[NASA APOD] Distortions and Breakups of Galaxies

Explanation:
A photograph of distortions and breakups caused by a massive galaxy cluster.

In this beautiful image taken by the Hubble Space Telescope in 1994, what exactly are those peculiar blue objects? The answer is—they are images of a blue, bead-like galaxy with an unusual ring-like appearance. This galaxy happens to be located directly behind the massive galaxy cluster (yellow) shown in the image. The powerful gravitational lensing effect of the cluster and its internal dark matter produces multiple distorted images of this background galaxy. Just as we often see multiple images of a single streetlamp when looking through a wine glass, the reason gravitational lensing creates multiple images of a background galaxy is quite similar. This peculiar galaxy, which may be in the process of forming, allows astronomers to easily identify that the images at the 4, 8, 9, and 10 o’clock positions all originate from the same source. Even the blue smudge to the left of the cluster’s center might be a mirage of this same galaxy.