Friday, 20 June 2014
he Universe is all of spacetime and everything that exists therein, including all planets, stars, galaxies, the contents of intergalactic space, the smallest subatomic particles, and all matter and energy. Similar terms include the cosmos, the world, reality, and nature. The observable universe is about 46 billion light years in radius. Scientific observation of the Universe has led to inferences of its earlier stages. These observations suggest that the Universe has been governed by the same physical laws and constants throughout most of its extent and history. The Big Bang theory is the prevailing cosmological model that describes the early development of the Universe, which is calculated to have begun 13.798 billion years ago. Observations of supernovae have shown that the Universe is expanding at an accelerating rate. There are many competing theories about the ultimate fate of the universe. Source
