Did you hear that whistling sound too?

Sounds like -- you know, outer-space type music.

I wonder what it is.

This was the conversation between Apollo 10 astronauts Eugene Cernan and John Young when their space craft flew around the far side of the moon. The transcripts of the conversation were released in 2008.

Screenshot | NASA

Stargazers, physics lovers and aspiring astronauts have always been fascinated to know what lies on the darker side of the moon, Hence when three astronauts of Apollo 10 mission in 1969 first heard whistling sounds, they too wondered what it was and were unsure on whether to report it.

They all heard a 'whoo.. whoo' sound which after a certain point of time became stopped.

Check out their mysterious time on Moon right here: