The subject of this image is a group of three galaxies. It is collectively known as NGC 7764A. They were imaged by the NASA/ESA Hubble Space Telescope. It has used its Advanced Camera for Surveys and Wide Field Camera 3. The two galaxies in the upper right of the image are interacting with one another. The long trails of stars and gas extending from them give the impression that they have both just been struck at great speed. They were thrown into disarray by the bowling-ball-shaped galaxy to the lower left of the image.
Interactions between galaxies happen over very long time periods. Galaxies rarely collide head-on with one another. It is not clear whether the galaxy to the lower left is interacting with the other two. They are relatively close in space that it seems possible that they are. The collective interaction between these galaxies caused the two on the upper right to form a shape.
From our solar system’s perspective, seems like the star ship known as the USS Enterprise from Star Trek. NGC 7764A is 425 million light-years from Earth in the constellation Phoenix. It is a fascinating example of just how awkward astronomical nomenclature can be.
The three galaxies are referred as NGC 7764A1, NGC 7764A2 and NGC 7764A3. The haphazard naming will make more sense when we consider that many astronomical catalogues were compiled over 100 years ago. It happened long before modern technology made standardizing scientific terminology easier.
