Sean has some more cool stuff on the LIGO accomplishment. A favorite quote:
The fact that Einstein’s prediction has turned out to be right is an enormously strong testimony to the power of science in general, and physics in particular, to describe our natural world. Einstein didn’t know about black holes; he didn’t even know about lasers, although it was his work that laid the theoretical foundations for both ideas. He was working at a level of abstraction that reached as far as he could (at the time) to the fundamental basis of things, how our universe works at the deepest of levels. And his theoretical insights were sufficiently powerful and predictive that we could be confident in testing them a century later. This seemingly effortless insight that physics gives us into the behavior of the universe far away and under utterly unfamiliar conditions should never cease to be a source of wonder.
The equations that Einstein wrote down predicted lasers, black holes, and gravitational waves. He explicitly doubted the existence of the latter two. It didn't matter. His equations were smarter than he was, or more precisely, were telling us all stuff that even he, their inventor, didn't realize.