A mysterious ‘alien call’ coming from 36,000ft below the Earth’s surface was recorded.

The Sun reported researchers at the Hatfield Marine Science Centre were shocked to hear the wailing noise while monitoring deep-sea whale communications in the Pacific Ocean’s Mariana Trench.

Lasting around three seconds, the moaning noise hits super-low, and then super-high frequencies.

The experts’ best guess is that they picked up a never before heard whale call while monitoring the uncharted depths.

Marine experts sent a machine called a hydrophone down to the deepest part of the trench, which lies between Japan and Australia.

The hydrophone can travel through the sea for months at a time and dive up to 1,000 metres.

It’s there that it picked up the strange booming sound.

Some believe it could be a mating call from a Baleen whale.

However, the bizarre sound pattern doesn’t quite fit with what we already understand about whales.

Sharon Nieukirk, a marine bioacoustics expert at Oregon State said: “If it’s a mating call, why are we getting it year round? That’s a mystery.”

The sound is “very distinct, with all these crazy parts” she added.

The scientists hope that by publishing the noise other researchers can help identify the “call” so they can get to the bottom of the noise.

This story first appeared on The Sun.