ANALYSIS: Dust Devils' Powerful Updrafts Could Drive Mars Climate
So we know that Mars is a windy world, capable of producing some of the most impressive dust devil specimens in the solar system, wouldn't it be great if we could detect them without the need of a robotic camera to be pointing in the right direction at the right time? They are, after all, random occurrences, we only really get to study their effects after they have come, gone and disturbed the dirt like a phantom leaf blower.
Seismic Wind-Print It just so happens that NASA is launching its next Mars lander next year, called the InSight mission. InSight will land on Mars to help us form a better idea about what lies beneath all that regolith. The lander will use a drill to bore through the topsoil, providing us with a first-ever look at heat-flow from the planet's interior up to 5 meters below the surface. It will also have a seismograph to study motions from within the planet. It's thought that, although the Red Planet is generally tectonically dead, "marsquakes" do occur and this will be our first opportunity to study them in depth.
And it turns out that InSight may also be a ready-made dust devil detector.
During their studies of dust devils on Earth, Lorenz and his colleagues planted a seismometer in the desert near the Goldstone Deep Space Communications Complex outside of Barstow, Calif. The area is remote, away from traffic and was fensed off to prevent wild donkeys and other wildlife from disturbing the dry lake bed. In the area surrounding the seismometer, the researchers also set up 8 air pressure gauges so they could correlate any rapid drops in pressure with a seismic signal.
PHOTO: Twisted Twister Spotted on Mars
When a dust devil forms, it creates a mini-low pressure region over the ground - the warm surface causes the air to rise and the air will start to rotate. Like an ice skater pulling her arms in while spinning on the spot, the spinning air will form a vortex, pulling air aloft (and any dust with it). This vortex will therefore be registered as a low pressure "blip" as it whirls across the surface.
Using this pressure sensor-seismometer combo, the researchers were able to detect 2 distinct dust devil pressure drops 10 minutes apart. They also registered seismic signatures as the surface layers were slightly distorted by the low pressure region the dust devils created. As the dust devil passed, the "sucked up" the top layers of desert. It turns out that the seismometer is crazy sensitive to any slight tilts in the ground created by this suction effect, registering a slope change of only 12 millionths of a degree.