Fun With Zero Gravity

On the International Space Station, an astronaut posted the image below. They injected an air bubble inside a big drop of water. Obviously the air bubble will only stay inside when’ there’s no gravity. This leads to fun with light waves.

For more on the science (of why the image in the bigger drop is inverted, but the inner image is not), check out Phil Plait. He gets appropriately geeked out over it.