2023-07-24 15:45:06
How is it possible that Venus has many more volcanoes than Earth and has been renewing its surface despite lacking plate tectonics?
Earth’s tectonic plates shift and continually change the shape of Earth’s surface through collisions between pieces of the crust. It is this plate tectonic activity that forges mountain ranges and, in some places, promotes volcanism. Venus has more volcanoes than any other planet in the solar system, but it has only one continuous plate for its surface. More than 80,000 volcanoes (60 times more than the Earth) have exerted and still exert a remarkable renewal of the planet’s surface, through floods of lava. An investigation seems to have unraveled the riddle of this apparent contradiction of having many volcanoes and at the same time lacking plate tectonics.
The study was carried out by a team including Simone Marchi and Raluca Rufu of the Southwest Research Institute (SwRI) in the United States.
Marchi and his colleagues have concluded that Venus probably experienced impacts from celestial bodies at a higher speed and with a greater power than those suffered by Earth. The consequence of this was that the core of Venus overheated to the point of promoting the extensive volcanism that has characterized the planet ever since and completely reshaping its surface.
Earth and Venus formed in the same neighborhood of the solar system and from the same type of raw material. Both are rocky planets with a similar mass. The slight difference between their respective distances from the Sun gave Venus a quite different history of impacts from celestial bodies than Earth, particularly the number and outcome of such events. These differences are due to Venus being closer to the Sun and moving faster around it, making impact conditions more dynamic. In addition, other orbital features make the impacts more powerful.
Artist’s impression of the impact of a celestial body against Venus. (Illustration: Southwest Research Institute)
Higher impact velocities melt more silicates, and it is estimated that in the case of Venus they melted up to 82% of its mantle. This produces a mixed mantle of globally redistributed molten materials and a superheated core, traits that Venus by all accounts possesses.
The study is titled “Long-lived volcanic resurfacing of Venus driven by early collisions”. And it has been published in the academic journal Nature Astronomy. (Source: NCYT from Amazings)
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