Friday, January 4, 2008

Dragons of Eden - Carl Sagan

The Cosmic Calender

"The most instructive way I know to express this cosmic chronology is to imagine the fifteen-billion-year lifetime of the universe (or at least its present incarnation since the Big Bang) compressed into the span of a single year. Then every billion years of Earth history would correspond to about twenty-four days of our cosmic year, and one second of that year to 475 real revolutions of the Earth about the sun. On pages 14 through 16 I present the cosmic chronology in three forms: a list of some representative pre-December dates; a calendar for the month of December; and a closer look at the late evening of New Year's Eve. On this scale, the events of our history books-even books that make significant efforts to deprovincialize the present-are so compressed that it is necessary to give a second-by-second recounting of the last seconds of the cosmic year. Even then, we find events listed as contemporary that we have been taught to consider as widely separated in time. In the history of life, an equally rich tapestry must have been woven in other periods-for example, between 10:02 and 10:03 on the morning of April 6th or September 16th. But we have detailed records only for the very end of the cosmic year.
The chronology corresponds to the best evidence now available. But some of it is rather shaky. No one would be astounded if, for example, it turns out that plants colonized the land in the Ordovician rather than the Silurian Period; or that segmented worms appeared earlier in the Precambrian Period than indicated. Also, in the chronology of the last ten seconds of the cosmic year, it was obviously impossible for me to include all significant events; I hope I may be excused for not having explicitly mentioned advances in art, music and literature or the historically significant American, French, Russian and Chinese revolutions.


Big Bang ~January 1
Origin of the Milky Way Galaxy ~May 1
Origin of the solar system ~September 9
Formation of the Earth ~September 14
Origin of life on Earth ~ September 25
Formation of the oldest rocks known on Earth ~October 2
Date of oldest fossils (bacteria and blue-green algae} ~October 9
Invention of sex (by microorganisms) ~ November 1
Oldest fossil photosynthetic plants ~November 12
Eukaryotes (first cells with nuclei) flourish ~November 15


Origin of Proconsul and Ramapithecus, probable ancestors of apes and men ~ 1:30 P.M.
First humans ~ 10:30 P.M.
Widespread use of stone tools ~11:00 P.M.
Domestication of fire by Peking man ~11:46 P.M.
Beginning of most recent glacial period ~11:56 P.M.
Seafarers settle Australia 11:58*.M.
Extensive cave painting in Europe ~11:59 P.M.
Invention of agriculture ~11:59:20 P.M.
Neolithic civilization; first cities ~11:59:35 P.M.
First dynasties in Sumer, Ebla and Egypt; development of astronomy ~11:59:50 P.M.
Invention of the alphabet; Akkadian Empire ~11:59:51 P.M.
Hammurabic legal codes in Babylon; Middle Kingdom in Egypt ~11:59:52 P.M.
Bronze metallurgy; Mycenaean culture; Trojan War; Olmec culture: invention of the compass ~11:59:53 P.M.
Iron metallurgy; First Assyrian Empire; Kingdom of Israel; founding of Carthage by Phoenicia ~11:59:54 P.M.
Asokan India; Ch'in Dynasty China; Periclean Athens; birth of Buddha ~11:59:55 P.M.
Euclidean geometry; Archimedean physics; Ptolemaic astronomy; Roman Empire; birth of Christ ~11:59:56 P.M.
Zero and decimals invented in Indian arithmetic; Rome falls; Moslem conquests- ~11:59:57 P.M.
Mayan civilization; Sung Dynasty China; Byzantine empire; Mongol invasion; Crusades ~11:59:58 P.M.
Renaissance in Europe; voyages of discovery from Europe and from Ming Dynasty China; emergence of the experimental method in science ~11:59:59 P.M.

Widespread development of science and technology; emergence of a global culture; acquisition of the means for self-destruction of the human species; The first steps in spacecraft planetary exploration and of the search for extraterrestrial intelligence. ~ Now: first second of New Year's Day.

The construction of such tables and calendars is inevitably humbling. It is disconcerting to find that in such a cosmic year the Earth does not condense out of interstellar matter until early September; dinosaurs emerge on Christmas Eve; flowers arise on December 28th; and men and women originate at 10:30 P.M. on New Year's Eve. All of recorded history occupies the last ten seconds of December 31; and the time from the waning of the Middle Ages to the present occupies little more than one second. But because I have arranged it that way, the first cosmic year has just ended. And despite the insignificance of the instant we have so far occupied in cosmic time, it is clear that what happens on and near Earth at the beginning of the second cosmic year will depend very much on the scientific wisdom and the distinctly human sensitivity of mankind." Excerpt from Sagan's Dragon's of Eden.


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