For faster navigation, this Iframe is preloading the Wikiwand page for Geologic Calendar.

Geologic Calendar

From Wikipedia, the free encyclopedia

The Geologic Calendar is a scale in which the geological lifetime of the Earth is mapped onto a calendrical year; that is to say, the day one of the Earth took place on a geologic January 1 at precisely midnight, and today's date and time is December 31 at midnight.[1] On this calendar, the inferred appearance of the first living single-celled organisms, prokaryotes, occurred on a geologic February 25 around 12:30 pm to 1:07 pm,[2] dinosaurs first appeared on December 13, the first flower plants on December 22 and the first primates on December 28 at about 9:43 pm. The first Anatomically modern humans did not arrive until around 11:48 p.m. on New Year's Eve, and all of human history since the end of the last ice-age occurred in the last 82.2 seconds before midnight of the new year.

A variation of this analogy instead compresses Earth's 4.6 billion year-old history into a single day: While the Earth still forms at midnight, and the present day is also represented by midnight, the first life on Earth would appear at 4:00 am, dinosaurs would appear at 10:00 pm, the first flowers 10:30 pm, the first primates 11:30 pm, and modern humans would not appear until the last two seconds of 11:59 pm.

A third analogy, created by University of Washington paleontologist Peter Ward and astronomer Donald Brownlee, who are both famous for their Rare Earth hypothesis, for their book The Life and Death of Planet Earth, alters the calendar so it includes the Earth's future leading up to the Sun's death in the next 5 billion years. As a result, each month now represents 1 of 12 billion years of the Earth's life. According to this calendar, the first life appears in January, and the first animals first appeared in May, with the present day taking place on May 18, even though the Sun won't destroy Earth until December 31, all animals will die out by the end of May.

See also


  1. ^ Kentucky Geological Survey (2011). "The Geological Time Scale v.3" (PDF). Kentucky Geological Survey. Retrieved 2013-06-03.
  2. ^ "Geologic History Compressed into 1 Calendar Year". time 2010. Retrieved 2013-06-03. ((cite web)): External link in |publisher= (help)

{{bottomLinkPreText}} {{bottomLinkText}}
Geologic Calendar
Listen to this article

This browser is not supported by Wikiwand :(
Wikiwand requires a browser with modern capabilities in order to provide you with the best reading experience.
Please download and use one of the following browsers:

This article was just edited, click to reload
This article has been deleted on Wikipedia (Why?)

Back to homepage

Please click Add in the dialog above
Please click Allow in the top-left corner,
then click Install Now in the dialog
Please click Open in the download dialog,
then click Install
Please click the "Downloads" icon in the Safari toolbar, open the first download in the list,
then click Install

Install Wikiwand

Install on Chrome Install on Firefox
Don't forget to rate us

Tell your friends about Wikiwand!

Gmail Facebook Twitter Link

Enjoying Wikiwand?

Tell your friends and spread the love:
Share on Gmail Share on Facebook Share on Twitter Share on Buffer

Our magic isn't perfect

You can help our automatic cover photo selection by reporting an unsuitable photo.

This photo is visually disturbing This photo is not a good choice

Thank you for helping!

Your input will affect cover photo selection, along with input from other users.