Learning article

How the Cosmic Calendar Works

The cosmic calendar turns 13.8 billion years into one familiar year, so the size of deep time can be felt instead of only counted.

A year that stands for 13.8 billion years

In this scale model, January 1 starts with the Big Bang and the end of December 31 stands for today. That means one calendar day represents about 37.8 million years.

The numbers are still enormous

At this scale, one hour is about 1.6 million years, one minute is about 26,000 years, and one second is about 438 years. Dinosaurs do not appear until late December, and humans arrive only minutes before midnight on the final day.

A scale model, not a literal calendar

The dates help us see relationships in time. They are not claims that ancient events happened on those calendar dates, and rounded scientific ages can move slightly as evidence improves.

Image credit: NASA/JPL-Caltech. Background source: Age-Defying Star.