Sun Intensity Will End Life On Earth In No More Than 3.25 Billion Years

Brett Smith for redOrbit.com – Your Universe Online

In one of the longest range weather forecasts ever made, a team of UK scientists has determined that the sun’s growing intensity will lead to the evaporation of the oceans and end of life on Earth in about 1.8 to 3.2 billion years – according to a new report published in the journal Astrobiology.

Using planets outside the Solar System and their stars as a model, the UK team considered our distance from the sun, its predicted growth and the temperatures that allow for a planet to have liquid water while making their forecast.

“We estimate that Earth will cease to be habitable somewhere between 1.75 and 3.25 billion years from now, “ said study author Andrew Rushby, an astrobiologist from University of East Anglia in Norwich, England. “After this point, Earth will 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.”

“Of course conditions for humans and other complex life will become impossible much sooner,” Rushby added. “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.”

Rushby said the new study was important for calculating the development and subsistence of complex life forms on a planet and the findings could be used when looking at other planets that orbit in their star’s so-called habitable zone.

“The amount of habitable time on a planet is very important because it tells us about the potential for the evolution of complex life – which is likely to require a longer period of habitable conditions,” he explained.

“Of course, much of evolution is down to luck, so this isn’t concrete, but we know that complex, intelligent species like humans could not emerge after only a few million years because it took us 75 per cent of the entire habitable lifetime of this planet to evolve,” Rushby said. “We think it will probably be a similar story elsewhere.”

The UEA scientist said he had difficulty finding other predictions based on the habitable zone of a solar system. While some scientists have used complex models to make estimates about Earth, these cannot be applied to other planets, according to Rushby.

“We compared Earth to eight planets which are currently in their habitable phase, including Mars,” Rushby said. “We found that planets orbiting smaller mass stars tend to have longer habitable zone lifetimes.”

“To date, no true Earth analogue planet has been detected. But it is possible that there will be a habitable, Earth-like planet within 10 light-years, which is very close in astronomical terms,” he continued. “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,” Rushby concluded. “It’s very close and will remain in the habitable zone until the end of the Sun’s lifetime – six billion years from now.”

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