We've known for a while that water ice exists on the Moon in deep, permanently shadowed craters near the lunar poles.
New observations, though, show the presence of water in a pretty surprising place: Sunlit craters.
That's surprising because without an atmosphere to block it, high-energy ultraviolet light from the Sun tends to break apart water molecules. However, it looks like this water exists because it's being protected somehow, possibly by being locked up in tiny glass beads formed from micrometeorite impacts.
OK, let's back up a bit. How was the water found?
The observations were made with SOFIA, the Stratospheric Observatory for Infrared Astronomy, a 2.5-meter telescope that literally looks out of a hole cut out of a specially designed 747 airplane. The plane flies at an altitude of about 12 kilometers, above most of the water in Earth's atmosphere. That's important, because the telescope observes infrared light, which is absorbed by water. Getting above the water in Earth's air allows the telescope to observe this interesting part of the electromagnetic spectrum.
Clavius is a crater about 230 kilometers wide in the Moon’s southern hemisphere. Credit: NASA's Goddard Space Flight Center/Arizona State University
The astronomers used SOFIA to look ...