When Philae lands on a comet, does it make a sound? Apparently yes.

[COMET SOUND]

The sound came from instruments in the lander's three feet.

(SOUNDBITE) (German) GERMAN AEROSPACE CENTRE (DLR) SCIENTIST MARTIN KNAPMEYER SAYING:

"At the moment the feet make contact with the surface of the comet, the sensor moves and we register that vibration. We do not need any air in between because we are in direct contact with the comet. It is like putting an ear to railtracks and listening to see whether a train is coming."

And it could provide important information.

(SOUNDBITE) (German) GERMAN AEROSPACE CENTRE (DLR) SCIENTIST MARTIN KNAPMEYER SAYING:

"Yes, we are trying to reconstruct the order in which the three feet (of the lander) touched the ground. "

They want to learn why and when the lander BOUNCED just after landing.

That's what left it stranded in a ditch without access to sunlight, resulting in the lander shutting down.