Mars' Dense Liquid Metal Core Evident Through Marsquakes and Meteorite Impacts

It turns out that Mars does indeed have a heavy heart.

Research has revealed that the Red Planet has a dense core of liquid iron encased in a comparatively thin layer of molten rock. This discovery solves a puzzling uncertainty that arose when seismic measurements on Mars implied the planet had an unexpectedly large, lightweight core abundant in low-density elements.

As described in two studies published in the Oct. 26 edition of Nature, the fresh perspective illustrates that Mars comprises elements typically found in the solar system at the time of the planet's formation. A lighter core would necessitate a compilation of elements with a ratio that's inconsistent with the dust and debris that ultimately formed the solar system.

By analysing seismic waves detected via NASA’s InSight lander, researchers were able to infer the structure of Mars' interior. The InSight lander recorded Marsquakes and vibrations from meteorite collisions on the planet for slightly over a four-year period.

Initial interpretation of waves reflecting from the molten rock layer suggested they bounced off the exterior of a core with a radius approximating 1,800 kilometers boasting a density of 6,200 kilograms per cubic meter. However, the recent research incorporated data from seismic waves that penetrate that molten layer to expose the planet's true core.

The core's radius is estimated to be about 10 percent smaller and its density greater than was previously reported. One study group determined a core density of 6,650 kilograms per cubic meter, while the other calculated 6,500 kilograms per cubic meter.

A more comprehensive understanding of Mars can impart significant insights beyond that of the Red Planet. Planetary scientist Henri Samuel of CNRS in Paris is a coauthor of one of the recent studies. He emphasizes that Mars and Earth were remarkably similar at their inception. However, these two planets ultimately developed differences. Mars currently is inhospitable, whereas Earth supports life. As such, comprehending this divergence can provide substantial knowledge about our very own planet.

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