http://up-ship.com/blog/?p=19134
In short: October 2014, comet C/2013 A1, discovered January 3, is expected to pass within 0.0007 AU... of Mars. An impact cannot be ruled out yet. Even better: it's on a hyperbolic trajectory; if it hits, it'll plow into Mars at 55 km/sec. Even betterer: while it's too early to really nail down how big it is, it's brightness suggests it's a monster... with a nucleus perhaps 50 km in diameter (the dinosaur killer was ~15 km). Impact energy would be measured in *petatons.*
In short: October 2014, comet C/2013 A1, discovered January 3, is expected to pass within 0.0007 AU... of Mars. An impact cannot be ruled out yet. Even better: it's on a hyperbolic trajectory; if it hits, it'll plow into Mars at 55 km/sec. Even betterer: while it's too early to really nail down how big it is, it's brightness suggests it's a monster... with a nucleus perhaps 50 km in diameter (the dinosaur killer was ~15 km). Impact energy would be measured in *petatons.*