One of the most impressive things accomplished in the 20th century was Einstein's Theory of Relativity. What we perceive as the force of gravity is actually a result of the curvature of space and time.
According to Space.com, 'Albert Einstein determined that the laws of physics are the same for all non-accelerating observers, and that the speed of light in a vacuum was independent of the motion of all observers. This was the theory of special relativity.'
I'm a long time fan of the television show The Big Bang Theory and I’ve always wondered what their process was for getting the science right. I just finished reading a fascinating article on NPR about how the show has its own science consultant! His name is David Saltzberg and he is a physics professor at UCLA.