By now everyone has heard of the recent detection of gravitational waves produced by two black holes colliding a billion miles away. By the time those waves reached us here on Earth they moved us (you, me, everything, the entire planet) a tiny fraction of the diameter of a proton. A. Proton. Not a fraction of an atom. A tiny, tiny fraction of a proton.
For a mere fraction of a second, we were able to detect that motion. As miniscule an effect as it was, and over so brief a time, it was still enough to cause me to get off my butt and drive about five hours to look at the machine built for the specifc purpose of detecting gravity waves.
I propose to describe my visit and some of my impressions here.
I'll begin with: What is a gravity wave? Here's the way I think of it. First, everything that has matter or energy has gravity. Which means everything attracts everything else. And when something moves, it turns out that it gives off waves. It's a bit like waves in water. Throw a rock in the water: waves come off. A boat moves through the water: waves come off.
But we're speaking of gravity waves. So, the moon moves around the Earth: waves are given off. With a water wave, it's pretty easy to see the water move. What exactly is moving when the moon gives off gravity waves? Space itself is moving. Ripples traveling through space. And everything they pass through ripples too.
The moon, even though it's very close, gives off gravity waves much to small for us to detect. Turns out, only really, really big events will even have a chance for us to detect. That's where black holes come in. Turns out, they can generate gravity waves big enough for us to detect, even though they are so very far away.
OK, at this point I suggest you go visit this website where the physicist Brian Green explains gravity waves to Stephen Colbert:
