We know that there are three fundamental forces: 1. Gravitational Force 2. Strong Nuclear Force 3. Quark-Quark Force (unified by Weak Nuclear and Electromagnetic Force) I've heard about the fourth fundamental force which was found in 1986 and changed the relation: F = G*m*M/R*R to some another relation. If you know about this force please briefly describe that here...and also that changed relation.