There are big waves, and there are BIG WAVES. This moving wall of hot gas falls into the latter category — it measures 200,000 light years across (that's about twice as wide as the Milky Way galaxy), and no one has volunteered to surf it — yet. A new study has found that this cosmic tsunami, which likely formed billions of years ago, rolls through the nearby Perseus galaxy cluster. Learn more https://goo.gl/mn3GcT | Space.com

253K views · 2.9K reactions | Einstein’s theory of general relativity predicted the discovery of gravitational waves and the physicists who discovered them last year have just won a Nobel prize. But what are they, and what's the big deal? | The Guardian | Facebook