No. 67: Jan-Feb 1990
Two recent items in the literature suggest ways in which flashes of light can be generated on the face of the moon. The first enlists the "Life-Saver effect (or "sugar-cube effect"). When Life Savers, sugar cubes, or rocks are fractured, light may flash from their broken surfaces. R.R. Zito, from Lockheed, thinks these flashes occur when energetic electrons are emitted from freshly fractured surfaces. Lunar rocks cracking under stress might very well produce flashes visible from earth. Zito also states that newly fractured rocks emit a curious burst of radio waves in the frequency range of 900-5,000 Hertz.
(Eberhart, J.; "Does the Moon Spark Like a Life-Saver?" Science News, 136: 375, 1989.)
The second explanation of lunar flashes blames them on earth satellites passing in front of the moon. Satellite surfaces can flash like a car's windshield in sunlight, thus simulating a lunar flash. It was just this mechanism that was used to explain the mysterious "flasher" in the constellation Perseus. (SF#53)
The May 23, 1985, lunar flash, reported in SF#64, may have been a reflection from a large military weather satellite that was transiting the moon at the time of the flash, say R.R. Rast and P. Maley. However, the timing and position of the satellite are not as convincing as some would like. Besides, the outline of the flash in the photograph is "confined by features of the lunar terrain."
(Anonymous; "Lunar Flash Mystery: Solved or Deepened?" Sky and Telescope, 78:461, 1989.)
Comment. Regardless, large numbers of lunar flashes were recorded before the advent of artificial satellites. See ALL** in our catalog: The Moon and the Planets. For details on this book, visit: here.