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No. 107: Sep-Oct 1996

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More Sparks On The Beach

Sharp eyes often pick out unusual phenomena in very usual places. From California, A. Hastings writes:

"I also had an experience with 'Sparks on the Beach' as in SF#104/4. This was on the Pacific Ocean Beach at San Gregorio, south of San Francisco, several years ago. I was walking on fairly wet sand, just above the tide line. As I stepped, the sand around my feet lit up with small bright dots of phosphorescence. I would not have said that the color was blue, but it could have been like blue-white, like the star Rigel. I found that if I stepped hard or stamped my foot, the lights flashed brighter and the lit area went out farther from my foot. I could see the movement expanding out. After a stamp or two, they did not light up as much. I assumed that this was caused by some organism that lit up when it felt pressure, and 'wore out' after it had done this a few times -- a refractory period probably occurred."

(Hastings, Arthur; personal communication, March 21, 1996)

Comment. This is probably a pressureinduced biological phenomenon, but we have no idea what kind of organism produces the lights. Footsteps do produce a rapidly expanding pressure wave on damp sand, which whitens the sand as it moves outward. But we have never seen any luminosity on our Atlantic beaches, even on dark nights.

From Science Frontiers #107, SEP-OCT 1996. 1996-2000 William R. Corliss