In 1997, researchers recorded a mysterious sound so powerful it was detected across the entire Pacific Ocean, and while some speculated it came from an undiscovered sea monster larger than a blue whale, scientists eventually determined the source was a fracturing ice sheet more than 3,100 miles away

In 1997, researchers recorded a mysterious sound so powerful it was detected across the entire Pacific Ocean, and while some speculated it came from an undiscovered sea monster larger than a blue whale, scientists eventually determined the source was a fracturing ice sheet more than 3,100 miles away

In 1997, NOAA researchers recorded a mysterious ultra-low-frequency noise so powerful it registered on sensors thousands of miles apart.