Researchers measure the gravity exerted by a 90 milligram object | Ars Technica
▻https://arstechnica.com/science/2021/03/researchers-measure-the-gravity-exerted-by-a-90-milligram-object
The result is an impressive technical achievement. But the researchers think that 90 mg is actually on the heavy side of the objects that might be measured this way. And, as things get lighter, there are some dramatically odd things that could potentially be tested.
For example, as mentioned above, our theory of gravity is incompatible with quantum mechanics. But we’ve managed to get ever-larger systems to behave as quantum objects. If we get these measurements sensitive enough, then it might be possible to measure the gravitational attraction of an object that is in a quantum superposition between two locations. In other words, there is no way to tell where exactly it is, while at the same time the gravitational force it exerts depends on where it is.
Other potential tests include some variants of string theory, modified Newtonian Dynamics (MOND, a hypothetical and unpopular replacement for dark matter), and some explanations for dark energy. But all of these will be utterly dependent upon this experimental setup working on masses that are far, far smaller than the milligram scale. So as a first step, it’s going to be important for the researchers behind this work to show that they have at least some of the promised ability to scale down.