NASA InSight Lander Says Mars Molten Core Has A Whooping 1800-km Radius!

For the first time, astronauts have looked at the heart of Mars. NASA's InSight spacecraft has discovered the planet's core scale by listening to seismic energy ringing through Mars' interior.

(Photo: Bill Ingalls/NASA via Getty Images)
VANDENBERG AIR FORCE BASE, CA - MAY 04: In this handout provided by NASA, the United Launch Alliance (ULA) Atlas-V rocket with the NASA InSight spacecraft onboard is seen shortly after the mobile service tower was rolled back on Friday, May 4, 2018, at Vandenberg Air Force Base in California. InSight, short for Interior Exploration using Seismic Investigations, Geodesy and Heat Transport, is a Mars lander designed to study the "inner space" of Mars: its crust, mantle, and core.

The Martian core radius is measured to be 1,810 to 1,860 kilometers, SlashGear claims. That's about half that of the Earth's. This is higher than any previous figures, indicating that the center is less dense than anticipated. The discovery indicates that, in addition to the iron and sulfur that make up so much of the core's composition, it must also contain lighter elements like oxygen. InSight scientists discussed their observations in a series of talks at the simulated Lunar and Planetary Science Conference in Houston, Texas, this week.

The shell, mantle, and heart of rocky planets like Earth and Mars are separated into three layers. Understanding how the planet shaped and evolved requires knowing the scale of of of those layers. InSight's details would help scientists evaluate how Mars' thick, metal-rich core differentiated from the planet's overlying rocky mantle as it cooled. Mars' heart is most likely still molten from its 4.5 billion-year-old fiery formation.

Earth vs. Mars: What's The Difference Between The Two Cores

Earth and the Moon are the two other rocky celestial bodies on which scientists have measured the nucleus. Researchers would be able to compare and contrast how the Solar System planets evolved with the inclusion of Mars.

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Mars, like Earth, once had a strong magnetic field produced by liquid sloshing through its core. However, the magnetic field has weakened significantly over time, allowing Mars' atmosphere to flee into space and the soil to become cold, sterile, and inhospitable to life.

Nature.com said the research draws on previous InSight results that revealed layers in the Martian crust. "Now we start to have that deep structure down to the core," said geophysicist Philippe Lognonné in another pre-recorded talk. Lognonné, based at the Paris Institute of Earth Physics in France, heads InSight's seismometer team.

What Is InSight Lander's Mission?

The almost $1 billion spacecraft arrived on Mars in 2018 and is the first mission to explore the interior of the red planet. The stationary lander is stationed above the Martian equator, listening for 'marsquakes,' which are the Martian counterpart to earthquakes. New Scientist said InSight had detected about 500 quakes so far, suggesting that the planet is seismically less active than Earth but more active than the Moon. According to Lognonné, the majority of marsquakes are very few. Still, approximately 50 of them have been between magnitude 2 and 4-strong enough to reveal details about the planet's interior.

InSight tests the Martian nucleus' size by studying seismic waves that have bounced off the deep boundaries between the mantle and the core, much as seismometers on Earth do. InSight scientists measured the depth of the core-mantle boundary and hence, the distance of the core using data from enough of these deep-traveling waves. Seismic evidence also suggests that the upper mantle, which ranges 700 to 800 kilometers underneath the atmosphere, comprises a thickened region where seismic energy spreads more slowly.