NASA’s InSight lander has revealed that Mars is hit by more meteorites than previously thought. A new study suggests that around 300 basketball-sized meteorites strike Mars’ surface every year. This is five times higher than estimates from a decade ago that were based on satellite images.
The findings come from data collected by InSight’s onboard seismometer, SEIS. The instrument recorded about 1,300 marsquakes during its four-year mission. Researchers found that 70 of these quakes, called “very high-frequency” events, were likely caused by meteorite impacts.
By studying the properties of these signals, the team predicts that between 280 and 360 meteorites land on Mars each year, leaving craters bigger than 26 feet (8 meters) wide. However, many of these craters have never been spotted by orbiting satellites.
Mars experiences frequent meteorite impacts
Lead author Natalia Wójcicka says, “There isn’t a place on Mars that is more likely to be hit than any other place.” She adds that these findings could help future missions to Mars choose safe landing spots and base camps. The study suggests that scientists miss many craters by just looking at Mars’ surface because they don’t image the entire planet all the time. Wójcicka says, “We almost didn’t believe it.”
In a companion study, a different team discovered eight large impact craters on Mars that were not previously seen by satellites.
Six were near InSight’s landing site, and two were among the largest ever spotted. This suggests that Mars is being hit much more often than can be seen with imaging alone. Better understanding impact rates can help scientists fine-tune their estimates of how old the Martian surface is.
If the impact rate is different than thought, it may require rethinking some models used to determine 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 what happened on Mars, scientists can better understand the history of our own planet.
