english topic free by valentino gomez

by valentino gomez                    the universe   (tittle)

(intro)

The Universe is all of spacetime and its contents,which includes planets, moons, minorsplanets, stars, galaxies, the contents of intergalactic space and all matterand energy. While the size of the entire Universe is still unknown, it is possible to measure the observable universe. 

(body)

The prevailing model for the evolution of the Universe is the Big Bang theory.The Big Bang model states that the earliest state of the Universe was extremely hot and dense and that it subsequently expanded. The model is based on general relativity and on simplifying assumptions such as homogeneity and isotrofy of space. A version of the model with a cosmological constant and cold dark matter, known as the lambda cdm model, is the simplest model that provides a reasonably good account of various observations about the Universe. The Big Bang model accounts for observations such as the correlation of distance and redsshiftof galaxies, the ratio of the number of hydrogen to helium atoms, and the microwave radiation background.he initial hot, dense state is called the planck epoch, a brief period extending from time zero to one planck time unit of approximately 10 seconds. During the Planck epoch, all types of matter and all types of energy were concentrated into a dense state, where gravitation is believed to have been as strong as the other fundamental forces, and all the forces may have been unified. Since the Planck epoch, the Universe has been expanding to its present form, possibly with a very brief period of cosmic inflation which caused the Universe to reach a much larger size in less than 10 seconds.After the Planck epoch and inflation came the quark, hadron, and lepton epochs. Together, these epochs encompassed less than 10 seconds of time following the Big Bang.

(conclusion)

The Universe also contains a mysterious energy called drak energy, the density of which does not change over time. After about 9.8 billion years, the Universe had expanded sufficiently so that the density of matter was less than the density of dark energy, marking the beginning of the present dark energy dominated era. In this era, the expansion of the Universe is accelerating due to dark energy.