Palaeos: Palaeos Deep Time
Time Cosmic Calendar

Carl Sagan's Cosmic Calendar

Carl Sagan's Cosmic Calendar

The 13.7 billion year lifetime of the universe mapped onto a single year. At this scale the Big Bang takes place on January 1 at midnight, the current time is December 31 at midnight, and each second is 434 years. The scale was popularized by Carl Sagan in his book The Dragons of Eden and on the television series Cosmos, which he hosted.
This image is the original work of Eric Fisk. Images are composited from Wikipedia, NASA, and other government sites. Creative Commons Attribution-ShareAlike 3.0, Wikipedia

Editor's note: The text on this page is from Wikipedia, apart from one or two light edits, taken verbatim because their presentation looks as good as any, and I can't be bothered reinventing the wheel. The main difference is colour coding according to eras and so on. MAK110824, 110917

The Cosmic Year

The Cosmic Calendar is a scale in which the 13.7 billion year lifetime of the universe is mapped onto a single year. This image helps to put cosmology, evolution, and written history in context. At this scale the Big Bang took place on January 1 at midnight, and the current time is mapped to December 31 at midnight. At this scale, there are 434 years per second, 1.57 million years per hour, and 37.7 million years per day. The concept was popularized by Carl Sagan in his book The Dragons of Eden and on his television series Cosmos as a way to conceptualize the vast amounts of time in the history of the universe.

Cosmic Evolution

The following includes Cosmological time and the start of Geological Time (Chaotian and Hadean).

Date / time bya Event
1 Jan 13.7 Big Bang, as seen through cosmic background radiation
11 May 8.8 Milky Way Galaxy formed
1 Sep 4.57 Sun formed (planets and Earth's moon soon thereafter)
16 Sep 4.0 Oldest rocks known on Earth

Evolution of life

Date / time bya Event
21 Sep 3.8 first life (prokaryotes)
12 Oct 3 photosynthesis
29 Oct 2.4 Oxygenation of atmosphere
8 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 0.065 K-T mass extinction, non-avian dinosaurs die out

Human evolution

The following continues with Geological Time, which then becomes Quaternary Time.

Date / time mya Event
30 Dec 65 Primates
31 Dec, 06:05 15 Apes
31 Dec, 14:24 15 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

The remainder of the calender pertains to Historical Time.

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

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

In contrast with the logarithmic and cosmological timelines, each successive time unit, each day or minute of the cosmic calendar, is the same length. Nevertheless, anthropocentric bias and the general anthropic perspective is still evident in the way that more and more events are crowded into the last minutes and seconds (ultimately, a logarithmic view of history and deep time is unavoidable). Inevitably, deep time requires several different timescales between cosmological time (here, the first eight or nine months) and archeological and historical time (the last 15 seconds or so of the cosmic calendar). MAK110824

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