Can someone explain what the last stage of our universe would be like?

Question

so after every bit of matter has decade what's the universe left with? also what would be the reason for this?

Answer 1

After the stars and the planets dissipate and even black holes get emptied, the protons themselves will decay and the universe will be an empty almost perfect vacuum with nothing but sub-atomic particles so far from any other particle that they have no effect.

Answer 2

No, but see the reference for some educated guesses.

Answer 3

Some scientists think that the universe is constantly expanding, but at a certain point it will stop expanding and start shrinking. So, the last stages of our universe would be the universe collapsing in to a tiny superdense point and the tiny point would become nothing. like the big bang theory in reverse. which means that something is going to turn into nothing and defy the laws of physics and chemistry.