Tuesday, July 25, 2006

shifting sands

Two cool unrelated stories about sand dunes in the paper this morning:
The dunes at Sand Mountain in Nevada sing a note of low C, two octaves below middle C. In the desert of Mar de Dunas in Chile, the dunes sing slightly higher, an F, while the sands of Ghord Lahmar in Morocco are higher yet, a G sharp.

Since at least the time of Marco Polo, desert travelers have heard the songs of the dunes, a loud — up to 115 decibels — deep hum that can last several minutes. ... While the songs are steady in frequency, the dunes do not have perfect pitch. At Sand Mountain, for example, dunes can sing slightly different notes at different times, from B to C sharp.
Secrets of the Singing Sand Dunes. Clickthrough to the article to hear the audio and find out what they figured out -- but hurry -- the link structure on both of these is thwarting the extended RSS link format -- this link will time out in a few days and only subscribers will be able to access it.

Had the scientists listened a little while longer, they may have discovered that the dunes were talking about the weather:
If that dune has been fixed in place since ancient times, you can know which way the wind blew back then, and by extension what the climate was like.

By analyzing the region of dunes known as the Nebraska Sand Hills, scientists at the University of Nebraska have determined that a major wind shift occurred on the Great Plains from 800 to 1,000 years ago. That shift, which brought dry air from the southwest, led to a prolonged drought that was much more severe than the Dust Bowl.
Shifting Sands and an Ancient Drought

Both bits were in today's New York Times (gotta love that Tuesday Science Times section).

1 comment:

Lolabola said...

love this post!

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