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If these observations are correct and the acceleration continues, the ultimate result of this trend will be an inability to see any other galaxies any more. A new theory of the end of the Universe based on this finding has been called the Big Rip, although whether the Big Rip occurs depends on the nature of the acceleration and how it changes over time.

Because the energy causing the acceleration of space-time cannot be directly observed, it has been dubbed dark energy. Two theoretical candidates for this energy are a non-zero cosmological constant and a more general repulsive energy known as quintessence. Any field would permeate all of space and therefore have the properties of a scalar field much like the one that dominated the expansion of the universe during cosmic inflation. In fact, the dark energy may have actually caused cosmic inflation in the first place.

The observation of an accelerating universe appears to present great problems for Dyson's eternal intelligence. This theory relies on a decelerating universe, which for many years was the dominant model in cosmology, since (in the absence of observational evidence for the existence of dark energy) it was thought that the gravitational attractionThis article covers the physics of gravitation. See also gravity (disambiguation). Gravitation is the tendency of masses to move toward each other. The first mathematical formulation of the theory of gravitation was made by Sir Isaac Newton and proved ast of the matter in the universe to itself would act to slow the expansion.

By apparently ruling out a Big CrunchIn cosmology, the Big Crunch is a hypothesis that states the universe will stop expanding and start to collapse upon itself; a counterpart to the Big Bang. If the gravitational attraction of all the matter in the observable horizon is high enough, then it, the accelerating universe also presents great problems for TiplerTipler is a professor of mathematical physics at Tulane University, New Orleans, physicist, theologian and cornucopian philosopher. He should not be confused with the physicist Paul A. Tipler ( emeritus at the Oakland University), author of a very popular's Omega Point.

Astronomers estimate that the acceleration of the Universe's expansion began 5 billion years ago. Before that, the expansion was decelerating. The Universe would have been decelerating due to the attractive influence of dark matterDark matter is matter that can't be detected by its emitted radiation but whose presence can be inferred from gravitational effects on visible matter such as stars and galaxies. Estimates of the amount of matter in the universe based on gravitational effe. However, it was still expanding, and as it expanded, the attraction of dark matter decreased and the repulsion of dark energy increased. Whenever the Universe doubles in size, dark matter's attraction decreases to one-fourth, but dark energy's repulsion doubles (if energy density remains constant). Thus, the current accelerating phase appears to be dominated by dark energy.