Cosmic Calendar

A graphical view of the Cosmic Calendar, featuring the months of the year, days of December, and the final minute.

The Cosmic Calendar is a method to visualize the chronology of the universe, scaling its current age of 13.8 billion years to a single year in order to help intuit it for pedagogical purposes in science education or popular science.

In this visualization, the Big Bang took place at the beginning of January 1 at midnight, and the current moment maps onto the end of December 31 just before midnight.^[1] At this scale, there are 437.5 years per second, 1.575 million years per hour, and 37.8 million years per day.

The concept was popularized by Carl Sagan in his book The Dragons of Eden (1977) and on his television series Cosmos.^[2] 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

The Cosmic Calendar shows the time-scale relationship of the universe and all events on Earth as plotted along a single 12-month, 365-day, year. On this scale, one second corresponds to 438 years; a minute is about 26,000 years; an hour is 1.6 million years; and a day is 38 million years.

Cosmology

Date	Bya (Billion Years Ago)	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	formation of the Solar System
6 Sep	4.4	Oldest rocks known on Earth

Date in year calculated from formula

T(days) = 365 days * 0.100/13.797 ( 1- T_Gya/13.797 )

Evolution of life on Earth

Date	Bya (Billion Years Ago)	Event
14 Sep	4.1	First known remains of biotic life (discovered 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; Ordovician–Silurian extinction events
21 Dec	0.4	Insects and Seeds
22 Dec	0.36	Amphibians; Late Devonian extinction
23 Dec	0.3	Reptiles
24 Dec	0.25	Permian–Triassic extinction event; 57% of all biological families and 83% of all genera die
25 Dec	0.23	Dinosaurs
26 Dec	0.2	Mammals; Triassic–Jurassic extinction event
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(Million Years Ago)	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(Thousand Years Ago)	Event
31 Dec, 23:59:33	12.0	End of the Ice Age
31 Dec, 23:59:41	8.3	Flooding of Doggerland
31 Dec, 23:59:46	6.0	Chalcolithic
31 Dec, 23:59:47	5.5	Early Bronze Age; Proto-writing; Building of Stonehenge Cursus
31 Dec, 23:59:48	5.0	First Dynasty of Egypt, Early Dynastic Period in Sumer, Beginning of Indus Valley Civilisation
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	Late Bronze Age to Early Iron Age; Minoan eruption
31 Dec, 23:59:53	3.0	Iron Age; Beginning of Classical Antiquity
31 Dec, 23:59:54	2.5	Buddha, Mahavira, Zoroaster, 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, Gupta Empire
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(Thousand Years Ago)	Event
31 Dec, 23:59:59	0.5	Modern History; the last 437.5 years before present.

Future

Future of the Earth and Solar System ("Year 2")

Date / time	kyr(Thousand years), myr (Million years), and Byr (billion years)	Event
1 Jan, 00:00:01	0.5 Kyr	Anthropocene Epoch
1 Jan, 00:00:23	10.0 Kyr	Antares explodes into a supernova
1 Jan, 00:00:50	20.0 Kyr	Chernobyl becomes safe
1 Jan, 00:00:57	20.0 Kyr	The Arecibo message reaches the M13 cluster
1 Jan, 00:01:54	50.0 Kyr	Niagara Falls erodes away
1 Jan, 00:03:48	100.0 Kyr	Proper motion makes all constellations unrecognizable
1 Jan, 00:11:24	300.0 Kyr	WR 104 explodes
1 Jan, 00:19:02	500.0 Kyr	Earth likely hit by 1 km asteroid
1 Jan, 00:38:05	1.0 Myr	Pyramids of Giza erode away
1 Jan, 04:34:17	7.2 Myr	Mount Rushmore erodes away
1 Jan, 16:30	20.00 Myr	Eastern Africa splits apart
2 Jan	50.00 Myr	Mediterranean Sea closes up due to Europe and Africa colliding
3 Jan	100.00 Myr	Saturn loses its rings
5 Jan	180.00 Myr	Earth's day becomes one hour longer
7 Jan	240.00 Myr	Solar System completes one galactic year
8 Jan	250.00 Myr	Formation of possible new supercontinent
16 Jan	600.00 Myr	Solar eclipses no longer possible
17 Jan	700.00 Myr	Atmospheric CO2 levels too low for photosynthesis, all complex life die
8 Feb	1.0 Byr	Earth's oceans evaporate away
1 Mar	2.0 Byr	All life on Earth dies
18 Mar	3.0 Byr	Milky Way-Andromeda collision
9 Apr	4.0 Byr	Sun expands into a red giant
16 Apr	4.0 Byr	Global surface temperatures reach 1330 deg C, hot enough to melt lead
28 Jul	7.9 Byr	Sun destroys the Earth
12 Aug	8.0 Byr	Sun becomes a white dwarf
31 Dec	12.0 Byr	Solar System ceases to exist

Future of the Universe ("Year 3" and beyond)

