The Big Bang

Before the quark epoch of the Universe (10^-12 to 10^-6 seconds after the Big Bang), theories were less accurate and more speculative.  This is due to the massive energy needed to duplicate the reactions.   Among these early epochs are the Planck epoch, the grand unification epoch, the inflationary epoch, and the electroweak epoch.  The first and most unknown period of the Universe was the Planck epoch (up to 10^-43 seconds after the Big Bang).  This epoch (named after Max Planck) happened before the first unit of Planck time was over.  Due to the fact that this is supposed to be the smallest unit of time possible, the happenings during that time would defy all laws of physics.  During the Planck epoch, all four of the forces were of equal strength, and therefore unified.  Scientists think that the development of the Quantum Gravity theory will shed light on the secrets of this epoch.  The second of the Universe's epochs was the grand unification epoch (10^-43 to 10^-36 seconds).  During this epoch gravity separated from the other three forces.   The inflationary epoch (10^-36 to 10^-32 seconds) was an epoch of extremely fast expansion.  The conditions of the Universe had not settled enough for quarks or anti-quarks to form.  This epoch is discussed more specifically in another article.

 The electroweak epoch (10^-36 to 10^-12 seconds) was the last of these early epochs.  This period was cool enough to separate the electromagnetic and the weak nuclear force (combined) from the strong nuclear force.  The beginning of this epoch allowed the formation of W, Z and Higgs bosons.  Also, the rapid, exponential expansion that occurred during the inflationary epoch had slowed to allow particles such as quarks and neutrinos, to form.  No matter what happened in the early Universe, the actual Big Bang and its causes may never be fully understood.  The best theory about the cause is the Big Bounce theory (discussed briefly in the Big Crunch article).  But this subject is mainly a topic of imagination.