Planck epoch

The Planck epoch is the earliest period of time in the history of the universe, before the time passed was equal to the Planck time (tₚ) ; that is from zero to approximately 10⁻⁴³ seconds. The Planck scale is the physical scale beyond which current physical theories may not apply and cannot be used to calculate what happened. At this time scale, all physical quantities like temperatures, energies, etc. were in the range of the Planck units' values. During the Planck epoch, the temperature and average energies within the universe were so high that even subatomic particles could not form and even the four fundamental forces that shape our universe were combined and formed one unified fundamental force.

Traditional Big Bang cosmology predicts a gravitational singularity before this time, but this theory relies on the theory of general relativity, which is thought to break down for this epoch due to quantum effects. Due to the extraordinarily small scale of the universe at the time, the quantum effects of gravity were the strongest and it is believed that cosmology and physics was dominated by the quantum effects of gravity. At this scale, the grand unified force is thought to be unified with gravity. The immeasurably hot and dense state of the Planck epoch is succeeded by the grand unification epoch, where gravity is separated from the grand unified force.

Related pages

Big Bang

Planck Epoch Media

The lookback time of extragalactic observations by their cosmological redshift up to z=20.
Diagram of evolution of the (observable part) of the universe from the Big Bang (left), the CMB-reference afterglow, to the present
9-year WMAP image of the cosmic microwave background radiation (2012). The radiation is isotropic to roughly one part in 100,000.^{:&hairsp;Script error: The function "hyphen2dash" does not exist.,&hairsp;[291]&hairsp;}
Hubble Space Telescope—Ultra Deep Field galaxies to Legacy Field zoom out (video 00:50; 2 May 2019)
Artist's impression of the first stars, 400 million years after the Big Bang
The Hubble Ultra Deep Fields often feature galaxies that are examples of what the early Stelliferous Era was like.
Another Hubble image shows an infant galaxy forming nearby, which means this happened very recently on the cosmological timescale. This shows that new galaxy formation in the universe is still occurring.
Phases of the reionization
Computer simulated view of the large-scale structure of a part of the universe about 50 million light-years across