See also: Detailed 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".[1] 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 it also 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.
In this table each row is defined in seconds after the Big Bang, with the 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 seconds after the Big Bang; the Sun and Earth formed about seconds after the Big Bang. 1020 seconds is 3 trillion years (years) in the future.
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 | ||
| 10−1 to 100 | last year | See, for example, -1 year}}#Events|Events in | ||
| 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 | Renaissance, printing press, Industrial Revolution, colonialism, firearms, steam engine, more... | |||
| align=center | 103 to 104 | 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 | ||
| align=center | 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 | ||
| align=center | 109 to | Precambrian, cosmology | Big Bang, Galaxy formation and evolution, Earth, life |