NASA deactivated its InSight lander in December, but its seismometer data will be studied for decades. Scientists have discovered that Mars‘ liquid iron core is thinner and denser than previously believed by analyzing seismic waves the device picked up during two temblors in 2021.

A report published on April 24 in the Proceedings of the National Academies of Sciences described the first direct observations of another planet’s core. The discoveries represent the first direct observations of the core of another planet ever made. In a groundbreaking discovery, the InSight team identified two seismic events that occurred on Aug. 25 and Sept. 18, 2021. These two temblors are the first of their kind to have originated on the far side of the planet, opposite where the lander is located. The team’s findings mark a significant milestone in our understanding of seismic activity on Mars.  The distance turned out to be important: the farther a quake occurs from InSight, the further its seismic waves can travel before being picked up.

The lead author Jessica Irving, who is an Earth scientist at the University of Bristol in the United Kingdom says: “We needed both luck and skill to find, and then use, these quakes,”. Moreover, she said: “Farside quakes are intrinsically harder to detect because a great deal of energy is lost or diverted away as seismic waves travel through the planet.”

Let’s discuss this,

Meteoroid Impact Helps Detect Marsquake on Red Planet:

After operating on Mars for over two Earth years, the Marsquake Service has honed its skills in examining seismographs. This was noted by Irving following the occurrence of two quakes on the Red Planet. A recent study has revealed that a meteoroid impact played a crucial role in providing precise location and accurate data for seismologists to analyze one of the two quakes. This discovery sheds light on the significance of meteoroid impacts in seismology and their potential to aid in earthquake research. Marsquakes primarily result from rock fractures, caused by heat and stress, due to the absence of tectonic plates on the planet. The size of the earthquakes played a significant role in their detection, according to recent reports.

seismic waves
This artist’s concept shows a cutaway of Mars, along with the paths of seismic waves from two separate quakes in 2021. Detected by NASA’s InSight mission, these seismic waves were the first ever identified to enter another planet’s core.
Credits: NASA/JPL-Caltech/University of Maryland

These two farside quakes were among the larger ones heard by InSight,” said Bruce Banerdt, InSight’s principal investigator at NASA’s Jet Propulsion Laboratory in Southern California. “If they hadn’t been so big, we couldn’t have detected them.

NASA’s InSight lander has faced a challenge in detecting certain earthquakes due to their occurrence in a “shadow zone”. This area of the planet refracts seismic waves away from the lander, making it difficult for the echo of a quake to reach InSight unless it is of significant magnitude. The InSight team has achieved a remarkable feat by detecting seismic waves that traverse through a shadow zone with just one seismometer on Mars. This is an incredibly challenging task, and the team’s success is truly impressive. In contrast to the distribution of many seismometers on Earth, it is worth noting that…

It took a lot of seismological expertise from across the InSight team to tease the signals out from the complex seismograms recorded by the lander,” Irving said.”

In a recent news update, it has been reported that the previous research paper which gave a preliminary insight into the core of the planet was based on seismic waves that reflected off its outer boundary, leading to less accurate data. Scientists Refine Models of Earth’s Core by Detecting Seismic Waves That Traveled Through It A recent paper has revealed that approximately 20% of the core is comprised of elements including carbon, sulfur, oxygen, and hydrogen.

“Determining the amount of these elements in a planetary core is important for understanding the conditions in our solar system when planets were forming and how these conditions affected the planets that formed,” said one of the paper’s co-authors, Doyeon Kim of ETH Zurich.

InSight’s mission has always been focused on studying the deep interior of Mars to aid scientists in comprehending the formation of all rocky planets, including Earth and its Moon.

Here’s a burning question…

When and where did the Mars earthquakes happen?

Two earthquakes occurred on August 25 and September 18, 2021. These tremors were initially determined by the InSight team to have originated on the side of Mars that is opposite the lander. The quakes were far-side temblors. The detection of seismic waves was challenging due to the distance. This is because a quake’s seismic waves can travel farther before being picked up on the planet the farther it happens from InSight. 

Jessica Irving, the paper’s principal author, claimed in a NASA press release that finding and using the earthquakes required both luck and talent. She said that far-side earthquakes are inherently more difficult to detect because so much energy is wasted or diverted as seismic waves pass through the Earth. 

The two earthquakes, one of which was brought on by a meteoroid impact, struck after InSight had been operating on Mars for more than a full Martian year, or roughly two Earth years. 

The fact that the earthquakes took place in a “shadow zone” presented another obstacle to detection. It is difficult for an earthquake’s echo to reach InSight in this region of Mars unless the temblor is quite big since seismic waves from this region of Mars tend to be refracted away from the lander. However, experts could analyze seismic waves because of their knowledge of seismology.

Before you go,

More About the Mission

NASA’s Science Mission Directorate has entrusted the management of InSight to JPL. Moreover, the InSight mission is being managed by The George C. Marshall Space Flight Center. The center is located in Redstone Arsenal, Alabama, as a part of the agency’s Discovery initiative. Lockheed Martin Space, a renowned aerospace company based in Denver, has successfully constructed the InSight spacecraft, which includes its cruise stage and lander, and provided crucial support for the mission’s spacecraft operations.

A principal investigator Tilman Spohn said in a statement at the time: “We’ve given it everything we’ve got, but Mars and our heroic mole remain incompatible,” Moreover, he added: “Fortunately, we’ve learned a lot that will benefit future missions that attempt to dig into the subsurface.”


Published by: Sky Headlines