HCG 87: A Small Group of Galaxies
Credit: Sally Hunsberger (Lowell Obs.), Jane Charlton (Penn State) et al.; Data: Hubble Legacy Archive; Processing: Robert Gendler
Posted on 07/06/2010 5:44:48 AM PDT by sig226
Explanation: Sometimes galaxies form groups. For example, our own Milky Way Galaxy is part of the Local Group of Galaxies. Small, compact groups, like Hickson Compact Group 87 (HCG 87) shown above, are interesting partly because they slowly self-destruct. Indeed, the galaxies of HCG 87 are gravitationally stretching each other during their 100-million year orbits around a common center. The pulling creates colliding gas that causes bright bursts of star formation and feeds matter into their active galaxy centers. HCG 87 is composed of a large edge-on spiral galaxy visible on the lower left, an elliptical galaxy visible on the lower right, and a spiral galaxy visible near the top. The small spiral near the center might be far in the distance. Several stars from our Galaxy are also visible in the foreground. The above picture was taken in 1999 July by the Hubble Space Telescope's Wide Field Planetary Camera 2. Studying groups like HCG 87 allows insight into how all galaxies form and evolve.
So what sort of super powerful black hole are these galaxies orbiting around? Just a rhetorical question
I really enjoy these posts.
thanks for the pic :)
wow, look! so many posts in before the ping :)
Although I do not know for certain, most likely they are orbiting about their common center of gravity. That is no one "body"/galaxy or a black hole, exists for them to orbit about. Still they are close enough that their mutual gravitational attraction shapes their paths.
The same thing happens with pairs (or more than 2) of stars. They orbit about their common center of mass, not a larger central object. Stars in multiple star systems are more common than singletons.
Cool!
That is a very nice Galaxy.
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