# A Questions of density

1. Dec 18, 2016

### K. Doc Holiday

White dwarfs are about the size of the earth but they are 200,000 to 400,000 times more dense. (They contain almost as much mass as the sun.)

Question one: can we duplicate this density in a lab? If so, when did we accomplish that?

Matter normally comes in five forms; the common 3 are solid, liquid and gas. The uncommon forms are the Bose - Einstein condensate and plasma. (One at extremely low temp the other at extremely high.)

Are white dwarfs composed of one or more of these 5? Or at these densities can we assume a more exotic form of matter is present?

For example, is it possible that they are composed, at least partially, of matter which has overcome electron degeneracy?

In other words, is it theoretically possible that the only way to compact matter to a density 200,000 times more dense than solid granite is to strip the electrons, leaving only atomic nuclei?

I apologize in advance for asking such stupid questions and i appreciate everyone's patience.

2. Dec 18, 2016

### Gan_HOPE326

I really don't think we've ever come any close to white dwarf density in laboratory. I don't know if something like that can be momentarily achieved in situations like the core of a nuclear explosion or such extreme circumstances; it's certainly not something you can reach with a really big hydraulic press.

White dwarfs are composed exactly of matter that's stabilised against gravitational collapse by electron degeneracy pressure. When they go beyond 1.4 solar masses the pressure isn't enough any more and that makes the electrons and protons merge, forming neutrons, thus forming a neutron star, stabilised by the neutron degeneracy pressure. What you suggested would not work for a simple reason: Coulomb's force. Ordinary matter stripped of all its electrons would be entirely positive and experience such crazy Coulombic repulsion there would be no way for it to be compressed easily. It would, instead, be impossibly hard to do so. This comes to mind: https://what-if.xkcd.com/140/.

3. Dec 18, 2016

### Drakkith

Staff Emeritus
The white dwarf is held up by degeneracy pressure, but the temperature is so high that, unlike in a solid metal, the atoms are completely ionized and form a degenerate gas. A degenerate gas is essentially an entirely different state or phase than anything else.

What do you mean by "overcoming" the degeneracy?