Earlier this week, the European Space Agency’s Philae lander successfully touched down on Comet 67P. And now, it seems, the comet is serenading us, and it’s awesome.
Ok, that’s only sort of what’s happening.
Among the instruments on the Rosetta spacecraft is the Rosetta Plasma Consortium (RPC). The RPC actually consists of five instruments on the spacecraft that gather a variety of information about the plasma environment surrounding Comet 67P.
Plasma is an electrically conductive gas that supports magnetic fields and can carry electric currents, which RPC is specifically designed to measure in the environment around Comet 67P as it interacts with plasma emitted from the Sun and with the comet’s tenuous atmosphere (properly known as a “coma”). It’s also designed to measure the physical properties of the comet’s surface and nucleus.
In measuring the plasma around Comet 67P, RPC has picked up on oscillations in the magnetic field in the comet’s environment. These oscillations are at the 40-50 millihertz level, which is well below human hearing range, but scientists have increased the frequency by a factor of 10,000 so we can hear these oscillations as sound.
What emerges is a song from the comet.
Mission scientists aren’t entirely sure what’s producing these oscillations but suspect it’s rooted in an active process by the comet. As it releases neutral particles into space, they interact with that plasma environment and become electrically charged or ionized. But that still doesn’t explain the physical mechanism behind the oscillations.
This kind of comet song isn’t something we’ve ever really seen (or heard, rather) before. And it’s one of the things that’s so exciting about Rosetta’s mission. We have this incredible chance to study a different kind of celestial body up close and personal. And to hear it sing.
Feature image via ESA