People from different parts of the world have been left terrified after hearing what is believed to be an evil-sounding trumpet noise coming from an unknown location in the sky.

Residents who were able to capture the ominous sound went to upload their recordings on social media sites. Several of these clips came from Canada, Australia, Germany and the United States.

In a video shot last month from Germany, a child can be seen frightened stiff as the strange noise blasted from afar.

In Canada, Kimberly Wookey was able to record numerous clips of these mysterious sounds. She uploaded several of them on Youtube.

"This is the second time I personally have heard these sounds here in Terrace BC Canada," Wookey wrote on her Youtube account. "First time was June 19th 2013 at approx. 9-9:30am but it was not quite as intense."

In another entry, dated Aug. 29, 2013, Wookey claimed she was awoken by the loud noise, which she knew she had heard before. She said that she went to see her seven-year-old son who was also terrified by the noise.

Wookey added that she does not believe that the events had any connection with religious acts, or that the noises could have come from aliens, trains or construction.

She does, however, believe it could have something to do with a geophysical phenomenon.

Aaron Traylor, a resident of Montana, said that he had been suffering from nightmares after he uploaded the frightening sounds.

He recounted how his wife woke him up one evening because he was screaming in his sleep.

Traylor said he first heard the noise while he was with his daughter and his dog. When they heard the eerie sound, his daughter was suddenly stopped in her tracks and his dog's ears perked up.

According to reports, scientists at the National Aeronautics and Space Administration (NASA) believe the noise could potentially be the "background noise" of the Earth.

"If humans had radio antennas instead of ears, we would hear a remarkable symphony of strange noises coming from our own planet," a spokesperson from NASA explained.

NASA said that the sound can be compared to the background music that can usually be heard in classic science fiction films. Experts, however, stressed that the noise coming from the Earth is not science fiction.

These natural radio emissions from the planet are very much real, NASA said. While most people are unaware of this phenomenon, the noises occur around people all the time.

Photo: NASA Goddard Space Flight Center | Flickr