NASA Scientists Classify the Time Before Earth Existed: the Chaotian Era

Moon Formation In The Late Hadean Period
Moon Formation In The Late Hadean Period courtesy of the Smithsonian Air and Space Museum

The geological time scale, with its familiar Cretaceous, Cambrian, and Eocene periods, works great as a calendar for the history of the Earth. Indeed, the different periods only cover the 3.8 billion years of life on Earth, with everything before that time lumped into one nondescript eon called the Hadean. But for some geologists, that lack of specificity simply won’t work any more.

Frustrated by referring to Hadean-era events with vague phrases like “around the time of Moon formation” or “shortly after Earth cooled”, four scientists, including two from NASA, have chopped up the Hadean into distinct geologic periods, and even extended the time scale back to the formation of the solar system, with a new eon called the “Chaotian.”

Under the new scheme, the Hadean Eon begins when Tellus, the proto-Earth, gets smacked into by Theia, a proto-planet absorbed into the Earth. This impact caused the formation of the Moon, and marks the beginning of Earth at its current size. Everything coming before that event takes place in the Chaotian.

During the Chaotian, the planets coalesce out of a giant disk of hot dust, cool, and form the solar system we know today. The Chaotian is also broken down into bombastic-sounding periods like the Hyperitian and the Titanomachean.

If the names seem a little out there, it’s because they’re drawn from classic Greek and Latin literature. Since no scientist can avoid naming something after Greek myths, the geologists drew the names from Hesiod’s Theogony, Aeschylus’s Prometheus Bound, and Thamyris’s Titanomachia. Which is to say, NERDS!

The scientists hope that the new time scale will enable geologists studying the early history of the planet to write more accurate papers. For the rest of us, just be happy that there’s a period of our history literally named “Clash Of The Titans.”

The Economist