El Calendario Cósmico - cosmos possible worlds parte 2

The cosmic calendar is a way for us to wrap our heads around the vastness of time. To grasp the history of the cosmos from the Earth of our universe to this very moment, we've compressed all of it into a single calendar year. On this scale, every month represents about a billion years. Every day represents nearly 40 million years. That first day of the cosmic year began with the Big Bang. That was 14 billion years ago. Nothing really happened in our neck of the universe until about 3 billion years later, March 15th of the cosmic year, when our Milky Way galaxy began to form. Six 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. This was our planet nearly 4 billion years ago, September 21st on the cosmic calendar, when we believe life began. The atmosphere was a hydrocarbon smog. No oxygen to breathe and no one to breathe it. We've only recently begun to appreciate how powerfully life has shaped the planet. When we think about the ways life has changed Earth, the first things that come to mind are the green expanses of forests and sprawling cities. But life began transforming the planet long before there were any such thing. A billion years after that tiny boomer at the bottom of the sea, life had become a global phenomenon, thanks to a champion that to this day has never been vanquished. I give you the cyanobacteria. In business for 2.7 billion years, cyanobacteria can make a living anywhere. Fresh water, salt water, hot springs, salt mines, makes no difference. It's all home to them. Over the next 400 million years, the cyanobacteria, taking in carbon dioxide and giving back oxygen, turned the sky blue. But the cyanobacteria didn't just change the sky. They reached into the very rocks themselves and changed them too. Oxygen rusted the iron, working its magic on the minerals. Of the 5,000 kinds of minerals on Earth, 3,500 of them arose as a result of the oxygen made by life. But here comes that day of reckoning.