The Rosetta spacecraft and its Philae lander have a lot to teach scientists about what Comet 67P/Churyumov-Gerasimenko looks like, is composed of, and even what it smells like, but what does the comet sound like? The day before Philae made history by landing on the surface of the comet, ESA released an audio clip of 67P/C-G singing. Unfortunately, its song is creepy as hell and sounds a lot like Predator, the alien that tried to kill Arnold Schwarzenegger.
Of course, sound waves can’t travel through space, so it isn’t a direct audio recording. Instead, Rosetta’s Plasma Consortium (RPC) picked up variations in the magnetic field around the comet, due to interactions between 67P/C-G’s coma and the plasma from the Sun, better known as solar wind. These variations resulted in frequencies between 40 to 50 millihertz, about 10,000 times lower than can be detected by humans. ESA scientists altered the frequency of the comet’s song into human hearing range, and discovered it was a series of clicks that are very reminiscent of Predator’s growl.
RPC scientists first picked up on these fluctuations in August as Rosetta approached the comet, but it isn’t entirely clear what is causing them.
“This is exciting because it is completely new to us. We did not expect this and we are still working to understand the physics of what is happening,” RPC principal investigator Karl-Heinz Glaßmeier said in a press release.
For now, the team’s best guess is that neutral material that is shedding off of the comet is becoming ionized, or charged, by the solar wind. As of right now, the mechanism that would accomplish that task is not known.
For a comparison, click here to listen to Predator’s clicking growl.
[Hat tip: CNET]