The mystery that nagged at Tsiolkovsky arose from his Copernican convictions, his belief that the universe is uniform throughout. If there is nothing uniquely fertile about our corner of the cosmos, he reasoned, intelligent civilisations should arise everywhere. They should bloom wherever there are planetary cradles like Earth. And if intelligent civilisations are destined to expand out into the universe, then scores of them should be crisscrossing our skies. Bostrom’s expanding bubbles of infrastructure should have enveloped Earth several times over.
— Ross Andersen interviews Nick Bostrom for Aeon