Jasin wrote on Jan 14
th, 2019 at 12:49am:
Every 26 million years.
Earth experiences a Mass Extinction.
Sorry, Doomsday Forecasters, Earth's Mass Extinctions Occur At Random
All told, in just the last 260 million years, eight major extinction events have been identified. Many scientists have speculated that these events don't occur at random, but have a periodic cause: like Earth's motion through the Milky Way or a geologically-driven effect. As exciting as these possibilities are, there's no scientific motivation. There's no periodic effect observed, as the science shows these extinction events occur at random.
In particular, the identified times for mass extinction events are as follows:
11.6 million years ago, Middle Miocene.
37.8 million years ago, Mid-Late Eocene.
66 million years ago, End Cretaceous.
93.9 million years ago, Cenomanian/Turonian.
145 million years ago, Jurassic/Cretaceous.
182.7 million years ago, Pliensbachian/Toarcian.
201.3 million years ago, Triassic/Jurassic.
252.2 million years ago, End-Permian.
https://www.forbes.com/sites/startswithabang/2018/02/16/sorry-doomsday-forecaste...No sign of a 26 million year cycle