How NASA's Voyager 1 Probe Recorded Sounds of Interstellar Space (Video)

Artist Concept Depicting NASA's Voyager 1
This artist's concept depicts NASA's Voyager 1 spacecraft entering interstellar space, or the space between stars. (Image credit: NASA/JPL-Caltech)

Beyond the border of interstellar space, the distant Voyager 1 spacecraft called back to Earth earlier this year with noises from its new environment. It's true that the void of space does not carry sound — there's no gas or other substance to transmit the waves — but the signal Voyager detected can be played back at frequencies the human ear can understand.

NASA announced in September that Voyager 1 had left the heliosphere in August 2012.  The heliosphere is a sheath of magnetic influence that emanates from the sun and expands through a stream of charged particles called the solar wind.

At the press conference, Don Gurnett, the principal investigator for Voyager 1's plasma wave science instrument, demonstrated a series of sounds the instrument had picked up.

"Strictly speaking, the plasma wave instrument does not detect sound. Instead, it senses waves of electrons in the ionized gas or 'plasma' that Voyager travels through," NASA stated in a statement. These waves, however, do take place at frequencies that humans can detect.

"We can play the data through a loudspeaker and listen," Gurnett, a physics professor at the University of Iowa, said in the statement. "The pitch and frequency tell us about the density of gas surrounding the spacecraft." [Hear What Voyager 1 Detected]

Within the heliosphere, the sounds had a frequency of about 300 Hz. Once Voyager left the scene, the frequency jumped higher, to between 2 and 3 kHz, "corresponding to denser gas in the interstellar medium," according to the NASA release.

This image is a visual representation of the sound of interstellar space recorded by NASA's Voyager 1 probe, which entered interstellar space in 2012. (Image credit: NASA)

There have been at least two verified instances of these tones: October to November 2012, and April to May 2013. Both occurred after huge coronal mass ejections (material from the sun) bumped up plasma activity around Voyager 1. There was a lag before scientists discovered the recordings because the data is only played back every three to six months, NASA said, and more time is required to interpret the results.

Gurnett further speculated that  "shock fronts" from beyond the solar system could be tearing through interstellar space and disturbing the plasma surrounding Voyager 1. He will be listening for any evidence of this activity in future recordings from humanity's furthest spacecraft, he said.

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Elizabeth Howell
Staff Writer, Spaceflight

Elizabeth Howell (she/her), Ph.D., is a staff writer in the spaceflight channel since 2022 covering diversity, education and gaming as well. She was contributing writer for for 10 years before joining full-time. Elizabeth's reporting includes multiple exclusives with the White House and Office of the Vice-President of the United States, an exclusive conversation with aspiring space tourist (and NSYNC bassist) Lance Bass, speaking several times with the International Space Station, witnessing five human spaceflight launches on two continents, flying parabolic, working inside a spacesuit, and participating in a simulated Mars mission. Her latest book, "Why Am I Taller?", is co-written with astronaut Dave Williams. Elizabeth holds a Ph.D. and M.Sc. in Space Studies from the University of North Dakota, a Bachelor of Journalism from Canada's Carleton University and a Bachelor of History from Canada's Athabasca University. Elizabeth is also a post-secondary instructor in communications and science at several institutions since 2015; her experience includes developing and teaching an astronomy course at Canada's Algonquin College (with Indigenous content as well) to more than 1,000 students since 2020. Elizabeth first got interested in space after watching the movie Apollo 13 in 1996, and still wants to be an astronaut someday. Mastodon: