Random X-Ray Pulses
It was found a while back that random, yet odd x-ray pulses were coming out of the core of both the Andromeda and Perseus galaxies. The light signature did not match any known particle or atom. This made astronomers giddy, as it was assumed they could be discovering something brand new here. In fact, many thought it could be the first true sign of dark matter recorded. Of course, dark matter is not easy to track or see. This is the entire issue for scientists. We know it accounts for most of the mass in the universe and we know it exists.
However, it’s hard to show people what it looks like obviously. It has been theorized for some time that dark matter is made of sterile neutrinos. It’s still debated if those even exist today. The reason this is a big deal is that those particles are believed to produce X-rays during their death throes. Meaning these random X-ray pulses could be caused by them. Since radiation also comes from the center of those galaxies, it’ll correspond with areas where major dark matter could likely be. The big issue here is that science still is not certain that this was what those X-ray pulses came from. Yet unlike others on the list, we’re close to finding out.