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The timeline of the Universe lists events from its creation to its ultimate final state. For a timeline of the universe from the present to its presumed conclusion, see: Timeline of the far future; Chronology of the universe; Timeline of the universe
1929 — George Gamow proposes hydrogen fusion as the energy source for stars; 1938 — Hans Bethe and Carl von Weizsäcker detail the proton–proton chain and CNO cycle in stars; 1939 — Rupert Wildt realizes the importance of the negative hydrogen ion for stellar opacity; 1952 — Walter Baade distinguishes between Cepheid I and Cepheid II ...
The time between recombination and the formation of the first stars. During this time, the only source of photons was hydrogen emitting radio waves at hydrogen line. Freely propagating CMB photons quickly (within about 3 million years) red-shifted to infrared, and the universe was devoid of visible light. Star and galaxy formation and evolution
c. 300 BC — star catalog of Timocharis of Alexandria; c. 134 BC — Hipparchus makes a detailed star map; c. 150 — Ptolemy completes his Almagest, which contains a catalog of stars, observations of planetary motions, and treatises on geometry and cosmology; c. 705 — Dunhuang Star Chart, a manuscript star chart from the Mogao Caves at Dunhuang
By applying new ideas from subatomic physics, Subrahmanyan Chandrasekhar predicts that the atoms in a white dwarf star of more than 1.44 solar masses will disintegrate, causing the star to collapse violently. In 1933, Walter Baade and Fritz Zwicky describe the neutron star that results from this collapse, causing a supernova explosion.
By 1781 the final published list grows to 103 objects, 34 of which turn out to be galaxies. 1785 – William Herschel carried the first attempt to describe the shape of the Milky Way and the position of the Sun in it by carefully counting the number of stars in different regions of the sky. He produced a diagram of the shape of the galaxy with ...
Timeline of neutron stars, pulsars, supernovae, and white dwarfs. Note that this list is mainly about the development of knowledge, but also about some supernovae taking place. For a separate list of the latter, see the article List of supernovae. All dates refer to when the supernova was observed on Earth or would have been observed on Earth ...
c. 475 BCE – Parmenides is credited to be the first Greek who declared that the Earth is spherical and is situated in the centre of the universe, believed to have been the first to detect the identity of Hesperus, the evening-star, and Phosphorus, the morning-star (Venus), [13] and by some, the first to claim that moonlight is a reflection of ...