Voyager 1 spacecraft detects deep-space 'hum'
TORONTO -- Launched 44 years ago, NASA’s Voyager 1 spacecraft is now the most distant human-made object in space – and it has sent back some new findings from past the edge of our solar system.
Travelling at approximately 61,152 kilometres per hour, Voyager 1 flew by Jupiter in 1979, then Saturn in late 1980, and has now crossed through the heliopause, the solar system’s border with interstellar space, also called the interstellar medium.
A new study led by Cornell University and published in the journal Nature Astronomy details how Voyager 1’s instruments have detected the “constant drone of interstellar gas” or plasma waves, according to a release.
The data, sent back from more than 22.5 billion kilometres away, allowed researchers to uncover the “hum.”
“It’s very faint and monotone, because it is in a narrow frequency bandwidth,” said Cornell doctorate astronomy student Stella Koch Ocker in a press release that accompanied the study. “We’re detecting the faint, persistent hum of interstellar gas.”
Voyager 1’s data allows researchers to understand how the interstellar medium interacts with solar wind, and how the protective bubble of our solar system’s heliosphere is shaped and modified by its deep space environment, the release said.
After entering interstellar space, Voyager 1’s “plasma wave system” detected disruptions in the gas, but in-between those – which are caused by the sun – researchers were able to uncover a steady, persistent sound produced by “the tenuous near-vacuum of space.”
"The interstellar medium is like a quiet or gentle rain," said senior author James Cordes, the George Feldstein Professor of Astronomy. "In the case of a solar outburst, it's like detecting a lightning burst in a thunderstorm and then it's back to a gentle rain."
Ocker believes there is more low-level activity in the interstellar gas than previously thought, and the new data will allow researchers to track the spatial distribution of the plasma Voyager 1 travels through.