Now 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!

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Mars from the InSight Out (Eos)