NASA’s “InSight” lander touched down on the surface of Mars, with the goal of examining the Red Planet’s interior. InSight has been in operation for around three months, and it’s already turned up some interesting results. According to reports, InSight has detected hundreds of “marsquakes”; planetary tremors that behave similarly to the ground-shaking natural phenomena we experience here on Earth.
These quakes are caused by the “long-term cooling” of Mars as the planet cools, its crust becomes more brittle and begins to crack or even shatter. The impact of these cracks can be felt on the way on the surface.
Many of the quakes that InSight detected were small enough that they probably wouldn’t be felt if they happened on Earth, Philippe Lognonné, principal investigator for one of the lander’s instruments, said in a press conference. “Mars is a place where we can probably say the seismic hazard is extremely low,” Lognonné added. “At least at this time.”
The 24 largest quakes discussed in the paper only reached a magnitude 3 or 4, which on Earth, might be powerful enough to be felt as a rumble on the ground but usually aren’t strong enough to cause serious damage. But unlike on Earth, where quakes can happen closer to the surface, it appears that the marsquakes InSight detected tended to originate far deeper in the planet (30 to 50 kilometers). The deeper the quake, the less shaking is felt on the surface.
“We’ve finally, for the first time, established that Mars is a seismically active planet,” said Bruce Banerdt, principal investigator on the InSight mission at Nasa’s Jet Propulsion Laboratory in California. The tremors show that Mars is less active than Earth but more active than the moon, where seismic activity was recorded during the Apollo programme.
Aymeric Spiga, an atmospheric scientist at Sorbonne University in Paris, said the afternoon sun warmed the ground and drove turbulence that whipped up the whirlwinds. The air is so thin that they pose little danger, but they do help by blowing dust off the solar panels used to power the lander.
Beyond the whirlwinds, whose meandering tracks were captured by InSight’s cameras, the lander detected giant oscillations known as gravity waves in the Martian atmosphere. These can be caused by winds slamming into mountains, sending powerful uprushes skywards.
Other strange effects were spotted in the evening, such as sudden blasts of air racing past the lander. These are likely Martian versions of the katabatic winds that batter Antarctica. When the sun goes down, the air cools fast and surges down mountainsides and out on to nearby plains. “It’s a kind of atmospheric tsunami,” said Spiga.
Further measurements show that the magnetic field at the landing site was 10 times stronger than expected. The field comes from ancient rocks that formed and became magnetised when Mars still had a global magnetic field, billions of years ago.
An ongoing glitch is affecting a spear-like heat probe designed to burrow five metres into the Martian soil to measure heat rising through the planet. The probe was deployed a year ago but became stuck after burrowing less than half a metre. Mission scientists plan to place the lander’s robotic arm on the probe to help it on its way.
InSight’s mission lasts for nearly another year, and the team here on Earth will continue to gather more data about the inner workings of the Red Planet until then.
