Neutron, White Dwarfs and Degeneracy Pressure

In summary, the cause of degeneracy pressure can be explained through the uncertainty principle, where trapping electrons in a smaller space causes an outward pressure due to their uncertain momentum approaching the speed of light. This explanation can be reconciled with conservation of energy by considering that the energy comes from whatever is used to trap the electrons, such as the gravitational potential energy in the case of a neutron star or white dwarf.
  • #1
Jimmy87
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17
Hi,

I have been trying to get some physics behind the cause of the degeneracy pressure but have some confusion with the stuff I have found. Apparently the cause of degeneracy pressure can be explained through the uncertainty principle. If you trap electrons in a smaller and smaller space the momentum becomes very uncertain and approaches the speed of light, hence causing an outward pressure. How does this explanation fit in with conservation of energy. It seems like trapping an electron suddenly gives it a very high velocity which seems to come form nowhere?

Any help is much appreciated
 
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  • #2
If I'm not mistaken, I believe the energy comes from whatever you use to trap it in the first place. In the case of a neutron star or white dwarf, the energy would come from the particle's gravitational potential energy it had prior to dropping to the degenerate state.
 
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Related to Neutron, White Dwarfs and Degeneracy Pressure

What is a neutron?

A neutron is a subatomic particle that is found in the nucleus of an atom. It is electrically neutral, meaning it has no charge, and has a mass slightly greater than that of a proton.

What is a white dwarf?

A white dwarf is a compact star that is formed when a low to medium mass star runs out of nuclear fuel and collapses under its own gravity. It is very dense, with a mass comparable to that of the sun but a size comparable to that of the Earth.

What is degeneracy pressure?

Degeneracy pressure is a quantum mechanical effect that occurs when particles, such as electrons, are packed so closely together that they are forced to occupy higher energy states. This creates a pressure that counteracts the force of gravity, providing support for the core of a white dwarf star.

How does degeneracy pressure prevent a white dwarf from collapsing?

As a white dwarf star loses its nuclear fuel and begins to collapse, the electrons in its core become increasingly packed together. This creates a strong degeneracy pressure that pushes outward, preventing the star from collapsing further. The pressure increases as the electrons are forced into higher energy states, until it reaches a point where it can no longer support the star and a catastrophic collapse occurs.

What is the Chandrasekhar limit?

The Chandrasekhar limit is the maximum mass that a white dwarf star can have before it collapses due to the overwhelming force of gravity. This limit is approximately 1.4 times the mass of the sun. If a white dwarf star were to exceed this limit, it would undergo a type Ia supernova explosion.

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