Hickson Compact Group

 

There are four galaxies in this image: two spiral galaxies (top and center), an elliptical galaxy (right; looks like a large bright star, but is a mass of stars surrounded by haze of other stars), and a disk-shaped galaxy viewed from the side (bottom large object).

The edge-on view of the bottom galaxy clearly shows vast lanes of cool dust and gas backlit by the stars.

Side-note: One interesting feature of this photo is that the three largest galaxies are in orbit around each other. The fourth, in the center, may also be in orbit or it may be an unrelated object in the background. The gravitational attraction between the elliptical galaxy (HCG 87b) and side-view galaxy (HCG 87a) is indicated by a faint bridge of stars pulled from the smaller to the larger of the two galaxies. Galaxies can exchange stars and, one assumes, any planets in orbit around the stars!

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Image credit: Hubble Space Telescope; The main source for HST images and explanations is HubbleSite.org.


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