Mars InSight probe: Listening to the silence of space

The UK team sending three tiny seismometers to Mars switched on their sensors during the long cruise to the Red Planet. What you hear is the sound from two of the microseismometers, speeded up 1,000 times. The background hiss is the noise from the sensors themselves, and the chirps are the thrusters of the InSight spacecraft as it keeps the solar arrays pointing at the Sun.