'Julia': The Eerie Underwater Sound That Sounds Like a Woman’s Voice

In March 1999, researchers from the National Oceanic and Atmospheric Administration (NOAA) recorded a bizarre acoustic signal in the eastern equatorial Pacific Ocean. The sound, dubbed “Julia”, lasted for nearly three minutes and stunned scientists due to its uncanny resemblance to a female human voice.

How and Where It Was Heard

What made the phenomenon even more astonishing was the sheer reach of the signal. The “Julia” sound was picked up by underwater microphones over 4,800 kilometers away from its estimated point of origin — a testament to the sound’s remarkable strength.

According to NOAA data, the signal originated from a region located between Bransfield Strait and Cape Adare, near the Antarctic coastline. This remote zone is notorious for its harsh climate, making direct investigations difficult and complicating the search for any definitive source.

Official Hypothesis: An Iceberg

In NOAA’s official report, the following statement was included:

“The most likely source of the sound known as ‘Julia’ is a large iceberg that ran aground near the Antarctic coast. Due to uncertainty in the azimuthal direction of signal transmission, the source is believed to be located between Bransfield Strait and Cape Adare, approximately corresponding to 1999 JD60 21:05 GMT.”

Scientists believe that the motion or structural shifts of massive ice formations, particularly when interacting with the seafloor, can generate such strong acoustic effects.

Alternative Theories Persist

Not all researchers are convinced by the iceberg explanation. Alternative hypotheses have emerged, including:

• Submarine seismic activity
• Ocean currents interacting with seabed features
• Other unexplained geophysical processes

The mystery surrounding the “Julia” sound has prompted ongoing debate within the scientific community.

Why It Remains a Mystery

Despite significant advances in hydroacoustic technology over the past two decades, the exact nature of the “Julia” signal remains unresolved. It has become one of the most famous unexplained phenomena in acoustic oceanography.

Interest in the topic continues to grow. Underwater research networks are expanding, and new instruments are being developed. Yet, even after 25 years, this strange “voice” of the ocean continues to guard its secrets.