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Galactic year - the estimated time it takes the Sun to orbit around the Milky Way galaxy.
The galactic year, also known as a cosmic year...one orbit range from 225 to 250 million terrestrial years, and the present age of the solar system is estimated at between 18 and 22 galactic years.
A a cosmic year is the period of time it requires for the solar system to orbit once around the center of the Milky Way galaxy. Estimates of the length of one orbit range from 225 to 250 million terrestrial years, and the present age of the solar system is estimated at between 18 and 22 galactic years. Because a billion-year scale does not allow for useful discrimination between geologic events, and the use of a million-year scale requires some rather large numbers, the galactic year is a good unit for measuring events which occur over a long duration of time.
The Permian mass extinction happened about 1 galactic year ago.
Cosmic Calendar - a theorized scale of the life of the universe.
The Cosmic Calendar is a scale in which the lifetime of the universe is mapped onto a calendrical year; that is to say, the Big Bang took place on a cosmic January 1 at precisely midnight, and today's date and time is December 31 at midnight. On this calendar, the solar system did not appear until September 9, life on Earth arose on September 30, the first dinosaurs appeared on December 25 and the first primates on December 30. Early Homo sapiens did not arrive until ten minutes before midnight on December 31, and all of human history has been recorded in the last 21 seconds. On this timescale, an average human life is about 0.15 seconds. The scale was popularized by Carl Sagan in his book The Dragons of Eden and on the television series Cosmos, which he hosted.
From Wikipedia, the free encyclopedia
If a cosmic year is 250 million terrestrial years
then a cosmic day is 684,931.5 terrestrial years
and a cosmic second is 11,415.5 terrestrial years
at least l millon years