User:Sffleck/Cosmos

Copernican Revolution
Copernicus' Heliocentric Solar System Commonly regarded as the foundation of modern astronomy, the common universal view of the cosmos shifted as Nicolaus Copernicus positioned the Sun as the center of the Universe.

Early Beliefs
Prior to the Copernican Revolution, the Ptolemaic system, also known as the geocentric model, was widely accepted. This put the Earth at the center of the universe, with the sun and other planets revolving around the earth in an epicyclic orbit. Aristole's geocentric model was also broadly acknowledged, along with his claim that the planets rotated but did not orbit. The reasoning behind this was due to the belief that all objects outside of the lunar sphere were celestial bodies, and therefore could not change, as they were made of quintessence.

There were notable critiques of this model prior to Copernicus. In the Islamic world, Ibn al-Haytham doubted Ptolemy's notion of the planetary orbits, and Muhammad al-Battani recalculated the parameters. However, both still agreed with the geocentric model.

One of the first known astronomers that supported the Heliocentric theory was Aristarchus of Samos. After observing a lunar eclipse, he came to the conclusion that the sun was farther away from earth than the moon and that the sun was much larger than Earth. He also claimed the sun was a star. While Aristarchus was later an influence on Copernicus and his groundbreaking work, prior to the 17th century Aristarchus' findings were obstructed by the more established theories of Ptolemy and Aristotle.

Copernican Theory
Astronomer and mathematician Nicolaus Copernicus was appointed by The Catholic Church as an official, as his uncle was a bishop in the church. He used his income to further his studies, eventually studying at the University of Bologna in Italy. Copernicus began doubting the knowledge of natural philosophers and their beliefs, claiming that geometrical astronomy instead would result in the true reality of the cosmos. His manuscript, De revolutionibus, pioneered ideas that would change the course of how both the cosmos and astrology were viewed. Most notably, Copernicus claimed that the sun was the stationary center of the universe. His work also included calculations on the motions of the moon, and the motions in latitude and longitude of the planets, all which orbit the sun. Copernicus' work was not immediately published as it disagreed with Biblical teachings, and he feared his work would be rejected by Catholic officials.

Neoplatonism
Copernicus' work was not entirely mathematical conviction. There is evidence that Copernicus was influenced by Neoplatonism. Founded by philosopher Plotinus, neoplatonism believes that the sun is the symbol of The One, or The Universal Soul. It would make sense then that Copernicus would place the god-like figure at the center of the universe. Neoplatonist Nicholas of Cusa claimed the universe was infinite, containing multiple earths and suns. This changed the belief of a finite universe to an infinite one, which emphasized a more obscure and incomplete version of God.

Etymology

Cosmos - "the universe, the world" (but not popular until 1848, when it was taken as the English equivalent to Humboldt's Kosmos in translations from German), from Latinized form of Greek kosmos "order, good order, orderly arrangement," a word with several main senses rooted in those notions: The verb kosmein meant generally "to dispose, prepare," but especially "to order and arrange (troops for battle), to set (an army) in array;" also "to establish (a government or regime);" "to deck, adorn, equip, dress" (especially of women). Thus kosmos had an important secondary sense of "ornaments of a woman's dress, decoration" (compare kosmokomes "dressing the hair," and cosmetic) as well as "the universe, the world."

Philosophical Cosmology

Philosophy of cosmology is an expanding discipline, directed to the conceptual foundations of cosmology and the philosophical contemplation of the universe

as a totality. It draws on the fundamental theories of physics — thermodynamics, statistical mechanics, quantum mechanics, quantum field theory, and special and general relativity — and on several branches of philosophy -- philosophy of physics, philosophy of science, metaphysics, philosophy of mathematics, and epistemology.

Cosmology’s Standard Model
Physical cosmology has achieved a consensus Standard Model (SM), based on extending the local physics governing gravity and the other forces to describe the overall structure of the universe and its evolution. According to the SM, the universe has evolved from an extremely high temperature early state, by expanding, cooling, and developing structures at various scales, such as galaxies and stars. This model is based on bold extrapolations of existing theories—applying general relativity, for example, at length scales 14 orders of magnitude larger than the those at which it has been tested—and requires several novel ingredients, such as dark matter and dark energy. The last few decades have been a golden age of physical cosmology, as the SM has been developed in rich detail and substantiated by compatibility with a growing body of observations. Here we will briefly introduce some of the central concepts of the SM to provide the minimal background needed for the ensuing discussion.

Early views of cosmos: India and Australia

Indian View
It is generally known that the Indians believed in a cyclic universe. This idea is related to three other beliefs: (i), time is endless and space has infinite extension; (ii), earth is not the center of the universe; and (iii), laws govern all development, including the creation and destruction of the universe. It was believed that there are connections between the physical and the psychological worlds, and an equivalence existed between the outer cosmos and the inner cosmos of the individual. This is expressed in the famous sentence-"yat pinḍe tad brahmṇḍe, “as in the cell so in the universe”."The Indian cyclic model assumes the existence of countless island universes, which go through their own periods of development and destruction. The conception of cyclicity is taken to be recursive. For an early exposition of these astronomical and cosmological ideas, one may like to read al-Bīrūnī’s classic history of Indian science, composed in 1030 AD, and for an even earlier, popular, view of Indian ideas, one may consult the great Vedantic text called the Yoga Vāsiṣṭha (YV), which at 32,000 shlokas is one of the longest books in world literature.

Australian View
Anaximander had a cylindrical Earth surrounded by air and a solid sphere. Holes in the solid sphere allowed the light from the outer rim of fire to shine through, appearing as stars and the Sun.

Anaximander's model of the Universe was revolutionary for two main reasons. Firstly it introduced a mechanistic view, moving beyond a mythological, supernatural explanation for the Universe. It also proposed the concept of spheres surrounding the Earth. This was to profoundly influence astronomy and cosmology for the next two millennia.Anaximenes refined Anaximander's model by suggesting that the stars were fixed on to a solid, transparent crystalline sphere that rotated about the Earth.

Later Ionians contributed more ideas and discoveries. Anaxogoras (c. 450 BC) realised that the Moon shone by reflected sunlight,had mountains and was inhabited and that the Sun was not a god but a large fiery stone much larger than Greece and a large distance from Earth. Empedocles suggested that light traveled fast but not at infinite speed. Democritus proposed not just at atomist model of matter but also proposed that the Milky Way was composed of thousands of unresolved stars.