Another Warning

A comet discoverd last year could slam into Mars next year, astronomers say.  They haven't observed the comet long enough yet to get an exact fix on its orbit, but, for now, the possinility of a collision is real.

We watched a comet collide with Jupiter twenty years ago.  We have ample evidence of close calls for Earth-- some of it dramatic, even stunning.  We see craters all over the Solar System, mute testimony of titanic impacts.  The case for a planetary defense system only gets stronger.