Science
This is the first step towards all sorts of plans we have for comets, such as one day mining them for minerals and water.
The particular people involved were from the European Space Agency. The probe is known as the Philae lander and we gave the comet the lovely name 67P/Churyumov-Gerasimenko.
It turns out, the comet speaks, or sings, as the scientists discovered. That's probably a generous term for it. Human ears can't actually hear its noises.
Sounds come from "oscillations in the magnetic field in the comet's environment," as the Rosetta's Plasma Consortium (RPC) describes it. Such oscillations emit sound in the 40-50 millihertz range, which the RPC explains is "far below human hearing, which typically picks up sound between 20 Hz and 20 kHz."
But the RPC was able to capture these sounds and, with the help of German composer Manuel Senfft, they became a song, uploaded to Soundcloud for all to hear.