Dark Energy Survey - El Gordo galaxy cluster
This image captured by the Dark Energy Camera shows the El Gordo galaxy cluster (in the lower right), all that remains of a collision of large-scale structures less than a billion years after the creation of the universe. El Gordo’s mass is roughly the same as the cluster that holds our Milky Way galax, but is more than 100 times hotter. Photo: Dark Energy Survey
The photo is free to use providing the Dark Energy Survey is credited.