These two galaxies are called Messier 100 and Messier 99. They both belong to the Virgo Cluster and are about 50 million light years away from our solar system. They are both located in the constellation Coma Berenices. Many other galaxies can also be seen in this image, for example NGC 4312, NGC 4298 and NGC 4302. This galaxy field can be seen from the northern hemisphere in late winter. 

Messier 99 is a spiral galaxy with no bar at its centre. The star-forming activity in this galaxy is three times higher than usual for such a galaxy. This may have been triggered by an encounter with the galaxy NGC 4254.

Messier 100 is an intermediate spiral galaxy, which means it lies between a barred and a spiral galaxy. M100 is considered a starburst galaxy, which means that it forms stars very quickly.