Prolemy proposes a geocentric universe in which the sun, moon and other planets revolve around the Earth in a complicated system of circular orbits
Jan 1, 1543
Copemicus introduces a heliocentric system with the planets in circular orbits
Italien scientist Giordano Bruno claims that neither Earth nor the sun is the center of the universe. Instead, he suggests that the sun is simply one of infinitely many stars and that there might be countless planets like Earth
Tycho Brahe proposes a system that combines aspects of both the Copernican and Ptolemaic models, with the sun revolving around the Earth and the other planets orbiting the sun
Johannes Kepler posits three laws of planetary motion
Galileo Galilei builds his first telescope
Isaac Newton publishes Mathematical Principles of Natural Philosophy
Friedrich Bessel, a German mathematician and astronmer, measures stellar parallax
Henrietta Swan Leavitt publishes her discovery of being able to calculate the distance of various Cepheids from Earth
Albert Einstein presents a trailblazing model of gravitation
Edwin Hubble discovers the Andromeda Galaxy is 900,000 light-years from Earth
George Lemaitre presents an early version of the big-bang theory based on the theory of relativity
Edwin Hubble discovers that the speed at which galaxies are moving away from us is proportional to their distance from the Earth
Fritz Zwicky discovers the first indications that the space between galaxies might contain an invisible form of matter
George Garnow publishes The Origin of Chemical Elements
Engilsh astronomer Fred Hoyle derides Gamow's theory, calling it the big bang, while revising and presenting the steady-state theory that posits the constant creation of new atoms in empty space
American astronomers Amo Penzias and Rovert Wilson stumble upon cosmic microwave backround radiation while testing a highly sensitive antenna
American astronomers Vera Rubin and Kent Ford show that stars on the outskirts of a spiral galaxy move much faster than expected
The COBE satellite shows, as predicted, that the cosmic microwave background is the remnant heat of the early universe
Research teams from the US and Australia independently show that the universe is expanding at a constantly increasing rate
450 BCE Anaxagoras proposes an infinitely large universe
260 BCE Aristarchus of Samos envisions a heliocentric universe were the sun is the center, but his theory gets little support
450 BCE Anaxagoras proposes an infinitely large universe, composed of atoms and empty space
Aristarchus of Samos envisions a heliocentric universe where the sun is the center, but his theory gets little support
450 BCE Anaxagoras proposes an infinitely large universe coposed of atoms and empty space
260 BCE Aristarchus of Samos envisions a heliocentric universe where the sun is the center, but his theory gets little support
260 BCE Aristarchus of Samos envisions a heliocentric universe where the sun is the center, but his theory gets little support
450 BCE Anaxagoras proposes an infinitely large universe composed of atoms and empty space
The Wilkinson Microwave Anisotropy Probe precisely measures the very small temperature differences in the afterglow of the big bang, which suggest that matter was not evenly distributed in the early universe but instead had "lumps" that became the seeds o
Maps of the universe's macrostructure reveal that galaxies are not distributed uniformly throughout the universe
