Reports of the heat-death of the universe may have been greatly exaggerated, at least according to a new study that shows that the universe may be heating up as it expands, instead of steadily cooling as time goes on, a belief commonly held amongst today’s physicists. The study, making use
Dark matter: all mass and no substance, this theoretical type of matter is used by physicists to explain why the universe acts as if it has five times more mass than we can see–basically if galaxies only had the mass that is represented by the visible matter in them, the strain that their rate of spin puts on them would cause them to fly apart. And this strange, invisible substance that doesn’t seem to interact at all with ordinary matter should be distributed as evenly as the rest of the matter in the universe… except that astronomers have recently found a galaxy that contains no dark matter at all, demonstrating that its theoretical presence isn’t as ubiquitous as we thought.
Astronomers have discovered something strange about an ultra-diffuse galaxy in the Coma Cluster called Dragonfly 44. It went largely overlooked by astronomers until recently, due to it only emitting 1 percent of the light that the Milky Way does, hence its "ultra diffuse" status. But Dragonfly 44 has recently been found to be nearly the same mass as our own galaxy, due to being made nearly entirely of dark matter.
Despite the fact that it is believed to make up around eighty per cent of the matter in the universe, so-called "dark matter" remains an enigma to scientists. It is totally invisible as it neither absorbs or emits light, and its presence has so far been determined only via its gravitational interaction with visible matter.