This is the Andromeda galaxy, our very own Milky Way's next-door neighbour. It's the best look we've ever managed to get at it — and there's something very strange hidden in this picture. This new snap was taken with NASA's Nuclear Spectroscopic Telescope Array, an X-Ray telescope designed especially for getting unusually deep-space views — and a far deep-space view is exactly what they got when they pointed it Andromeda's way.
Because it was an X-ray view, though, NuSTAR also picked up something else: over 40 different instances of a mysterious space object called an X-ray binary. X-ray binaries are the result of either a dead or exploded star that sucks in huge amounts of nearby (living) stars and space debris, while throwing off a steady stream of X-ray radiation.
Finding so many different instances of X-ray binaries was a surprise in itself, but an even bigger was how close they were, putting them at the perfect spot to keep a closer eye on them. And keeping an eye on them may turn out to be well worth it, because scientists have long suspected that X-ray binaries may have a key, but shadowy, role in letting galaxies form at all. Now that scientists know where to look, we may figure out much more about just how they do it.