World Cosmologies
Name 
Source and Date 
Classification 
Remarks 
Rigveda (c. 1700–1100 BC) 
Cyclical or oscillating, Infinite in time 
One cycle of existence is around 311 trillion years and the life of one universe around 8 billion years. This Universal cycle is preceded by an infinite number of universes and to be followed by another infinite number of universes. Includes an infinite number of universes at one given time. 

Jain Agamas (written around 500 AD as per the teachings of Mahavira 599–527 BC) 
Cyclical or oscillating, eternal and finite 
Jain cosmology considers the loka, or universe, as an uncreated entity, existing since infinity, the shape of the universe as similar to a man standing with legs apart and arm resting on his waist. This Universe, according to Jainism, is broad at the top, narrow at the middle and once again becomes broad at the bottom. 

Babylonian literature (c. 3000 BC) 
Flat earth floating in infinite "waters of chaos" 
The Earth and the Heavens form a unit within infinite "waters of chaos"; the earth is flat and circular, and a solid dome (the "firmament") keeps out the outer "chaos"ocean. 

Parmenides (c. 515 BC) 
Finite and spherical in extent 
The Universe is unchanging, uniform, perfect, necessary, timeless, and neither generated nor perishable. Void is impossible. Plurality and change are products of epistemic ignorance derived from sense experience. Temporal and spatial limits are arbitrary and relative to the Parmenidean whole. 

Genesis creation narrative (c. 500 BC) 
Flat earth floating in infinite "waters of chaos" 
Based on Babylonian cosmology. The Earth and the Heavens form a unit within infinite "waters of chaos"; the earth is flat and circular, and a solid dome (the "firmament") keeps out the outer "chaos"ocean. 

Anaxagoras (500–428 BC) & later Epicurus 
Infinite in extent 
The universe contains only two things: an infinite number of tiny seeds (atoms) and the void 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. Incorporates Leucippus' principle of causality: "nothing happens at random; everything happens out of reason and necessity". The universe was not ruled by gods. 

Philolaus (d. 390 BC) 
Existence of a "Central Fire" at the center of the Universe. 
At the center of the Universe is a central fire, around which the Earth, Sun, Moon and planets revolve uniformly. The Sun revolves around the central fire once a year, the stars are immobile. The earth in its motion maintains the same hidden face towards the central fire, hence it is never seen. First known nongeocentric model of the Universe.^{[15]} 

PseudoAristotle (d. 250 BC or between 350 and 200 BC) 
The Universe is a system made up of heaven and earth and the elements which are contained in them. 
Thus then five elements, situated in spheres in five regions, the less being in each case surrounded by the greater — namely, earth surrounded by water, water by air, air by fire, and fire by ether — make up the whole Universe.^{[16]} 

Stoics(300 BC – 200 AD) 
The cosmos is finite and surrounded by an infinite void. It is in a state of flux, and pulsates in size and undergoes periodic upheavals and conflagrations. 

Aristotle(384–322 BC) 
Geocentric, static, steady state, finite extent, infinite time 
Spherical earth is surrounded by concentric celestial spheres. Universe exists unchanged throughout eternity. Contains a fifth element, called aether, that was added to the four classical elements. 

Aristarchean universe 
Aristarchus(circa 280 BC) 
Earth rotates daily on its axis and revolves annually about the sun in a circular orbit. Sphere of fixed stars is centered about the sun. 

Ptolemy (2nd century AD) 
Geocentric (based on Aristotelian universe) 
Universe orbits around a stationary Earth. Planets move in circular epicycles, each having a center that moved in a larger circular orbit (called an eccentric or a deferent) around a centerpoint near Earth. The use of equants added another level of complexity and allowed astronomers to predict the positions of the planets. The most successful universe model of all time, using the criterion of longevity. Almagest (the Great System). 

