Have you ever been to Death Valley?  This is a national park that straddles California and Nevada.    It’s below sea-level, almost always in drought conditions, that is amazingly hot in the summer day- and amazing cool at night.

But, what I remember most of all I remember the varying terrain.  Salt flats, valleys, canyons, mountains, sand dunes, and badlands.  And, some days when I wandered through the park, I saw track marks.  Like an alien came and dragged the humongous boulders through the dirt from point A to point B.

How did they get moved?  For decades we never really had a good answer.  But, as is true for many a wonderful scientific discovery, training AND serendipity yielded the solution.

Richard (Scripps Institution of Oceanography) and James (a research engineer at Interwoof) Norris were doing what I (and many, many others) had done last December (21).  They were just wandering through the area, buy they heard loud cracking noises.  It turns out that the very shallow lake (barely ankle deep) that occasionally forms and then freezes during the cold nights in Death Valley was fracturing.  The floes that formed moved atop the water surface with the wind and dragged 200 pound rocks along with them.  The rocks were able to move across the muddy bottom of what is normally a dry lake bed, the Racetrack Playa.

But, it turns out that this was not totally serendipity, either.  The two scientists built weather stations and affixed GPS devices to rocks that would register movement and velocity.  And, the study lasted almost 3 years until they got results.

It turns out this phenomenon can move even 600 pound rocks, too. And, the trails these movements leave include snake trails, hooks, or rectangles.  Without any human (or animal) footprints.  Which is how the mystery presented itself before the observations of the Norris cousins.

Now, these rocks are not speed demons.  They move 10 to 15 feet a minute.  (That’s about a 1/10 of a mile an hour.)  And, this movement doesn’t occur every day- it happens infrequently, so it was certainly chance that the Norris cousins discovered the true reasons behind the phenomenon.  (You know that maxim about watching a pot boil… Just ask Dr. Ralph Lorenz [Johns Hopkins], who believed this was the cause – and tried to prove it over a decade, using time lapse photography.)

According to the article in PLOS One (coauthored with Dr. Lorenz, as well as Jib Ray [Interwoof] and Brian Jackson [Boise State]) , there are a few requirements for the scenario.  The first is that the climate has to be absolutely dry.  Then, rainwater and runoff has to accumulate on the playa- typically to an inch or two of depth.  And, the temperature has to drop quickly enough that the water freezes before it gets a chance to evaporate away.  Which is then followed by bright sunlight that thaws the ice, followed by strong winds to break the fractured ice into floes that can travel over the thin layer of water underneath.  (You do remember that ice floats on water because when it is just melting, it’s less dense than water- right?)

Now, that mystery is solved, let’s move on to the next.

Can there be progress on Capitol Hill?

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