On the right is the famous stationary star Polaris, the 45th brightest star in the sky.It will always appear in the same direction as North Celestial Pole points near it. On the left, ten million times closer, is Comet Lovejoy, who changes position by the hour and will only appear near the North Star for a few more weeks. NASA Astronomy Picture of the Day: June 2, 2015
Sit back and watch a star explode. The actual supernova occurred back when dinosaurs roamed the Earth, but images of the spectacular event began arriving last year. Supernova 2015F was discovered in nearby spiral galaxy NGC 2442 by Berto Monard in 2015 March and was unusually bright -- enough to be seen with only a small telescope. The pattern of brightness variation indicated a Type Ia supernova
It's back. Never before has an observed supernova been predicted. The unique astronomical event occurred in the field of galaxy cluster MACS J1149.5+2223. Most bright spots in the featured image are galaxies in this cluster. The actual supernova, dubbed Supernova Refsdal, occurred just once far across the universe and well behind this massive galaxy cluster.