Earth Settles Into Middle Age

Life on Earth has another good 1.75 billion years to go, study says

Earth could continue to host life for at least another 1.75 billion years, as long as nuclear holocaust, an errant asteroid or some other disaster doesn't intervene, a new study calculates.

But even without such dramatic doomsday scenarios, astronomical forces will eventually render the planet uninhabitable. Somewhere between 1.75 billion and 3.25 billion years from now, Earth will travel out of the solar system's habitable zone and into the "hot zone," new research indicates.
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Simple cells first appeared on Earth nearly 4 billion years ago. "We had insects 400 million years ago, dinosaurs 300 million years ago and flowering plants 130 million years ago," lead researcher Andrew Rushby of the University of East Anglia in the United Kingdom said in a statement." 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."
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They calculated that Earth's habitable-zone lifetime is as long as 7.79 billion years. (Earth is estimated to be about 4.5 billion years old.) Meanwhile, the other planets had habitable-zone lifetimes ranging from 1 billion years to 54.72 billion years.

"If we ever needed to move to another planet, Mars is probably our best bet," Rushby said in a statement. "It's very close and will remain in the habitable zone until the end of the sun's lifetime — 6 billion years from now."

No rush...