NASA's SOFIA, a large flying observatory that takes measurements at altitudes up to 45,000 feet, picked up a wavelength of light that's specific to water while observing the Clavius Crater, a large body near the Moon's South Pole that's very much in the sunlight.
As exciting as that discovery is, it's also baffling. "Without a thick atmosphere, water on the sunlit lunar surface should just be lost to space," NASA researcher Casey Honniball said in a press release. "Yet somehow we're seeing it. Something is generating the water, and something must be trapping it there."