DLR audio – The Sound of Science
Science is simulating, measuring, and evaluating data in order to gather knowledge. On an elementary level, however, science is a description of human experience: touching, observing, and listening. Helicopter rotors make a very particular sound; satellites send beacon signals from outer space; wind tunnels also produce a characteristic soundscape.
One of the latest audio recordings in the SoundCloud archives comes from the School_Lab in Göttingen, and it is a real treat for stereo enthusiasts.##markend## What sounds like a vacuum cleaner meandering through a room is in fact a satellite model. It is attached to a table, where it circles the Earth – perhaps not true to scale, but that is irrelevant for our experiment. The small hovercraft model is pulled toward the centre of the table whenever it comes to rest, simulating Earth's gravitational pull. But as soon as it is pushed into orbit around the Earth at a certain speed, its position remains stable. It does not ‘fall down’ (in terms of our model: it is not dragged to the centre of the table), but instead the satellite 'falls continuously around the Earth'.
The classic 'Alien' movie ends with a famous line, "In space, no one can hear you scream." Still, it was a sound from outer space that grabbed the world's attention in 2015. It was the sound the Rosetta lander Philae recorded when it touched down on Comet 67P/Churyumov-Gerasimenko in November 2014:
Besides the fascinating pull of this acoustic testimony to a cosmic world, another question presented itself: how is it possible for sound to be recorded in a vacuum – and therefore without a medium to transport the waves? The answer: internal sensors in the lander's feet recorded the vibrations, which we perceive as sound. This does not require air as a medium. Currently registering over 300,000 hits, the touchdown by the now renowned landing craft is among our most popular sounds – at least for now.
Whether in space or on Earth, the research conducted by DLR generates a plethora of sounds. Sometimes they are deliberately produced by our researchers: for instance, our sound researchers are using a sonorous engine rumble to investigate 'anti-noise' as a means of reducing sound levels in aircraft cabins.
Would you like to hear more? The DLR SoundCloud channel has plenty more authentic sounds from our everyday world of science. #SoundOfScience