For the period of a complete revolution of our solar system around the center of the Milky Way used the Russian astronomer Pavel Petrovich Parenago 1952 in a paper on the distribution of mass in our galaxy for the first time the term galactic year (FY ). Its duration is now generally valued at approximately 225 million years ago.
Related to species extinction?
The experiments of paleontologists to explain patterns in the frequency distribution of extinctions with galactic orbits were favored because the first astronomers were only able to roughly determine the value for the galactic year and therefore there was room for coincidences. Since the infrared astronomy enables the view of the galactic center, is also determined from its apparent motion against the background galaxies, the orbital period to 250 million years, a number of assignments refuted.
There is also no reason why disasters with this or the half period should occur, because the sun does not move easily on an inclined orbital plane twice per orbit through the galactic plane, but it oscillates much more common up and down - the information for the half period are between 30 and more than 40 million years ago. But this period is now believed by some paleontologists recover their data.
Time in galactic years
This listing is for one GJ = 225 million years.
- 0 GJ: The sun arises
- 4 GJ: On Earth, the oceans arise
- 5 GJ: The first forms of life on Earth
- 6 GJ: arise prokaryotes
- 7 GJ: arise bacteria
- 10 GJ: Fixed Continents arise
- 13 GJ: arise eukaryotes
- 16 GJ: arise multicellular organisms
- 17.8 GJ: Cambrian Explosion
- 19 GJ: Permian-Triassic boundary ( mass extinction )
- 19.6 GJ: Cretaceous-Tertiary boundary ( KT- Impact, Dinosaur extinction, etc.)
- 19,999 GJ: The modern man (homo sapiens) appear
- 20 GJ: Today
- Astronomical amount of time
- Milky Way
- Sun as a star