A fifth fundamental force could really exist, but we haven`t found it yet
(PHYSorg.com Physics)

The universe is governed by four fundamental forces: gravity, electromagnetism and the strong and weak nuclear forces. These forces drive the motion and behavior of everything we see around us. At least, that`s what we think. But over the past several years, there`s been increasing evidence of a fifth fundamental force. New research hasn`t discovered this fifth force, but it does show that we still don`t fully understand these cosmic forces.