The Antennae : this is a classic example of a merger in the early stages. These galaxies are currently separated by about 50,000 light years (15 kpc).
"Atoms for Peace" : this is typical of a late-stage merger. This appears to be an on-going merger of two massive spiral galaxies, in the process of forming a single elliptical galaxy.
Arp 220 : this merger appears to be nearly complete. Note that these galaxies are roughly 250 million light years away from us.
Recent images of the Antennae were taken with the Hubble Space Telescope. The image is given below. Click here to read a CNN story on this image.
