Can someone explain degeneracy pressure in simple terms?

In summary: I'll be sure to read more.In summary, degeneracy pressure is the opposing force that manifests itself as an opposing force as a particle becomes more confined.
  • #1
Kulu
3
0
Sorry for the noob question, but is there a resource anyone can point me to for an easy to understand explanation of degeneracy pressure?

I have no scientific background at all, so when I say easy I'm not kidding, but I am looking for a bit more than the pop sci bit of the Wikipedia entry.

All help gratefully received, and thank you in advance.
 
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  • #2
If all you found in Wikipedia was 'quantum degeneracy pressure',

try looking under 'electron degeneracy pressure' and

'neutron degeneracy pressure',I think those are pretty good.

edit: also,

http://en.wikipedia.org/wiki/Tolman–Oppenheimer–Volkoff_limit

The Tolman–Oppenheimer–Volkoff limit (or TOV limit) is an upper bound to the mass of stars composed of neutron-degenerate matter (i.e. neutron stars). The TOV limit is analogous to the Chandrasekhar limit for white dwarf stars.
 
  • #3
Thank you, I will take a look.
 
  • #4
Here are a couple of quotes I keep for such issues:
[from Wikipedia somewhere]

I hope these are not too basic...

...The electrons do not orbit the nucleus in the sense of a planet orbiting the sun, but instead exist as standing waves. The lowest possible energy an electron can take is therefore analogous to the fundamental frequency of a wave on a string. Higher energy states are then similar to harmonics of the fundamental frequency.
...
Quantized energy levels result from the relation between a particle's energy and its wavelength. For a confined particle such as an electron in an atom, the wave function has the form of standing waves. Only stationary states with energies corresponding to integral numbers of wavelengths can exist; for other states the waves interfere destructively, resulting in zero probability density.

What these imply is that as a particle [really a wave] becomes more confined, it becomes more energetic opposing further compression. If you know the energy of a wave is
E = hf =1/λ then you'll know that the wavelength λ is constrained when the particle is confined...it has to fit a smaller and smaller boundary...λ gets smaller and so energy gets larger opposing gravity squeezing subatomic particles together...
this opposition manifests itself as an opposing force...degeneracy pressure...
 
  • #5
Naty1

That's excellent, thank you.
 

1. What is degeneracy pressure?

Degeneracy pressure is a type of pressure that occurs in quantum systems, such as in the cores of stars or in white dwarfs. It is caused by the Pauli exclusion principle, which states that no two fermions (particles with half-integer spin) can occupy the same quantum state at the same time. This creates a repulsive force that acts to prevent the particles from getting too close to each other.

2. What is the difference between degeneracy pressure and thermal pressure?

Thermal pressure is caused by the random motion of particles in a gas or fluid, while degeneracy pressure is a result of the quantum mechanical properties of particles. Thermal pressure is dependent on temperature, while degeneracy pressure is not affected by temperature.

3. How does degeneracy pressure support stars?

In the cores of stars, the high temperature and pressure cause atoms to lose their electrons and become ionized. This results in a gas of degenerate electrons, which exert degeneracy pressure to counteract the gravitational collapse of the star. This keeps the star from collapsing in on itself and helps to maintain its size and stability.

4. Can degeneracy pressure overcome gravitational collapse?

In most cases, degeneracy pressure can overcome gravitational collapse and prevent a star from collapsing further. However, there is a limit to the strength of degeneracy pressure, known as the Chandrasekhar limit. If the mass of a star exceeds this limit, degeneracy pressure is not strong enough to counter the force of gravity and the star will collapse into a black hole.

5. How is degeneracy pressure related to the stability of white dwarfs?

White dwarfs are small, dense stars that have exhausted their nuclear fuel and are supported by degeneracy pressure. If the mass of a white dwarf exceeds the Chandrasekhar limit, degeneracy pressure is no longer strong enough to support it and the star can undergo a catastrophic collapse known as a Type Ia supernova. Therefore, degeneracy pressure plays a crucial role in determining the stability and ultimate fate of white dwarfs.

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