Why should you listen to Vivaldi's "Four Seasons"? - Betsy Schwarm

Awesome!

What the discovery of gravitational waves means [#astronomy #video]

1.3 billion years ago, in a distant, distant galaxy, two black holes locked into a spiral, falling inexorably towards each other and collided, converting three Suns' worth of stuff into pure energy in a tenth of a second.
Two black holes, the densest thing in the Universe, one with a mass of 29 Suns and one with a mass of 36 Suns, whirling around each other 100 times per second before they collide. Just imagine the power of that. It's fantastic. And we know it because we heard it.