APOD 4.5- The Antennae

Nearly 60 million light-years away in the constellation of Corvus, molecular clouds of two galaxies are colliding and causing mass star formation to occur. Although the clouds of dust are colliding together, NGC 4038 and NGC 4039, the stars within the galaxies, are not colliding. This process of collision will take hundreds of millions of years for the galaxies completely move together. The two galaxies span about 500 thousand light-years across and parts of dust and stellar material expands out even further from the collision as it has been moved by gravitational tidal forces. As the trails of dust material is left behind, it form what appears to be the antennae of the galaxies.