Strucutre of the earth

• Essentially, beliefs on how the universe began and how its structure was formed are summarized under either theism or atheism
• Historically, we can trace hypotheses on the nature and origin of the universe from creation myths and stories by early civilizations such as the Egyptians, Greeks, and Chinese.
• Geocentrism was eventually replaced by the heliocentric universe initially by Aristarchus of Samos and improved by Galileo and Copernicus.
• geocentrism - the belief that the Earth is the center of the universe

  heliocentrism - the belief that the Sun is the center of the universe
• theism - the belief that the universe is created by a higher being (God)

  atheism - the belief that the universe just spawned out of nowhere and is constant
• Edwin Hubble discovered that the universe is expanding bc matter is expanding which is through the discovery with red shifts (matter is not static, but dynamic)
• The universe is dynamic and evolving
• Red shifts produce the data about those particles out in space
• Philosophers involved in the theory of the geocentric universe were Eudoxus , Aristotle , Eratosthenes , and Ptolemy
• Violet is natural while purple isn’t
• Russian-American physicist George Gamow refined Lemaitre's proposal and, in 1940, postulated that cosmic background radiation remains after the initial explosion.

  This started the dynamic universe model.
• The steady state theory of the expanding universe (1948) by Austrian-American astronomers Herman Bondi and Thomas Gold tries to explain an expanding universe even without a beginning. They proposed that although galaxies are moving apart, the universe has always existed in its present state. When galaxies move apart, new matter is created, and new galaxies are formed. Therefore, according to this theory, there is a continuous creation of matter rather than an origin.
• The Steady-State theory was based on the perfect cosmological principle, which ascribes to the idea that the universe is homogeneous, isotropic, and constant in time. This principle is incompatible with observations that the universe evolved over time.