Astronomy Photo of the Day: 12/09/14 — Arp 116
The galaxy in the upper right almost looks like it’s superimposed on an image of the large galaxy pictured front and center, but these galaxies are actually two pebbled floating nearby in a large, cosmic pond.
The larger of the two, called Messier 60, is an elliptical galaxy found about 54 million light-years from Earth, while the smaller one is NGC 4647. It’s a little more distant, situated around 63 million light-years from Earth.
Messier 60 spans an impressive 120,000 light-years across, which makes it about 20 percent larger than the Milky Way. Its brilliant, egg-like shape comes from a large number of older, more evolved stars, containing well over a trillion times the mass of the Sun.
NGC 4647 might be smaller, but it certainly has more character. This spiral galaxy spans about 90,000 light-years across, and its appearance is the result of young, hot, blue-white stars; a mix of interstellar gas and dust; and numerous winding spiral arms that form a flattened disk.
Collectively, they are known as Arp 116. Both galaxies belong to the Virgo Galaxy Cluster. In this particular group, all objects have the tendency to collect on the eastern side, which explains why they are so close together, while they are nearly 10 million light-years apart (The Milky Way is separated from its closest neighbor by nearly 2.5 million light-years, for comparison).
Sources & Other References: http://bit.ly/1yypSB9
Image Credit: NASA/ESA