NASA lander makes first direct observations of another planet's core
The mission may be defunct, but NASA’s InSight Mars lander is still uncovering new things about the Red Planet. Scientists poring over data have now made the first direct observations of another planet’s core, finding that it’s not quite what we thought.
The InSight lander was sent to Mars to study the planet’s interior, mostly by way of marsquakes. As you may have guessed, these are seismic tremors similar to earthquakes on our home planet, but because Mars doesn’t have plate tectonics they’re generally much weaker. Nevertheless, they can provide some clear insights into the structure and composition of the different layers below the red surface. Contact with the probe was lost in December 2022, but there’s still much to be gleaned from the data it gathered during its tenure.
In the new study, NASA scientists have made direct observations of the Red Planet’s core, thanks to a pair of quakes that occurred on August 25 and September 18, 2021. These were the first events detected from the opposite side of the planet, meaning their seismic waves had to travel farther to reach the detector, passing through the core on the way.
Seismic waves travel at different speeds through different materials and structures, and the variations in the data that eventually reach the detector can carry an imprint of the whole journey. This can tell scientists a lot about the interior of a planet.
In this case, the detections allowed the team to deduce that the Martian core is smaller and denser than previously thought. And while it’s mostly made of liquid iron, about one fifth consists of elements like sulfur, oxygen, carbon and hydrogen.
“Determining the amount of these elements in a planetary core is important for understanding the conditions in our solar system when planets were forming and how these conditions affected the planets that formed,” said Doyeon Kim, co-author of the study.
InSight may have finished gathering data, but the existing data will likely continue to fuel new discoveries for decades, the team says.
The research was published in the journal Proceedings of the National Academy of Sciences.