... 24.07.2000 . ... At only 23 million light years distant and fully 65 thousand light years across, M51 , also known as NGC 5194, is one of the brightest and most picturesque galaxies on the sky. The smaller galaxy appearing here below and to the left is well behind M 51, as can be inferred by the dust in a foreground spiral arm blocking light from this smaller galaxy. ... July 2000 . ... Publications with keywords: M51 - spiral galaxy . Publications with words: M51 - spiral galaxy . ...