Nearly 11 kilometers deep, the ocean is still a noisy place, according to scientists that have eavesdropped on the deepest part of the world's ocean, and instead of finding a sea of silence, discovered a cacophony of sounds both natural and caused by humans.

For three weeks, a titanium-encased hydrophone recorded constant ambient noise from the ocean floor at a depth of more than 36,000 feet, or 7 miles, in the Challenger Deep trough in the Mariana Trench near Micronesia. The ambient sound field is dominated by the sound of earthquakes, both near and far, as well as distinct moans of baleen whales, and the clamor of a category 4 typhoon that just happened to pass overhead.

The hydrophone also picked up sound from ship propellers. Challenge ...

The elusive Cuvier's beaked whale has set a new world record for the deepest and longest dive performed by any mammal. A new study has shown they can dive to nearly three kilometres below the surface, and can stay down there for more than two hours.