Zero-energy Universe
Encyclopedia
The zero-energy universe hypothesis states that the total amount of energy in the universe
Universe
The Universe is commonly defined as the totality of everything that exists, including all matter and energy, the planets, stars, galaxies, and the contents of intergalactic space. Definitions and usage vary and similar terms include the cosmos, the world and nature...

 is exactly zero. When the energy of the universe is considered from a pseudo-tensor point of view, zero values are obtained in the resulting calculations. The amount of positive energy in the form of matter
Matter
Matter is a general term for the substance of which all physical objects consist. Typically, matter includes atoms and other particles which have mass. A common way of defining matter is as anything that has mass and occupies volume...

 is exactly canceled out by the negative energy in the form of gravity.

Free-lunch interpretation

A generic property of inflation is the balancing of the negative gravitational energy
Gravitational energy
Gravitational energy is the energy associated with the gravitational field. This phrase is found frequently in scientific writings about quasars and other active galaxies.-Newtonian mechanics:...

, within the inflating region, with the positive energy of the inflaton field to yield a post-inflationary universe with negligible or zero energy density. It is this balancing of the total universal energy budget that enables the open-ended growth possible with inflation; during inflation energy flows from the gravitational field (or geometry) to the inflaton field—the total gravitational energy decreases (becomes more negative) and the total inflaton energy increases (becomes more positive). But the respective energy densities remain constant and opposite since the region is inflating. Consequently inflation explains the otherwise curious cancellation of matter and gravitational energy on cosmological scales which is a feature of a zero-energy free-lunch universe, which is consistent with astronomical observations.

Quantum fluctuation

Due to quantum uncertainty energy fluctuations such as electron
Electron
The electron is a subatomic particle with a negative elementary electric charge. It has no known components or substructure; in other words, it is generally thought to be an elementary particle. An electron has a mass that is approximately 1/1836 that of the proton...

 and its anti-particle a positron
Positron
The positron or antielectron is the antiparticle or the antimatter counterpart of the electron. The positron has an electric charge of +1e, a spin of ½, and has the same mass as an electron...

 can arise spontaneously out of vacuum space but must disappear rapidly. The lower the energy of the bubble, the longer it can exist. A gravitational field has negative energy. Matter has positive energy. The two values cancel out provided the universe is completely flat. In that case the universe has zero energy and can theoretically last forever.

See also

  • Vacuum genesis
    Vacuum genesis
    Vacuum genesis is a hypothesis about the Big Bang that states that the universe began as a single particle arising from an absolute vacuum, similar to how virtual particles come into existence and then fall back into non-existence....

  • Ex nihilo: Cosmological arguments
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