My friend's son (age 5) absolutely loves space. It's great to see such a strong interest in science in kids that age. He calls me the astronaut guy since I told him I've wanted to be an astronaut since I was a kid, and that I also love space. We recently shared a discussion about the planets of the solar system, and how Earth is the only planet to have liquid water on its surface. I guess he had recently learned about rainbows in school, and knew that it was the water vapor in the atmosphere that allowed us to see rainbows after a storm. He told me he was sad because there was no water in space, and therefore there weren't any rainbows in space. Now I know water exists in space, but as ice and gas rather than liquid water due to pressure and temperature limitations. His comment made me realize that I had never thought about whether rainbows exist in space outside of a planet's atmosphere. I suppose all a rainbow requires is a transparent material to refract the light, and ice water in space could certainly do that. Have we ever imaged a "space rainbow" before?