General Theory of Relativity

What would happen if you were to place a bowling ball on top of a nice fluffy pillow? The mass of the bowling ball would cause the pillow to bend or sink. Space bends the same way. Space surrounds everything -- the planets, stars, and even you! Einstein's General Theory of Relativity proved that when an object has mass, it bends the space around it. You are bending space right now!

Discovered by: Albert Einstein
What it means: any object that has mass causes the space around it to bend
Proven by: Sir Arthur Eddington
When proved: in 1919 during the solar eclipse seen on Principe Island (Africa)

Image credits: main image, © AMNH/Eric Hamilton.