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Either the Universe will exist forever, or it will cease to exist at some time. It is unknown which of these possibilities will hold true. It is also not known whether the Universe will continue to support life.
Until fairly recent times, the mainstream scientific view of the universe was of an eternal and unchanging existence, known as the Steady state theory. After Edwin Hubble's discovery of universal expansion, however, the notion of a beginning and a possible end became an important subject of scientific investigation.
The beginning of the Universe is most commonly referred to as the Big Bang. Theories about the end can be divided into five major groups:
All theories must come to terms with general relativityGeneral relativity (GR or general relativity theory (GRT is the theory of gravitation published by Albert Einstein in 1915. The conceptual core of general relativity, from which its other consequences largely follow, is the Principle of Equivalence which, which provides a common background for cosmological speculation. Most of these theories are solutions of GR equations, only differing in their parameters (such as average density or the value of the cosmological constantThe cosmological constant (usually denoted by the Greek capital letter lambda: Λ) is a value occurring in Einstein's theory of general relativity. The units of Λ are 1/ second2. The constant is proportional to the energy density of the vacuu).
The first three groups are not discussed in this article, as they nullify the very concept of an "ending of the Universe". In such theories, some kind of meaningful activity can last forever.
In an open Universe , General Relativity shows that the Universe can exist indefinitely in the future, but will settle down into a state where life as we know it will cease to exist; for a possible timeline based on current physical theories, see 1 E19 s and moreTo help compare orders of magnitude of different times, this page lists times longer than 1019 seconds (320,000 million years) See also times of other orders of magnitude. See the article about the ultimate fate of the Universe for more discussion of thes.
In 20032003 is a common year starting on Wednesday (link will take you to calendar), and also: The International Year of Freshwater The European Disability Year Summary Perhaps the defining global event of the year 2003 was the Invasion of Iraq launched by the U, New ScientistNew Scientist is a weekly international science magazine covering recent developments in science and technology for a general English-speaking audience. As well as covering current events and news from the scientific community, the magazine often features magazine reported a preprint by Robert R. Caldwell, Marc Kamionkowski and Nevin N. Weinberg which puts forward the hypothesis that the end of the Universe may occur as a " Big RipThe Big Rip is a cosmological hypothesis about the ultimate fate of the Universe. The key to this hypothesis is the amount of dark energy in the universe. If the universe contains enough dark energy, it could end with all matter being pulled apart. The ke", which will shred the physical structure of the Universe.
In this model, a cosmological constant causes the Universe's rate of expansion to accelerate. Taken to the extreme, an ever-accelerating expansion means that all physical objects in the Universe, starting with galaxies and down to individual human beings, bacteria, and grains of sand, will eventually be torn to pieces and then to elementary particles. The Universe will be then reduced to single elementary particles forever accelerating away from one another.