A transient lunar phenomenon (TLP) is a sometimes inexplicable change of color or shape seen on the surface of the moon. Some may be caused by gas escaping from underground cavities after moonquakes.

See also:

External Links

"Light Side of the Moon" -- An article from the Fortean Times for December 1997 by the astronomer Peter Grego

Transient Lunar Phenomena (and other weirdness) -- Essay on TLP followed by links

Chronological Catalog of Reported Lunar Events, July 1968 -- NASA report on TLP sightings from 1540 to 1968