New simulations show that dark matter, the invisible material that makes up most of the universe’s mass, can clump together to form atoms. These “dark atoms” could radically change evolution galaxies and formation starsgives astronomers a new opportunity to understand this mysterious substance.

Dark matter It has more than 80% of the mass of every galaxy and galaxy cluster in it. Universe. All our observations indicate that dark matter is a new kind of particle that does not interact with ordinary matter or even light. We can only identify dark matter through its gravitational interaction with everything else. Whatever dark matter is, it’s beyond our current understanding of physics. But it still has mass, so it still has gravity.

We do not yet know whether dark matter is simple or complex. It can be made from a single type of particle that dominates the universe and barely interacts with itself. Or it may consist of many types of particles with the same variety as we see in ordinary matter. Apart from that, we know only four fundamental forces of nature: gravity, electromagnetism, strong nuclear force and weak nuclear force. However, there may be additional forces acting only between dark matter particles and not interfering with normal matter at all.

get together

The concept of extra dark matter particles and dark forces is not as exaggerated as it might seem. Our understanding of physics is based on symmetries, which are deep mathematical connections between particles. It is possible that there are other symmetries in the laws of nature that make dark matter the counterpart of normal matter, and that any interaction that normal matter can enter has a counterpart in the dark sector.

For example, we can build simple structures from ordinary materials. atoms: proton And electronare interconnected by a photon, the carrier of the electromagnetic force, which is the mediator of the interaction. We could also have a dark matter version of the same structure with a dark proton attached to dark electrons via dark photons: dark atoms.

Atomic dark matter would behave much differently than dark matter, which consists of only one particle. Most importantly, simple dark matter will be very difficult to clump together, and will do so gradually over hundreds of millions of years. Ordinary matter collects in these smooth pools of dark matter to form galaxies, but other than that, they live differently. However, atomic dark matter can form its own shadow galaxies, disk-like structures that mimic the size and position of visible galaxies.

A team of astrophysicists used this intriguing possibility to model the evolution of galaxies and see if observed differences might arise. They allowed atomic dark matter to evolve according to its own forces, and then explored how these new structures would affect visible galaxies through the new structure of gravity. They published their results in an online preprint database. arXiv Resource in April