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Sept. 14, 2022
A space mission has made it possible to verify with record precision that two bodies of different mass or composition fall in a vacuum with the same acceleration.
Image above: A representation of the MICROSCOPE satellite launched in 2016 (artist view). Image Credit: CNES/CNRS.
"This is a new victory for general relativity proposed by Albert Einstein more than a century ago," welcomed the French National Center for Space Studies (CNES) on Wednesday. The MICROSCOPE space mission has achieved record accuracy in verifying the “equivalence principle” of physics, according to several studies whose results were presented on Wednesday.
Launched in 2016, MICROSCOPE was installed in orbit at an altitude of 710 km, and provided data for two and a half years. The microsatellite, built by CNES, housed two T-SAGE accelerometers from ONERA, the French aerospace research center. The latter was also in charge of data processing, thanks to the simulation and data processing tools developed by the Côte d’Azur Observatory.
Galileo
It all starts with Galileo, in the 17th century, who postulated that by releasing two bodies of different mass and composition at the same time, they hit the ground at the same time. Three centuries later, an astronaut of the Apollo XV mission will illustrate this by dropping, apparently at the same speed, a feather and a hammer on the surface of the Moon.
Most precise test of general relativity's Weak Equivalence Principle. Video Credit: ONERA
Curvature of space-time
Meanwhile, Newton postulated the “equivalence principle” between the gravitational force and the inertial force that a body would experience in an accelerating situation. This principle is a pillar of Albert Einstein's theory of relativity, which describes gravity as a curvature of spacetime distorted by matter.
It has been verified on Earth with a degree of relative precision up to the 13th decimal in 2007. But space is the ideal environment to go further, freeing itself from multiple disturbances specific to the Earth's surface. The result presented on Wednesday, which is the subject of publications in the prestigious journals “Physical Review Letters” and “Classical Quantum Gravity”, verifies the principle of equivalence with a measurement precise to the fifteenth decimal place.
Related links:
CNES MICROSCOPE MISSION: https://microscope.cnes.fr/en/MICROSCOPE/index.htm
ONERA MICROSCOPE MISSION Press Release (in French): https://www.onera.fr/fr/presse/communiques-presse/les-resultats-finaux-de-la-mission-microscope-atteignent-une-precision
Image (mentioned), Video (mentioned), Text, Credits: CNES/CNRS/ObsCoteAzur/Orbiter.ch Aerospace/Roland Berga.
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