This is the most colossal known smash-up observed in the universe. This awesome bundle of galaxies, nicknamed Pandora's cluster, turns out to be the result of a violent mashup between at least four separate galaxy clusters that occured over hundreds of millions of years.
The cluster's official name is Abell 2744. Using various telescopes including NASA's Hubble Space Telescope and the European Southern Observatory's Very Large Telescope in Chile, astronomers have mapped all of its ingredients and pieced together its violent history.
The image suggests that several galaxy clusters have collided over about 350 million years, with right visible galaxies make up 5 per cent of the mass, while searingly hot gas that glows in X-rays makes up 20 per cent. The rest is the invisible x-factor, dark matter, a mysterious force that reveals itself away only because its gravity bends light from background galaxies.
Provided by The Daily Galaxy - newscientist.com and NASA, ESA, ESO