Date / time	Byr (billion years) and above	Event
Year 8, 1 Apr	100.0	Galaxies disappear beyond light horizon
Year 7247, 13 Dec	100 trillion	Star formation ends
Year 72,479, 11 Jul	1 quadrillion	Sun cools down to -268 deg C
Year 7.94*10³⁵	3*10⁴³	Black Hole Era
Year 4.54*10⁹⁸	1.7*10⁹⁸	Dark Era
Year 10¹⁵⁰⁰		Iron stars
Year 10^10⁵⁰		Boltzmann brain appears
Year 10^10⁷⁸		Last black holes evaporate
Year 10^10¹²⁰		Final entropy state
Year 10^{10^10⁵⁶}		Possible new Big Bang occurs

References

^ Therese Puyau Blanchard (1995). "The Universe At Your Fingertips Activity: Cosmic Calendar". Astronomical Society of the Pacific. Archived from the original on 2007-12-16. Retrieved 2007-12-15.
^ Cosmos, episode 1 (1980)
^ Episode 1: The Shores of the Cosmic Ocean (Cosmos: A Personal Voyage, Carl Sagan)
^ "First Galaxies Born Sooner After Big Bang Than Thought". Space.com. Retrieved 2015-11-07.
^ Borenstein, Seth (19 October 2015). "Hints of life on what was thought to be desolate early Earth". Excite. Yonkers, NY: Mindspark Interactive Network. Associated Press. Retrieved 2015-10-20.
^ Bell, Elizabeth A.; Boehnike, Patrick; Harrison, T. Mark; et al. (19 October 2015). "Potentially biogenic carbon preserved in a 4.1 billion-year-old zircon" (PDF). Proc. Natl. Acad. Sci. U.S.A. 112 (47): 14518–21. Bibcode:2015PNAS..11214518B. doi:10.1073/pnas.1517557112. ISSN 1091-6490. PMC 4664351. PMID 26483481. Retrieved 2015-10-20. Early edition, published online before print.
^ 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. 7: 25–28. Bibcode:2014NatGe...7...25O. doi:10.1038/ngeo2025.
^ 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. 13 (12): 1103–24. Bibcode:2013AsBio..13.1103N. doi:10.1089/ast.2013.1030. PMC 3870916. PMID 24205812.
^ Erwin, Douglas H. (9 November 2015). "Early metazoan life: divergence, environment and ecology". Phil. Trans. R. Soc. B. 370 (20150036): 20150036. doi:10.1098/rstb.2015.0036. PMC 4650120. PMID 26554036.
^ "Cosmos: A Spacetime Odyssey (@35min)". Archived from the original on 2014-03-11. Retrieved 2014-03-11.

External links

[astrosocietyorg-1] Therese Puyau Blanchard (1995). "The Universe At Your Fingertips Activity: Cosmic Calendar". Astronomical Society of the Pacific. Archived from the original on 2007-12-16. Retrieved 2007-12-15.

[2] Cosmos, episode 1 (1980)

[3] Episode 1: The Shores of the Cosmic Ocean (Cosmos: A Personal Voyage, Carl Sagan)

[4] "First Galaxies Born Sooner After Big Bang Than Thought". Space.com. Retrieved 2015-11-07.

[AP-20151019-5] Borenstein, Seth (19 October 2015). "Hints of life on what was thought to be desolate early Earth". Excite. Yonkers, NY: Mindspark Interactive Network. Associated Press. Retrieved 2015-10-20.

[PNAS-20151014-pdf-6] Bell, Elizabeth A.; Boehnike, Patrick; Harrison, T. Mark; et al. (19 October 2015). "Potentially biogenic carbon preserved in a 4.1 billion-year-old zircon" (PDF). Proc. Natl. Acad. Sci. U.S.A. 112 (47): 14518–21. Bibcode:2015PNAS..11214518B. doi:10.1073/pnas.1517557112. ISSN 1091-6490. PMC 4664351. PMID 26483481. Retrieved 2015-10-20. Early edition, published online before print.

[NG-20131208-7] 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. 7: 25–28. Bibcode:2014NatGe...7...25O. doi:10.1038/ngeo2025.

[AP-20131113-8] Borenstein, Seth (13 November 2013). "Oldest fossil found: Meet your microbial mom". AP News. Retrieved 15 November 2013.

[AST-20131108-9] 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. 13 (12): 1103–24. Bibcode:2013AsBio..13.1103N. doi:10.1089/ast.2013.1030. PMC 3870916. PMID 24205812.

[PTRS-2015-10] Erwin, Douglas H. (9 November 2015). "Early metazoan life: divergence, environment and ecology". Phil. Trans. R. Soc. B. 370 (20150036): 20150036. doi:10.1098/rstb.2015.0036. PMC 4650120. PMID 26554036.

[11] "Cosmos: A Spacetime Odyssey (@35min)". Archived from the original on 2014-03-11. Retrieved 2014-03-11.

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