Mystery keeps on creeping even decades after the Apollo 10 mission ended. Declassified tapes reveal that the astronauts on the said mission heard odd music on the far side of the moon.

The Apollo 10 mission run by smoothly and according to plan, the public believes. In fact, the agency said that it was successful in fulfilling its goals.

"All mission objectives were achieved," NASA wrote.

However, recent revelations of "strange, otherworldly music coming through the Apollo module's radio" signifies that there was a little bumpy ride along the way.

Astronauts heard the sound in 1969 when Apollo 10 entered the lunar orbit, including the far side of the moon. They lost all signal from the Earth when they arrived at this part and for one whole hour, not a single person on Earth was able to hear or see what was happening.

Now, after nearly four decades, that lost hour in history appears to be a very monumental one. Declassified tapes from that moment were revealed, exposing what the three astronauts were up to during that time.

What The Astronauts Heard

The sounds that the astronauts heard were featured in an episode of Youtube's Science Channel entitled "NASA's Unexplained Files."

The recordings clearly reveal that the astronauts had a noteworthy conversation about a strange music. One was heard describing the sound as "outer space-type of music," while another described it as whistling. Ultimately, the third astronaut said it was indeed weird music.

Astronauts Undecided To Reveal Experience

Just before they traveled back nearer the Earth and restored radio signal contact, the astronauts were heard discussing whether or not they should reveal their strange experience when they arrive back home.

"Shall we tell them about it?" one astronaut was heard saying.

"I don't know. We ought to think about it," responded the other.

Things sure seem a lot creepier as years passed.

Was It Strange At All?

Considering that they were miles away from the Earth, it is not surprising to detect unfamiliar things such as that sound. But according to Apollo 15 astronaut Al Worden, the Apollo 10 astronauts were very much used to what they should be hearing in space.

"Logic tells me that if there was something recorded on there, then there was something there," he says.

Years Later, Debates Spark

The recordings were kept sealed in the archives of NASA until 2008. With this, ongoing debate regarding the strange sound still remains heated.

The incident happened a long time ago that recent revelations raise concerns about whether people are just making things up or if there was really something there, says Worden.

In the end, Worden says he has an open mind about it but stresses the value of evidence versus mere memory. "Recollection is one thing, but actual proof is something entirely different," he closes.

Photo: Daniel R. Blume | Flickr