Antennae Galaxies: This image could also be named "The Dancing Galaxies" as actually these interacting galaxies are absorbed in a cosmic dance. NGC 4038 (left) and NGC 4039 (right) started their approach to each other under the influence of their gravitational forces some 900 Mio years ago. 600 Mio years ago the two spiral galaxies passed through each other, releasing stars, gas and dust (the antennae like arcs) about 300 Mio years ago by tidal forces.
In 400 Mio years they will probably merge to one huge elliptical galaxy. This scenario is probably very similar to what Milky Way and Andromeda Galaxy will perform in the future.
The Antennae Galaxies are 45 Mio LY from us.

The image was taken at the IAS astronomical site at the Hakos farm in Namibia.