At first glance, MACS J0717.5+3745 (MACS J0717, for short) might not seem like a lot to look at, until you realize you’re looking at one of the largest and most peculiar galaxy clusters we’ve discovered to date. This image, captured by the Hubble Space Telescope, is massive-- spanning some 13-million light-years and covering 202-million pixels at full size. J0717 is located in the constellation of Auriga and can be found 5.4-billion light-years away.
The cluster itself has an unusual shape, more like a tube or stream of galaxies instead of a clump. This is because the cluster was formed when four individual galaxy clusters merged together. This is the first time a filament – that trail of matter and dark matter – has been observed. This cluster also gives astronomers a unique platform to study relativity by analyzing distorted light from the background galaxies.
See a larger image here.