Answer to Brain Drain: Spring 2002
Photograph by Martin Miller, image used with permission.
Question: Have you known any rocks to move on their own leaving telltale trails? How do these rocks do it? They even move slightly uphill. Give it some thought before peeking at the answer.
Answer: No one had seen it happen before. It took high-tech monitoring using GPS technology to solve this mystery. Sensors show that rocks move with the wind when the surface of the playa lake is wet. Driven by wind, the rocks glide across the nearly flat surface of a very slippery and mud-slickened playa lake.
The mysterious sliding rocks of Racetrack Playa
Keep scrolling down the first page and follow "Dig Deeper" for more on this mystery.
http://wrgis.wr.usgs.gov/docs/usgsnps/deva/ftrac1.html
More about Death Valley
http://wrgis.wr.usgs.gov/docs/usgsnps/deva/deva1.html