I am a PhD student of Cosmology. I work in the paradigm of Dark Matter. Let me explain a little.
In the latest decades the observations indicate that most of the matter in the universe is entirely unknown. I mean, its nature is totally different to the matter we know and we are made.
We can just detect it by means of its gravitational influence in the large scales. By large scales I mean, galaxies and super clusters of galaxies. That means that the light can not interact with this exotic matter, for that reason it was called "Dark Matter".
The big problem is that we can no detect it by direct means. So people is looking for indirect efects of the Dark Matter in the "normal" matter we know.
In particular I am investigating one possibility in the nature of this: A scalar field as a candidate to be Dark Matter.
If you wanted to know more, don't doubt to tell me. Best regards!!