Whatever it was, marine scientists agreed that it wasn't man-made
In 1997, using special underwater microphones, scientists studying beneath the sea phenomena, recorded an extremely loud and low frequency sound. The sound was so loud that it was picked up by listening devices over 3,000 miles away from the source. From scientific data it was determined that the source of the sound was located somewhere west of the South American tip.
Played back at 16 times the original recorded speed the sound resembled what the scientist dubbed ‘the bloop', and due to the unique low frequency signature marine scientists believe that the sound couldn't have been created by something man-made, or even by any underwater volcanic activity. But what they agreed on was that ‘the bloop' sound seemed to match the sound of a large underwater mammal such as a blue whale.
The problem with the blue whale theory, is that the loudest sound ever made by a blue whale could only reach a little under 1,000 miles. Whatever it was that created ‘the bloop' sound must have been six times larger than a blue whale? What's even more creepier, ‘the bloop' sound slowed down to normal recorded speed?