Aryabhatan model 
Aryabhata(499) 
Geocentric or Heliocentric 
The Earth rotates and the planets move in elliptical orbits around either the Earth or Sun; uncertain whether the model is geocentric or heliocentric due to planetary orbits given with respect to both the Earth and Sun. 
Medieval universe 
Medieval philosophers(500–1200) 
Finite in time 
A universe that is finite in time and has a beginning is proposed by the Christian philosopher John Philoponus, who argues against the ancient Greek notion of an infinite past. Logical arguments supporting a finite universe are developed by the early Muslim philosopher Alkindus, the Jewish philosopher Saadia Gaon, and the Muslim theologian Algazel. 
Fakhr alDin alRazi(1149–1209) 
Multiverse, multiple worlds and universes 
There exists an infinite outer space beyond the known world, and God has the power to fill the vacuum with an infinite number of universes. 

Maragha models 
Maragha school (1259–1528) 
Geocentric 
Various modifications to Ptolemaic model and Aristotelian universe, including rejection of equant and eccentrics at Maragheh observatory, and introduction of Tusicouple by AlTusi. Alternative models later proposed, including the first accurate lunar model by Ibn alShatir, a model rejecting stationary Earth in favor of Earth's rotation by Ali Kuşçu, and planetary model incorporating "circular inertia" by AlBirjandi. 
Nilakanthan model 
Nilakantha Somayaji(1444–1544) 
Geocentric and heliocentric 
A universe in which the planets orbit the Sun, which orbits the Earth; similar to the later Tychonic system 
Nicolaus Copernicus(1473–1543) 
Heliocentric with circular planetary orbits 
First described in De revolutionibus orbium coelestium. 

Tycho Brahe(1546–1601) 
Geocentric and Heliocentric 
A universe in which the planets orbit the Sun and the Sun orbits the Earth, similar to the earlier Nilakanthan model. 

Giordano Bruno (1548–1600) 
Infinite extent, infinite time, homogeneous, isotropic, nonhierarchical 
Rejects the idea of a hierarchical universe. Earth and Sun have no special properties in comparison with the other heavenly bodies. The void between the stars is filled with aether, and matter is composed of the same four elements (water, earth, fire, and air), and is atomistic, animistic and intelligent. 

Keplerian 
Johannes Kepler (1571–1630) 
Heliocentric with elliptical planetary orbits 
Kepler's discoveries, marrying mathematics and physics, provided the foundation for our present conception of the Solar system, but distant stars were still seen as objects in a thin, fixed celestial sphere. 
Static Newtonian 
Isaac Newton(1642–1727) 
Static (evolving), steady state, infinite 
Every particle in the universe attracts every other particle. Matter on the large scale is uniformly distributed. Gravitationally balanced but unstable. 
Cartesian Vortex universe 
René Descartes, 17th century 
Static (evolving), steady state, infinite 
System of huge swirling whirlpools of aethereal or fine matter produces what we would call gravitational effects. But his vacuum was not empty; all space was filled with matter. 
Hierarchical universe 
Immanuel Kant, Johann Lambert, 18th century 
Static (evolving), steady state, infinite 
Matter is clustered on ever larger scales of hierarchy. Matter is endlessly recycled. 
Albert Einstein, 1917 
Static (nominally). Bounded (finite) 
"Matter without motion". Contains uniformly distributed matter. Uniformly curved spherical space; based on Riemann's hypersphere. Curvature is set equal to Λ. In effect Λ is equivalent to a repulsive force which counteracts gravity. Unstable. 

Willem de Sitter, 1917 
Steady state. Λ > 0 
"Motion without matter." Only apparently static. Based on Einstein's general relativity. Space expands with constant acceleration. Scale factor increases exponentially (constant inflation). 

MacMillan universe 
Static and steady state 
New matter is created from radiation; starlight perpetually recycled into new matter particles. 

Friedmann universe, spherical space 
Spherical expanding space. k= +1 ; no Λ 
Positive curvature. Curvature constant k = +1 Expands then recollapses. Spatially closed (finite). 

Friedmann universe, hyperbolic space 
Alexander Friedmann, 1924 
Hyperbolic expanding space. k= 1 ; no Λ 
Negative curvature. Said to be infinite (but ambiguous). Unbounded. Expands forever. 
Paul Dirac1930s 
Expanding 
Demands a large variation in G, which decreases with time. Gravity weakens as universe evolves. 

