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Centauri Dreams

Life from a Passing Star

3 Jul 2019, 15:55 UTC
Life from a Passing Star ESO/M. Kornmesser

Remember ‘Nemesis’? The idea was that mass extinctions on Earth recur on a timescale of between 20 and 40 million years, and that this recurrence could be accounted for by the existence of a faint star in a highly elliptical orbit of the Sun. Put this object on a 26 million year orbit and it would, so the theory ran, destabilize Oort cloud comets, causing some to fall into the inner system at a rate matching the record of extinctions. Thus a cometary bombardment was to be expected on a regular basis, as were the mass extinctions that were its consequence.

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