Some theories suggest there could be many more dimensions that we're unaware of, mostly because they're imperceptibly tiny. Now, Japanese researchers have taken the search for extra dimensions down to the nanoscale, using a neutron beam to study the gravitational force more precisely than ever before.

According to the Standard Model of particle physics, the world is governed by four fundamental forces: gravity, electromagnetism, and the weak and strong nuclear forces. Although things act a bit "spooky" down on the quantum level, science has managed to generally describe all of these forces at both the macro and quantum scales – except gravity.

Newton's law of universal gravitation says that the gravitational force between two objects gets stronger as objects get more massive, and weaker the further apart those objects get. But it's only really been shown experimentally down to the submillimeter scale, which is still "macro". According to some theories of quantum gravity, on smaller levels that law might break down.