The Cosmic Calendar | Cosmos: Possible Worlds

This cosmic calendar compresses all of the last 13.8 billion years since the Big Bang into a single calendar. Either every month is a little more than a billion years, every day a little less than 40 million. A single hour is almost 2 million years. That first day of the cosmic year began with the Big Bang almost 14 billion years ago.

Nothing really happened in our neck of the universe until about 3 billion years later, March 15th, when our Milky Way galaxy began to form. 6 billion years after that, our star, the Sun, was born. It was August 31st on the cosmic calendar. Jupiter and the other planets, including our own, would soon follow.

The atmosphere on Earth was a toxic environment for our kind of life. Then, September 21st on the cosmic calendar, tiny creatures that could shove off the methane and eat carbon dioxide and sunlight for breakfast found a way to make a living in the ocean by gobbling up the carbon dioxide and giving off oxygen. They turned the sky blue, and then the oxygenation of the atmosphere created the ozone layer for the first time.

Life was free to leave the oceans for the land. Now life could grow larger and venture forth into new territories. Sometime on December 26th, about 200 million years ago, the first mammals evolved. They brought a new feature to life on Earth: the neocortex.

Then, late on New Year's Eve, a mutation occurred in the DNA of just one of our ancestors. One base pair of a single gene programmed the neocortex to grow larger still. Maybe it was a random zap from a cosmic ray or a simple error in transmission from one cell to another. Whatever it was, it led to a change in our species that ultimately affected every other species of life on Earth.

By the last second of the cosmic year, there was no place on Earth that we had left untouched. All of it comes down to nothing more than a single run on our tiny DNA ladder to the stars. [Music]