There’s something flashing us on the moon, and we don’t know what it is. But that might be about to change.
We have known about the mysterious flashes since at least the late 1960s, when the astronomers Barbara Middlehurst and Patrick Moore reviewed the scientific literature and found nearly 400 reports of strange events on the moon. Small regions of the lunar surface would get suddenly brighter or darker, without obvious explanation. The scientists’ survey of the flashes and dimming, which they called “lunar transient phenomena,” was published in the journal Science on Jan. 27, 1967. (Later, astronomers flipped the words around, terming the events “transient lunar phenomena.”)
“The emitted light is usually described as reddish or pinkish, sometimes with a ‘sparkling’ or ‘flowing’ appearance,” wrote the astronomer A. A. Mills in the March 1970 journal Nature.. “The coloration may extend for a distance of 10 miles [16 kilometers] or more on the lunar surface, with brighter spots 2 to 3 miles [3 to 5 km] across, and is commonly associated with veiling of the surface features. The average duration of an event is some 20 minutes, but it may persist intermittently for a few hours.”