20 Jun 2016 03:39 AM PDT Hello Guys, I know how spontaneous emission and stimulated emission in classic laser works. With the three energy levels of the atom, the atom in the excited state and whatsoever. I know how Quantum Dots work. Small crystals below the Bohr radius of the atom. I know (kind of) why the emitted Photons of a Quantum Dot has a wavelength dependent of the size of the Quantum Dot. What I don't understand is, why are the emitted Photons in a Semiconductor Quantum Dot Laser coherent? Coherent means in phase with each other and the same wavelength, right? It is understandable for me with the stimulated emission in a normal Laser, but i don't get how it works in a Quantum Dot Laser. It would be cool if someone is able to explain this to me. I need to know this :P [link] [comments]  |
| During normal thought, does that "inner voice" actually create vibrations on your vocal cords? Posted: 19 Jun 2016 04:39 PM PDT |
| How can one prove the Laws of Conservation? Posted: 20 Jun 2016 04:14 AM PDT |
| Other than humans, are there any known species on Earth that have increased their natural lifespans? Posted: 19 Jun 2016 04:38 PM PDT |
| The paradox of calculus - zero but not zero: is there a good explanation? Posted: 19 Jun 2016 09:58 PM PDT Here's what's always bothered me about calculus and real analysis. I understand how the limit as delta x approaches zero, the slope gets infinitely accurate. But delta x cannot be zero, or else the function is undefined. I see how you can factor and get a value that isn't defined, such as how the derivative of x2 simplifies to 2x+h and then the h term is treated as exactly zero. But we still treat delta x is zero even though it can't be zero! For example, with the tangent line, Leibniz defined it as two points that are infinitely close together - this makes sense but it seems that modern calculus and standard analysis thew this idea out the window. We now define the tangent as the line touching at one point with the same instantaneous rate of change at that point. But if it touches at one point, then that means delta x is zero and the function is actually undefined! In summary: I can't see how we don't just say the function's slope is tending to "a" as the distance becomes infinitely small. We say it's exactly "a". We say it touches at exactly one point. But the idea of exactness and the tangent line instead of an infinitely accurate secant line makes me frustrated because there's a paradox I can't get over. Is there a good explanation as to how I can understand why we can say what we do without it really being a contradiction? [link] [comments]  |
| Anything Smaller Than a Sub-Atomic Particle? Posted: 20 Jun 2016 07:40 AM PDT So, I was wondering, is there anything with mass that could be smaller than a sub-atomic particle, like a quark or gluon? I would imagine that the smallest piece of matter physically possible would be the Planck length, but I'm not sure if that's really a possibility. [link] [comments]  |
| how carbon and gamma rays interact? Posted: 20 Jun 2016 06:55 AM PDT Hello, I have a series of questions but I will start with this one and a question leading from it here first. So here we go. 1) My first question is about gamma ray and carbon interaction, If I was to blast gamma rays at carbon what thickness would be nessesery to lower the radiation to safe levels. 1.2) are there any interactions that would effect the carbon from gamma rays? heating or changes in structure? or would they just pass through and deflect? and leading from that 2) Would the shape of the material gratly effect the interactions? I have in mind to have a conal or triangular shape. I know it would increase the thicknes on a direct angle of attack. That is all for now. Thanks in advance. [link] [comments]  |
| Is the sheer size of the yellowstone magma chamber keeping it from erupting? Posted: 19 Jun 2016 05:08 PM PDT I think it doesn't matter how big it is, it WILL erupt. But my brother thinks that maybe the sheer size of the chamber is keeping it from erupting. He thinks that the amount of energy required to erupt it is too much at this point. [link] [comments]  |
| Can we determine animal behavior solely from fossil records? Posted: 20 Jun 2016 05:21 AM PDT For example, would we know hippos are so territorial and aggressive if the only evidence we had of them was from fossil records? [link] [comments]  |
| What geological evidence do we have to prove that ice ages are cyclical?? Posted: 19 Jun 2016 06:11 PM PDT |
| Posted: 19 Jun 2016 04:30 PM PDT |
| Can wind patterns cancel each other out? Posted: 19 Jun 2016 05:18 PM PDT I was just looking at >this site< and I see in the middle of the hellfire that is the northern Mexico there is one point (green circle) where all the wind systems seem to be targetted at. ALL wind. This doesn't seem right. Is there some sort of cancellation effect? Is this map simply incorrect? Is the Maw of Cthulhu opening in the desert and sucking the energy of the planet dry? [link] [comments]  |
