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).
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.
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
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".
The Cosmic Year
Evolution of life on Earth
| Date / time
| 31 Dec, 23:59:47
|| First writing (marks end of prehistory and beginning of history), beginning of the Bronze Age
| 31 Dec, 23:59:48
|| First dynasty of Egypt, Early Dynastic period in Sumer, Astronomy
| 31 Dec, 23:59:49
|| Alphabet, Akkadian Empire, Wheel
| 31 Dec, 23:59:51
|| Code of Hammurabi, Middle Kingdom of Egypt
| 31 Dec, 23:59:52
|| Mycenaean Greece; Olmec civilization; Iron Age in Near East, India, and Europe; founding of Carthage
| 31 Dec, 23:59:53
|| Kingdom of Israel, ancient Olympic games
| 31 Dec, 23:59:54
|| Buddha, Confucius, Qin Dynasty, Classical Greece, Ashokan Empire, Vedas completed, Euclidean geometry, Archimedean physics, Roman Republic
| 31 Dec, 23:59:55
|| Ptolemaic astronomy, Roman Empire, Christ, invention of numeral 0
| 31 Dec, 23:59:56
|| Muhammad, Maya civilization, Song Dynasty, rise of Byzantine Empire
| 31 Dec, 23:59:58
|| Mongol Empire, Crusades, Christopher Columbus voyages to the Americas, Renaissance in Europe, classical music to the time of Johann Sebastian Bach
The current second
- ^ Therese Puyau Blanchard (1995). "The Universe At Your Fingertips Activity: Cosmic Calendar". Astronomical Society of the Pacific. Retrieved 2007-12-15.
- ^ Cosmos, episode 1 (1980)
- ^ 
- ^ 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.
- ^ Borenstein, Seth (13 November 2013). "Oldest fossil found: Meet your microbial mom". AP News. Retrieved 15 November 2013.
- ^ 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) 13 (12): 1103–24. Bibcode:2013AsBio..13.1103N. PMC 3870916. PMID 24205812. doi:10.1089/ast.2013.1030. Retrieved 15 November 2013.
- ^ Cosmos: A Spacetime Odyssey (@35min)