See also http://dx.doi.org/10.1103/PhysRevLett.129.121102 (limited access)The MICROSCOPE team published preliminary results in 2017, showing no signs of violation at a sensitivity of one part in 1014 over the two and a half years the experiment was in orbit. Now they have analyzed the data even further, confirming those 2017 results and improving the precision to one part in 1015.
The Weak Equivalence Principle is a fundamental concept in physics that states that all objects, regardless of their mass or composition, will fall at the same rate in a gravitational field. This principle is a cornerstone of Einstein's theory of general relativity.
The MICROSCOPE (Micro-Satellite à traînée Compensée pour l'Observation du Principe d'Equivalence) satellite is a French space mission launched in 2016 to test the Weak Equivalence Principle with unprecedented precision. It is a joint project between the French Space Agency (CNES) and the French National Center for Scientific Research (CNRS).
The MICROSCOPE satellite used a set of accelerometers and electrostatic actuators to measure the acceleration of two test masses made of different materials in Earth's gravitational field. The results showed that the two masses fell at the same rate, confirming the Weak Equivalence Principle to a precision of 10^-15.
Confirming the Weak Equivalence Principle is important because it validates Einstein's theory of general relativity, which is the basis for our understanding of gravity and the structure of the universe. It also helps scientists to further refine and improve our understanding of gravity and its effects on the universe.
The MICROSCOPE satellite's results have important implications for future space missions and experiments that rely on the Weak Equivalence Principle, such as tests of alternative theories of gravity and the search for dark matter. It also sets a new standard for precision in testing the Weak Equivalence Principle, paving the way for even more accurate experiments in the future.