Listen: Meteoroids Make Tiny ‘Bloop’ Sounds When They Hit Mars

If a meteoroid crashes on a planet and no one is around to hear it, does it make a sound? If NASA’s Mars InSight lander is nearby, it may be able to pick it up. The spacecraft has detected the seismic waves from four space rocks that crashed on Mars in 2020 and 2021. These are the first impacts detected by InSight’s seismometer since it landed on Mars in November 2018, and the first time seismic and acoustic waves from an impact have been observed. detected on the Red Planet.

An article published in the magazine this week Natural Geosciences details the impacts on Mars, which ranged between 53 and 180 miles from InSight’s location. InSight is located in an area of ​​Mars called Elysium Planitia, a smooth flat land just north of the planet’s equator.

The first of four confirmed meteoroids (a space rock before it hits the ground) made the most dramatic entrance, according to NASA. It entered the Martian atmosphere just over a year ago on September 5, 2021 and exploded into at least three shards, each leaving a crater.

[Related: NASA’s new Mars lander is in for ‘seven minutes of terror’ on Monday.]

To confirm the location, NASA’s Mars Reconnaissance Orbiter flew over the estimated impact site and used its black-and-white Context Camera to reveal three dark spots on the surface. After locating these impact points, the orbiter’s team used the High-Resolution Imaging Science Experiment camera (HiRISE) to capture a full-color close-up of the craters. While it’s possible the meteoroid left additional craters on the planet’s surface, they would be too small to see in the images taken by HiRISE.

NASA has released an image of the Mars meteoroid making an impact, where Star Wars-like “bloop” sounds are heard three times as the meteoroid enters the atmosphere, explodes into pieces and hits the surface.

“After three years of waiting InSight to detect an impact, those craters looked beautiful,” Brown University’s Ingrid Daubar, a co-author of the paper and an impact specialist on Mars, said in a press release. The team confirmed that three other effects had occurred. One on May 27, 2020 and two others on February 18 and August 31, 2021.

A collage of three other meteoroid impacts detected by NASA’s InSight Lander’s seismometer and captured by the HiRISE camera on the Mars Reconnaissance Orbiter. CREDIT: NASA/JPL-Caltech/University of Arizona.

Mars is right next to our solar system’s main asteroid belt, leading researchers to wonder why they haven’t discovered more of these meteoroid impacts on the Red Planet. More meteoroids pass through Mars’ atmosphere without disintegrating, as it is only about one percent as thick as Earth’s.

InSight’s seismometer, provided by the French space agency Center National d’Études Spatiales (CNES), has detected more than 1,300 Marsquakes. CNES is one of a number of European partners providing support to the InSight mission, including it and the German Aerospace Center (DLR).

The seismometer is so sensitive that it can detect seismic waves thousands of kilometers away. The dramatic meteoroid that hit Mars in September 2021 marks the first time an impact has been confirmed as the cause of the seismic waves. The InSight team suspects that sound from wind or seasonal changes in the Martian atmosphere may have obscured the sound of other impacts. Scientists expect to find more in InSight’s nearly four years of data after the seismic signature of an impact on the Red Planet has been discovered.

[Related: NASA has officially detected ‘marsquakes’ on the Red Planet.]

Scientists are looking to seismic data from Mars for clues that will help them better understand the planet. Most Marsquakes are caused by underground rocks bursting from heat and pressure, and by studying how the resulting seismic waves change as they move through other material, scientists can study the crust, mantle and core of Mars. The four confirmed meteoroid impacts caused small earthquakes (no more than a magnitude of 2.0). Those smaller earthquakes give scientists a glimpse into Mars’ crust. However, the seismic signals from larger earthquakes (a magnitude 5 event occurred in May 2022) can tell scientists more about Mars’ mantle and core.

These impact events will also be critical in refining the timeline and history of Mars. “Impacts are the clocks of the solar system,” French lead author Raphael Garcia of the Higher Institute of Aeronautics and Space in Toulouse said in a statement. “We need to know today’s impact velocity to estimate the age of various surfaces.”

The data from InSight will help researchers analyze the trajectory and magnitude of the shock wave produced when the meteoroid enters the atmosphere and once it hits the ground. “We’re learning more about the impact process itself,” Garcia said. “We can now tune craters of different sizes to specific seismic and acoustic waves.”

The lander’s mission is quickly coming to a close, as dust buildup on its solar panels reduces its power, eventually leading to the spacecraft’s shutdown. According to NASA, it’s difficult to predict exactly when it will shut down, but based on the latest power measurements, engineers think the InSight lander could shut down between October 2022 and January 2023.