system
Given the following post, respond as if you're commenting on Reddit:
human
Can enough gravity crush an atom?

Can enough gravity crush an atoms electrons into its core? How small could an atom get this way?
gpt
This is basically what happens in a neutron star. 

Above about 1.4 solar masses, white dwarfs (or the iron cores of massive stars) do not have sufficient pressure to support themselves against gravity. Admittedly, there are no atoms in these systems. Nuclei are all pressure ionized and the electrons form a sort of gas. 

If the iron core exceeds this mass limit, run-away electron capture occurs on protons, producing neutrons and neutrinos. This gives you a supernova and a neutron star. 

We don't entirely know core density of neutron stars yet, but it seems to be a couple times greater than the density of protons and neutrons in nuclei that we see in normal matter.