A year ago, NASA’s InSight mission began its scientific quest to look deep beneath the Martian surface. In its first year, it has suffered some setbacks but also made some incredible discoveries. Researchers have now published five papers in Nature Geoscience detailing what we have learned so far about the fascinating geophysical properties of the Red Planet.
While attempts to actually dig deep into Mars' interior hasn't gone quite to plan, what with its Mole drill refusing to do much digging, InSight also comes equipped with a seismometer, magnetometer, sensor for gauging winds, and a probe to take the planet's temperature, all of which have been monitoring away.
“This is the first mission focused on taking direct geophysical measurements of any planet besides Earth, and it’s given us our first real understanding of Mars’ interior structure and geological processes,” co-author of one of the papers, Nicholas Schmerr, an assistant professor of geology at the University of Maryland, said in a statement.
The most headline-grabbing discovery has been the confirmation that Mars is seismically active in the form of Marsquakes. The planet hasn’t got plate tectonics like Earth, but apparently it still shakes. InSight’s Seismic Experiment for Interior Structure (SEIS) has registered more than 450 seismic signals to date, with the vast majority of those being quakes. Interestingly, Mars experiences more quakes than expected, but they are also milder. The most powerful one had a recorded magnitude of 4, not enough to move deep through the planet’s interior below the crust.
But that's not all. The lander’s magnetometer has also provided some surprises for scientists. Magnetic signals picked up where InSight is located, an area nicknamed Homestead hollow, are 10 times stronger than expected. Mars no longer has a magnetic field, having lost it billions of years ago. However, when it did, it magnetized some of the rocks. These magnetized rocks, the researchers suspect, must be fairly deep underground as the top layer is too young to have been there back when the planet had a strong magnetic field.
“We're combining these data with what we know from seismology and geology to understand the magnetized layers below InSight,” lead author Catherine Johnson, a planetary scientist at the University of British Columbia and the Planetary Science Institute, said in a statement. “How strong or deep would they have to be for us to detect this field?”
The magnetic field also changes over the Martian day, pulsing around midnight. This might be due to interactions with the solar wind and the atmosphere but it is too early to tell.
Finally, this multitasking lander also constantly measures the planet’s thin atmosphere. The air pressure, as well as the wind speed and direction, are constantly being monitored. InSight has detected thousands of passing whirlwinds, which are called dust devils when they pick up dirt and become visible. Dust devils have been observed on Mars by many other missions but despite the incredible number of whirlwinds detected in Homestead hollow, InSight’s cameras are yet to capture even a single seemingly-invisible devil.
This first year of data is just the start for this incredible mission, there is a lot more yet to come. Data is also being collected to see if Mars' core is solid or liquid by detecting the planet's "wobble". And this month, the team will try once again to get its Mole to dig deep into the soil. Mars can't keep its secrets forever.