Last year, experimental physicist Erik Verlinde shook things up by proposing that gravity is not a traditional force like electromagnetism, rather it is an "emergent phenomenon" that takes the guise of a traditional force through the manifestation of entropy in the universe. This process causes matter to distribute to maximize entropy, causing a redistribution effect that looks much like what we know as gravity.
The key idea in Verlinde's findings is that gravity is a statistical effect. If a particle is influenced by a statistically large number of influences, then its effects are felt. But what about the effect of gravity on quantum particles? According to Archil Kobakhidze of the University of Melbourne, this relationship must be taken into account when describing the effects of gravity:
"Since each quantum particle must be described by a large number of other particles, this leads to a particular equation that describes the effect of gravity."
For the past ten years, physicists have been monitoring the force of gravity at the level of neutrons, and the results of the study "matched the predictions of traditional gravitational theory". According to Kobakhidze, these "experiments on gravitational bound states of neutrons unambiguously disproves the entropic origin of gravitation proposed by Verlinde."
As a new point is made in the evolving debate, it seems clear that hundreds of years post-Newton we still have much to learn about this force of nature that we thought we'd figured out.
