astrophysics
March 1, 2003
Final countdown
Only 7.5 billion years from now, a burned-out cinder of a planet called Earth will be engulfed by its sun, a bloated red giant that will melt away any evidence that the planet ever existed.
September 1, 1990
Extinction on their minds
A sudden change in the environment killed off the dinosaurs 66 million years ago. Could it happen again, this time to the human race?