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Phantom energy is a hypothetical form of dark energy satisfying the equation of state = with <. It possesses negative kinetic energy , and predicts expansion of the universe in excess of that predicted by a cosmological constant , which leads to a Big Rip .
Some special cases of quintessence are phantom energy, in which the energy density of quintessence actually increases with time, and k-essence (short for kinetic quintessence) which has a non-standard form of kinetic energy such as a negative kinetic energy. [53] They can have unusual properties: phantom energy, for example, can cause a Big Rip.
In physics, quintessence is a hypothetical form of dark energy, more precisely a scalar field minimally coupled to gravity, postulated as an explanation of the observation of an accelerating rate of expansion of the universe. The first example of this scenario was proposed by Ratra and Peebles (1988) [1] and Wetterich (1988).
In physical cosmology, the Big Rip is a hypothetical cosmological model concerning the ultimate fate of the universe, in which the matter of the universe, from stars and galaxies to atoms and subatomic particles, and even spacetime itself, is progressively torn apart by the expansion of the universe at a certain time in the future, until distances between particles will infinitely increase.
This phantom energy density would become infinite in finite time, causing such a huge gravitational repulsion that the universe would lose all structure and end in a Big Rip. [26] For example, for w = − 3 / 2 and H 0 =70 km·s −1 ·Mpc −1 , the time remaining before the universe ends in this Big Rip is 22 billion years.
In this scenario, the equation of state = of the dark energy, relating its pressure and energy density, can cross the boundary = associated with the cosmological constant. The boundary separates the phantom-energy-like behavior with w < − 1 {\displaystyle w<-1} from the quintessence-like behavior with w > − 1 {\displaystyle w>-1} .
The energy that a physical body possesses due to its motion, defined as the work needed to accelerate a body of a given mass from rest to its stated velocity. The body continues to maintain this kinetic energy unless its velocity changes. Contrast potential energy. Kirchhoff's circuit laws. Also called Kirchhoff's rules or simply Kirchhoff's laws.
A cyclic model (or oscillating model) is any of several cosmological models in which the universe follows infinite, or indefinite, self-sustaining cycles. For example, the oscillating universe theory briefly considered by Albert Einstein in 1930 theorized a universe following an eternal series of oscillations, each beginning with a Big Bang and ending with a Big Crunch; in the interim, the ...