Historical Cosmologies

Significant Cosmological Models: 1900BC- 1917AD

http://physics.gmu.edu/~jevans/astr228/Graphics/web_print.jpg
http://physics.gmu.edu/~jevans/astr228/Graphics/web_print.jpg



Babylonian Cosmology: 1900-1200BC
Founders & Contributors - Ancient Greeks, Babylonians

As one of the earliest types of cosmologies, not too much is known about the Babylonian views. Babylonians viewed Cosmology separately from astronomy however traces of cosmology are found throughout Babylonian mythology and literature.The Babylonians depicted the Earth and heavens as "spatially whole" and having circumference, suggesting it was round in shape. However they did not believe that it was geocentrically based. Babylonians believed there were numerous earths and heavens, an idea that stems from Sumerian incantations that believed there were 7 Earths and 7 heavens. Babylonians thought that the numerous earths and heavens revolved around a center "ultimate cosmic ruler" who held total authority.(2)

Brahmanda (Hindu) Cosmology: (1700-1100BC)
Founders & Contributors - Hindu Rigveda

Hindu Cosmology and timelines are the closest of the historical cosmologies to modern scientific timelines. The term Brahmanda comes from the word Brahma, meaning God the creator. Hindu Cosmological views are largely based on puranic view, the major type of Buddhist religious texts. The puranic view asserts that the universe is created, destroyed, and re-created in an eternally repetitive series of cycles. The universe is considered to constantly expand since creation and disappear into a thin haze after billions of years.(4)

Atomist Universe: (500-428BC)
Founders & Contributors - Anaxgoras, Epicurus

The universe contains only two things: an infinite number of tiny seeds, called atoms, and the abyss of infinite extent. All atoms are made of the same substance, but differ in size and shape. Objects are formed from atom aggregations and decay back into atoms. It incorporates Leucippus' principle of causality: "nothing happens at random; everything happens out of reason and necessity." Atomist view says that gods did not rule the universe. (3)

Pythagorean Universe: (around 390BC)
Founders & Contributors - Philolaus

Believed that the very center of the universe is a central fire that the Sun, Earth, Moons and Planets all revolve around uniformly. The Sun orbits the central fire once every year. The Earth and planets revolved around the central fire as well, but did not rotate themselves. All the planets keep the same face toward the central fire for eternity; therefore the majority of each planet never sees the central fire. Contrary to the sun and planets, stars remain stationary. The Pythagorean Universe is the first non-geocentric model of the universe on record. (1)

http://www.crystalinks.com/pythagsun.gif
http://www.crystalinks.com/pythagsun.gif


Stoic Universe: (300BC-200AD)
Founders & Contributors - The Stoics

Developed during the end of the Hellenistic period. They believed that the universe was made up of a matter, referred to as reasoning substance that they called God or Nature. The stoics have divided the matter of the universe into two main classes. The two classes are the active and the passive matter. The active substance they referred to as “fate” or Universal Reason. It is intelligent and acts on all passive matter. It is the catalyst to setting passive matter into motion. Without active matter, passive matter would remain sluggish material forever. If left alone passive matter will remain dormant. Stoic philosophers believed that everything was subject to fate and happened according to its own nature in the universe. (4)

http://www.math.dartmouth.edu/archive/c2w99/public_html/wklyimages/Stoic.Cosmos.jpg
http://www.math.dartmouth.edu/archive/c2w99/public_html/wklyimages/Stoic.Cosmos.jpg


Ptolemaic Model: (2nd Century AD)
Founders & Contributors - Ptolemy, Aristotle

The Ptolemaic model states that the universe orbits around a stationary Earth. The planets all move in elliptical patterns around a point near the Earth. This allowed astronomers to predict the future positions of the planets and is viewed as the most successful universe model of all time. It is also referred to as Almagest or the Great System. (5)

http://www.vikdhillon.staff.shef.ac.uk/teaching/phy105/celsphere/ptolemy.gif
http://www.vikdhillon.staff.shef.ac.uk/teaching/phy105/celsphere/ptolemy.gif


Maragha Models: (1259-1528AD)
Founders & Contributors - Maragha School, Maragheh

Originating from Persian astronomers, Maragha is a combination and modification of the Ptolemaic model and the Aristotelian Universe.(1)

Keplerian: (1571-1630AD)
Founders & Contributors - Johann Kepler

A combination of mathematics and physics, Keplerian discoveries have the same foundation as our present conception of the Solar system. The idea of a Kepler orbit is the elliptical orbit of any body of matter. The matter orbits in an elliptical pattern forming a two-dimensional plane in space. It describes the gravitational relationship between two bodies in space and doesn’t account for the gravitational effect from any of the other bodies around those two. Kepler proclaimed that at the center of each “system” is a major, central mass.(3,1)

Static Newtorian: (1642-1727AD)
Founders & Contributors - Sir Isaac Newton

The belief that every particle in the universe is attracted to every other particle. All matter across the universe is, consequently, distributed in a "uni"form way. Gravity between the uniformly distributed matter leaves the universe gravitationally balanced but ultimately unstable. Newton's laws on gravity are similar to Kepler's laws of planetary motion. Newton's use of Kepler's laws helped disprove the doubt surrounding heliocentric ideas. This advancement greatly contributed to the Scientific Revolution in the 16th Century.(3)

http://csep10.phys.utk.edu/astr161/lect/history/gravity.gif
http://csep10.phys.utk.edu/astr161/lect/history/gravity.gif


Cartesian Vortex: (17th Century)
Founders & Contributors - René Descartes, Copernicus

An evolving and infinite state of the universe. A theory that the universe is a system of huge swirling whirlpools that create what we now know to be gravitational effects. Based strongly off of Copernicus' "Copernican Universe". A heliocentric view, Descartes greatest contributions to the scientific revolution include his laws of motion and universal gravitation.(1)


Einstein Universe, “The Cosmological Constant”: (1917)
Founders & Contributors - Albert Einstein, Sir Isaac Newton

“Matter without motion”. Einstein believed in a universe made of evenly distributed matter in a spherical shaped space. Similar to Riemann’s hypershere, the curve of the universe is directly proportionate to the force that counteracts gravity. The universe in this case was viewed as unstable but finite and bound to some end. (1,2,4)

Citations:
1. http://www.newscientist.com/topic/cosmology
2. http://map.gsfc.nasa.gov/universe/
3. http://csep10.phys.utk.edu/astr161/lect/history/kepler.html
4. http://www.polaris.iastate.edu/EveningStar/Unit2/unit2_sub1.htm
5. http://abyss.uoregon.edu/~js/glossary/ptolemy.html