When you hear scientists discuss the dark matter, don’t feel like they are saying something that you could never understand. They really don’t know how it works either. We’re serious…no one really does. This is why dark matter can refer to literally any substance that interacts mostly with gravity (and has visible matter). We know it makes up roughly 85% of the matter in the known universe.
Astronomers have also been able to determine that astrophysical observations, especially gravitational ones, can be explained by dark matter. As laws of gravity are universal, when they differ from that…dark matter likely played a role. The reason it is called “dark” is that it does not interact with electromagnetic fields. Therefore, it does not absorb, reflect, or emit radiation; making it nearly impossible to detect.