Friedmann zerocurvature 
Einstein and DeSitter, 1932 
Expanding flat space k= 0 ; Λ = 0 Critical density 
Curvature constant k = 0. Said to be infinite (but ambiguous). "Unbounded cosmos of limited extent". Expands forever. "Simplest" of all known universes. Named after but not considered by Friedmann. Has a deceleration term q =½, which means that its expansion rate slows down. 
The original Big Bang (FriedmannLemaître) 
Georges Lemaître 1927–29 
Expansion Λ > 0 Λ > Gravity 
Λ is positive and has a magnitude greater than gravity. Universe has initial highdensity state ("primeval atom"). Followed by a twostage expansion. Λ is used to destabilize the universe. (Lemaître is considered the father of the big bang model.) 
Oscillating universe (FriedmannEinstein) 
Favored by Friedmann, 1920s 
Expanding and contracting in cycles 
Time is endless and beginningless; thus avoids the beginningoftime paradox. Perpetual cycles of big bang followed by big crunch. (Einstein's first choice after he rejected his 1917 model.) 
Eddington universe 
Arthur Eddington1930 
First static then expands 
Static Einstein 1917 universe with its instability disturbed into expansion mode; with relentless matter dilution becomes a DeSitter universe. Λ dominates gravity. 
Milne universe of kinematic relativity 
Edward Milne, 1933, 1935; William H. McCrea, 1930s 
Kinematic expansion without space expansion 
Rejects general relativity and the expanding space paradigm. Gravity not included as initial assumption. Obeys cosmological principle and special relativity; consists of a finite spherical cloud of particles (or galaxies) that expands within an infinite and otherwise empty flat space. It has a center and a cosmic edge (surface of the particle cloud) that expands at light speed. Explanation of gravity was elaborate and unconvincing. 
Friedmann–Lemaître–Robertson–Walker class of models 
Howard Robertson, Arthur Walker, 1935 
Uniformly expanding 
Class of universes that are homogeneous and isotropic. Spacetime separates into uniformly curved space and cosmic time common to all comoving observers. The formulation system is now known as the FLRW or Robertson–Walker metrics of cosmic time and curved space. 
Steadystate expanding 
Hermann Bondi, Thomas Gold, 1948 
Expanding, steady state, infinite 
Matter creation rate maintains constant density. Continuous creation out of nothing from nowhere. Exponential expansion. Deceleration term q = 1. 
Steadystate expanding 
Fred Hoyle1948 
Expanding, steady state; but unstable 
Matter creation rate maintains constant density. But since matter creation rate must be exactly balanced with the space expansion rate the system is unstable. 
Cellular universe, expanding by means of matter–antimatter annihilation 
Based on the concept of plasma cosmology. The universe is viewed as "metagalaxies" divided by double layers and thus a bubblelike nature. Other universes are formed from other bubbles. Ongoing cosmic matterantimatterannihilations keep the bubbles separated and moving apart preventing them from interacting. 

Expanding 
Based on Mach's principle. G varies with time as universe expands. 

Alan Guth1980 
Big Bang modified to solve horizon and flatness problems 
Based on the concept of hot inflation. The universe is viewed as a multiple quantum flux—hence its bubblelike nature. Other universes are formed from other bubbles. Ongoing cosmic expansion kept the bubbles separated and moving apart. 

Eternal inflation (a multiple universe model) 
Andreï Linde, 1983 
Big Bang with cosmic inflation 
Multiverse based on the concept of cold inflation, in which inflationary events occur at random each with independent initial conditions; some expand into bubble universes supposedly like our entire cosmos. Bubbles nucleate in a spacetime foam. 
Expanding and contracting in cycles; Mtheory. 
Two parallel orbifold planes or Mbranes collide periodically in a higherdimensional space. With quintessence or dark energy. 

Deepak Chopra; Menas Kafatos 2017 
Participatory, experiential universe defined by consciousness 
In a modern synthesis of quantum mechanics and Vedanta, the reality experienced by conscious entities is only cemented by perceptual awareness, thus consciousness is the defining filter of known reality. 