Measuring Gravitational Waves

Two of the most significant differences between Newton's theory of gravity and Einstein's theory of relativity are the role and nature of space/time and the concept of action at a distance. According to Newton, bodies are attracted to each other due to a 'force' that the mass of the objects exert on each other instantaneously. Not too long later, the Scottish philosopher David Hume criticized Newton for appealing to metaphysically obscure notions such as invisible forces. As with most things Hume, it would be a couple of centuries until someone, Einstein in this case, would confirm his acute observations. According to Einstein's model, the reason bodies seem to be attracted to each other simply has to do with the geometry of the universe: massive objects create a greater influence on the curvature of the fabric of spacetime, thereby creating the illusion of a force between them. Here is an excerpt from Brian Greene's documentary, The Elegant Universe, describing the differences between these two theories.

It may all sound nice in theory, but do we have any actual empirical observations that confirm or falsify Einstein's views? That's where LIGO comes in. LIGO, which stands for Laser Interferometer Gravitational Wave Observatory, is a clever way, as you'll see, of attempting to measure the existence of gravitational waves passing through our planet.

And finally, here is a little more detail on the same topic.

And in case you want to watch the first two parts of The Elegant Universe, which I would highly recommend, go here and here.
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