Paradoxically, we know much more about the surface of Mars than about the earth's ocean floor. Today this gap has been partially closed with the help of ESA's CryoSat-2 and NASA satellites - CNES Jason-1. Data from previous space missions of the 1980s and 1990s were also used. Thanks to the information received, it was possible to create the most accurate map of the Earth's ocean floor at a scale of 5 km per pixel.
The main difficulty in creating with such a map is that water refracts, absorbs and reflects light too well. Already at a depth of several tens to hundreds of meters, the bottom becomes invisible under the water column. There have been attempts to use ultrasonic devices to study the bottom surface, but the range of their action, as a rule, was limited by the route of the scientific vessel.
David Sandwell of the Scripps Institute of Oceanography (San Diego, Calif.) And Walter Smith of the National Oceanic and Atmospheric Administration have spent most of the past 25 years in talks with US defense officials and satellite operators to gain access to sea and surface gravity measurements. Earth.
The result of their joint work was a huge amount of information about mountain ranges and valleys based on the changing gravitational field of the planet. So the shades of red and orange correspond to the places where the greatest pressure is exerted on the seabed, that is, at the locations of seamounts, ridges and along the edges of tectonic plates. Shades of blue coincide with the deepest ocean trenches.