Cosmic Calendar

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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 1/4 of a second).

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 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".[3]

The Cosmic Year

Big Bang

Date bya Event
1 Jan 13.8 Big Bang, as seen through cosmic background radiation
14 Jan 13.1 Oldest known Gamma Ray Burst
22 Jan 12.85 First galaxies form[4]
16 Mar 11 Milky Way Galaxy formed
12 May 8.8 Milky Way Galaxy disk formed
2 Sep 4.57 Sun formed (planets and Earth's moon soon thereafter)
6 Sep 4.4 Oldest rocks known on Earth

Date in year calculated from formula

T(days) = 365.25 days * ( 1- T_bya/13.8 )

Evolution of life on Earth

Date bya Event
14 Sep 4.1 "Remains of biotic life" found in 4.1 billion-year-old rocks in Western Australia.[5][6]
21 Sep 3.8 first life (prokaryotes)[7][8][9]
30 Sep 3.4 photosynthesis
29 Oct 2.4 Oxygenation of atmosphere
9 Nov 2 complex cells (eukaryotes)
5 Dec 0.8 first multicellular life[10]
7 Dec 0.67 simple animals
14 Dec 0.55 arthropods (ancestors of insects, arachnids)
17 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
24 Dec 0.25 Permian-Triassic extinction event, 90% of species die out
25 Dec 0.23 dinosaurs
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[11]

Human evolution

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

Date / time kya Event
31 Dec, 23:59:46 6.0 First cities of Mesopotamia
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,Maratha Empire , Crusades, Christopher Columbus voyages to the Americas, Renaissance in Europe, classical music to the time of Johann Sebastian Bach

The current second

Date / time kya Event
31 Dec, 23:59:59 0.5 modern science and technology, music of Josef Haydn and later composers, American Revolution, French revolution, general abolition of slavery in most countries, World War I, World War II, decolonialization, Apollo Moon landing

See also

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2

References

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External links

  1. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  2. ↑ Cosmos, episode 1 (1980)
  3. ↑ [1]
  4. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  5. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  6. ↑ Lua error in package.lua at line 80: module 'strict' not found. Early edition, published online before print.
  7. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  8. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  9. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  10. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  11. ↑ Cosmos: A Spacetime Odyssey (@35min)
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