Only 0.001 percent of the deep ocean floor has ever been seen by human eyes — an area roughly the size of Rhode Island — according to a May 2025 study in Science Advances, meaning more than 99.999 per
A May 2025 study reveals that humans have visually explored only 0.001 percent of the deep ocean floor. Despite covering two-thirds of the Earth's surface, the vast majority of this ecosystem remains unseen and largely unmapped.
Why it matters
The deep ocean is critical for global carbon cycling and climate regulation, yet our lack of exploration limits our understanding of the planet's largest ecosystem.
The deep ocean covers approximately two-thirds of the Earth s surface. By the standard scientific definition, it begins at 200 metres below sea level — the depth at which sunlight effectively stops penetrating — and extends to the bottom of the deepest ocean trenches, more than 11,000 metres down.
The article reports on scientific findings from a peer-reviewed study without political or ideological framing.
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