Seismic waves from quakes detected by NASA’s robotic InSight lander have helped scientists decipher the anatomy of Mars, including the first estimates of the size of its large liquid metal core, the thickness of its crust, and nature of its mantle. The findings disclosed on Thursday shed light on what had been a poorly understood internal structure of Earth’s smaller neighbour and provided a few surprises as well as confirmation that the Red Planet’s center is molten.
The InSight lander, which touched down in 2018 to begin the first mission to study the deep interior of Mars, has detected more than 700 marsquakes, most of the modest strength.
Waves generated by quakes vary in speed and shape when journeying through different material inside a planet. Data from InSight’s seismometer instrument covering about three dozen marsquakes enabled the contours of the planet’s interior to come into focus.
“The real importance of these findings is that, for the first time, we actually have measurements of dimensions - sizes - of the fundamental building blocks of the planet Mars," said planetary geophysicist Bruce Banerdt of NASA’s Jet Propulsion Laboratory, the InSight mission’s principal investigator.
InSight has been on the Red Planet since 2018 and during the tremors experienced, the lander measured the seismic waves created. First, the ones near the surface and travelling in a relatively straight line from the origin to the lander. Next, those that bounce around within the planet before reaching the detectors. With these, it creates a seismogram of the quake activity.
The data suggests most of these waves bounce off between the core and the mantle. Using the time it took for them to bounce after the first surface tremors and direction, the team earlier calculated Mars’s core must have a radius of about 1810 to 1860 kilometres. Simon Stähler at the Swiss Federal Institute of Technology in Zurich led this study and presented the result at the virtual Lunar and Planetary Science Conference.
(With Reuters inputs)
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