Scientists have proven that Einstein’s general theory of relativity is correct with a remarkable degree of accuracy, even though it has been around for more than a century.
The team behind the research wanted to test a component of Einstein’s general theory of relativity It’s called the weak equivalence principle, which states that all objects, regardless of their mass or composition, must fall the same way into a given gravitational field when interference from factors such as air pressure is eliminated. To do this, scientists measured the acceleration of falling objects in a French satellite called MICROSCOPE, which was launched in 2016.
One of the most famous tests of the weak equivalence principle occurred during Apollo 15 walking on the moon, when astronaut David Scott threw a feather and a geological hammer at the same time; Without air resistance, both objects would accelerate toward the surface of the Moon at the same rate. In a similar fashion, the microscope holds free-fall test blocks made from an alloy of platinum and titanium. Electrostatic forces keep the test masses in the same relative positions to each other, so any resulting difference in this applied electrostatic force must be the result of deviations in the acceleration of the objects.
The team’s results, the culmination of 20 years of research, revealed that the accelerations in pairs of objects in free fall differ by no more than one part in 10^15, or 0.000000000000001, meaning they found no violations of the larger weak equivalence principle. So.
In addition to placing constraints on deviations in the weak equivalence principle, the results also reject any deviations in Einstein’s 1915 theory from gravity, General Relativity, as a whole. Scientists continue to search for such deviations because general relativity, our best description of gravity, is incompatible with quantum physics, our best model of reality at incomprehensible small scales.
So no sign of aberration means there is still no hint of extensions of general relativity waiting to be found that could bridge the gap to quantum physics.
“We have new and much better constraints for any future theory because these theories should not violate the equivalence principle at this level,” said Gilles Mitris, a member of the MICROSCOPE team and a scientist at the Côte d’Azur Observatory in France. statement (Opens in a new tab) From the American Physical Society that published the research.
The microscope was launched in April 2016 and mission personnel released its preliminary results for 2017. Data analysis continued even after the experiment ended in 2018.
The fact that the new research found no violation of the weak equivalence principle places the highest limitation to date on this element of general relativity, and the results lay the groundwork for more sensitive tests in the future.
That’s because the scientists included suggestions on how to improve the experimental setup they used. They wrote that potential upgrades include reducing defects in the satellite’s coating that could affect accelerometer measurements as well as replacing wired systems with systems that use wireless connections.
A satellite implementing these improvements can pick up violations of the weak equivalence principle as small as one part in 10^17, 100 times more sensitive than a microscope. But the team expects that these improvements won’t be feasible for some time yet, which means that for now, the MICROSCOPE experiment will remain the best test of the weak equivalence principle.
“For at least one decade or maybe two decades, we won’t see any improvement in the experience of space satellites,” Manuel Rodriguez, a member of the MICROSCOPE team and a scientist at ONERA, a French research institute specializing in space, said in the same statement. .
The team’s research was published Wednesday (September 14) in the journal physical review messages (Opens in a new tab) And a special number of “Classic and Quantum Gravity”.