The seismic motions of Mars reveal its internal structure

(CNN) – When NASA’s Insight Lander touched down in 2018, the mission team hoped that the stationary spacecraft would be able to conduct a survey of the interior of the red planet. Now, Insight and its instruments have surpassed those goals, and scientists have until now avoided the mysteries of Mars’ crust, mantle and center.This is the first time we have observed and mapped the interior of another planet beyond Earth. The Insight Mission team also achieved this extraordinary feat by observing the Martian earthquakes on the red planet, also known as the “Marscakes”, which are slightly different from the earthquakes we experience on Earth.

Insight’s seismic measurement, also known as the Inner Structure seismic test, detected 733 different “markwaves”. The researchers analyzed 35 of them and measured between 3.0 and 4.0, confirming the thickness of Mars, the depth of the planet’s mantle and, most importantly, the melting of the planet’s desert core.

The findings were shared in three studies, all published in the journal Science on Thursday.

Before Insight went to Mars, all of the previous robotic explorations of the Red Planet had been exploring its surface.

“When we started developing mission concept a decade ago, we expected information from this work to finally be available,” said Bruce Bonert, NASA’s chief analyst at NASA’s Jet Propulsion Laboratory in Pasadena, California. “It marks the culmination of all the work and concern of the last decade.”

Discover Mars by its seismicity

Unlike the rovers of Curiosity and Perseverance, the Insight is limited to where it landed, unable to search the surface for maneuver. However, the lander’s incredibly sensitive seismic magnitude is capable of detecting marmots hundreds and thousands of kilometers away. You do not need movement to study Mars.

When we experience an earthquake, the tectonic plates of the earth change, move and collide. So far, Earth is the only planet with these plates.

How do earthquakes occur on Mars? Imagine Mars Crust being a single giant plate. This crust has bugs and fractures on its interior as the planet continues to cool. This puts pressure on the Martian crust, causing it to stretch and crack.

As the seismic waves from the Marscakes traveled through different objects in the interior of Mars, they allowed researchers to study the planet’s internal structure. It helps us to understand the mysterious interior of Mars and to use this research to understand how other rocky planets, including ours, are formed.

Insight was able to uncover some of the secrets of the interior of Mars, shedding light on how all rocky planets form.

The seismic maps collected by Insight are filled with ripples, and these ripples can be noisy caused by wind or Markwake vibrations.

“What we are looking for is an echo,” said lead writer Aamir Khan Mantle study And EDH in a report by a scientist at the Zurich Institute of Geophysics and Zurich Physics.

“Direct seismic waves from an earthquake are like the sounds of our voices in the mountains: they produce echoes,” said Philippe Lagnonne, a seismologist and professor at the University of Paris in a statement. “These are the echoes that are reflected in the center, or even at the crust-table interface or on the surface of Mars, we searched for signals, thanks to their similarity with direct waves.”

Billions of years ago, Earth, Mars, and other planets in our solar system formed from the disk of matter around the Sun, which contained dust and rocks. The planets will be incredibly hot as they form. Over time, during those first million years, different layers appeared on Mars, including the mantle and core.

“The seismic data we see now confirm that Mars was completely melted before splitting in the mantle and center, but these are different from Earth,” Khan said.

The Earth has a thin shallow rock that surrounds a thick rock mantle that often surrounds a center made of iron and nickel.

The data collected by Insight helped researchers find that the thinner Mars crust is about 12 miles deeper than expected. This crust may contain sub-layers extending to a depth of about 23 miles from the surface.

This artist’s description shows the Insight Lander, its sensors, cameras and equipment.

“Stratification within the overlay is something we can always find on Earth,” said lead author Brigitte Knopmeyer-Endrone. Bar inspection And Geophysics at the University of Cologne, in a report. “Waves in an earthquake map may exhibit properties such as a change in porosity or a more broken layer.”

Understanding how the Mars Crust formed compared to Earth may help researchers understand another part of why the planets in our solar system differ from each other.

At the bottom of the overlay is the shield, which travels a further 1,559.5 kilometers before reaching the liquid metal center.

The researchers were able to confirm the size of the center with a larger radius than expected over an area of ​​1,830 km, and were able to determine if the core had melted. The liquid core contains iron and nickel, as well as lighter elements such as sulfur, oxygen, carbon and hydrogen.

“This study is a once-in-a-lifetime opportunity,” said Simon Stoller, lead author of the main study and seismologist at EDH Zurich. “It took scientists hundreds of years to measure the center of the Earth; after the Apollo missions, it took 40 years to measure the center of the moon. Inside it took only two years to measure the center of Mars.”

Earth has a molten outer core that orbits a solid inner core. The Insight mission, which has been extended to 2022, will continue to search for data that could show whether it is similar or different from Mars in this regard.

Insight is waiting for the big moment

Mars was once a volcanic planet. Volcanic areas across the Red Planet are visible today, thanks to pictures of orbits.

Most of the large Martian earthquakes detected by Insight came from a specific area: Cerberus Foss. This area, which may have functioned as a volcano only a few million years ago, is scattered by rocky tracks that formed when it moved due to earthquakes.

The largest earthquakes detected by NASA’s Insight appear to have occurred in the region of Mars’ Cerberus Fossa, which was captured by a Hirris camera on NASA’s Mars Renaissance Orbiter.

Meanwhile, other volcanic areas on Mars appear to be quiet. But Insight is still waiting to hear of more than 4.0 Mars.

“We want to see one bigger one,” said Mark Bonning, co-author of the cruise study and JBL research scientist on planetary interiors and geophysics. “We have to process very carefully to get what we want from this data. Having a big event will make all of this easier.”

The steady stream of data that Insight sends to scientists on Earth will end in about a year, and solar cells can no longer generate enough power. But to know as much as possible about our mysterious planetary neighborhood, researchers will spend decades studying the findings of Insight.

“Mars continues to present many mysteries, and the question arises as to whether they were created simultaneously, or whether our earth is made of the same substance,” said author Dominico Giardini, professor of seismology and geophysics at ETH. From Zurich.