Sept. 7, 2012 — You'd be hard pressed to find two galaxies as different as Messier 60, a giant, extremely bright elliptical galaxy, and NGC 4647, a beautiful spiral aglow with blue light from its many hot, young stars.
Yet the duo are bound in long-term relationship, though, like some marriages, the underlying ties are difficult to discern.
Scientists are not sure if the pair, collectively known as Arp 116, are actually interacting, even though from the perspective of Earth they appear to overlap.
For example, there's no clear evidence that gravitational tugs between the two are causing a burst of star formation, which is typical for interacting galaxies.
New images from the Hubble Space Telescope suggest that perhaps the process is just getting started. If the two are just neighbors, they surely are very close, as this mosaic assembled from visible and infrared Hubble images shows.