August 13, 2016

"The reason we cannot find other life outside of Planet Earth is because we may be ahead of the curve, according to scientists from the Harvard Smithsonian Center for Astrophysics."

Laboratory News: The universe is 13.8bn years old, with Earth forming less than five billion years ago. via Journal of Cosmology and Astroparticle Physics

'One school of thought among scientists is that there is life billions of years older than us in space. But this recent study in the Journal of Cosmology and Astroparticle Physics argues otherwise.

'Avi Loeb, lead author from the Harvard Smithsonian, said: “If you ask, ‘When is life most likely to emerge?’ you might naively say, now. But we find that the chance of life grows much higher in the distant future.”

'Life first became possible 30m years after the Big Bang, when stars first provided the universe with enough carbon and oxygen. Life is predicted to end in 10 trillion years when all the stars in the universe have faded and died. Loeb and a team of researchers considered the likelihood of life between those two parameters.

'They concluded the main factor would be the lifetime of stars. Stars larger than approximately three times the Sun’s mass will perish before life has a chance to evolve. This is because the higher a star’s mass the shorter its lifetime. The smallest stars weigh less than a tenth as much as the sun and will glow for 10 trillion years, meaning life has lot of time to begin on those planets orbiting them in the habitable zone. The probability of life increases over time so the chance of life is many times higher in the distant future than now.'

"Relative Likelihood for Life as a Function of Cosmic Time" by Abraham Loeb, Rafael A. Batista, and David Sloan here

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