Is the Universe headed for the Big Crunch?
The Big Crunch says the fate of the expanding universe will eventually succumb to gravity, slow down its expansion, and finally reverse.
It will collapse into a very big crunch.
The Big Bang says the universe expanded from a single point. But the Big Bang may have been caused by a previous Big Crunch.
But, a Big Crunch does not seem likely now because the expansion of the universe is accelerating - and we don't know why, Dark energy is an unknown force causing the rate of expansion to accelerate over time, rather than slow down.
Observations suggest that the expansion of the universe will continue forever.
Because of this, the universe will become too cold to sustain life. This future scenario is now known as the "Big Chill" or the "Big Freeze".