Photos: Moving rocks

Richard Norris looks over a few of the moving rocks that have left trails on Racetrack playa in Death Valley National Park. Norris, a paleobiologist at Scripps Institution of Oceanography, and his cousin James Norris, a research engineer, are the first to actually photograph the rocks in motion. They are lead authors of a peer-reviewed study of the phenomenon published Aug. 27 in the online scientific journal Plos One.  (Louis Sahagun / Los Angeles Times)

The source of motion for the rocks on Death Valley’s Racetrack playa had long puzzled geologists.  (Louis Sahagun / Los Angeles Times)

Richard Norris, James Norris and Daniel Gaskell make their way across the sun-baked surface of the Racetrack playa in Death Valley National Park.   (Louis Sahagun / Los Angeles Times)

Grooves in the dry mud trace the paths of the moving rocks.  (Don Bartletti / Los Angeles Times)

The Racetrack playa’s moving rocks are a mystery no more.  (Don Bartletti / Los Angeles Times)

Rocks on the Racetrack playa in Death Valley National Park.  (Don Bartletti / Los Angeles Times )