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2 - Early Speculations. For thousands of years, many have found it absurd to think of Earth as the ONLY place where life existed. c. 400 BCE - Metrodorus of Chios - "It is unnatural in a large field to have only one shaft of wheat and in the infinite universe only one living world.”
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For thousands of years, many have found it absurd to think of Earth as the ONLY place where life existed c. 400 BCE - Metrodorus of Chios - "It is unnatural in a large field to have only one shaft of wheat and in the infinite universe only one living world.” c. 50 BCE - Lucretius - "Nothing in the universe is unique and alone, and therefore in other regions there must be other Earths inhabited by different tribes of men and breeds of beasts.” On the Nature of Things There cannot be more worlds than one. Aristotle (384-322 B.C.) - WRONG!
The Copernican Revolution 1543 - De Revolutionibus Orbium Caelestium (The Revolution of the Heavenly Orbs) Earth is NO LONGER at the Center 1600 - Giordano Bruno burned at the Stake for teaching Copernican astronomy & the idea that there must be "an infinite number of suns with planets and life around them". 1609 - Christian Huygens Cosmotheoras - argued for similarity of worlds & their life forms. Durand
1900 - Percival Lowell Claims to see canals on Mars Describes physiological, social, and political traits of martians…..
Communicating with ETs c. 1820 - Karl Gauss - Plant huge forest of trees in “right triangle” - demonstrate to ETs that we know the Pythagorean Theorem (visible from Mars?) c. 1840 - Joseph von Littrow - do same thing but use kerosene-filled trenches in Egypt
1899 - Nicolai Tesla - Attempts to send radio burst as “message” & listen for a “reply” 1922 - Marconi - listen for signals from a boat at a remote ocean location
Fermi-Hart Paradox: 1950’s - Enrico Fermi: If life is abundant in the galaxy, ETs ought to be HERE They are not So where ARE they? 1970’s - Michael Hart Sets out to do first calculations of planetary evolution to see if life should be common or rare