The Bloop

During the summer of 1997, the US National Oceanic and Atmospheric Administration (NOAA) detected an ultra low frequency underwater several times that they could not identify. So named for the sound made, the source of the "Bloop" remains unknown.

The Bloop originated off the southwest coast of South America. It was picked up several times using US Navy equipment designed to detect Soviet submarines. The Bloop rose in frequency for over a minute and was strong enough to be heard from over 5,000 km. The scientists who have heard the Bloop say that it matches the audio profile of a living being, however, there is no known animal large enough to have made the noise. If it did come from an animal, the creature would have to be bigger even than the largest known animal on Earth, the Blue Whale.

Hear the Bloop here.

The Taos Hum

The Taos Hum is a low-pitched sound heard in numerous places throughout the world, with the most reports coming from Taos, New Mexico. It has proven to be undetectable by microphones or "VLF antennae". Its source and nature are a complete mystery. In 1997 Congress had a study conducted in an attempt to uncover answers relating to the odd noise, but to this day, none have been found.