La Ley

Throughout recorded history, several cosmologies and cosmogonies have been proposed to account for observations of the universe. The earliest quantitative geocentric models were developed by theancient Greeks. Over the centuries, more precise observations and improved theories of gravity led to Copernicus's heliocentric model and the Newtonian model of the Solar System, respectively. Furtherimprovements in astronomy led to the realization that the Solar System is embedded in a galaxy composed of billions of stars, the Milky Way, and that other galaxies exist outside it, as far asastronomical instruments can reach. Careful studies of the distribution of these galaxies and their spectral lines have led to much of modern cosmology. Discovery of the red shift and cosmic microwavebackground radiation revealed that the universe is expanding and apparently had a beginning.[citation needed]

This high-resolution image of the Hubble ultra deep field shows a diverse range of galaxies,each consisting of billions of stars. The equivalent area of sky that the picture occupies is shown as a red box in the lower left corner. The smallest, reddest galaxies, about 100, are some of the mostdistant galaxies to have been imaged by an optical telescope, existing at the time shortly after the Big Bang.
According to the prevailing scientific model of the universe, known as the Big Bang, theuniverse expanded from an extremely hot, dense phase called the Planck epoch, in which all the matter and energy of the observable universe was concentrated. Since the Planck epoch, the universe hasbeen expanding to its present form, possibly with a brief period (less than 10−32 seconds) of cosmic inflation. Several independent experimental measurements support this theoretical expansion and,more generally, the Big Bang theory. Recent observations indicate that this expansion is accelerating because of dark energy, and that most of the matter in the universe may be in a form which cannot...