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3

When the thermos is closed, the air at the top of the thermos will be warm relative to the ice-cold water below it. As time proceeds, the two materials that are in contact with each other at the surface of the water will exchange heat due to their different temperatures. This will cool the air. When gasses are cooled they move more slowly and they don't ...


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The electron having mass will exhibit gravitational attraction and begin moving again, however; unless there is a larger object near the electron to it's nucleus it will orbit around it's original host and eventually regain it's original velocity as long as the Lagrange point is not breached.


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Yes and no. A vacuum solution could be stationary, could be static, could be neither. For the orbiting black holes you end up with gravitational waves and gravitational radiation. You either have some going out, and the bodies in spiraling or you have some coming in and driving the system or both. And the point is that you have to specify the state of the ...


2

Gravity. You can think of planets like wells or deep holes in the ground (gravity wells). Denser things fall to the bottom (rocks), less dense things rest on top of that (water), even less dense things on top of that (air), and finally the least dense thing on top of everything (vacuum). The air, for the most part, isn't leaving the planet for the same ...


1

To give a simple answer: Space is an (almost) vacuum, since there is simply not enough air left to be there. Where did all this air go? Due to gravity the air is attracted to large objects, like planets and exactly this gravity is also keeping the air close to the object - preventing it from "flowing back into space"


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Air fails to escape into space for the same reason you fail to: gravity. As noted in Kevin's answer, occasionally some do get going fast enough to escape. You would too, if enough stuff hit you hard enough. :) Space is a vacuum (for some definition of vacuum), because vacuum is simply the absence of air/gas pressure, and there aren't enough gas molecules in ...


29

The typical speed of an air molecule is a few hundred meters per second, while escape velocity from Earth is over 10,000 meters per second. So almost all the air molecules just fall back down. They're affected by gravity just like everything else! We do lose some air molecules this way, though. In particular, hydrogen and helium are lighter, so they move ...


3

To get an understanding on quantum field theory issues, you have to understand the difference between virtual particles and real particles. Virtual particles, in contrast to real particles, are a mathematical construct inspired by the Feynman diagrams used to describe interactions. These diagrams start with real particles, i.e. particles that have the mass ...


0

Nothing must be described by not equations: Not only does natural science replace all theory, but it also replaces not theory [6]. For example, consider the following not equation: Each symbol represents a not, except where it does. The square of any not is an is, not a not, but a not cubed is a not and is not an is. This not equation implies ...


2

You can describe nothingness in a rigorous and consistent way, even with a canonical categorical model. If nothing is not just absence of stuff and light otherwise darkness in an empty area, but absence of space and time itself, how is it possible to describe it mathematically? Just the exact same way you use axioms such as $\forall x\forall y \exists ...


0

Many things stop you. Firstly, it turns out forces do not cause accelerations. Forces increase momentum, and for slow speeds when you double the momentum you almost double your speed, and it is so close to doubling that for hundreds of years we thought it was doubling. But now that we've learned how to make things go fast and how to measure their momentum ...


1

A simple answer is that there is no point at which you are close to the speed of light, you might be close to the speed of light relative to other objects however you can keep trying to accelerate, and your slow relative to other objects. Your both fast and slow. From the point of view of an object looking at you, they may see you travelling close to the ...


1

Yes, in space this would be possible. The reason that one cannot open up a space inside a plastic bag when it is empty and sealed is because of the air pressure surrounding the bag. A huge number of air molecules are constantly bombarding the plastic bag from all directions (a.k.a. air pressure), so it would take a large amount of evenly distributed force ...


0

Define 'empty' bag. If the bag had legitimately nothing in it, then it would already be a vacuum, so no problem there you already have what you want. If the bag had some air in it, if you send it to space it would explode outwards, because space is 'empty' like you say, so the air within the bag would push outwards, eventually tearing the bag apart. In ...


0

How do EM waves travel in a vacuum? Like waves travel through other things. Electromagnetic waves are comprised of photons, which have an energy E=hf or E=hc/λ where f is frequency and λ is wavelength. The frequency and wavelength are there because photons have a wave nature, not a billiard-ball nature. And as per any wave, the speed depends on the ...


1

The real underlying basis of an electromagnetic wave is a synergy of zillions of photons. In this sense it is only macroscopically that the classical theory applies. The way the build up happens, photons into an electromagnetic wave, is not simple but an example can be seen here. Hand waving: the photon as an elementary particle is a quantum mechanical ...


0

As I understand the question, it is: what are the possible unbroken subgroups when a symmetry group G is spontaneously broken? If we assume that Lorentz invariance is unbroken, then we can look at the possible vacuum expectation values of a scalar field that transforms under some representation R of the symmetry group G. This can be calculated for specific G ...



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