This has been around for three years now, but it bears some notice nonetheless.

In its 4.5 billion years, Earth has evolved from its hot, violent birth to the celebrated watery blue planet that stands out in pictures from space. But in a new book, two noted University of Washington astrobiologists say the planet already has begun the long process of devolving into a burned-out cinder, eventually to be swallowed by the sun.

By their reckoning, Earth's "day in the sun" has reached 4:30 a.m., corresponding to its 4.5 billion-year age. By 5 a.m., the 1 billion-year reign of animals and plants will come to an end. At 8 a.m. the oceans will vaporize. At noon – after 12 billion years – the ever-expanding sun, transformed into a red giant, will engulf the planet, melting away any evidence it ever existed and sending molecules and atoms that once were Earth floating off into space.

"The disappearance of our planet is still 7.5 billion years away, but people really should consider the fate of our world and have a realistic understanding of where we are going," said UW astrophysicist Donald Brownlee. "We live in a fabulous place at a fabulous time. It's a healthy thing for people to realize what a treasure this is in space and time, and fully appreciate and protect their environment as much as possible."

Leave it to a bunch of scientists to suck all the fun out of an end-of-the-world watch.  No Armageddon predictions, no nuclear accident, not even a stray zombie attack — just the Earth shriveling up and getting swallowed by the Sun.  How are we supposed to get riled up about that?

I think most of us would rather imagine a more poetic ending than that.