Despite the fact that nearly a year has passed by since the Cassini spacecraft was self-destructed as it dived into Saturn, the data it compiled during its final months of mission continues to reveal surprise after surprise.
Now, astronomers going through the massive amount of data gathered by Cassini gave found a new and hitherto unknown interaction between Saturn and its moon Enceladus: a “river” of plasma waves moving between the two bodies that researchers have turned into sound.
Listening to the inaudible
As the Cassini spacecraft was approaching the ringed giant, and before it was to be devoured by the planets stormy atmosphere forever, scientists took advantage of its proximity to Saturn to take readings that would not have been possible at greater distances.
And it was during one of the closest approaches, just two weeks before the crafts last and final dive, when they used the Radio Plasma Wave Science (RPWS) instrument to capture the sounds of the plasma waves continually as they travel between Saturn and Enceladus, further demonstrating for the first time that these waves travel along the magnetic field lines connecting the two worlds.
Sulaiman is the lead author of a pair of papers describing the findings, published recently in Geophysical Research Letters.
Of course, as we already know by now, there isn’t really any sound in space, since it consists of a vibration that needs a medium (like air) to spread and when it reaches our eardrums it is perceived as sound. But in space, there is no air, so these vibrations cannot be propagated.
But. There’s always that but. Radio waves are not sound, but a form of electromagnetic radiation, like light, that is created through electric and magnetic fields that, yes, propagate and can travel freely through space.
And it turns out that we are capable of converting those radio waves into audible sounds, using the same technology that we use to communicate here on Earth.
The plasma waves in the frequency range of the audible are also electromagnetic, and that is precisely what the RPWS instrument of the Cassini probe picked up.
Then, on Earth, the scientists converted those signals into audio, and accelerated the result, compressing the original 16 minutes to 28.5 seconds of the following recording: