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 currently understood 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 cosmic second, 1.575 million years per cosmic hour, and 37.8 million years per cosmic day.

The concept was popularized by Carl Sagan in his 1977 book The Dragons of Eden and on his 1980 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]

A similar analogy used to visualize the geologic time scale and the history of life on Earth is the Geologic Calendar


DateGya (billion years ago)Event
1 Jan13.8Big Bang, as seen through cosmic background radiation
14 Jan13.1Oldest known Gamma Ray Burst
22 Jan12.85First galaxies form[4]
16 Mar11Milky Way Galaxy formed
12 May8.8Milky Way Galaxy disk formed
2 Sep4.57Formation of the Solar System
6 Sep4.4Oldest 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

DateGya (billion years ago)Event
14 Sep4.1First known remains of biotic life (discovered in 4.1 billion-year-old rocks in Western Australia).[5][6]
21 Sep3.8First Life (Prokaryotes)[7][8][9]
30 Sep3.4Photosynthesis
29 Oct2.4Oxygenation of atmosphere
9 Nov2Complex cells (Eukaryotes)
5 Dec0.8First multicellular life[10]
7 Dec0.67Simple animals
14 Dec0.55Arthropods (ancestors of insects, arachnids)
17 Dec0.5Fish and Proto-amphibians
20 Dec0.45Land plants; Ordovician–Silurian extinction events
21 Dec0.4Insects and seeds
22 Dec0.36Amphibians; Late Devonian extinction
23 Dec0.3Reptiles
24 Dec0.25Permian–Triassic extinction event; 57% of all biological families and 83% of all genera die
25 Dec0.23Dinosaurs
26 Dec0.2Mammals; Triassic–Jurassic extinction event
27 Dec0.15Birds (avian dinosaurs)
28 Dec0.13Flowers
30 Dec, 06:240.065Cretaceous–Paleogene extinction event, non-avian dinosaurs die out[11]

Human evolution

Date / timeMya (million years ago)Event
30 Dec65Primates
31 Dec, 06:0515Apes
31 Dec, 14:2412.3Hominids
31 Dec, 22:242.5Primitive humans and stone tools
31 Dec, 23:440.4Domestication of fire
31 Dec, 23:520.2Anatomically modern humans
31 Dec, 23:550.11Beginning of most recent Glacial Period
31 Dec, 23:580.035Sculpture and painting
31 Dec, 23:59:320.012Agriculture

History begins

Date / timekya (thousand years ago)Event
31 Dec, 23:59:3312.0End of the last Ice Age
31 Dec, 23:59:418.3Flooding of Doggerland
31 Dec, 23:59:466.0Chalcolithic
31 Dec, 23:59:475.5Early Bronze Age; Proto-writing; Building of Stonehenge Cursus
31 Dec, 23:59:485.0First Dynasty of Egypt, Early Dynastic period in Sumer, beginning of Indus Valley Civilisation
31 Dec, 23:59:494.5Alphabet, Akkadian Empire, wheel
31 Dec, 23:59:514.0Code of Hammurabi, Middle Kingdom of Egypt
31 Dec, 23:59:523.5Late Bronze Age to early Iron Age; Minoan eruption
31 Dec, 23:59:533.0Iron Age; beginning of classical antiquity
31 Dec, 23:59:542.5Buddha, Mahavira, Zoroaster, Confucius, Achaemenid Empire, Qin Dynasty, Classical Greece, Ashokan Empire, Vedas Completed, Euclidean geometry, Archimedean Physics, Roman Republic
31 Dec, 23:59:552.0Ptolemaic astronomy, Roman Empire, Christ, invention of numeral 0, Gupta Empire
31 Dec, 23:59:561.5Muhammad, Maya civilization, Song Dynasty, rise of Byzantine Empire
31 Dec, 23:59:581.0Mongol Empire, Maratha Empire, Crusades, Christopher Columbus voyages to the Americas, Renaissance in Europe, Classical music to the time of Johann Sebastian Bach
31 Dec, 23:59:590.5Modern History; the last 437.5 years before present.


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

Date / timekyr(Thousand years), myr (Million years), and Byr (billion years)Event
1 Jan, 00:00:010.5 KyrAnthropocene Epoch
1 Jan, 00:00:2310.0 KyrAntares explodes into a supernova
1 Jan, 00:00:5020.0 KyrChernobyl becomes safe
1 Jan, 00:00:5720.0 KyrThe Arecibo message reaches the M13 cluster
1 Jan, 00:01:5450.0 KyrNiagara Falls erodes away
1 Jan, 00:03:48100.0 KyrProper motion makes all constellations unrecognizable
1 Jan, 00:11:24300.0 KyrWR 104 explodes
1 Jan, 00:19:02500.0 KyrEarth likely hit by 1 km asteroid
1 Jan, 00:38:051.0 MyrPyramids of Giza erode away
1 Jan, 04:34:177.2 MyrMount Rushmore erodes away
1 Jan, 16:3020.00 MyrEastern Africa splits apart
2 Jan50.00 MyrMediterranean Sea closes up due to Europe and Africa colliding
3 Jan100.00 MyrSaturn loses its rings
5 Jan180.00 MyrEarth's day becomes one hour longer
7 Jan240.00 MyrSolar System completes one galactic year
8 Jan450.00 MyrFormation of possible new supercontinent
16 Jan600.00 MyrSolar eclipses no longer possible
17 Jan700.00 MyrAtmospheric CO2 levels too low for photosynthesis, all complex life die
8 Feb1.0 ByrEarth's oceans evaporate away
1 Mar2.0 ByrAll life on Earth dies
18 Mar3.0 ByrMilky Way-Andromeda collision
9 Apr4.0 ByrSun expands into a red giant
16 Apr4.0 ByrGlobal surface temperatures reach 1330 deg C, hot enough to melt lead
28 Jul7.9 ByrSun destroys the Earth
12 Aug8.0 ByrSun becomes a white dwarf
31 Dec12.0 ByrSolar System ceases to exist

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

Date / timeByr (billion years) and aboveEvent
Year 3, 21 Mar100.0 ByrGalaxies disappear beyond light horizon
Year 4, 13 Dec100 trillionStar formation ends
Year 5, 11 Jul1 quadrillionSun cools down to -268 deg C
Year 7, 31 Dec3×1043Black Hole Era
Year 4.54×10981.7×1098Last black holes evaporate
Year 10100Dark Era begins, Heat death of the universe
Year 101500Iron Stars form, assuming protons do not decay
Year 101050Possible Boltzmann brain appears
Year 101076Last black holes evaporate
Year 1010120Final entropy state, (Dark Era begins, Heat death of the universe)
Year 10101056Possible new Big Bang occurs

See also

  • History of Earth – Development of planet Earth from its formation to the present day


  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". Retrieved 2015-11-07.
  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.
  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.
  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.
  8. ^ Borenstein, Seth (13 November 2013). "Oldest fossil found: Meet your microbial mom". AP News. Retrieved 15 November 2013.
  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.
  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.

External links

Media files used on this page

Crab Nebula.jpg
This is a mosaic image, one of the largest ever taken by NASA's Hubble Space Telescope, of the Crab Nebula, a six-light-year-wide expanding remnant of a star's supernova explosion. Japanese and Chinese astronomers recorded this violent event in 1054 CE, as did, almost certainly, Native Americans.

The orange filaments are the tattered remains of the star and consist mostly of hydrogen. The rapidly spinning neutron star embedded in the center of the nebula is the dynamo powering the nebula's eerie interior bluish glow. The blue light comes from electrons whirling at nearly the speed of light around magnetic field lines from the neutron star. The neutron star, like a lighthouse, ejects twin beams of radiation that appear to pulse 30 times a second due to the neutron star's rotation. A neutron star is the crushed ultra-dense core of the exploded star.

