Ask Ethan: Could Dark Matter Not Be A Particle…

Ask Ethan: Could Dark Matter Not Be A Particle At All?

“If dark energy can be interpreted as an energy inherent to the fabric of space itself, could it also be possible that what we perceive as “dark matter” is also an inherent function of space itself – either tightly or loosely coupled to dark energy? That is, instead of dark matter being particulate, could it permeate all of space with (homogeneous or heterogeneous) gravitational effects that would explain our observations – more of a “dark mass”?”

When it comes to all the matter and radiation in the Universe that we know of, at a fundamental level, every bit of it is made out of particles. From photons to neutrinos to leptons and quarks, there’s a quantum of energy for every type of energy we know of. Except, that is, for dark energy, which appears to be inherent to space itself, and doesn’t have a particle counterpart. There’s no evidence for clumping, inhomogeneities, or changes in dark energy over time. Well, what about dark matter, then? Is it possible that the most elusive form of mass in our Universe isn’t a particle at all, but rather can be interpreted as some sort of function inherent to space itself? While it does need to clump, and drives the formation of galaxies and the other structure in the Universe, it doesn’t necessarily need to be particle-based in nature.

It could, in fact, behave as a perfect cosmological fluid! What are the alternatives, constraints, and how do we know? Find out on this week’s Ask Ethan!