The question of what consists of dark matter is one of the most astonishing questions of modern astronomy. We know the presence of dark matter, we can feel the gravitational effect, but we do not know exactly what it is because it does not interact with light. Probably dark matter is an action.
Axion is the theoretical element proposed in 1977 by Peccei-Quinn's theory to solve the strong CP problem in quantum color dynamics. The action maintains a certain balance of power, thus maintaining the symmetry of CP. But we do not know clearly whether there is any action.
If we want to execute the universe with dark matter, this dark matter must have certain properties. Dark matter does not interact with itself and other substances. In addition, dark matter should be pretty, stable and lasting. Here are some of the characteristics of the actions that meet the required qualifications. If we allow the action to be a dark matter, we can usually observe the dark matter.
In addition to Event Horizon, we do not have a black hole with a super table. We can only see the materials that rotate and appear around them. We can calculate the size and mass of the black holes by the properties of this material, but we can not directly observe the black holes. So there can be no black holes. Black holes can be nuclei of action stored in the centers of galaxies. As the galaxy grows, it contains more substances for action and the core of action in the medium grows.
This means we can use the relationship between black holes or actions and the galaxy to limit the properties of the actions. If the action is played with particle mass, it affects the connection of black holes or actions with the galaxy.
A group of astronomers recently used the link between the black holes and the galaxies to do just that, and the action that directs to future experiments has managed to put some upper limits on the mass of the particles.
Are the actions responsible for the dark matter in the universe? We can not yet get an answer to this question, but we hope that one day the issue will come out bright.