Galaxies often hit each other. But what about galactic clusters? It happens — and this is what it looks like when the largest gravitationally bound objects in the universe slam into one another.
The universe's oldest galaxies are showing their whippersnapper counterparts a thing or two when it comes to producing baby stars. A shockingly modern-looking galactic cluster from ten billion years ago is churning out new stars in ways never before seen.
See that bullet-shaped golden object in the galaxy cluster? That's Albert Einstein shooting down the competing theories to his General Theory Of Relativity. (Actually, it's X-ray data showing material flowing into a galaxy cluster, as a result of a merger.)