In 2010, Erik Verlinde surprised the world with a completely new theory of gravity. According to Verlinde, gravity is not a fundamental force of nature, but an emergent phenomenon. In the same way that temperature arises from the movement of microscopic particles, gravity emerges from the changes of fundamental bits of information, stored in the very structure of spacetime.Lots of cutting edge theoretical physics is focused on information. I'm not sure how much of that is a sort of fad derived from the prominence of computers in our lives, and how much it will end up explaining. But I find all of these new approaches promising.
In his 2010 article (On the origin of gravity and the laws of Newton), Verlinde showed how Newton's famous second law, which describes how apples fall from trees and satellites stay in orbit, can be derived from these underlying microscopic building blocks. Extending his previous work and work done by others, Verlinde now shows how to understand the curious behaviour of stars in galaxies without adding the puzzling dark matter. . . .
According to Verlinde, there is no need to add a mysterious dark matter particle to the theory. In a new paper, which appeared today on the ArXiv preprint server, Verlinde shows how his theory of gravity accurately predicts the velocities by which the stars rotate around the center of the Milky Way, as well as the motion of stars inside other galaxies.
"We have evidence that this new view of gravity actually agrees with the observations, " says Verlinde. "At large scales, it seems, gravity just doesn't behave the way Einstein's theory predicts."
Saturday, November 12, 2016
As I wrote a few days ago about the debate among physicists about gravity and dark matter. Now Physorg has a nice little article on one of the new theories of gravity, which is called Emergent Gravity: