Astrobiologists at the UEA reveal life on Earth for at least another 1.75 billion years
06:00 19 September 2013
It may not be time to make a note in your diary just yet but a study by astrobiologists at the University of East Anglia has revealed habitable conditions on Earth will be possible for at least another 1.75 billion years.
The findings, published today in the journal Astrobiology by lead author Andrew Rushby, were based on Earth’s distance from the sun and temperatures at which it is possible for the planet to have liquid water.
The research team used recently discovered planets outside our solar system as examples as they investigated the potential for these planets to host life.
Mr Rushby, from the UEA’s school of Environmental Sciences, said: “We estimate that Earth will cease to be habitable somewhere between 1.75 and 3.25 billion years from now.
“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. 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.”
Mr Rushby went on to explain that the amount of habitable time on a planet was important to highlight potential for the evolution of complex life.
“It allows us to investigate the potential for other planets to host life.
“Looking back a similar amount of time, we know that there was cellular life on earth. We had insects 400 million years ago, dinosaurs 300 million years ago and flowering plants 130 million years ago. Anatomically modern humans have only been around for the last 200,000 years – so you can see it takes a really long time for intelligent life to develop.
“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 75pc of the entire habitable lifetime of this planet to evolve.”
Almost 1,000 planets outside our solar system have been identified by astronomers and the research team looked at some of these as examples. Earth was compared to eight planets - which are currently in their habitable phase - including Mars.
“If we ever needed to move to another planet, Mars is probably our best bet,” Mr Rushby said.
“It’s very close and will remain in the habitable zone until the end of the Sun’s lifetime - six billion years from now.”
• 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 today.