Comet 46P/Wirtanen will pass within 12 million km of the Earth on December 16th. Astronomically speaking that's getting close to a near miss. Current thinking is that is should be a fairly easy naked eye comet, but these things are unpredictable.
It's about 1 kilometre across and currently out near the orbit of Mars.
Comets used to be seen as harbingers of doom, so best leave yer Xmas shopping to the last minute to save a few bob.
