On the eve of the planned first landing on comet 67P/Churyumov-Gerasimenko, the European Space Agency (ESA) announced that the unmanned Rosetta orbiter carrying the Philae lander has recorded a "song" emanating from the comet. The electromagnetic melody was detected by the probe’s Rosetta Plasma Consortium, which is a suite of five instruments used to study 67P.

The Rosetta Plasma Consortium is designed to measure the characteristics of the cloud of ionized plasma that surrounds 67P due to the interaction of the solar wind with the gases emanating from the comet. One of these instruments is a fluxgate magnetometer carried on a 1.5 m (5 ft) boom extending from the orbiter.

According to ESA, the oddly syncopated song was first heard in August when the probe came within 100 km (62 mi) of the the comet, and reappeared during recent maneuvers to bring Rosetta into position to release the Philae lander.

Aside from being a radio signal in the vacuum of space, ESA says that the comet song cannot be heard by the human ear because it broadcasts at 40 to 50 millihertz, which is outside the range of human hearing. However, ESA scientists have been able to make this music of the spheres audible by boosting its frequencies by a factor of 10,000.

Exactly what produces the song remains a mystery, but scientists believe it may have something to do with 67P’s magnetic field – possibly due to neutral particles becoming electrically charged as they’re exposed to the solar wind. Space sirens can probably be ruled out.

You can listen to the comet's "song" using the controls below.

Source: JPL