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Q & A: infinite pressure?

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Most recent answer: 02/16/2015
Q:
My question is as follows....When a gas is pressurized(in favorable conditions)it turns into liquid. Further pressurizing it turns into solid. Now I exert infinite pressure on an uniform solid(form all directions). What will happen?Also what will happen if I subject a fundamental particle(a particle not made of any particle - yet to be discovered)is subjected to infinite pressure?
- Soumyadeep Bhattacharjee (age 15)
Kolkata, West Bengal, India
A:

Where could the infinite pressure come from? It doesn't sound consistent with any physical system. Pressure can, however, become very large. One way that happens is by the gravitational pull from big masses. As a large star collapses the pressure can get so large that protons and electrons combine to form neutrons. The result is a very dense neutron star. Even larger stars can then continue to collapse to the point where Newtonian gravity on a Euclidean space and time becomes a very poor approximation to the local spacetime. These big objects collapse toward forming black holes. One way of looking at the result, from the outside, is as a spherical surface sheet of some ultra-elementary particles (string states?).

Mike W.


(published on 02/14/2015)

Follow-Up #1: very high pressure

Q:
What will happen if I subject a fundamental particle(a particle not made of any particle - yet to be discovered)is subjected to very large pressure close to infinity?
- Soumyadeep Bhattacharjee (age 15)
Kolkata, West Bengal, India
A:

One property of infinity is that you can't get close to it. Any finite number is still infinitely short of the mark. 

Still, we can ask what happens to some little particle as the pressure on it gets big. Its wavefunction will get forced into smaller and smaller volumes.  This sounds like a very small-scale version of the collapse to a black hole that we discussed when the pressure is supplied by gravity.

For a small particle, however, the black hole would be unstable to quantum fluctuations and would quickly evaporate via something like Hawking radiation. It wouldn't exactly be Hawking radiation because the un-named particle may carry some conserved quantities other than energy and angular momentum, which are all that pure photons can carry away. This is a reminder that, so far as we know, there are no real building blocks of nature. There are only conserved quantities and some rules about what little packages they can travel in.

Mike W.


(published on 02/16/2015)

Follow-up on this answer.