For decades, the depths of Earth’s oceans have remained more mysterious than the surface of the Moon. But a groundbreaking collaboration between NASA and the French space agency CNES (Centre National d’Études Spatiales), through the Surface Water and Ocean Topography (SWOT) satellite, is rapidly changing that, providing unprecedented insights into our planet’s hidden underwater landscapes.
While ship-based sonar offers incredibly detailed measurements of the ocean floor, only about 25% has been surveyed this way. To create a global picture, researchers have increasingly relied on satellite data. The SWOT mission, launched in December 2022, primarily measures the height of water across Earth’s surface, but it’s proving to be a game-changer for seafloor mapping.
Why Seafloor Maps Matter
More accurate maps of the ocean floor are crucial for a variety of reasons, from practical applications to scientific discovery:
- Navigation and Infrastructure: They are vital for safe navigation and the efficient laying of underwater communication cables.
- Economic Opportunities: Seafloor mapping supports emerging economic opportunities like rare-mineral seabed mining, optimizes shipping routes, and aids in hazard detection.
- Scientific Understanding: These maps are key to understanding deep-sea currents and tides, which profoundly affect marine life and geological processes like plate tectonics. Underwater features like seamounts and abyssal hills influence the movement of heat and nutrients, creating vital oases in the deep sea.
How SWOT Delivers Detailed Seafloor Insights
SWOT leverages a fascinating principle: massive geological features on the ocean floor, like seamounts, exert a slightly stronger gravitational pull. This pull creates tiny, measurable bumps on the sea surface above them. The satellite, which covers approximately 90% of the globe every 21 days, is sensitive enough to detect these minute differences in sea surface height with centimeter-level accuracy.
This advanced capability allows SWOT to identify seamounts less than half the height detectable by previous satellites, potentially increasing the number of known seamounts from 44,000 to an astounding 100,000. It can also map abyssal hills, which are the most abundant landform on Earth, covering about 70% of the ocean floor, despite their small size.
A New Era of Exploration
The improved view from SWOT is providing researchers with deeper insights into Earth’s geological history, revealing how tectonic plates have moved over time through the orientation and extent of abyssal hill bands. While the international scientific community aims to map the entire seafloor using ship-based sonar by 2030, SWOT’s contributions are invaluable in accelerating this ambitious goal.
The SWOT satellite, a collaborative effort involving NASA, CNES, the Canadian Space Agency (CSA), and the UK Space Agency, is truly revolutionizing our ability to understand the vast, largely unexplored depths of our oceans, promising a future with more accurate maps and a greater understanding of our “Deep World.”
