Multiverse moments of truth

Commentary • The Daily Dose: ID and the Muslim world • Davies's third way Science & Religion Guide • Confirm or deny: Science and faith in the murky multiverse • Chance or creation? Only the multiverse knows for sure • Physicist plucks away at our tightly strung universe • Masters of the multiverse • Read all about it • Multiverse moments of truth News & Features • A universe of universes? • The science of eternity • When 'universe' too small, 'multiverse' may fit • Scientists at Harvard fail to reach consensus on why we are here

1513 Nicolaus Copernicus first writes about his theory that the sun, not Earth, was at the center of our universe.

1576 Thomas Digges modifies Copernicus’ universe system by replacing its outer rim with star-filled unbounded space; the concept of the universe grows.

1610 Johannes Kepler argues for a finite universe based on the dark night sky; he argues that if the universe is infinite and contains an infinite number of stars, there should be no spaces of dark sky.

1823 Adding to the work of Kepler, Heinrich Wilhelm Olbers develops Olbers’ paradox. He mathematically backs the question: If the universe and the amount of stars are infinite, why is the night sky dark?

1915 Albert Einstein publishes the general theory of relativity, portraying gravity as a distortion in spacetime geometry and laying the foundations for all modern cosmological theory.

1918 Harlow Shapley determines that the sun lies toward one edge of a galaxy of stars. This is the first reliable indication of the size of the Milky Way.

1929 Edwin Hubble formulates Hubble’s Law, which measures how quickly galaxies recede from each other. This theory eventually will lead to the idea of the big-bang theory.

1965 Cosmic microwave background radiation is discovered, confirming the big-bang theory that our universe began with a huge explosion.

1981 Alan Guth proposes a modified big-bang theory — inflation — which states, “the expansion of the universe was propelled by a repulsive gravitational force generated by an exotic form of matter.”