Contact

Aliens, science and speculation in the wake of 'Oumuamua. The question of extraterrestrial life is one of the great unknowns. Matthew Bothwell — a public astronomer at the University of Cambridge — reflects on what the recent discovery of a piece of flying cosmic debris says about how space-faring science works when data is scarce: is ʻOumuamua an alien-made artefact or just interstellar rubble?