For the first time, scientists have mapped the deep innards of Mars.

Behold, the interior of Mars. (Image credit: Chris Bickel/Science)

The core of Mars occupies nearly half of the planet's interior, which is far greater than scientists had anticipated.

Mars unveils its inner mysteries in the first-ever map of an extraterrestrial planet's innards, unveiled as part of three new research published July 22 in the journal Science, like a bruised peach cut apart to reveal an enormous yellow pit.

This first view at the Martian interior is the result of two years of investigation (and decades of planning) by NASA's InSight lander, a stationary science robot that was launched to Mars in 2018 with the primary aim of investigating the planet's undiscovered interiors. InSight used its robotic arm to instal a tiny seismometer on the surrounding Martian surface about a month after landing on the flat, smooth plain known as Elysium Planitia, and began listening for marsquakes – seismic oscillations within the planet that are similar to earthquakes on Earth.

Mars, unlike Earth, lacks tectonic plates, and its crust resembles one huge plate, according to NASA researchers. Faults, or rock cracks, do emerge in the Martian crust as a result of stresses induced by the planet's minor shrinkage as it cools.

These fractures can cause seismic waves, and InSight has discovered 733 of them in the last two years. NASA researchers determined how quickly and how far seismic waves travelled through the planet using 35 of the greatest marsquakes (each registering between magnitude 3.0 and 4.0), allowing them to map the planet's core architecture.

The scientists discovered that the interior of Mars, like Earth's, is made up of three layers: a crust, mantle, and core, although the sizes and compositions of these layers differ significantly. The Martian crust, for example, is far thinner than scientists thought, measuring between 12 and 23 miles (20 to 37 kilometres) deep and comprising two or three sub-layers (the Earth's crust, by comparison, extends to a maximum depth of around 62 miles, or 100 kilometres).

A large mantle extends 969 miles (1,560 kilometres) beneath the Martian surface, followed by a massive core that begins roughly midway between the surface and the planet's centre. The molten core, like Earth's outer core, was larger and more liquid than the scientists had anticipated.

Scientists are still unsure whether Mars has a solid inner core like Earth, but the researchers believe that simply measuring the planet's outer core after only a few years of investigation is a tremendous achievement.

According to Simon Stähler, principal author of one of the new articles and professor of Earth sciences at the Swiss research institution ETH Zurich, measuring Earth's core required hundreds of years. It took 40 years to measure the moon's core after the Apollo flights. InSight took only two years to measure the core of Mars.

Originally published by Live science.


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