From an informal look, the heavy rocks that line Racetrack Playa should not be able to horizontal motion. It is fully degree floor, in spite of everything — the rocks might initially fall from the encompassing cliff faces, however as soon as they’re on strong floor, they should not be going wherever, at the least not with out one thing to nudge them alongside. Seems, although, one thing was nudging them alongside; it simply wasn’t one thing we might see with the bare eye.
In 2014, utilizing a mixture of time-lapse cameras and small sensors connected to the rocks themselves, researchers had been in a position to not solely get an precise view of their motion for the primary time in historical past but in addition in a position to decide what was transferring them: ice.
The factor about desert climates is that, whereas they’re blisteringly sizzling through the day, at evening, the flat elevation and lack of protection trigger the local weather to flip to bitter chilly. Very not often, throughout winter, a small quantity of rain manages to fall on Demise Valley and, by extension, onto the rocks. This rain kinds a really slight sheet of ice on the bottom. When the solar rises, and the temperature cranks again up, the ice melts, turning the encompassing floor muddy. However a small raft of ice stays beneath the rocks for somewhat longer. At that time, all it takes is a lightweight breeze, and the rocks begin sliding.