First impact sounds of space rocks on Mars detected by NASA lander

Washington: Four space rocks that collided with Mars in 2020 and 2021 have been identified by NASA's InSight lander as the source of impact sounds. This is the first instance in which seismic and acoustic waves from an impact have been found on Mars.

The impacts, which ranged in distance from InSight's site in the Elysium Planitia region of Mars, from 85 to 290 kilometres, are described in a recent report published in Nature Geoscience.

The most spectacular entry was made by the first of the four verified meteoroids: it impacted Mars' atmosphere on September 5, 2021, exploding into at least three shards that each created a crater in its wake.

Then, NASA's Mars Reconnaissance Orbiter flew over the estimated impact site to confirm the location.

After locating these spots, the orbiter's team used the High-Resolution Imaging Science Experiment camera, or HiRISE, to get a colour close-up of the craters.

"After three years of InSight waiting to detect an impact, those craters looked beautiful," said Ingrid Daubar of Brown University, a co-author of the paper.

After combing through earlier data, scientists confirmed three other impacts had occurred on May 27, 2020, February 18, 2021, and August 31, 2021.

InSight's seismometer has detected over 1,300 marsquakes.

Provided by France's space agency, the instrument is so sensitive that it can detect seismic waves from thousands of miles away.

"But September 5, 2021, event marks the first time an impact was confirmed as the cause of such waves," said NASA.

The sound of a meteoroid striking Mars - created from data recorded by NASA's InSight lander - is like a "bloop" due to a peculiar atmospheric effect.

The four meteoroid impacts confirmed so far produced small quakes with a magnitude of no more than 2.0.

But the impacts will be critical to refining Mars' timeline.

"Impacts are the clocks of the solar system," said the paper's lead author Raphael Garcia. "We need to know the impact rate today to estimate the age of different surfaces."

Scientists can approximate the age of a planet's surface by counting its impact craters: The more they see, the older the surface.

With inputs from IANS