Do We Understand the Deep Sea Less Than the Moon or Mars?

Fast Summary

• Less than 0.001% of Earth’s seafloor has been directly visually explored,according to marine scientist Katy Croff Bell’s study. This area is comparable in size to the state of Rhode Island.
• the study analyzed data from 43,681 submersible expedition records reaching a depth of at least 200 meters conducted by institutions from 14 countries.
• There is a regional bias in exploration; waters near wealthier nations such as the U.S., Japan, and New Zealand have seen most direct observations.
• “exploration” encompasses visual imaging, terrain mapping via sonar or satellites, and biological/geological sampling; mapping dominates but detailed optical imaging remains limited.
• visual representation disparities exist between Earth’s ocean floor and celestial bodies like Mars and the moon-due partly to the technical challenges posed by water pressure and darkness below sea level compared with planetary surfaces observable from orbit.
• Experts argue that while we understand more about Earth’s oceans in terms of processes (e.g., hydrothermal vents), higher-resolution visual insights could unveil further complexities such as plate tectonics or biodiversity in unexplored regions.

!diveconcentrationheatmappacificocean.png?m=1746745430.909&w=900″>Concentration Heatmap – Pacific Ocean
This heatmap shows concentration of known deep-sea dives along coasts near Asia.

!Scientific American Article Link