Since the end of November 2018, the research probe "InSight" has been on Mars. In the following weeks, it has placed two measuring instruments on the surface with a gripper arm. Now, one of them probably caught the sounds of a quake on the Red Planet for the first time. The weak audio signal was recorded on April 6, said the US space agency Nasa with.
The tremor detected by the probe's seismic instrument seemed to come from within Mars rather than from its surface like wind, it said. According to Nasa, scientists are still busy researching the exact cause of the signal.
According to the responsible scientific team, the event probably took place less than 500 kilometers from the landing site on the Elysium Planitia plain. The seismic waves are strongly scattered. This suggests that at least the uppermost kilometers of the Martian crust - as on the moon - are severely rugged by meteorite impacts.
On Earth, such fractures are usually gradually chemically closed again. Water is responsible for that. It transports dissolved minerals, which then work as anchorage and bridge the gap. On Mars, this process apparently does not take place on the moon, at least not near the landing site, according to a researcher involved. However, the earthquake had been too weak to explore the deep interior of Mars, that is, beyond the top crust layers.
"Finally a proof that Mars is seismically active"
"This event officially marks the beginning of a new field of research: Earthquake Science of Mars," said InSight Science Director Bruce Banerdt of the Jet Propulsion Laboratory (JPL) in Pasadena, California. "We have been waiting for months for a signal like this," rejoiced Philippe Lognonne, an earthquake specialist at the French Physics Institute Institute of Physique du Globe de Paris (IPGP). "It's so exciting to finally have proof that Mars is still seismically active."
In addition to the signal from April 6, the researchers have recorded three more signals that could be signs of quakes. The analysis is not yet finished here.
InSight will spend at least two years exploring the interior of Mars, learning more about its structure and dynamics beneath its surface. The robot can not roll like the Rover "Curiosity", but stays in one place. According to Nasa, in December sensors of the probe had caught noises of winds on the Red Planet.
The "InSight" mission costs about 650 million euros. Also involved is the German Aerospace Center (DLR). Under his leadership, a device has been developed to study the heat flow in the interior of the planet. However, this Mars mole is currently standing still, probably because it hit a rock in the ground. Experts are now looking for a strategy to save the experiment yet.