Table of Contents
What is the Cosmic Calendar by Sagan?
The Cosmic Calendar is a scale in which the 13.7 billion year lifespan of our universe is mapped onto a single year. This chronological arrangement was done by famous astronomer Carl Sagan. In this mapping, the Big Bang took place on January 1st at 12 a.m., while the present moment is 12 p.m. on December 31st.
When did humans appear on the Cosmic Calendar?
about 300,000 years ago
It wasn’t until approximately 11:48 PM on the cosmic calendar, or about 300,000 years ago in actual time, that anatomically modern humans, Homo sapiens, arose for the first time.
How long ago did life on Earth?
about 3.7 billion years old
The earliest life forms we know of were microscopic organisms (microbes) that left signals of their presence in rocks about 3.7 billion years old.
How long did dinosaurs exist in the Cosmic Calendar?
| August 1st | Apparition of life (bacteria) | -4 billion years |
|---|---|---|
| December 14th | First vertebrates (fish). | -500 million years |
| December 16th | Plants start growing. | -440 million years |
| December 19th | Insect and amphibians appear on Earth. | -390 millions years |
| December 22nd | Dinosaurs. | -280 million years |
When did the dinosaurs go extinct in the Cosmic Calendar?
65 million years ago
(*) December 29 (65 million years ago): Dinosaurs become extinct, thought to be because of a giant meteorite impact on Earth.
How many Earth years is a cosmic day?
37.8 million years
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….Cosmology.
| Date | Gya (billion years ago) | Event |
|---|---|---|
| 2 Sep | 4.57 | Formation of the Solar System |
| 6 Sep | 4.4 | Oldest rocks known on Earth |
Did we complete a galactic year?
The galactic year, also known as a cosmic year, is the duration of time required for the Sun to orbit once around the center of the Milky Way Galaxy. One galactic year is 230 million Earth years….Timeline of the universe and Earth’s history in galactic years.
| 16.889 galactic years ago | Life begins on Earth |
| Present day |
|---|