NASA’s InSight lander has ‘heard’ and detected the vibrations of four space rocks as they slammed into Mars over the past two years.
Not only are these the first impacts detected by the spacecraft’s seismometer since InSight touched down on the Red Planet in 2018, it also marks the first time seismic and acoustic waves from an impact have been detected on Mars.
The US space agency has released a recording of one of the Martian meteoroid impacts, with a distinctive ‘bloop’ sound ringing out three times as the space rock enters the atmosphere, explodes into pieces and hits the surface.
The impacts ranged from 53 to 180 miles (85 to 290 kilometres) away from the stationary lander’s position in a region of Mars called Elysium Planitia, a smooth plain that is just north of the planet’s equator.
The first of the four meteoroids – the term used for space rocks before they hit the ground – made the most dramatic entrance.
NASA’s InSight lander has ‘heard’ and detected the vibrations of four space rocks as they slammed into Mars over the past two years (pictured)
Not only are these the first impacts detected by the spacecraft’s seismometer since InSight touched down on the Red Planet in 2018, it also marks the first time seismic and acoustic waves from an impact have been detected on Mars
EXPLAINED: THE DIFFERENCE BETWEEN AN ASTEROID, METEORITE AND OTHER SPACE ROCKS
An asteroid is a large chunk of rock left over from collisions or the early solar system. Most are located between Mars and Jupiter in the Main Belt.
A comet is a rock covered in ice, methane and other compounds. Their orbits take them much further out of the solar system.
A meteor is what astronomers call a flash of light in the atmosphere when debris burns up.
This debris itself is known as a meteoroid. Most are so small they are vapourised in the atmosphere.
If any of this meteoroid makes it to Earth, it is called a meteorite.
Meteors, meteoroids and meteorites normally originate from asteroids and comets.
For example, if Earth passes through the tail of a comet, much of the debris burns up in the atmosphere, forming a meteor shower.
It entered the Red Planet’s atmosphere on September 5, 2021 and exploded into at least three shards that each left a crater behind.
NASA’s Mars Reconnaissance Orbiter then flew over the estimated impact site to confirm the location.
It used its black-and-white Context Camera to reveal three darkened spots on the surface.
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 a new research paper about the discovery and a specialist in Mars impacts.
After combing through earlier data, scientists confirmed three other impacts had occurred on May 27, 2020, February 18, 2021, and August 31, 2021.
Researchers have puzzled over why they haven’t detected more meteoroid impacts on Mars.
The Red Planet is next to the solar system’s main asteroid belt, which provides an ample supply of space rocks to scar the planet’s surface.
As Mars’ atmosphere is just 1 per cent as thick as Earth’s, more meteoroids pass through it without disintegrating.
InSight’s seismometer has already detected over 1,300 marsquakes.
Provided by France’s space agency, the Centre National d’Études Spatiales, the instrument is so sensitive that it can detect seismic waves from thousands of miles away.
But the September 5, 2021, event marks the first time an impact was confirmed as the cause of such waves.
InSight’s team suspects that other impacts may have been obscured by noise from wind or by seasonal changes in the atmosphere.
But now that the distinctive seismic signature of an impact on Mars has been discovered, scientists expect to find more hiding within InSight’s nearly four years of data.
The US space agency has released a recording of one of the Martian meteoroid impacts, with a distinctive ‘bloop’ sound ringing out three times as the space rock enters the atmosphere, explodes into pieces and hits the surface
The impacts ranged from 53 to 180 miles (85 to 290 kilometres) away from the stationary lander’s position in a region of Mars called Elysium Planitia, a smooth plain that is just north of the planet’s equator
Seismic data offers various clues that will help researchers better understand the Red Planet.
Most marsquakes are caused by subsurface rocks cracking from heat and pressure. Studying how the resulting seismic waves change as they move through different material provides scientists a way to study Mars’ crust, mantle, and core.
The four meteoroid impacts confirmed so far produced small quakes with a magnitude of no more than 2.0.
Those smaller quakes provide scientists with only a glimpse into the Martian crust, while seismic signals from larger quakes, like the magnitude 5 event that occurred in May 2022, can also reveal details about the planet’s mantle and core.
But the impacts will be critical to refining Mars’ timeline.
Seismic data offers various clues that will help researchers better understand the Red Planet
‘Impacts are the clocks of the solar system,’ said the paper’s lead author, Raphael Garcia of Institut Supérieur de l’Aéronautique et de l’Espace in Toulouse, France.
‘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.
InSight’s data, in combination with orbital images, can be used to rebuild a meteoroid’s trajectory and the size of its shock wave.
Every meteoroid creates a shock wave as it hits the atmosphere and an explosion as it hits the ground. These events send sound waves through the atmosphere.
The bigger the explosion, the more this sound wave tilts the ground when it reaches InSight.
The lander’s seismometer is sensitive enough to measure how much the ground tilts from such an event and in what direction.
‘We’re learning more about the impact process itself,’ Garcia said. ‘We can match different sizes of craters to specific seismic and acoustic waves now.’
The new paper has been published in the journal Nature Geoscience.
WHAT ARE SOME OF THE KEY FEATURES ON MARS?
The Mars Curiosity rover was initially launched from Cape Canaveral, an American Air Force station in Florida, on November 26, 2011.
In late January, 2018, the Curiosity team on Earth received copious new images from the rover through a record-setting relay by Nasa’s Maven orbiter, surpassing a gigabit of data during a single relay session from Mars for the first time in history.
Nasa’s Jet Propulsion Laboratory in Pasadena, California, released this image as a single panoramic shot, which gives an overview of the rover’s path along the crater’s outer edge.
The image features a number of key features spotted by the rover on its travels. This included:
– Darwin is an impact crater that is around 109 miles (176km) in diameter.
– It was first spotted by an orbiting spacecraft
– Experts believe it could reveal the inner makeup and history of the plains on the floor of Gale Crater.
– It could also provide insight into past flows of water and may provide evidence of whether water played a roll in layering rock in the region.
– This area is Curiosity’s landing site
– It was named after the late author Ray Bradbury who wrote various books about Mars including ‘The Martian Chronicles’.
– The rocks at Yellowknife Bay record an ancient lake and stream deposits
– This area could have offered favourable conditions for microbial life.
– Rocks were exposed around 70 million years ago by the removal of overlying layers due to wind erosion
– The name of this dune field is a tribute to British military engineer Ralph Bagnold (1896 to 1990) who studied how winds move sand particles of dunes on Earth.
– These dunes are actively migrating. They are the first active dunes explored in situ on another planet
– Researchers are hoping it will help us understand modern winds and aeolian processes
– Experts believe intense underground steam explosions created these ‘twin’ craters.
– The larger of the two craters was named Arima after a town on the island of Trinidad and the smaller crater has been left unnamed.
– Both are more than 31 miles (50km) across.
– The smaller crater has several staggered terraces between the upper edge of the crater wall and the floor
– Many nearby smaller impact craters suggest there was subsurface water or ice on the planet in the past