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Linné on line arrow Physics and the Cosmos arrow Macrocosmos arrow Big Bang arrow Grand unification

Grand unification

The time between 10-43 and 10-34 s is the epoch when the four forces were approximately of the same strength. In fact we believe that during this epoch they could be treated with the same theory (GUT, Grand Unified Theory).

During this time span the temperature is so high that particles are created and annihilated by the interaction of radiation and particles with each other.

From what we have learned through accelerator experiments, a particle cannot be created without the corresponding anti-particle also being created. If this was also true in the early Universe the same amount of particles and anti-particles should have been created. Today we do not think that there are large amounts of anti-matter in the Universe but only matter. Could this asymmetry between the number of particles and anti-particles possibly depend on the anti-matter decaying into particles? This model has been studied in detail lately, but it does not appear to be able to explain the asymmetry.

Another idea to explain the asymmetry that has received a lot of attention recently, is that it may have arisen in a phase transition. The phase transition should be connected with the Universe entering the next phase of evolution which is dominated by the electroweak interaction.