The end of the world is not nigh. Life will thrive on Earth for at least another 1.75billion years and perhaps as many as 3.5billion.
Beyond then, the Sun will have become so hot that nothing will be able to survive, scientists believe.
Ever since it was formed, our planet has been at just the right distance from the Sun to make it habitable.
Being in this ‘Goldilocks’ zone has allowed oceans to develop in temperatures neither too hot to boil the water away, nor too cold to freeze it into permanent ice.
The problem is, however, that stars become hotter over time, ensuring that the habitable period cannot last.
As the stars emit more heat, any surface water on nearby planets dries up and without water nothing can survive.
At this point, the Earth will have ‘moved’ out of the habitable zone even though its position will be exactly the same.
The prediction comes from experts at the University of East Anglia, who believe the world can expect between 6.3billion and 7.8billion years of ‘Goldilocks’ conditions from its birth around 4.55billion years ago.
That means there can only be 1.75billion to 3.5billion years of life left. Andrew Rushby, a researcher at the university, said: ‘After this point, the Earth would be in the hot zone of the Sun, with temperatures so high that the seas would evaporate.
‘We would see a catastrophic and terminal extinction event for all life.’
Humans would be among the first species to be wiped out – and well before even the 1.75billion-year timescale.
‘Humans would be in trouble with even a small increase in temperature and near the end only microbes in niche environments would be able to endure the heat,’ said Mr Rushby.
The research project also examined the prospects of finding life on other planets with a long habitable lifetime.
Mr Rushby examined seven candidates – the most likely being a planet known as Gliese 581d, which Mr Rushby estimates will have the right temperature for life for up to 55billion years.
Roughly twice as big as the Earth, Gliese 581d is a daunting 20 light years way.
Mr Rushby added: ‘It is possible that there will be a habitable Earth-like planet within ten light years, which is very close in astronomical terms.
‘However, reaching it would take hundreds of thousands of years with our current technology. If we ever needed to move to another planet, Mars is probably our best bet.
‘It’s very close and will remain in the habitable zone until the end of the Sun’s lifetime – six billion years from now.’
The team’s calculations for the Earth’s lifespan are based on the rate at which the Sun is warming up.
The larger figure, 3.5billion years, adjusts for atmospheric changes.
