One of the frustrating aspects of cosmology is how difficult it is to actually apply the scientific method to it. You can't make a couple stars in a lab and see how they behave, the same way you can for particle physics. Fundamentally, most of cosmology comes down to observation, not true experimentation, where the experimenter is directly acting and comparing that to a control group. There are some experiments that can be done, but there are just some fundamental limitations. This is also the case in the so-called "soft sciences" like economics and psychology. But it's even true in some corners of the "hard sciences" like evolutionary biology.