In a previous blog entry, I speculated as to what a lunar eclipse might look like on the moon (which, from that point of view, would be a solar eclipse). No more speculating—the Japanese Kaguya probe took a picture of exactly that!

Now, this isn’t a fully total eclipse, as you can see from the sun brightly peeking out from the lower right, but it is enough to show the halo. Due to refraction, the parts of the halo near the sun turn red, while the parts of the atmosphere further away scatter blue light. All of this is for the same reasons that the sky is blue and sunsets are red. If the sun were directly behind the Earth, you likely would see a red halo all the way around.

It’s not only a beautiful sight, but it’s also wonderful when you consider that no human being in history has ever seen this before!