NASA’s Marsquake Recording Joins the Soundtrack of the Cosmos
Space is far from silent, and we can learn a lot if we know how to listen
Like many other planets in the solar system, Mars was once very geologically active. It had massive volcanoes and rivers and lakes of water. It may also have experienced internal quakes — marsquakes.
When NASA’s InSight lander touched base on Mars in November 2018, the spacecraft brought with it a suite of instruments to study the interior of the planet. One of these instruments is an extremely sensitive and custom-made seismometer called SEIS, which is used on Mars to detect any marsquakes taking place deep in the planet’s interior. Last week, NASA announced that the InSight team caught the first marsquake ever detected. The agency also released audio of the marsquake along with the announcement, following common practice for seismologists studying quakes here on Earth.
“Turning seismic signals into sound is just a different way of appreciating the seismic waveforms,” says Mark Panning, a seismologist on the InSight team at NASA’s Jet Propulsion Laboratory. “Basically it comes down to speeding up the signals we’re already recording into the audible frequency range.”
We might imagine space as largely silent, but historically, recordings from space have led to valuable insights about the cosmos.
While this first marsquake was too small to tell scientists much about the internal workings of the planet, the hope is that future recordings will help scientists break down the nuances in the movements. And the more often they detect active quakes, the more they’ll learn about what exactly is happening inside Mars.
We might imagine space as largely silent — the place where no one can hear you scream — but historically, recordings from space have led to valuable insights about the cosmos. These eerie soundtracks are held in a mini online NASA library called — really — Spooky Sounds from Across the Solar System. One of the most famous is a clip from the Voyager spacecraft. This is the sound of the plasma (hot ionized gases) detected by Voyager’s plasma instrument. As Voyager traveled far beyond Neptune and into the interstellar medium, the changes registered by its plasma instrument were relayed back to Earth. By converting the radio signal into an audible frequency, humans can hear what that environment is like for Voyager.
While we tend to think the black void between planetary objects is empty, it isn’t — not fully. “Plasmas streaming away from the sun pervade interplanetary space,” says Ali Sulaiman, a science team member for the Cassini mission to Saturn. “Like air or water, plasmas are capable of supporting waves which carry information over large distances in space. We convert the data of such observations to the audible range to emphasize that interplanetary space is far from ‘nothingness.’”
The aim, says Sulaiman, is to bring the public “as close as possible to what it would be like if they were able to perceive such phenomena.”
During the 13 years the Cassini spacecraft was in orbit around Saturn, it collected massive amounts of radio and scientific data. One surprising finding was the sound of the electromagnetic waves moving between Saturn and its icy moon Enceladus. Scientists knew that these two bodies interacted, but by collecting the magnetic field data and converting it to sound, they realized that Saturn was actually responding to Enceladus via magnetic field lines.
When NASA’s Juno spacecraft entered Jupiter’s magnetosphere, it collected sound information from its environment. Even stranger was the encounter of NASA’s Galileo spacecraft with Jupiter’s famous icy moon, Ganymede. It’s Jupiter’s largest moon and also the largest moon in the solar system. Because Ganymede is so massive, it has its own environment and magnetic field, and as a result, caused changes in Galileo’s instruments during the first flyby. When those changes were converted to audio, it famously sounded like a horror movie soundtrack. Those sounds also told scientists a lot about the environment of Ganymede, including its magnetic fields and solar winds.
The sound waves InSight will collect going forward will reveal critical information about the Martian environment. “Our whole mission is to record ground motions,” says Panning. “By converting them into audible frequencies, we get a different perspective.” We are used to photos and even video teaching us about space, but the sounds of the cosmos can no longer be denied their place in the library of useful information.