The solar system is currently playing host to a fascinating visitor, the interstellar object 3I/ATLAS. For most astronomers, it is a rare scientific opportunity. For Harvard astrophysicist Avi Loeb, however, it is a sign that humanity must urgently confront its own extinction.
Loeb has ignited a firestorm of controversy by linking his dire predictions for Earth to this mysterious object, proposing a radical solution: humanity must build a 'space ark', and it must start now. His reasoning draws on long-standing, controversial theories that have now crystalised around this new celestial traveller.
