comet noise plasma

Comet 67P ‘singing’ in an Electric Universe?

comet noise plasmaComet 67P is emitting a surprising sound that appears to involve the plasma around it.

RPC consists of five instruments on the Rosetta orbiter that provide a wide variety of complementary information about the plasma environment surrounding Comet 67P/C-G. (Reminder: Plasma is the fourth state of matter, an electrically conductive gas that can carry magnetic fields and electrical currents.)

But one observation has taken the RPC scientists somewhat by surprise. The comet seems to be emitting a ‘song’ in the form of oscillations in the magnetic field in the comet’s environment. It is being sung at 40-50 millihertz, far below human hearing, which typically picks up sound between 20 Hz and 20 kHz.

The scientists think it must be produced in some way by the activity of the comet, as it releases neutral particles into space where they become electrically charged due to a process called ionisation. But the precise physical mechanism behind the oscillations remains a mystery.

“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,” says Karl-Heinz.
The singing comet

Links:
The Rosetta comet is singing: as the orbiter approaches, the ESA uploads audio of the comet’s warbling magnetic ‘song’
Listen to Rosetta’s comet ‘sing’: Scientists baffled by mysterious sounds recorded near 67P ahead of Philae landing
The singing comet