© NASA/JPL-Caltech/York University
While driving across the Naukluft plateau, a gnarly terrain riven with rock shards, last summer, Curiosity captured these early morning clouds.
NASA's
Curiosity rover usually keeps its instruments firmly focused on Mars's ground, zapping grit with its laser or drilling cores in bedrock. But every few days, the SUV-sized robot, like any good dreamer, shifts its sights upward to the clouds.
Well into its fifth year, the rover has now shot more than 500 movies of the clouds above it, including
the first ground-based view of martian clouds shaped by gravity waves, researchers
reported here this week at the Lunar and Planetary Science Conference. (Gravity waves, common atmospheric ripples on Earth that result from air trying to regain its vertical balance, should not be confused with
gravitational waves, cosmological ripples in spacetime.) The shots are the best record made so far of a mysterious recurring belt of equatorial clouds known to influence the martian climate.
Understanding these clouds will help inform estimates of ground ice depth and perhaps recurring slope lineae, potential flows of salty water on the surface, says John Moores, a planetary scientist at York University in Toronto, Canada, who led the study with his graduate student, Jake Kloos. "If we wish to understand the water story of Mars's past," Moores says, "we first need to [separate out] contributions from the present-day water cycle."
The observations seem likely to constrain fine-grained models of martian clouds, which have been built in the past with limited information, says Nicholas Heavens, a planetary scientist at Hampton University in Virginia, who is unaffiliated with the study. "These cloud videos are not just pretty pictures."
Comment: See also: Solar system-wide climate change: 'Physically impossible' clouds appeared over Mars in 2012 - NASA has no clue what's going on