Astronomy Picture of the Day

Big, beautiful spiral galaxy M101 is one of the last entries in Charles Messier's famous catalog, but definitely not one of the least. Messier 101 Credit: Hubble Legacy Archive, ESA, NASA; Processing and additional imaging - Robert Gendler Explanation: Big, beautiful spiral galaxy M101 is one of the last entries in Charles Messier's famous catalog, but definitely not one of the least. About 170,000 light-years across, this galaxy is enormous, almost twice the size of our own ... Full Story