HOW DENSE CAN MATTER REALLY GET?????

Have you ever wondered how dense matter can become? We have a fairly intuitive understanding of the relationship between density and strength thanks to our perceptual abilities. Wrapping our hands around a cast iron rod, for example, allows us to feel its strength and weight. We know it's not so good for cotton.
However, our understanding is limited for things we cannot touch or feel.

Did you know that certain substances have such incredible densities that a single teaspoon of them weighs approximately 6 billion tonnes?

That's correct! The density of matter inside neutron stars is due to giant stars collapsing onto themselves after death. Supernovas, which are many times the size of our sun, run out of fuel and explode in a massive explosion. As a result, the pressure that is causing them to stretch outward is relieved. This forces these massive structures, the size of which far exceeds that of our own sun, to be packed into abnormally small spaces (of a few kilometres) in comparison to their mass.

However, how is this possible?
In general, there is a limiting force that prevents matter from packing itself into smaller spaces. Even at absolute zero temperature, when the vibrational energy in molecules is zero, the limiting force known as Fermionic Repulsion Pressure (FRP) keeps molecules apart, defining an upper-bound for density. The closer molecules get to each other after a certain point, the stronger the FRO. However, when supernovas collide, the force is so strong that not even FRP can hold it together, resulting in matter collapsing into itself!!