The decay of a false vacuum. It is for this reason that the whole Universe can perish. And not just any, but ours. The authors of the YouTube channel Kurzgesagt, who are seriously worried about this threat, have published a video in which they tried to explain the problem in an accessible form. Watch the video below.
In general, the point is that the entire observable world is in a state of true or false vacuum. If we live in a true vacuum, then there is absolutely nothing to fear - it corresponds to the minimum energy potential of the Higgs field and therefore is stable.
But if the observable Universe is in fact in a false vacuum, then it’s time for us to find another one, because this one at any second can go to a deeper level, that is, into that very true vacuum. Previously, of course, having collapsed. That is, destroying, in particular, all of its content.
Our little planet as well. But don't worry. Even if we live in a false vacuum (it's a shame, of course, but what can we do), and it is about to be transformed into a true one - it’s just about - for millions or a billion years, so this problem does not threaten the current human civilization too much.
Kolesnikov Andrey