Where is everybody?
Fans of the Fermi Paradox – the conflict between the high probability of alien life and the lack of proof of any – have new support for their argument. A new study suggests that life formed on Earth prematurely in relation to the rest of the universe and should only now have actually started. Not only that, it predicts that new life – other than Earth’s – will not form in the universe for at least ten trillion years.
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.
According to his new paper in the in the Journal of Cosmology and Astroparticle Physics, Avi Loeb of the Harvard-Smithsonian Center for Astrophysics says that the key to life forming on a planet is the expected lifetime of the star it orbits. The longer a star lives, the greater the likelihood a planet in its habitable zone will form life.
What determines whether a star will have a long life-producing existence? Loeb points to mass – low mass stars live longer than high mass stars. He calculates that stars with just three times the mass of our own sun will not live long enough to help create life on planet. On the other hand, stars with the lowest mass – weighing less than 10 percent of the sun – will live for 10 trillion years, with the chance of life occurring on their planets increasing over time.
So then you may ask, why aren't we living in the future next to a low-mass star? One possibility is we're premature. Another possibility is that the environment around a low-mass star is hazardous to life.
Loeb uses the paradox of the red dwarf to answer his own question. Red dwarfs have a low mass and long lives. However, in their early years, red dwarfs release massive flares and ultraviolet radiation that can render planets in the habitable zone uninhabitable.
Are we alone in the universe … the result of an early birth or a lucky fluke? Loeb says the answer may be around those low-mass red dwarfs.
Spectroscopic searches for biosignatures in the atmospheres of transiting Earth-mass planets around low mass stars will determine whether present-day life is indeed premature or typical from a cosmic perspective.
Will we ever go from “Where is everybody?” to “There is everybody!”?