InSight Mission Captures Impacts, Offers New Knowledge of Planet’s Structure and Formation
Photo by NASA/JPL-Caltech/University of Arizona
Although it was billions of years ago that massive asteroids bombarded the rocky planets of the inner solar system, an international team of researchers with NASA’s InSight mission that includes a University of Maryland geologist today showed how the face of Mars continues to change.
Using data from a seismometer and visuals acquired from the Mars Reconnaissance Orbiter, the team located four new craters created by impacts on the planet’s surface over 16 months in 2020 and 2021— the first time researchers have been able to listen to impacts on Mars. The discoveries were published in the journal Nature Geoscience.
Meteoroids and other projectiles in space change the atmosphere and surface of a planet through impact, said UMD geology Associate Professor Nicholas Schmerr, a co-author of the paper.
“We’ve seen this on Earth, where these objects can hurtle through the atmosphere, hit the ground and leave behind a crater,” he said. “But before this, we’ve never been able to capture the dynamics of an impact on Mars, where there’s a much thinner atmosphere.”
As space projectiles enter the planetary atmosphere and impact the ground, the projectiles trigger acoustic (i.e., sound) waves that travel through fluid or gas, and seismic waves that travel through the ground or another solid medium.
Schmerr and his InSight colleagues used these waves, measured by the SEIS (Seismic Experiment for Interior Structure) instrument on InSight, to estimate the approximate locations of resulting impact sites, observing the unique physics that dictated the projectiles’ movements. The team then matched their approximations to visuals of craters ranging from a few feet to almost 19 feet in diameter provided by high-resolution cameras, confirming the sites and accuracy of the team’s modeling.
These findings demonstrate how planetary seismology can be used to identify sources of seismic activity—whether quakes, volcanoes or meteorite strikes. According to Schmerr, this ability may help researchers measure how often new impacts occur throughout the inner solar system—an observation essential to understanding the population of near-Earth objects like asteroids or rock fragments that may pose a danger to Earth.
Geophysicists like Schmerr anticipate that new advances in planetary seismology will allow them to better investigate underlying tectonic activities and other sources of seismic activity within Mars. The findings ultimately bring researchers another step closer to understanding planetary formation and evolution.
“Studying how impacts work on Mars is like opening a window into the fundamental processes of how terrestrial planets form,” Schmerr said.
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