Within which time frame from the initial Big Bang do we believe all four fundamental forces of nature were united into a single force?

Question

Luke Allen · Accepted Answer

It is thought that the fundamental forces were unified less then #10^(-36)# seconds after the Big Bang.

The theories indicate that at high energies the photon and Z boson become indistinguishable, and only the electromagnetic and weak forces have been unified in terms of unifying the fundamental force. The next theory which is required is a Grand Unified Theory (GUT) with unifies the strong and electroweak forces. The problem is that we don't know how to make a particle accelerator powerful enough to reach the energies to detect the particle required for a GUT. There are candidate theories and it is estimated that the three forces were unified some #10^(-36)# seconds after the Big Bang. It is thought that the GUT forces separated around #10^(-12)# seconds after the Big Bang. It will be a long time before we can attempt to unify gravity with a GUT to form a Theory of Everything, since the GUT forces are described by quantum theories, and gravity is described geometrically as the curvature of spacetime. Any unification of all four forces would have to be much earlier than #10^(-36)# seconds aftr the Big Bang.

Hazel Asher · Answer

undefined The Planck epoch is the time interval after the Big Bang when scientists believe all four fundamental forces of nature were combined into one force, roughly between 10^(-43) and 10^(-36) seconds.