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| Posted: 19 Jun 2016 09:31 AM PDT |
| Is there a typical bond length cutoff for hydrogen bonding? Posted: 20 Jun 2016 06:03 AM PDT I am wondering about heuristics for quick evaluation of expected hydrogen bonding of a structure by inspection. Is there a rule of thumb judging by bond distance only to say whether or not you probably can expect there is significant hydrogen bonding in the solid state? Especially for these: I am doing DFT studies of NMR parameters in some molecular crystals containing C, H, N, O. I am interested in how hydrogen bonding effects the electronic structure (and hence the magnetic resonance) near Nitrogens. [link] [comments]  |
| How are the amplitude and frequency of gravitational waves related to the source of said waves? Posted: 19 Jun 2016 08:08 PM PDT If a body produces gravitational waves, does the amplitude increase with the mass of the body? What about the frequency? Could especially high frequency gravitational waves bring two points in space much closer together from the viewpoint of a higher spatial dimension than the three we perceive in spacetime? [link] [comments]  |
| Posted: 20 Jun 2016 02:00 AM PDT |
| What happens to tectonic plates when continents move? Posted: 19 Jun 2016 05:23 PM PDT I understand that continents move BECAUSE tectonic plates exist. But I don't understand how is that tectonic plates make continents move, I can see why earthquakes happen and why mountains arise in Earth history. But considering that tectonic plates are very well embedded, I just don't understand what happens with them when continents move. Or how would they move across such a distance. For example, in this speculative video of continents moving, I don't know what's happening with the plates beneath the ocean. I've found several videos showing how continents evolved from Pangea to their current place, and speculative videos of how continents will evolve to form Pangea Ultima, but I've never found a video of how tectonic plates evolved from Pangea to their current place (or how they will behave to form Pangea Ultima). [link] [comments]  |
| Relativistic space travel thought experiment: Time dilation, how does it work? Posted: 19 Jun 2016 01:13 PM PDT So I have some difficulties understanding the "real world" implications of special relativity time dilation. Most examples you find on the internet deal with one observer at rest and one observer moving past the first tangentially at near light speed. They also all deal with magical telescopes that ignore redshifting and the actual distances traveled. This of course doesn't take into account how it'd look like for an observer at rest at the start or end of the journey so that the crew moves directly away from/at them respectively. So the spaceship Z by virtue of the WonderDrive(TM) is able to accelerate to 99.999X% of light speed within a day without disintegrating. This is used to make the trip from Earth to Proxima Centauri that is exactly 4 light years away in this experiment. Now what I am interested in is what the observers named Earth, Proxima and Spaceship-Z see in their respective frames. The predictions I'd make is what is so paradoxical to me since in my opinion point 2 and 3 contradict the usual examples when taking account the actual propagation of the light waves:
So I am sure a lot of my assumptions here are wrong because I adhere to classical mechanics wave propagation too much. It'd be nice if an astrophysicist could drop in and explain to me why my hypotheses 2 and 3 are at odds with the notion that Spaceship Z should in turn see time slowed at Proxima and Earth at the same rate as they should see it slowed in the Spaceship. [link] [comments]  |
| Why is the interstellar medium made of hydrogen atoms and not H2 gas? Posted: 19 Jun 2016 01:13 PM PDT From Wikipedia: Approximately 70% of the mass of the interstellar medium consists of lone hydrogen atoms; most of the remainder consists of helium atoms. Given enough time and collisions, why doesn't the hydrogen atoms form diatomic hydrogen gas? [link] [comments]  |
| Do black holes move through space? [Physics] Posted: 19 Jun 2016 04:09 PM PDT I would imagine they would, but I'm curious if something like a black hole would still be bound by inertia and velocity. Some part of me wants to imagine them as essentially a hole in space/ time. Though they obviously produce a gravitational pull to other objects, are they, themselves, also subject to these forces? Apologies if my question has an obvious answer. My background is in chemistry and biology, so although I have an interest in astrophysics, my understanding of physics on an astronomical scale is limited. [link] [comments]  |
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