Comet 67P, currently the home of the European space probe Philae. Comet 67P/Churyumov-Gerasimenko, to give it its full name, is a rubber duck-shaped celestial body more than four billion years old. Earlier this week, a European Space Agency probe called Philae ended its aeons of isolation by making a historic, if slightly awkward, landing.

The mission has already contributed greatly to our understanding of comets – and one discovery is of great interest to music lovers: scientists have revealed that the comet has been singing for four billion years. John Cage’s 640-year-long Organ²/ASLSP doesn’t come close.

So, how does a comet vocalise? Oscillations in the magnetic field of Comet 67P are creating a sound at a wavelength of around 40-50 millihertz, far below the range of human hearing. ESA scientists have increased the frequency by a factor of 10,000 in order to hear the song.

Karl-Heinz Glaßmeier, head of Space Physics and Space Sensorics at the Technische Universität Braunschweig, Germany, says they are still trying to work out what is happening, but adds: “This is exciting because it is completely new to us.”

That’s interesting, because after playing it in Classic FM towers, it didn’t sound particularly new to us . Have a listen to the comet below – and then listen to Continuum for Harpsichord by 20th-century Hungarian composer Gyorgy Ligeti. In fact, why not go ahead and play both at the same time?