EarthSci

• Original author of heliocentrism - aristarchus
• Christian cosmology - inconsistent due to evolving beliefs of various authors
• Rigveda - a Hindu text about cosmology; describes universe as oscillating universe
• RIgveda started as Brahmanda (cosmic egg), collapsed into Bindu (concentrated point)
• Anaxagoras - everything came from Primordial universe (mixture of fragments into separation and formation of present objects)
• Leucippus and Democritus - everything is made of indestructible particles atomos (tiny building blocks); Atomic universe
• Aristotle and Ptolemy - geocentrism (Aristotelian universe); early solar system model
• Nicolaus Copernicus - heliocentrism to counter geocentrism; from Aristarchus of Samos (copernican universe)
• Isaac Newton - universe is a steady-state universe, it is gravitationally balanced but unstable (static/newtonian universe)
• Rene Descartes - notes Newton's model is not completely empty, but it is filled with matter (cartesian vortex universe)
• Big Bang - belgian priest Georges Lemaitre; widely accepted theory
• Georges Lemaitre - discovery of cosmic microwave background and study of galactic redshifting
• Oscillating universe - Albert einstein; universe exapnds and collapses cyclically. Big Bang = expansion state; Big crunch = collapse
• Steady-state universe - everything is constant despite the expansion, new matter is added to universe to retain density.
• Inflating Universe - Alan Guth; based on big bang; introduces a short early period of exponential cosmic inflation
• Multiverse model - Andre Linde, the universe is one bubble in an interconnected multiverse
• Abrahamic universe - john philoponus of alexandria; universe is finite in timee
• Partially Heliocentric universe - Somayaji Nilakantna; geocentric, rest of planets orbit the sun, sun orbits earth
• Nebular Hypothesis - Immanuel Kant and pierre-Simon Laplace; solar system is made up of a dense nebula (collapsed gases due to gravity and spiral movement)
• Encounter hypothesis - sun encountered hypervelocity rogue star, ripping off materials from each other
• Planetesimal Theory - Thomas Chowder-Chamberlain and Forest Ray Moulton; Viktor safronor (original). Collision of a star and protosun into thin disks from the spin of the nebula; disks from sun - planetesimals
• Dust Cloud Theory - Harold Urey and Carl Von Weizacken; came from a protosun (nebula) made of He and H. Rotation due to charges, causing heavy materials to stay, which later on become planets.
• Protoplanet Hypothesis - Gerard Kuiper; Nebula served as protosun that came from interstellar cloud composed of light elements. Accretion of materials = protoplanets. accretion of protoplanets = jovian and terrestrial planets
• Edwin Hubble - first suggested Big Bang Theory 1920s
• Thomas Digger - infinite position of the stars
• Giordano - solar system is not just the center of the universe
• Johannes Kepler - elliptical orbits