The universe might be about to collapse, scientists have announced.
It has long been predicted that the universe, which has been expanding since the event known as the Big Bang, might one day reach a point where the process would reverse.
In that scenario - which could have several causes - the universe would begin to contract and eventually compact into a small hard ball - a similar state to the pre-Big Bang.
But one of the many unanswered questions that surround that theory is exactly when this might occur.
Now physicists say they might have evidence it could be sooner rather than later.
A team at the University of Southern Denmark say that according to their calculations, it is possible that a process called a universal "phase transition" could begin at virtually any time in which every particle in existence becomes extremely heavy.
The idea is that a "bubble" in the universe could form where the Higgs Field - associated with the Higgs Boson, or the particle which gives matter mass - could shift into a different value. If that value is lower than before, and the bubble is large, it would expand at the speed of light and all elementary particles inside it would become extremely heavy - kicking off a chain reaction that would pull apart the seams of existence.
The new calculations show that a phase transition will occur - and that it's more likely than we thought.
"Many theories and calculations predict such a phase transition– but there have been some uncertainties in the previous calculations. Now we have performed more precise calculations, and we see two things: Yes, the universe will probably collapse, and: A collapse is even more likely than the old calculations predicted", said Jens Frederik Colding Krog, PhD student at the Center for Cosmology and Particle Physics Phenomenology at University of Southern Denmark.
Worse still, it may have already happened:
"The phase transition will start somewhere in the universe and spread from there. Maybe the collapse has already started somewhere in the universe and right now it is eating its way into the rest of the universe. Maybe a collapse is starting right now right here. Or maybe it will start far away from here in a billion years."
Luckily, the new calculations do allow for the possibility that a phase transition in the Higgs field will not occur, or that the universe could contain undiscovered particles which would mean throwing out the whole idea - in which case "the collapse will be canceled" said Krog.