Update: This was explained many years ago, and was simply interference between the Lunar Module's and command module's VHF radios creating a strange whistling sound. To briefly summarize the article: it seems that astronauts aboard Apollo 10 heard strange theremin-style noises which they were recorded referring to as 'Outer-space-type music' while blocked from Earth's radio transmissions by the Moon. The writer heavily implies that extraterrestrial radio transmissions are the best explanation. http://www.huffingtonpost.com/entry...ned-music-at-moon_us_56c80662e4b0928f5a6c0679 The Huffington Post is not above insinuating that extraterrestrial radio transmissions are the likeliest explanation.... But what do members here make of this? What could the noises have been?