Photons are massless, but yet possess some energy, can this energy be converted to mass? Can a photon become to a piece of mass at some circumstances? |
- Photons are massless, but yet possess some energy, can this energy be converted to mass? Can a photon become to a piece of mass at some circumstances?
- Is the sun a black body?
- Have we ever observed quantum behaviour on a macro scale?
- When I touch either very hot or very cold, I instantly recognize it is an extreme temperature, but sometimes it takes me a moment to realize which of the two it is... Why is that?
- If the earth is protected from radiation and stuff by a magnetic field, why can't it be used on spacecraft?
- How can a permanent magnet do work on an object?
- Why doesn't the greenhouse effect deflect energy from the sun before it hits the earth?
- Does transparent material like glass affects wifi as much as non transparent wall?
- Could the greenhouse effect change the colour of the sky?
- Is the maximum velocity of every atom the same (i.e. is the maximum velocity of an iron atom the same as the maximum velocity of a plutonium atom?)?
- Why don't planes use single blade propellers with a counterweight?
- Why does "1+4+7" takes us longer to answer than "7+4+1"?
- Could someone please explain how sunscreen works to me?
- Are there other ways of representing position than coordinates?
- What is the acceleration of light?
- "Island of stability" elements: are they real?
- If Bioquark was cleared to try and revive dead brains, why can't they revive a brain dead person's brain?
- Charcoal and the conservation of energy; What happens?
- (Why) does light have momentum?
- Does nuclear fusion happen within a neutron star? If not, why are they called stars?
- Does freezing meat in liquid nitrogen kill the same bacteria's that heating it does? Why cant you eat raw meat that has been frozen in liquid nitrogen and then reheated to room temperature?
- Can SpaceX's rockets travel faster than the speed Earth orbits the Sun?
- Are there any elements of pure chance in the laws of nature as we understand them?
- Why do trees branch out as they do? Has anybody done it mathematically?
| Posted: 03 Jun 2016 04:37 AM PDT |
| Posted: 02 Jun 2016 09:09 PM PDT I know this is in an idealized context, but I've seen the sun described as a black body before. Does that mean it's in thermal equilibrium if it emits black body radiation? [link] [comments]  |
| Have we ever observed quantum behaviour on a macro scale? Posted: 02 Jun 2016 03:25 PM PDT I know about the famous slit experiment, but I was wondering if there are any other interesting examples. I heard that scientists somewhere got a whole gram of material almost down to absolute zero, were they able to see anything exciting or interesting? [link] [comments]  |
| Posted: 03 Jun 2016 06:14 AM PDT I hope this isn't a silly question and I hope this phenomenon isn't particular to me. I actually just asked a friend who mentioned how he poorly microwave-defrosted a chicken, and drew back his hand thinking he'd been burnt before realizing it was still partially frozen and he'd touched ice. It's like the brain recognizes there is a big temperature difference between my skin and the surface, before it determines which is the hotter and which is the colder. I know a little physics. I understand temperature in terms of average kinetic energy of molecules (though I guess solids might be different). I had it explained to me once that burns hurt because of energy transfer. But hot and cold seem objectively very different. Is there a crude part of the sensory system that recognizes temperature difference first? If so, how does the brain come to realize the sensation was in fact cold rather than hot? That doesn't seem to be a conscious judgment. [link] [comments]  |
| Posted: 01 Jun 2016 07:36 PM PDT Is it just the sheer magnitude and strength of earth's that protects it? Is that something that we can't replicate on a small enough scale to protect a small or large ship? [link] [comments]  |
| How can a permanent magnet do work on an object? Posted: 02 Jun 2016 09:38 PM PDT If you place two permanent magnets next to each other (with opposite poles facing each other) they will attract each other. The two magnets will accelerate toward each other and gain kinetic energy. Now I know that a charge in a magnetic field does not have work done on it as the force is perpendicular to the displacement (W=F*d where * is a dot product). In the case of the two permanent magnets it seems like the force is in the direction of the velocity. The force cannot be perpendicular as it makes no physical sense. So I assume that one magnet is doing work on the other and visa versa. How is this possible? Where is the energy coming from and how is this consistent with the first law of thermodynamics? I am assuming that some energy is needed to align the e- in the magnet. If that PE is used than wouldn't the magnet be discharged every time it "does work" on something? [link] [comments]  |
| Why doesn't the greenhouse effect deflect energy from the sun before it hits the earth? Posted: 02 Jun 2016 07:51 PM PDT I have been recently looking into the greenhouse effect out of curiosity, and one thing that I have found is that the greenhouse effect warms the earth as when energy from the sun hits the earth, most of it is absorbed, and the rest is reflected back into space. The energy reflected back into space, however, first goes through the atmosphere, and some energy is reflected back into the Earth. My question is that should some of the energy from the sun be reflected back into space, and because there is more energy coming from the sun that reflecting off the earth, why doesn't the earth become cooled from this effect? [link] [comments]  |
| Does transparent material like glass affects wifi as much as non transparent wall? Posted: 03 Jun 2016 04:52 AM PDT |
| Could the greenhouse effect change the colour of the sky? Posted: 02 Jun 2016 08:23 AM PDT A clear daytime sky is blue because molecules in the atmosphere (Nitrogen, Oxygen, Argon) scatter blue light from the sun more than they scatter other types of light. So if enough greenhouse gases (Water Vapor, CO2, CH4, etc.) were released into the atmosphere then could they change the colour of the sky? [link] [comments]  |
