Gravitational waves - level 3
“Ladies and gentlemen… We have detected gravitational waves. We did it!”
“A gravitational wave is a ripple in space and time. Einstein told us space and time respond to matter within it, and just like the surface of a pond if you put your finger into a pond and move it, you create water waves. The same thing happens as mass moves through space-time; it creates ripples, those are the gravitational waves.
We've known about them nearly a hundred years, so one year or so after Einstein came up with his theory of general relativity, he discovered gravitational waves, but it's taken this long to actually detect them.
As a gravitational wave passes through space and time, it changes the distance between two objects that are just freely sitting there in space and time, and so what LIGO and gravitational wave detectors try and do is to create objects that are suspended in such a way that they’re free to move in some directions, and then when a gravitational wave moves past and changes the space and time, it actually changes the distance between these objects and then LIGO, for example, measures that distance change by bouncing a laser beam between these masses.”
“What’s really exciting is what comes next. Four hundred years ago, Galileo turned a telescope to the sky and opened the era of modern observational astronomy. I think we're doing something equally important here today. I think we're opening a window on the universe, a window of gravitational wave astronomy.”
“It is potentially possible, depending on how the universe started, that the echo from the very beginning, the earliest epoch in the universe may be detectable as a gravitational wave signal. Because the gravity waves are so weak they've been preserved pristinely and there will be an amazing way to view this very early epoch.”
Difficult words: ripple (a small wave), matter (material, thing), detect (to measure, to notice, to see), suspend (to hang), bounce (to come into contact with something and then be reflected back), beam (a ray, bits of light), epoch (an era, an age), pristinely (perfectly).