A COMET AS BIG AS THE FULL MOON: Hyperactive comet 46P/Wirtanen is approaching Earth for one of the closest Earth-comet encounters of the Space Age. Observers report that the comet's gaseous green atmosphere now covers a patch of sky as large as the full Moon--and it is growing larger. Sky maps and expert observing tips are featured on today's edition of Spaceweather.com.
Above: Comet 46P/Wirtanen, photographed on Dec. 2nd by Mike Broussard of Perry, Louisiana. A picture of the Moon has been inserted for scale. More images may be found in Spaceweather.com's Realtime Comet Gallery.
