The universe is commonly defined as the totality of existence, including planets, stars, galaxies, the contents of intergalactic space, and all matter and energy. Definitions and usage vary and similar terms include the cosmos, the world and nature.
Scientific observation of earlier stages in the development of the universe, which can be seen at great distances, suggests that the universe has been governed by the same physical laws and constants throughout most of its extent and history. The universe is believed to be at least 93 billion light years in diameter and has existed for about 13.7 billion years, since it was created by the Big Bang.
There are various multiverse hypotheses, in which physicists have suggested that the universe might be one among many universes that likewise exist. The farthest distance that it is theoretically possible for humans to see is described as the observable universe. Observations have shown that the universe appears to be expanding at an accelerating rate, and a number of models have arisen to predict its ultimate fate.
Read more about Universe: Etymology, Synonyms and Definitions, Size, Age, Contents, Structure, and Laws, Historical Models, Theoretical Models, Shape of The Universe
Famous quotes containing the word universe:
“The universe constantly and obediently answers to our conceptions; whether we travel fast or slow, the track is laid for us. Let us spend our lives in conceiving then. The poet or the artist never yet had so fair and noble a design but some of his posterity at least could accomplish it.”
—Henry David Thoreau (1817–1862)
“In a universe that is all gradations of matter, from gross to fine to finer, so that we end up with everything we are composed of in a lattice, a grid, a mesh, a mist, where particles or movements so small we cannot observe them are held in a strict and accurate web, that is nevertheless nonexistent to the eyes we use for ordinary living—in this system of fine and finer, where then is the substance of a thought?”
—Doris Lessing (b. 1919)
“There are certain queer times and occasions in this strange mixed affair we call life when a man takes this whole universe for a vast practical joke, though the wit thereof he but dimly discerns, and more than suspects that the joke is at nobody’s expense but his own.”
—Herman Melville (1819–1891)