Cosmic Calendar

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The Cosmic Calendar is a method to visualize the vast history of the universe in which its 13.8 billion year lifetime is condensed down into a single year. In this visualization, the Big Bang took place at the beginning of January 1 at midnight, and the current moment is mapped onto the end of December 31 at midnight.[1] At this scale, there are 438 years per second, 1.58 million years per hour, and 37.8 million years per day. This concept was popularized by Carl Sagan in his book The Dragons of Eden and on his television series Cosmos.[2] In the 2014 sequel series, Cosmos: A Spacetime Odyssey, host Neil deGrasse Tyson presents the same concept of a Cosmic Calendar, but using the revised age of the universe of 13.8 billion years[3] as an improvement on Sagan's 1980 figure of 15 billion years. Sagan goes on to extend the comparison in terms of surface area, explaining that if the Cosmic Calendar is scaled to the size of a football field, then "all of human history would occupy an area the size of [his] hand".[4]

The Cosmic Year[edit]

The 13.8 billion year history of the universe mapped onto a single year, as popularized by Carl Sagan. At this scale the Big Bang takes place on January 1 at midnight, the current time is December 31 at midnight, and the longest human life is a blink of an eye (about 1/4th of a second).

Big Bang[edit]

Date bya Event
1 Jan 13.8 Big Bang, as seen through cosmic background radiation
15 Mar 11 Milky Way Galaxy formed
31 Aug 4.57 Sun formed (planets and Earth's moon soon thereafter)
16 Sep 4.0 Oldest rocks known on Earth

Evolution of life on Earth[edit]

Date bya Event
21 Sep 3.8 first life (prokaryotes)[5][6][7]
12 Oct 3 photosynthesis
29 Oct 2.4 Oxygenation of atmosphere
9 Nov 2 complex cells (eukaryotes)
5 Dec 1 first multicellular life
14 Dec 0.67 simple animals
14 Dec 0.55 arthropods (ancestors of insects, arachnids)
18 Dec 0.5 fish and proto-amphibians
20 Dec 0.45 land plants
21 Dec 0.4 insects and seeds
22 Dec 0.36 amphibians
23 Dec 0.3 reptiles
26 Dec 0.2 mammals
27 Dec 0.15 birds
28 Dec 0.13 flowers
30 Dec, 06:24 0.065 Cretaceous–Paleogene extinction event, non-avian dinosaurs die out[8]

Human evolution[edit]

Date / time mya Event
30 Dec 65 Primates
31 Dec, 06:05 15 Apes
31 Dec, 14:24 12.3 hominids
31 Dec, 22:24 2.5 primitive humans and stone tools
31 Dec, 23:44 0.4 Domestication of fire
31 Dec, 23:52 0.2 Anatomically modern humans
31 Dec, 23:55 0.11 Beginning of most recent glacial period
31 Dec, 23:58 0.035 sculpture and painting
31 Dec, 23:59:32 0.012 Agriculture

History begins[edit]

Date / time kya Event
31 Dec, 23:59:47 5.5 First writing (marks end of prehistory and beginning of history), beginning of the Bronze Age
31 Dec, 23:59:48 5.0 First dynasty of Egypt, Early Dynastic period in Sumer, Astronomy
31 Dec, 23:59:49 4.5 Alphabet, Akkadian Empire, Wheel
31 Dec, 23:59:51 4.0 Code of Hammurabi, Middle Kingdom of Egypt
31 Dec, 23:59:52 3.5 Mycenaean Greece; Olmec civilization; Iron Age in Near East, India, and Europe; founding of Carthage
31 Dec, 23:59:53 3.0 Kingdom of Israel, ancient Olympic games
31 Dec, 23:59:54 2.5 Buddha, Confucius, Qin Dynasty, Classical Greece, Ashokan Empire, Vedas completed, Euclidean geometry, Archimedean physics, Roman Republic
31 Dec, 23:59:55 2.0 Ptolemaic astronomy, Roman Empire, Christ, invention of numeral 0
31 Dec, 23:59:56 1.5 Muhammad, Maya civilization, Song Dynasty, rise of Byzantine Empire
31 Dec, 23:59:58 1.0 Mongol Empire, Crusades, Christopher Columbus voyages to the Americas, Renaissance in Europe

The current second[edit]

Date / time kya Event
31 Dec, 23:59:59 0.5 modern science and technology, American Revolution, French revolution, World War I, World War II, Apollo Moon landing

See also[edit]

References[edit]

  1. ^ Therese Puyau Blanchard (1995). "The Universe At Your Fingertips Activity: Cosmic Calendar". Astronomical Society of the Pacific. Retrieved 2007-12-15. 
  2. ^ Cosmos, episode 1 (1980)
  3. ^ Cosmos: A Spacetime Odyssey (@~27min)
  4. ^ [1]
  5. ^ Yoko Ohtomo, Takeshi Kakegawa, Akizumi Ishida, Toshiro Nagase, Minik T. Rosing (8 December 2013). "Evidence for biogenic graphite in early Archaean Isua metasedimentary rocks". Nature Geoscience. doi:10.1038/ngeo2025. Retrieved 9 December 2013. 
  6. ^ Borenstein, Seth (13 November 2013). "Oldest fossil found: Meet your microbial mom". AP News. Retrieved 15 November 2013. 
  7. ^ Noffke, Nora; Christian, Daniel; Wacey, David; Hazen, Robert M. (8 November 2013). "Microbially Induced Sedimentary Structures Recording an Ancient Ecosystem in the ca. 3.48 Billion-Year-Old Dresser Formation, Pilbara, Western Australia". Astrobiology (journal). Bibcode:2013AsBio..13.1103N. doi:10.1089/ast.2013.1030. Retrieved 15 November 2013. 
  8. ^ Cosmos: A Spacetime Odyssey (@35min)

External links[edit]