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Letter: Weighing up the odds of alien life

Published 30 December 2025

From Bryn Glover Ripon, North Yorkshire, UK

Michel Brahic tells us that the formation of the last universal common ancestor from a soup of chemicals was “an extremely unlikely event, with a probability estimated at less than 1 in a billion” (6 December, p 30).

He then goes on to speculate that life elsewhere in the universe, if it exists, could be based on even more unlikely events. Surely, in the face of such massive adverse odds, if life has happened elsewhere, then it is most likely to be a duplication of what has happened here.

Issue no. 3576 published 3 January 2026

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