In about five billion years time, our sun will expand, engulfing our planet in fire - and killing anything that might live on the surface.
But there’s still a chance - however small - that humans might survive this cataclysm, fleeing our planet in spacecraft as our solar system dies.
But what about the end that we CAN’T escape - the end of the universe itself?
The one thing we know is that it’s coming.
Not only that, but our universe is dying ‘multiple deaths’ - none of which sound particularly pleasant.
THE LIGHTS GO OUT
Observations this year showed that the universe is already dying - as old stars die faster than new stars are born to replace them.
John Beacom of the University of Ohio said at the time, ‘This pretty much closes the case. Yes, it’s coming to an end.’
The European Southern Observatory used ground-based telescopes to measure the energy output of 200,000 galaxies as part of the Galaxy And Mass Assembly (GAMA) and concluded, cheerily: ‘The universe is dying’.
‘The Universe will decline from here on in, sliding gently into old age. The Universe has basically sat down on the sofa, pulled up a blanket and is about to nod off for an eternal doze,’ concludes Simon Driver of the University of Western Australia.
THE BIG FREEZE
As if it’s not bad enough that the stars are twinkling out, leaving us in the dark, everything is also flying apart - which will also lead to a cold, lifeless universe.
It’s not clear which will happen first - the stars going out or the universe ‘going dark’ as it accelerates apart due to dark energy.
Jochen Liske of the University of Hamburg told IFLScience, ‘The universe is dying multiple deaths.’
Liske said, ‘It depends on how big the acceleration of the universe is. That’s a question we haven’t quite answered. We don’t know what causes the accelerating expansion yet.”
Even if some stars DO survive, this scenario would see everything fly apart until even the stars go out, and black holes evaporate.
Then, the universe is dead forever.
THE BIG CRUNCH
Other scientists believe that there’s not quite enough dark energy to sustain infinite expansion - and the universe will collapse in on itself.
For those of us inside it, this will be equally bad news.
Last year, University of Nottingham scientists said that this might happen ‘imminently’ scientists warn - and the signs of ‘impending doom’ are already here.
We should point out that the University of Nottingham scientists are using the term ‘imminently’ a little differently from you or I - they’re talking tens of billions of years away.
But the end is coming, the scientists warn, in a paper entitled simply, ‘The End’ in the jounral Physical Review Letters.
‘The fact that we are seeing dark energy now could be taken as an indication of impending doom, and we are trying to look at the data to put some figures on the end date,’ says Antonio Padilla of the University of Nottingham.
Padilla says, ‘In this scenario, once the collapse trigger begins to dominate, it does so in a period of ‘slow roll’ that brings about the accelerated expansion we see today. Eventually the Universe will stop expanding and reach a turnaround point at which it begins to shrink, culminating in a 'big crunch’
NOT QUITE THE END?
After the Big Crunch, it is possible that there will be another Big Bang - and the process will start all over again.
Other scientists believe that there may be other universes, separated from our own in space - and never touching.
One physicist claims that he may already have seen one - suggesting that weird ‘bright spots’ in signals from the furthest reaches of space suggest that our universe is being disrupted by something ‘bumping’ into our universe.
That ‘something’ could be an entirely different universe.
Dr Ranga-Ram Chary of California Institute of Technology told Phys.org, ‘Unusual claims like evidence for alternate universes require a very high burden of proof.’
That would mean that even if our universe did burn out, there are others.
All of this, of course, is not relevant to our lives as human beings.
By the time any of these scenarios occur, we - and everyone we know - will have been dead for billions of years.