RECEIVED IDEA. Earth tides do exist, and are even observable with the naked eye in water sources. Explanations.
By Erwan Seznec
© Michel GAILLARD/REA FOR “LE POINT”
Published on
ATAs surprising as it may seem, tides are not just a maritime phenomenon. Indeed, the gravitational forces of the Moon and the Sun which set the oceans in motion also deform the Earth’s crust. The earth rises and falls more than 50 centimeters twice a day at the equator.
At our latitudes, the amplitude of the terrestrial tide is around twenty centimeters higher or lower, between two points 300 kilometers apart (about the distance that separates the Eiffel Tower from the International Tide Center land, in Brussels). This is small compared to ocean tides, but it must be taken into account to calibrate very precise tools, such as satellite geopositioning systems and very large particle accelerators.
READ ALSOWhy the level of the Mediterranean sea has fallen so much
Earth tides are observable with the naked eye in water sources, the flow of which varies subtly throughout the day, following a regular period.
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