Futurizonte Editor’s Note: At one time the universe was “fuzzy”, that is, non-binary. Perhaps there is a lesson for us (and our thinking) there.
Original writer and publication date: Jennifer Chu – Oct. 3, 2019
Summary: Scientists simulate early galaxy formation in a universe of dark matter that is ultralight, or “fuzzy,” rather than cold or warm.
Dark matter was likely the starting ingredient for brewing up the very first galaxies in the universe. Shortly after the Big Bang, particles of dark matter would have clumped together in gravitational “halos,” pulling surrounding gas into their cores, which over time cooled and condensed into the first galaxies.
Although dark matter is considered the backbone to the structure of the universe, scientists know very little about its nature, as the particles have so far evaded detection.
Now scientists at MIT, Princeton University, and Cambridge University have found that the early universe, and the very first galaxies, would have looked very different depending on the nature of dark matter. For the first time, the team has simulated what early galaxy formation would have looked like if dark matter were “fuzzy,” rather than cold or warm.
In the most widely accepted scenario, dark matter is cold, made up of slow-moving particles that, aside from gravitational effects, have no interaction with ordinary matter. Warm dark matter is thought to be a slightly lighter and faster version of cold dark matter. And fuzzy dark matter, a relatively new concept, is something entirely different, consisting of ultralight particles, each about 1 octillionth (10-27) the mass of an electron (a cold dark matter particle is far heavier — about 105 times more massive than an electron).
In their simulations, the researchers found that if dark matter is cold, then galaxies in the early universe would have formed in nearly spherical halos. But if the nature of dark matter is fuzzy or warm, the early universe would have looked very different, with galaxies forming first in extended, tail-like filaments. In a fuzzy universe, these filaments would have appeared striated, like star-lit strings on a harp.
As new telescopes come online, with the ability to see further back into the early universe, scientists may be able to deduce, from the pattern of galaxy formation, whether the nature of dark matter, which today makes up nearly 85 percent of the matter in the universe, is fuzzy as opposed to cold or warm.
“The first galaxies in the early universe may illuminate what type of dark matter we have today,” says Mark Vogelsberger, associate professor of physics in MIT’s Kavli Institute for Astrophysics and Space Research. “Either we see this filament pattern, and fuzzy dark matter is plausible, or we don’t, and we can rule that model out. We now have a blueprint for how to do this.”