The measurement suggests that the radius of the Martian core is 1,810 to 1,860 kilometers, about half that of Earth. That’s larger than some previous estimates, which means that the core is less dense than had been predicted. The finding suggests that the core must contain lighter elements, such as oxygen, in addition to El Hierro and sulfur that make up much of its composition. InSight scientists reported their measurements this week at the 52nd Lunar and Planetary Science Conference.
Rocky planets like Earth and Mars are divided into the fundamental layers of crust, mantle and core. Knowing the size of each of those layers is crucial to understanding how the planet formed and evolved. InSight measurements will help scientists determine how the dense, metal-rich core of Mars separated from the overlying rock mantle as the planet cooled. The core is likely still molten from the fiery birth of Mars, about 4.5 billion years ago.
The only other rocky planetary bodies for which scientists have measured the nucleus are the Earth and the Moon. Adding Mars will allow researchers to compare and contrast how the planets of the world evolved. Solar system. Like Earth, Mars once had a strong magnetic field generated by the liquid stirring its core, but that magnetic field decreased dramatically over time, causing the atmosphere of Mars to escape into space and the surface to turn cold. , sterile and much less hospitable to life than on Earth.
Simon Stähler, a seismologist at the Swiss Federal Institute of Technology in Zurich, reported the core findings in a prerecorded presentation on March 18 for the virtual conference. The work builds on previous InSight findings that detected layers in the Martian crust.
Insight landed on Mars in 2018 and is the first mission to study the interior of the red planet. The stationary lander is near the Martian equator and hears the Mars equivalent of earthquakes. So far, InSight has detected around 500 earthquakes, which means that the planet is less seismically active than Earth but more than the Moon. Most of the earthquakes are very small but almost 50 of them have been of magnitude 2 and 4, strong enough to provide information about the interior of the planet.
Like seismometers on Earth, InSight measures the size of the Martian core by studying seismic waves that bounced off the deep mantle-core boundary. With enough information from these deep-traveling waves, the InSight scientists were able to calculate the depth of the boundary between the core and the mantle, and therefore the size of the core. Seismic data also suggest that the upper mantle, which extends about 700 to 800 kilometers below the surface, it contains an area of thickened material in which seismic energy travels more slowly.
In an effort to replicate conditions within planetary cores, other researchers have squeezed combinations of different chemical elements at high pressures and temperatures. InSight’s estimate of the density of the Martian core agrees with many of those lab-based estimates, says Edgar Steenstra, a geochemist at the Carnegie Institution for Science, cited by Nature.com.