The end of the Universe :
Pre year 2000 it was assumed to be heat death. No more Hydrogen left to create any more star. And existing stars dying off. But that was for too far off a time, 10e100 years.
Things changed after discovery of dark energy. Now the dominant theory is big rip. That the universe will tear itself off. The whole universe, will destruct within a short period of time. 30 minutes before big rip our earth will explode and so will every star and planet in the universe.
Next question : how far is that time?
Estimations seem to be bringing the time line closer.
First it was 20 billion years.
Next reviewed to 6 billion years.
Compare it with the age of the universe : 14 billion years.
And lifetime left for the sun : 6 billion years.