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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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