Singing Comet 67p is a mystery to the scientists of the Rosetta mission who successfully landed the Philae probe on the comet's surface yesterday. The comet is emitting a strange "song" into space, which was first detected by instruments on the Rosetta orbiter several months ago.
The comet is emitting the sound in the form of oscillations in the magnetic field in the comet's environment. The sounds are at the frequency of 40-50 millihertz, a level that is far below the frequency audible to humans. Humans can typically hear sound between 20Hz and 20 kHz.
The music was detected by a magnetometer experiment (RPC-Mag). To make the music audible to the human ear, the frequencies had to be increased by a factor of about 10,000.
German composer Manuel Senfft took the RPC-Mag data and turned it into sound that is audible to human ears.
According to the Rosetta blog, scientists think the sound is being produced in some way by the comet's activity, as it releases neutral particles into space where they become electrically charged through a process called ionization. But scientists are still mystified as to the physical process behind the oscillations.
RPC principal investigator Karl-Heinz Glassmeier said "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."
The Philae probe made history yesterday when it became the first unmanned space probe ever to land on a comet. The probe has begun transmitting photos taken from the comet's surface. The first photo showed that the Philae had landed in the shadow of a cliff, which will make it difficult for the probe to charge its battery systems, necessary for the probe to continue its mission.
