There are few questions where the answers “yes” and “no” are both momentous. But this is one of them: beyond our solar system, are there other planets supporting life? Friday night’s take-off of Nasa’s Kepler telescope, to search the galaxy for planets like our own, brings us one step closer to knowing.

It is a launch that lifts the spirit. For centuries, humans have been fascinated by the idea of contact with other worlds. Kepler means we should know within 30 years whether there is life beyond Earth.