The Crab Nebula derived its name from its appearance in a drawing made by Irish astronomer Lord Rosse in 1844, using a 36-inch telescope. When viewed by Hubble, as well as by large ground-based telescopes such as the European Southern Observatory's Very Large Telescope, the Crab Nebula takes on a more detailed appearance that yields clues into the spectacular demise of a star, 6,500 light-years away.

The newly composed image was assembled from 24 individual Wide Field and Planetary Camera 2 exposures taken in October 1999, January 2000, and December 2000. The colors in the image indicate the different elements that were expelled during the explosion. Blue in the filaments in the outer part of the nebula represents neutral oxygen, green is singly-ionized sulfur, and red indicates doubly-ionized oxygen.
Author/Creator: ESO, European Southern Observatory, Licence: CC BY 4.0
Artist's impression of "the oldest star of our Galaxy": HE 1523-0901
  • About 13.2 billion years old
  • Approximately 7500 light years far from Earth
  • Published as part of Hamburg/ESO Survey in the May 10 2007 issue of The Astrophysical Journal
Author/Creator: Me, Licence: Copyrighted free use
SVG replacement for File:Spaceship and the Sun.jpg. A stylized illustration of a spaceship and the sun, based on the description of the emblem of the fictional Galactic Empire in Isaac Asimov's Foundation series ("The golden globe with its conventionalized rays, and the oblique cigar shape that was a space vessel"). This image could be used as a icon for science-fiction related articles.
This view of the rising Earth greeted the Apollo 8 astronauts as they came from behind the Moon after the fourth nearside orbit. Earth is about five degrees above the horizon in the photo. The unnamed surface features in the foreground are near the eastern limb of the Moon as viewed from Earth. The lunar horizon is approximately 780 kilometers from the spacecraft. Width of the photographed area at the horizon is about 175 kilometers. On the Earth 240,000 miles away, the sunset terminator bisects Africa.
Solar system.jpg
This is a montage of planetary images taken by spacecraft managed by the Jet Propulsion Laboratory in Pasadena, CA. Included are (from top to bottom) images of Mercury, Venus, Earth (and Moon), Mars, Jupiter, Saturn, Uranus and Neptune. The spacecraft responsible for these images are as follows:
  • the Mercury image was taken by Mariner 10,
  • the Venus image by Magellan,
  • the Earth and Moon images by Galileo,
  • the Mars image by Mars Global Surveyor,
  • the Jupiter image by Cassini, and
  • the Saturn, Uranus and Neptune images by Voyager.
  • Pluto is not shown as it is no longer a planet, and no spacecraft has yet visited it when this montage was taken. The inner planets (Mercury, Venus, Earth, Moon, and Mars) are roughly to scale to each other; the outer planets (Jupiter, Saturn, Uranus, and Neptune) are roughly to scale to each other. PIA 00545 is the same montage with Neptune shown larger in the foreground. Actual diameters are given below:
  • Sun (to photosphere) 1,392,684 km
  • Mercury 4,879.4 km
  • Venus 12,103.7 km
  • Earth 12,756.28 km
  • Moon 3,476.2 km
  • Mars 6,804.9 km
  • Jupiter 142,984 km
  • Saturn 120,536 km
  • Uranus 51,118 km
  • Neptune 49,528 km
Cosmic Calendar.png
(c) Efbrazil, CC BY-SA 3.0
The 13.8 billion year lifetime of the universe mapped onto a single year. At this scale the Big Bang takes place at the instant of midnight going into January 1, and the current time is the end of December 31 at midnight, and the longest human life is about 1/4th of a second, a blink of an eye.[1] The scale was popularized by Carl Sagan in his book The Dragons of Eden and on the television series Cosmos, which he hosted.
Carl Sagan Planetary Society.JPG
Part of Image:Planetary society.jpg Original caption: "Founding of the Planetary Society Carl Sagan, Bruce Murray and Louis Friedman, the founders of The Planetary Society at the time of signing the papers formally incorporating the organization. The fourth person is Harry Ashmore, an advisor, who greatly helped in the founding of the Society. Ashmore was a Pulitizer Prize winning journalist and leader in the Civil Rights movement in the 1960s and 1970s."