NGC 4631 is a spiral galaxy that lies 25 million lightyears away and appears edge-on when seen from Earth. It is located in the Canes Venatici constellation and is often referred to as the Whale Galaxy, due to its similarity in shape to the aquatic mammal.
The Whale Galaxy is interacting gravitationally with dwarf elliptical galaxy NGC 4627, which can be seen just above NGC 4631 in images of the pair.
NGC 4627 looks like a smaller companion accompanying the massive Whale Galaxy on its journey through the cosmic ocean, earning it the nickname the Pup Galaxy. The pair are often known as the Whale and the Pup.
NGC 4631 Whale Galaxy by Andre van der Hoeven, HI-Ambacht, The Netherlands. Equipment: SXV-H9, NEQ-6, C11 f6.3
The Whale Galaxy is a huge star-forming region, as is clear by the pockets of hot newborn stars that glow bright blue in images.
Despite the fact that the galaxy appears edge-on from our perspective (just like NGC 891 or the Needle Galaxy, for example), images of the Whale Galaxy still reveal a bright, luminous centre and incredibly dusty disc.
The centre is so bright because of the tremendous light coming from newborn stars along with the heating of cosmic gas by stellar explosions known as supernovae.
Below is a selection of images of the Whale Galaxy with its companion the Pup Galaxy captured by astrophotographers and BBC Sky at Night Magazine readers from around the world.
