Fuzzy Dark Matter: Hiding In The Universe's Shadowland

Most of the mysterious Universe is hiding in the shadows. The so-called "ordinary" atomic matter, that makes up the world we are most familiar with, is the runt of the cosmic litter of three. An unidentified exotic form of material, that scientists call dark matter, is thought to account for 25% of the Cosmos. But what is this strange form of non-atomic matter, thought to be the substance responsible for giving rise to the first galaxies to dance in the ancient Universe? Several theories have been proposed over the years, but the identity of this shadowy exotic material has not been determined. In October 2019, a team of astronomers offered a new explanation--that the dark matter is really "fuzzy". Soon after the Big Bang birth of the Universe, about 13.8 billion years ago, particles of the dark matter would have merged together to create clumps within gravitational "halos". The clumps pulled in surrounding clouds of gas into their cores, which gradually cooled off and condensed into the first galaxies. Even though dark matter is considered to be the "hidden wiki " of the large scale structure of the Universe, scientists know very little about its true identity. This shadowy substance has kept its secrets well. However, a team of scientists from MIT, Princeton, and the University of Cambridge have now proposed their new findings that the primordial Universe, and the very first galaxies, would have appeared very different depending on the true nature of the mysterious ghostly and invisible material. The dark stuff is invisible, or transparent, because it does not interact with "ordinary" atomic matter except through the force of gravity. For the first time, the team has simulated what ancient galaxy formation would have looked like if dark matter were "fuzzy"--rather than "cold"or "warm". According to the most widely accepted model, the ghostly matter is "cold"--that is, it is composed of slow-moving particles that, with the exception of gravitational effects, do not dance with "ordinary" atomic matter. In contrast, "warm" dark matter is believed to be slightly lighter than if it were "cold"--and, as a result, would also zip around more quickly.