The initial singularity is a

singularity Singularity or singular point may refer to: Science, technology, and mathematics Mathematics * Mathematical singularity, a point at which a given mathematical object is not defined or not "well-behaved", for example infinite or not differentiabl ...

predicted by some models of the

Big Bang theory The Big Bang theory A theory is a reason, rational type of abstraction, abstract thinking about a phenomenon, or the results of such thinking. The process of contemplative and rational thinking is often associated with such processes as obs ...

to have existed before the Big Bang and thought to have contained all the

energy In physics Physics is the that studies , its , its and behavior through , and the related entities of and . "Physical science is that department of knowledge which relates to the order of nature, or, in other words, to the regula ...

energy

and

spacetime In physics, spacetime is any mathematical model which fuses the three-dimensional space, three dimensions of space and the one dimension of time into a single four-dimensional manifold. Minkowski diagram, Spacetime diagrams can be used to visuali ...

of the

Universe The universe ( la, universus) is all of space and time and their contents, including planets, stars, galaxy, galaxies, and all other forms of matter and energy. The Big Bang theory is the prevailing cosmological description of the development ...

. The instant immediately following the initial singularity is part of the

Planck epoch The chronology of the universe describes the history and Future of an expanding universe, future of the universe according to Big Bang cosmology. The earliest stages of the universe's existence are estimated as taking place 13.8 billion years ...

, the earliest period of time in the history of our universe.

Traditional models of our Universe

The use of only general relativity to predict what happened in the beginnings of the Universe has been heavily criticized, as

quantum mechanics Quantum mechanics is a fundamental theory A theory is a reason, rational type of abstraction, abstract thinking about a phenomenon, or the results of such thinking. The process of contemplative and rational thinking is often associated with ...

becomes a significant factor in the high-energy environment of the earliest Universe, and general relativity on its own fails to make accurate predictions. In response to the inaccuracy of considering only general relativity, as in the traditional model of the Big Bang, alternative theoretical formulations for the beginning of the Universe have been proposed, including a

string theory In physics, string theory is a Mathematical theory, theoretical framework in which the Point particle, point-like particles of particle physics are replaced by Dimension (mathematics and physics), one-dimensional objects called String (physic ...

-based model in which two

branes In string theory In , string theory is a in which the of are replaced by objects called . String theory describes how these strings propagate through space and interact with each other. On distance scales larger than the string scal ...

, enormous membranes much larger than the Universe, collided, creating mass and energy. Although there is no direct evidence for a singularity of infinite density, the

cosmic microwave background The cosmic microwave background (CMB, CMBR), in Big Bang The Big Bang theory A theory is a rational Rationality is the quality or state of being rational – that is, being based on or agreeable to reason Reason is the capacity ...

is evidence that the universe expanded from a very hot, dense state.

Alternatives to the singularity

Various new models of what preceded and caused the Big Bang have been proposed as a result of the problems created by quantum mechanics. One model, using loop quantum gravity, aims to explain the beginnings of the Universe through a series of Big Bounces, in which quantum fluctuations cause the Universe to expand. This procreation also predicts a cyclic model of universes, with a new universe being created after an old one is destroyed, each with different physical constants. Another procreation based on M-theory and observations of the

(CMB), states that the Universe is but one of many in a multiverse, and has budded off from another universe as a result of quantum fluctuations, as opposed to our Universe being all that exists.

References

{{Portal bar, Physics, Astronomy, Stars, Spaceflight, Outer space, Solar System, Science Big Bang Cosmology