NASA’s InSight lander has revealed that Mars is hit by more meteorites than previously thought. The lander’s seismometer, called SEIS, detected seismic waves from meteorite impacts on the Red Planet’s surface. Researchers analyzed the data and found that SEIS recorded about 1,300 marsquakes during its four-year mission.
Among these were 70 “very high-frequency” events, which were likely caused by meteorite strikes. By studying the properties of these signals, scientists predict that between 280 and 360 basketball-sized meteorites land on Mars each year. These impacts leave behind craters bigger than 26 feet (8 meters) in diameter.
This new impact rate is five times higher than estimates from a decade ago, which were based on satellite images. The findings suggest that many craters are missed when only looking at the planet’s surface. “We were certainly very excited,” says study lead author Natalia Wójcicka of Imperial College London.
Meteorite impacts on Mars unveiled
“We almost didn’t believe it.”
Satellites don’t capture all of Mars all the time, making it difficult to associate craters with the events InSight heard. Smaller craters are also harder to spot in images.
Another team of scientists recently found eight football field-sized impact craters on Mars that were not previously seen by satellites. This further indicates that the planet is hit more frequently than can be detected through imaging alone. Understanding impact rates helps scientists determine the age of planetary surfaces.
Higher impact rates mean less time is needed to accumulate the same number of craters. If the impact rate on Mars is different than previously thought, it may require rethinking some models used to estimate the age of surfaces throughout the solar system. The findings are important for understanding our solar system, the population of impacting bodies, and the hazards they pose to Earth and other planets.
By studying Mars, scientists can better understand the history of our own planet.
