NASA’s Insight Lander offers unprecedented view of the gut of Mars

For the first time, we know what the interior of another planet like ours will look like. In three studies published in the journal Thursday, July 22nd Science, An international team of more than 40 scientists has revealed how Mars’ center, mantle and crust differ from those of Earth.

By analyzing seismic data collected by Lander Insight From NASA on the Red Planet, researchers estimated the size of the center of Mars, the thickness of its crust, and the makeup of its mantle (middle layer). “We only have this kind of information for the Earth and the Moon,” Brigitte Knappmeyer, co-author of new research at the University of Cologne and a co-author of new research, told Insider “But the moon can’t compare very well with the earth because it’s so small.”

Also read – Little is known about the presence of methane on Mars

However, Mars doubles our small terrain. New research suggests that its center is less dense than Earth, but larger in size.

The propagation of seismic waves through the heart of Mars

Insight, NASA’s Robotics Science Center, cost $ 28,828 million (approximately $ 4,704 million) to land on Mars in November 2018. Since then, Lander has used its seismometers – which detect and record earthquakes – to hear similar earthquakes. Tuesday. Earthquake waves from 12 of these Mars tremors, which traveled in the middle of the planet, bounced off the layers and helped Brigitte Knappmeyer-Andrun’s team map the crust and center boundaries.

“Imagine you have a closed box, you want to know what’s inside,” Brigitte Knappmeyer-Entrun filmed. “This method is like taking that box and putting it in the X-ray machine.”

The center of Mars is larger than scientists thought

Its radius is about 1,839 km. “Bigger than expected,” Amir Khan, seismologist and co-author of the study at EDH Zurich, Switzerland, told Insider. The boundary of Earth’s liquid outer core – which surrounds a solid metal inner core – is 2,900 km deeper than Mars. Earth is twice as wide as Mars, and its center is twice as wide.

On the contrary Earth Core It is dominated by nickel and iron, with lighter elements such as hydrogen and oxygen in the lower density center of Mars. According to Simon Stoller, co-author of another study and Khan’s colleague at ETH, it appears that the red planet has no inner center. “We don’t know, we’m going to find out,” Simon Stoller told the insider, “the temperature may be too high to form an inner core.”

This indicates that Mars’ shield is relatively thin compared to Earth. It lacks a dense layer of a mineral called bridgemanite, which keeps the Earth’s mantle stable under high pressure, which may explain the unexpected size of the center. Minerally, Amerkan said, Mars’ shield is a “simpler” version of Earth.

Mars had its protective magnetic field, lost

Earth’s core plays an important role in protecting the planet from dangerous wind and solar radiation. The liquid iron circulation in the outer center creates one Magnetic field It extends from there to the space around our planet.

Part of this vortex is caused by a process in which the warmer, lighter material of the outer center rises into the mantle above. There it is replaced by a cold, dense mantle material, which sinks in the lower center. This phenomenon is called convection. Although Mars has a liquid core, it does not have this spiral motor called the dynamo.

Fragments of the magnetized Mars crust suggest that this magnet once had a magnetic field 4 to 4.5 billion years ago. The absence of the Bridgemanite layer in Mars’ armor could explain why its dynamo ceased to exist about 300,000 years after it formed. Without this layer, the interior of Mars loses its heat very rapidly, which paralyzes the convection that takes place there. In addition, “Mars is small, so it’s cooling faster than Earth,” said Simon Stoller. “Different planet, different story”.

The crust of the red planet is like Earth

Although the crust of Mars has two or three layers, the crust of the two planets is of similar thickness, says Brigitte Knoppmeier-Endron. The average thickness of the Martian crust ranges from 22 to 71 km. Thickness The crust of the earth It varies greatly – under the oceans it is 4.8 km thin – but under the continents it is 29 to 71 km thick.

But he said the crust of Mars is very old and stable compared to Earth. The envelope of our planet is fragmented into tectonic plates. By convection, these plates sometimes collide or sink together, i.e. new crust fragments continue to form.

Mars is absent Tectonic plates, Thus no new crust has formed since the formation of the planet’s crust 4.5 billion years ago. The planet was once “completely melted” and this hot liquid mass then differs into a crust, mantle and core, Khan said.

According to Simon Stohler, the lack of plate tectonics, on the sidelines, is associated with a slowdown in convection. Water scarcity also plays a role. “Water lubricates the movement of plates in the earth,” Stoller explained. “On Mars, after the dynamo was gone, the water was lost very early after the solar wind blew through the atmosphere.”

Insight’s next destination? The moon

Scientists have previously used the mass, diameter and rotation of Mars to observe from space and predict what its inner layers will look like. Simon Stoller was pleased that Insight’s results matched previous predictions. “We were able to confirm the most difficult estimates made from orbit, so we now know how much we can count on the internal structure estimates of Venus or Mercury,” he said.

PurposeInsight The Red Planet is expected to last until the end of 2022, but Lander’s scientific research will not stop next year. Visiting Insight நிலா As part of NASA’s commercial lunar payload services plan for 2024, Stoller said.

Original version: Aileen Woodward / Insider

Also read – NASA’s Insight Lander reveals that Mars will be much weaker than we thought