Over hundreds of years, observers have reported numerous unexplained events occurring on the surface of the Moon. These include flashes, brightenings, darkenings, and cloud-like phenomena. In a recent study, Dr. Arlin Crotts reports evidence that these historical transient lunar phenomena (TLP) are correlated with outgasing of lunar volatiles which releases radioactive radon gas that can be detected by orbiting spacecraft.

With the arrival of the Japanese lunar orbiter SELENE, and two more spacecraft on the way, there is now an opportunity to test the outgassing hypothesis by conducting simultaneous optical observations from Earth using small robotic telescopes. Dr. Crotts and I, and our students have developed and installed a prototype robotic telescope at CTIO. This telescope monitors the Moon every clear night, recording images with a CCD camera once per minute. We hope to upgrade this telescope with a higher-resolution camera, and install similar systems at other locations around the world.