New study suggests we might have spotted a fifth force of nature
As far as we know, there are four fundamental forces that hold our Universe together – gravity, electromagnetism, and the strong and weak nuclear forces.
But, in April last year, physicists in Hungary saw evidence of a possible fifth force of nature, one that could potentially explain some of the lingering mysteries in our Universe, such as dark matter.

http://www.sciencealert.com/new-study-confirms-physicists-might-have-spotted-a-fifth-force-of-nature