| Posted: 02 Jun 2016 03:46 PM PDT |
| Why don't planes use single blade propellers with a counterweight? Posted: 02 Jun 2016 02:47 PM PDT A two blade design creates more drag comparatively as one blade must travel through the wake of the other, so wouldn't the weight of the counterweight be overcompensated by the increased efficiency? [link] [comments]  |
| Why does "1+4+7" takes us longer to answer than "7+4+1"? Posted: 03 Jun 2016 04:22 AM PDT Or any questions with the smaller number first. It might be me that counts slower that way. [link] [comments]  |
| Could someone please explain how sunscreen works to me? Posted: 03 Jun 2016 04:19 AM PDT If I search on the internet, it says that a tan comes from UV-A and UV-B rays. Sunscreen is said to block UV-A and UV-B rays. How could a tan possibly build up at the same speed? Also, is the risk of skin cancer equally as high with the same 'tan-level'? [link] [comments]  |
| Are there other ways of representing position than coordinates? Posted: 03 Jun 2016 04:19 AM PDT I saw a comment stating that a sufficiently large chessboard could describe the universe, and thought "Well, what about infinitely divisible things like distances?" Later I figured it could probably be done accurately by using fractions, but I still wonder if there's a better - or even different at all - way of representing position than x y z. [link] [comments]  |
| What is the acceleration of light? Posted: 02 Jun 2016 03:22 PM PDT If I turn on a light source, how long does a photon take to accelerate to 3.0 x 108 m/s? Or rather, what is a photon's acceleration? [link] [comments]  |
| "Island of stability" elements: are they real? Posted: 02 Jun 2016 02:20 PM PDT Are these real things, or is it wishful thinking by the science-fiction crowd? If they're a real theory, is there any evidence for or against them? [link] [comments]  |
| Posted: 03 Jun 2016 05:08 AM PDT Link for those who don't know http://fortune.com/2016/05/07/bioquark-cleared-to-try-and-revive-dead-brains/ [link] [comments]  |
| Charcoal and the conservation of energy; What happens? Posted: 02 Jun 2016 04:48 PM PDT During the process of creating charcoal, does the resulting charcoal have more or less energy than the original wood?
What happens? [link] [comments]  |
| (Why) does light have momentum? Posted: 03 Jun 2016 03:02 AM PDT I've heard from my physics teacher that light has momentum, as well as from things like explanations of solar sails. To my knowledge, p = mv. So, what gives? [link] [comments]  |
| Does nuclear fusion happen within a neutron star? If not, why are they called stars? Posted: 03 Jun 2016 03:02 AM PDT I was just thinking that if a neutron star was entirely composed of neutrons, then there would be no way that nuclear fusion could occur, but then it wouldn't technically be a star. So if it is a star, how does fusion occur? [link] [comments]  |
| Posted: 03 Jun 2016 03:01 AM PDT |
| Can SpaceX's rockets travel faster than the speed Earth orbits the Sun? Posted: 02 Jun 2016 08:24 AM PDT So I was reading the article about SpaceX planning on sending a rocket to Mars every ~26 months because that's when the Earth and Mars are closest to each other in their orbits. So that got me thinking, if the rocket were to take off when the Earth isn't at it's closest point, will Earth overtake the rocket (assuming it's orbit takes it towards Mars at first)? If my question is too confusing, how about this: if you leave earth, at what point is its gravity not strong enough to keep you with it, and Earth starts moving away from you (google says it orbits at 30km a sec!). And would this be a gradual movement or suddenly the Earth is moving away quickly? And is 30 km/sec faster than our spacecraft can travel? So if a spacecraft were to fall out of Earths gravity, it wouldn't be able to catch Earth and it would have to wait for it to orbit the Sun? So relating to my original question about SpaceX, if the rocket took off at an inopportune point in Earths orbit relative to Mars, would the Earth "pass" the rocket or do our rockets go faster than 30 km/sec in space? Sorry if it's too many questions or is confusing. All of a sudden I'm really interested in this. Edit: I realize the phrase "fall out of Earth's gravity" will probably make some of you cringe, but I don't know how else to word it. [link] [comments]  |
| Are there any elements of pure chance in the laws of nature as we understand them? Posted: 02 Jun 2016 01:51 PM PDT My brother had this idea (which i guess is nearer to philosophy than science) that if there is no room for chance in the physical laws of the universe, then everything must be predestined. I've taken a decent amount of science courses in my schooling (engineering undergrad) and never heard of a law or equation having any actual chance built in. I figured I'd ask some people much smarter than me if his premise makes sense. [link] [comments]  |
| Why do trees branch out as they do? Has anybody done it mathematically? Posted: 03 Jun 2016 02:12 AM PDT So, I was drinking coffee when my mind wandered off to a large rain tree nearby. I started to wonder, why do trees branch out as they do? There has been some explanation here from botanists/biologists:https://www.reddit.com/r/askscience/comments/1518gx/what_determines_whenwhere_a_branch_will_grow_on_a/ But I wonder if it is just some kind of maximization/Lagrangrian problem. Has anybody tried this? I was thinking, the tree probably was maximizing their canopy coverage (my noob phrase for area for sunlight absorption) while minimizing the branches to keep pressure pumping nutrients upward high. And I was thinking of the equations for this. I guess to rephrase this, how do we find the most efficient count of branches in order to have the widest canopy area for possible sunlight absorption, given whatever constraint a tree has (gravity, capillary effect[?], etc)? Has anybody thought of the same thing? (Please don't bite me) [link] [comments]  |
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