A team of researchers in Europe has come up with a new way to determine the gravitational constant G. Rather than relying on using torque based techniques to measure gravitational pull, the researchers instead attempted to measure the attraction between a cloud of cold rubidium atoms and tungsten weights. They came up with a value for G of 6.67191(99) x 10−11 m3 kg−1 s−2. In their paper published in the journal Nature, the team describes their technique in great detail, and suggest it can be used to further refine a value for G. Stephan Schlamminger offers a News & Views piece describing the new technique and what it might mean, in the same journal issue.
It was Isaac Newton who first came up with the law describing how gravity pulls everything together, though he wasn’t able to come up with an actual constant value. That was left to Henry Cavendish—he measured the torque that resulted from the gravitational attraction of weights attached to a rotating balance. Subsequent attempts have used roughly the same strategy with better precision. Unfortunately, as more precision is introduced the more differences researchers see in their results compared to what others find—there are just too many other attractive forces interfering. To overcome some of those problems, the researchers working on this new effort took an entirely new approach.
Read more at: Phys.org