Thy sky is not falling, no matter what pessimistic economists such as Nouriel "Dr Doom" Roubini may say. But now experts at the US space agency Nasa have warned of a more prosaic, literal concern: objects falling from the sky.
The 5.9-tonne Upper Atmosphere Research Satellite, launched in 1991 and decommissioned in 2005, is coming down. Nasa says some chunks of it may not burn up on re-entry as they fall to earth in about three weeks.
We are not unduly worried - it's a big planet and mostly water - but even if no one is hit by debris, we can't help being struck by the metaphor.
Fifty years ago humankind was moving resolutely into space, challenging the barriers of the vast unknown. "We choose to go to the Moon," President John F Kennedy said in 1962, "because that goal will serve to organise and measure the best of our energies and skills."
Now the heady optimism of those days has itself fallen to earth, and human space efforts consist of one space station and desultory Russian and Chinese programmes. To be sure, unmanned vehicles still roam the Martian surface, and farther-ranging satellites keep sending back images of wonder and beauty. But the first great age of man in space has receded, leaving us with only distant grey images of rover tracks on the moon, a fearful eye on the heavens and a sadly diminished sense of what's possible.
