Scientists recognize four fundamental natural forces. They are gravity, electromagnetism, and the strong and weak nuclear forces found inside atoms. Could there be a fifth?
Basically, maybe. On August 14, 2016, physicists at University of California, Irvine (UCI) announced they have confirmed at least theoretical evidence for this force based on experimental data from Hungary.
Here’s where we get into the physics. The Hungarians were exploring dark matter, which comprises most of the universe. They were looking for a carrier, which they hypothesized would be dark photons. What they found was an anomaly in radioactive decay, which suggested a new light particle. But the UCI scientists thinks the evidence points to an entirely new force.
Such a force would completely change our understanding of the universe. For example, physicists have been trying to tie the four known forces together into one grand, unifying theory. Will a new force help or hinder that work?
As I said, there’s a lot we still don’t understand.
If you want to get into the physics, the basic article is at http://earthsky.org/space/physicists-confirm-a-possible-5th-force , and the UCI study is published at http://arxiv.org/abs/1608.03591 . The illustration is from the EarthSky site.