The darkest prognosis is that bio, cyber or environmental catastrophes could foreclose humanity’s potential. But there is an optimistic option.
On Christmas Eve 1968, the Apollo 8 astronaut William Anders took a photograph of the view outside the window as his spaceship orbited the moon. The now iconic Earthrise image shows our half-moon blue planet under a decoration of clouds rising from the blackness of space over the lunar surface.
The picture encapsulated Earth’s precariousness in the cosmos and, for many, contained a message of humility and stewardship for our home.
We’ve had Earthrise and images like it from the Apollo missions for half a century now. But suppose some aliens had been viewing our planet for its entire 4.5bn-year history. What would they have seen?
Over nearly all that immense time, changes would have been very gradual: continents drifted; the ice cover waxed and waned; successive species emerged, evolved and became extinct during a succession of geological eras.
