It seems that physicists first construct mathematical models, then devise instruments to find just what they are looking for. In an attempt to prove the model wrong (because no one believed it), dozens of different experiments were set up. This is why 6th grade science experiments are pointless (except for edjucation or whatever), and why botched experiments and accidental discoveries are so useful. As it happens, both the relativity model and quantum model held up to experiment, and so we still use them today. But the second someone travels all the way around the planet, all of your theories are instantly useless.