There's a new meteorologist on Mars. Although NASA's InSight spacecraft landed on the red planet in 201
The space agency has set up a website to share that information , which includes only daily high and low temperatures, but unprecedented hourly data on wind speed, direction and air pressure for InSight's location near the equator in Elysium Planitia. "We thought it was something that people might have fun with," Cornell University's Don Banfield, who leads InSight's weather science, told Ars.
Other spacecraft have brought comparable temperature and wind sensors to Mars before, but none have carried such. a precise air pressure sensor. The new sensor is 10 times more sensitive than any previous instrument because it needs to detect slight movements in the Martian ground, and from such movements in details about the red planet's interior. For this, weather matters.
The Martian atmosphere may be very thin — typically it varies between 700 and 740 pascals at the surface, less than one percent of Earth's surface pressure — but it is nonetheless to induce slight tilts in the Martian surface. The air pressure sensor will therefore help scientists calibrate the lander's seismometer so that any tilting to higher or lower air pressure can be filtered out of the data. It's actually pretty amazing that even so thin can have a slight effect on the Martian surface, and that InSight's seismometer is sensitive enough to detect it.
A Martian mystery
Since InSight landed in November or last year, Banfield and other scientists have been studying data from the air pressure sensor, and they've made a few discoveries. Some were expected, such as gravity waves in the Martian atmosphere. The instrument has these repetitive oscillations in the atmosphere most evenings. Such gravity waves are also observed in Earth's atmosphere, especially when a uniform air mass is perturbed by a mountain or island.
But scientists have found something of a mystery in the pressure data on the surface of Mars. Twice a Martian day, at around 7am and 7pm, there are hiccups in what otherwise should be a smooth rise and fall in surface pressures. Initially, the scientists believed this to be caused by something on the land, but eventually they were able to rule out a cause due to an instrument anomaly or heating source on InSight.
This feature is repetitive and "slightly strange," said Banfield. It wasn't predicted in any of the global or regional weather models for Mars. Currently, the scientists believe the feature must be some kind of atmospheric wave related to sunrise and sunset on Mars. Perhaps there are downslope air flows moving off steep topography, related to the Sun's movement, which briefly sets up the atmospheric changes.
In terms of temperatures and winds, there have been fewer surprises. Martian days aren't too cold, with highs in the range of -10 to -15 degrees Celsius. The nights are bitterly cold where InSight is, falling to around -95 degrees Celsius. The interplay of dust and wind on Mars remains one of the outstanding questions that scientists like Banfield hope to more fully understand before humans visit the red planet. Dust plays a huge role on Mars in the amount of energy the planet's surface absorbs, and how much it radiates back into space. Scientists also want to understand the minimum winds needed to lift dust off the surface, and a necessary precursor for dust devils and dust storms. Banfield said he has built a sensor to make just such measurements, and that he hopes to fly this on a future mission to Mars.