NASA’s InSight Maps Mars’ Interior

NASA’s InSight lander detects over 700 marsquakes, and scientists used the data to put together a map of the red planet’s interior layers.

Beth Johnson

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IMAGE: A hardworking seismometer has helped scientists reveal the interior structure of Mars in more detail than ever before. CREDIT: Mary Heinrichs, AGU

Let’s talk about our favorite lander that works despite Mars’ attempts to prevent it from doing so: NASA’s InSight. This can-do lander has managed to insulate its seismometer and clear dust off its solar panels, and while the probe into the surface may not have worked, it’s pretty amazing what else the lander’s team has accomplished.

So far, that seismometer has detected over 700 marsquakes, and just as we use earthquakes here on Earth to understand the inner structure of our planet, scientists are doing the same with all those marsquakes. When a quake happens, the seismic waves travel from the hypocenter or focus where the rocks actually moved to the surface. Those waves also reflect and bend through the interior of the planet depending on the composition, and by monitoring for the different types of waveforms, we can determine the composition of the different layers and even how thick they are. As scientist Amir Khan explains: What we’re looking for is an echo. We’re detecting a direct sound — the quake — and then listening for an echo off a reflector deep underground.

With all these various quakes, scientists have determined that Mars has a crust that is thicker than Earth’s, relative to the size of the planet, and under that crust is a more fluid mantle, and below that is a liquid metal core. All in all, the red planet is similar to our own pale blue dot but smaller, and that’s kind of reassuring to me. I like knowing our rocky worlds follow a pattern. Next up, Venus!

More Information

Mars from the InSight Out (Eos)

This story was written for the Daily Space podcast/YouTube series. Want more news from myself, Dr. Pamela Gay, and Erik Madaus? Check out DailySpace.org.

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Beth Johnson

Planetary scientist, podcast host. Communication specialist for SETI Institute and Planetary Science Institute. Buy me a coffee: https://ko-fi.com/planetarypan