Logarithmic timeline

A logarithmic timeline is a timeline laid out according to a logarithmic scale. This necessarily implies a zero point and an infinity point, neither of which can be displayed. The most natural zero point is the Big Bang, looking forward, but the most common is the ever-changing present, looking backward. (Also possible is a zero point in the present, looking forward to the infinite future.)

The idea of presenting history logarithmically goes back at least to 1932, when John B. Sparks copyrighted his chart "Histomap of Evolution". Around the same time it was also explored by the cyberneticist Heinz von Foerster, who used it to propose that memories naturally fade in an exponential manner. Logarithmic timelines have also been used in futures studies to justify the idea of a technological singularity.

A logarithmic scale enables events throughout time to be presented accurately, but enables more events to be included closer to one end. Sparks explained this by stating:

As we travel forward in geological time the more complex is the evolution of life forms and the more are the changes to be recorded. Further, the most recent periods of evolution hold the most interest for us. We need therefore increasingly more space for our outline the nearer we approach modern times, and the logarithmic scale fulfills just this condition without any break in the continuity.

Two examples of such timelines are shown below, while a more comprehensive version (similar to that of Sparks' "Histomap") can be found at Detailed logarithmic timeline.

Example of a forward-looking logarithmic timeline

In this table each row is defined in seconds after the Big Bang, with earliest at the top of the chart. (see Cosmological decade)

Seconds after Big Bang	Period
10−45 to 10−40	Planck epoch
10−40 to 10−35
10−35 to 10−30	Grand unification epoch
10−30 to 10−25
10−25 to 10−20
10−20 to 10−15
10−15 to 10−10	Electroweak epoch
10−10 to 10−5
10−5 to 100	Hadron epoch
100 to 105	Lepton epoch
105 to 1010	Epoch of Nucleosynthesis
1010 to 1015	Epoch of Galaxies
1015 to 1020

The present time is approximately 4.3×10¹⁷ seconds after the Big Bang; the Sun and Earth formed about 2×10¹⁷ seconds after the Big Bang. 10²⁰ seconds is 3 trillion years (3×10¹² years) in the future.

Example of a backward-looking logarithmic timeline

In this table each row is defined in years ago, that is, years before the present date, with the most recent at the top of the chart. Each event is an occurrence of an observed or inferred process. (Note that the logarithmic scale never actually gets to zero.)

Years ago	Period	Event, invention or historical development
10−3 to 10−2	last 3 days	See, for example, the content of Today's events, -1 day}}|Yesterday's and -2 days}}|the day before.
10−2 to 10−1	last 36 days	See, for example, the content in Portal:Current events
10−1 to 100	last year	Events in 2023
100 to 101	2012 onward	Internet, biotechnology, nanotechnology, global warming, more...
101 to 102	20th century	Car to spacecraft, nuclear power, antibiotics, electronics, totalitarianism, world wars, more...
102 to 103	1000 to 1900	Renaissance, printing press, Industrial Revolution, colonialism, firearms, steam engine, more...
103 to 104	Start of Holocene, 8000 BCE to CE 1000, Neolithic, Bronze Age, Iron Age	Cities, empires, writing, wheel, civilization, religions, philosophy, more...
104 to 105	Pleistocene ends, Paleolithic ends, Mesolithic, beginning of Neolithic	Ice Age, music, art, cave paintings, dance, tally stick, medicine, Neandertal extinction, Flores Man extinction, advanced Homo erectus sub-species extinction, Ice Age ends, domestication – agriculture and animal husbandry
105 to 106	Pleistocene, Paleolithic	Humans (150 kya), language, spirituality
106 to 107	Pliocene, Paleolithic begins, Lower Paleolithic	hunting-gathering, tools, fire
107 to 108	Late Cretaceous, Cenozoic	Grasses, mammals, Cretaceous–Paleogene extinction event
108 to 109	Paleozoic, Mesozoic	Cambrian explosion of life, animals, flowering plants, Permian–Triassic extinction event
109 to 1.4×1010	Precambrian, cosmology	Big Bang, Galaxy formation and evolution, Earth, life

External links

• Interview with Heinz von Foerster
• Detailed logarithmic timeline of the Universe
• History and Mathematics
• Exploring Time from Planck time to the lifespan of the universe