The Duality of Time Theory

In 1930, after Hubble’s confirmation that the Universe is expanding, as it was proposed by Lemaitre who also introduced the Big Bang concept as we shall see in section 6.3, Einstein considered the Universe following an eternal series of oscillations, each beginning with a big bang and ending with a big crunch due to gravitational attraction of matter which causes it to collapse back in and undergo a bounce. This theory, however, failed because, according to the Second Law of Thermodynamics, entropy can only increase, implying that successive cycles will grow longer and larger, and by extrapolating back in time, cycles before the present one become shorter and smaller, culminating again in a Big Bang and thus not replacing it.

This puzzling situation remained for many decades until the early 21st century when the recently discovered dark energy component provided new hope for a consistent cyclic cosmology. In 2011, a five-year survey of 200,000 galaxies and spanning 7 billion years of cosmic time confirmed that “dark energy is driving our Universe apart at accelerating speeds”. This was followed by several cyclic models, such as the brane cosmology model and others relying on the notion of phantom energy, conformal cyclic cosmology and Loop quantum cosmology.

The cyclic Steady-State model was proposed by Geoffrey Burbidge in 2008, in which the Universe continuously goes through stages of expansion and contraction, each cycle on a length far greater thanyears, with very hot and massive active galaxies and black holes playing roles in the formation of elements in each cycle. The model attempts to address issues with standard Lambda-CDM cosmology, including the lack of viable or confirmed non-baryonic dark matter sources, uncertainty regarding dark energy, early galaxy formation and constraints on inflation, while also reconciling and taking account with recent observations and element abundances without the need of additional new physics beyond the Standard Model.

The conformal cyclic cosmology is based on General Relativity, where the Universe expands until all the matter decays and is turned to light, so there is nothing in the Universe that has any time or distance scale associated with it. This permits it to become identical with the Big Bang, thus starting the next cycle.

Loop quantum cosmology models predict a “quantum bridge” between contracting and expanding cosmological branches.