In my realm of interest there are really only two types of scientists:
1. Experimental physicists carrying out experiments in laboratories,
2. Astrophysicists (or cosmologists) who use the universe as their ‘laboratory’.
Both construct mathematical models to describe their observations. Both test their models against those observations.
However the experimentalists (type 1) can interact with their experiments in a way the astrophysicists cannot. For example, they can send in a light signal and measure the response in the system, i.e. see what comes out. But the astrophysicists (type 2) cannot interact with what they are observing in the universe. The universe is just too large to do that.
It is also too large for us to look at stars or even "solar system" from all sides. But even so, thanks very much for admission!/HGL
Why is Dark Matter everywhere in the cosmos?
A product of the Dark Side
by John G. Hartnett Published: 31 March 2015