Instruments aboard NASA’s Voyager 1 spacecraft, which nine years ago exited our solar system’s outer reaches, have detected a faint monotonous hum caused by the constant vibrations of the small amounts of gas found in the near-emptiness of interstellar space, scientists said.
It essentially represents the background noise present in the vast expanse between star systems. These vibrations, called persistent plasma waves, were identified at radio frequencies in a narrow bandwidth during a three-year period as Voyager 1 traverses interstellar space.
“The persistent plasma waves that we’ve just discovered are far too weak to actually hear with the human ear. If we could hear it, it would sound like a single steady note, playing constantly but changing very slightly over time,” said Stella Koch Ocker, a Cornell University doctoral student in astronomy and lead author of the study published this week in the journal Nature Astronomy.
The Voyager 1 spacecraft, launched in September 1977, is currently located about 14.1 billion miles (22.7 billion km) from Earth - roughly 152 times the distance between our planet and the sun - and is still obtaining and transmitting data.
Having decades ago visited the huge planets Jupiter and Saturn, Voyager 1 is now providing insight into interstellar space.
Courtesy of NASA, Reuters and JPL