Scientists have detected the pull of gravity on the microscopic scale, a feat that lays the foundation for investigating the nature of gravity in the mysterious quantum realm.
In experiments using the latest superconducting equipment cooled to below absolute zero and brass weights attached to the wheels of electric bicycles, physicists found that particles less than 1 millimeter wide have a gravitational force as small as 1/30 quintillion newtons. recorded the gravitational force of
The demonstration is a sign that researchers will aim to measure the gravitational force produced by smaller particles in the future to understand how unusual forces act in the subatomic world, where quantum laws govern. This opens the way for research.
“We know that quantum mechanics, general relativity, and Einstein's theory of gravity, as we currently formulate them, are incompatible,” said experimental physicist Tim Fuchs, a postdoctoral fellow at the University of Southampton. Stated. “Theories don't work together, so we know that either something has to be given or both have to be given. This is what we're trying to do to bridge the gap with real experiments.”
For more than a century, physicists have tried and failed to combine gravity, which explains how mass bends space-time, with quantum theory, the rules of the particle world. Understanding gravity at the quantum scale could help solve some of the universe's grand mysteries, from the beginning of the universe to what happens inside black holes. But while theorists have come up with a number of promising ideas, designing experiments to see which one nature has chosen has proven difficult.
In their latest study, Fuchs and his colleagues at Leiden University in the Netherlands and the Institute of Photonics and Nanotechnology in Italy have devised a way to measure the extremely subtle forces of gravity that exist between small objects.
The experiment was tightly protected from vibrational interference and centered around magnetic particles suspended on top of a superconductor cooled to 1/100 degrees below absolute zero, or -273.15 degrees Celsius, the coldest temperature in the universe. It was held on. They then rotated an electric bicycle wheel with a brass weight attached to it about a meter away, moved the weight closer to the particle, and then brought it back again, measuring the almost negligible gravitational force on the floating particle.
“When you start spinning the wheel, the particle moves like a trapeze. Gravity pulls on it, then it starts to let go, and then it pulls on it again,” Fuchs said.
The force of gravity between two objects depends on their masses and the distance between them. The larger and closer it is, the stronger the gravitational force.
Writing in Science Advances, physicists describe how in an experiment a 0.5 milligram particle was gently pulled by a force of 30 attonnewtons. An atnewton is one billionth of a newton. “It's definitely not quantum gravity yet, but it's a stepping stone towards it,” Fuchs told the Guardian.
Having demonstrated that the device works, the researchers now hope to measure how gravity acts between particles that are increasingly subject to the laws of quantum mechanics. But it takes time. Fuchs believes the first such measurements could take another five to 10 years. “This is something that clearly needs to be investigated experimentally,” he said.
