Giant Impacts Can Dramatically Lower the Internal Pressure of Planets
The internal pressure of
planets can be dramatically be lowered due to giant impacts, according to a
study by Caltech. This finding could significantly change the current model of
planetary formation.
The impacts, such as the one that is thought to have caused the formation of
the earth's moon roughly 4.5 billion years ago, could cause random fluctuations
in core and mantle pressures that would explain some puzzling geochemical
signatures in Earth’s mantle.
"Previous studies have
incorrectly assumed that a planet's internal pressure is simply a function of
the mass of the planet, and so it increases continuously as the planet grows.
What we've shown is that the pressure can temporarily change after a major
impact, followed by a longer term increase in pressure as the post-impact body
recovers. This finding has major implications for the planet's chemical
structure and subsequent evolution," says Simon Lock, postdoctoral
researcher at Caltech and lead author of a paper explaining the new model that
was published by Science Advances on September 4.
Lock authored the paper with
colleague Sarah Stewart (PhD '02), professor of planetary science at the
University of California, Davis, a 2018 MacArthur Fellow, and an alumna of the
Caltech Division of Geological and Planetary Sciences.
Planetary systems typically
begin as a disk of dust that slowly accretes into rocky bodies. The end of the
main stage of this process is characterized by high-energy collisions between
planet-sized bodies as they coalesce to form the final planets.
Source:
Caltech.edu
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