From the Royal Observatory, Greenwich, Measuring the Universe! So how exactly do we measure things that are incredibly far away? Positioning over time, light, and math, math, math! This video contains a lot of information — even about sound waves and color shifts in light — but it’s such a great start to understanding how we see and measure what’s out beyond our Earth and our galaxy. And it demonstrates how important math and patience are in science!
via The Awesomer.