Earth Will be Able to Sustain Life for the Next 1.75 Billion years, Researchers Estimate

We have about 1.75 billion years to find another planet that can sustain life.

Researchers at the University of East Anglia estimated habitable lifetime of earth to be about 1.75 billion years based on the distance between earth and sun. They also assessed the temperature at which the planet could hold water in its liquid form.

The research team looked at exoplanets for signs of life using their distance from nearby stars.

"We used the 'habitable zone' concept to make these estimates - this is the distance from a planet's star at which temperatures are conducive to having liquid water on the surface," said Andrew Rushby, from UEA's school of Environmental Sciences.

The habitable zone is a crude measure of determining whether or not the planet can sustain life. It depends on many factors including the brightness of its parent star. One exoplanet studied by researchers is the Kepler 22b, which lies 600 light years from Earth and is present in the constellation of Cygnus. Researchers estimate its habitable zone to be between 4.3bn and 6.1bn years, The Guardian reported.

"We used stellar evolution models to estimate the end of a planet's habitable lifetime by determining when it will no longer be in the habitable zone," Rushby added.

A recent study said that in about 2.8 billion years from now, bacteria will be the last living creatures on earth due to their ability to survive in extreme environment. According to io9.com, in about 1.1 billion years, the sun will grow larger and hotter. The ice-caps on Earth will melt and eventually all the water on earth will boil away. Then, about 3.5 billion years later, the earth will look like Venus- an inferno or molten rock. A few billion years more and the sun would be a large, orange star heating up the frigid Pluto.

In the present study, researchers estimate that the earth will cease to be habitable "somewhere between 1.75 and 3.25 billion years from now."

Of course, humans won't be there to see the end of earth. According to researchers, global warming would have already killed humans by the time earth becomes a barren land.

"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," he said in a news release.

'Habitable Zone Lifetimes of Exoplanets around Main Sequence Stars' by Andrew Rushby, Mark Claire, Hugh Osborne and Andrew Watson is published in the journal Astrobiology.