It’s a New Year and a New Decade: but is it a New Era?
Not only is it a new year, but 2020 is also the start of a new decade. You might even hear people say “it’s the beginning of a new era.”
But if we’re talking about geological time, we’re still in the same era as we were last year. Geological eras last for millions and millions of years.
Eras are the second longest unit of geologic time. The longest unit of geologic time is the eon. Eons are divided into eras.
Currently, we’re in the Phanerozoic eon. This eon is divided into three eras: Paleozoic, Mesozoic, and Cenozoic.
Paleozoic means “old life.”
Fossils of trilobites and land plants are from this era.
Mesozoic means “middle life.”
Fossils of dinosaurs come from this era.
Cenozoic means “new life.”
It’s the era we’re in right now. This is the era of mammals.
The end of every era is marked by mass extinctions. For example, we shifted from the Mesozoic era to the Cenozoic era when all the dinosaurs died.
So far, we haven’t suffered a mass extinction of all the mammals from the face of the earth. That's one way we can know we’re still in the same era as we were last year.
When you hear someone say “it’s the end of an era” - you can relax. They’re speaking dramatically or poetically, not geologically!
Happy New Year! We hope you can enjoy living in the same geologic era for many years to come.