Wonders of the Universe

Destiny

1. Why are we here? Where do we come from? These are the most enduring of questions. And it's an essential part of human nature to want to find the answers. And we can trace that ancestry back hundreds of thousands of years to the dawn of humankind. But in reality, our story extends far further back in time.

2. Our story starts with the beginning of the universe. It began 13.7 billion years ago. And today it's filled with over 100 billion galaxies, each containing hundreds of billions of stars. In this series, I want to tell that story because ultimately we are part of the universe. So its story is our story. It's a story that you couldn't tell without something so fundamental that it's impossible to imagine the universe without it. It's woven into the very fabric of the cosmos. TIME.

3. The relentless flow of time has driven the evolution of the universe and created many extraordinary wonders. These wonders take us from the very first moments in the life of the universe to its eventual end. This is Chankillo on the north-western coast of Peru. And it's one of South America's lesser known archaeological sites. But, for me, it is surely one of the most fascinating.

4. Around 2,500 years ago, a civilisation we know almost nothing about built this fortified temple in the desert. Its walls were once brilliant white and covered with painted figures. Today, all but the smallest fragments of the decorations are gone. The details of this culture and all traces of its language are lost. And yet, if you stand in the right place, you can still experience the true purpose of Chankillo, in just the same way as you could the day that it was built.

5. But, to do that, you have to be here before the sun rises. These towers form an ancient solar calendar. Now, at different times of year, the sunrise point is at a different place on the horizon. 21st December, which here in the southern hemisphere is the summer solstice, the longest day, and the sun rises just to the right of the right-most tower.

6. Then, as the year passes, the sun moves through the towers until on 21st June, which is the winter solstice, the shortest day, it rises just to left of the left-most tower. Actually just in between that mountain you can see in the distance and the left-most tower. So, at any time of year, if you watch the sun rise, you can measure its position and you can tell, within an accuracy of two or three days, the date.

7. Today's date is September the 15th. So that means the sun will rise between the fifth and the sixth towers. Chankillo still works as a calendar because the sun still rises in the same place today as it did when these stones were first laid down. That's a magnificent sight, as the sun burns through the towers. You can almost feel the presence of the past here.

8. Imagine what it must have been like. Thousands of citizens stood here to greet the sun, which was almost certainly a deity. Almost certainly their god. What a magnificent achievement. Probably one of our earliest attempts to begin to measure the heavens. Over the millennia, that desire to measure what's going on in the sky has led to modern astronomy and the foundations of our modern civilisation.

9. I might build one in my garden. I want one! The 13 towers that line this ridge stand testament to our enduring fascination with the clockwork of the heavens. And to the direct connection between our lives and the cosmos. The rising and setting of the sun provides an epic heartbeat that allows us to mark the passage of time.

10. A day on Earth is the 24 hours，which takes our planet to rotate once on its axis. Our months are based on the 29-and-a-half days, which takes the moon to wax and wane in the night sky. And a year is the 365-and-a-quarter days，which takes us to orbit once around the sun. These familiar timescales mark the passing of our lives.

11. But the life of the universe plays out on a much grander scale. When you look up into the night sky, you don't just see stars. Those tiny points of light are a million different clocks, whose lifespans mark out the passage of time over billions, or even trillions, of years. This film is about the greatest expanses of time. The deep time that shapes the universe. From its fiery beginnings, through countless generations of stars, planets and galaxies, to its eventual demise, the fate of the universe is determined by the passage of time.

12. Timescales in the cosmos seem so unimaginably vast, it's almost impossible to relate to them. Yet there are places on Earth where we can begin to encounter time on these universal scales. This is Ostional on the northern Pacific coast of Costa Rica. And I've come here to witness a natural event that's been happening long before there were any humans here to see it. And I suppose it really is a window into the distant past of life on our planet.

13. Once the sun has dipped below the horizon and the moon conspired to make the tides just right, this beach is visited by prehistoric creatures. Under the cover of darkness, they emerge from the ocean. Playa Ostional is one of the few beaches in the world where large numbers of sea turtles make their nests. But what makes this truly remarkable is the sheer length of time scenes like this have been playing out. This is part of one of the oldest life-cycles on Earth.

14. On nights like these, for the last 100 million years, turtles like this have been hauling themselves out of the ocean to lay their eggs. It's an almost incomprehensible timespan. 100 million years ago, there were dinosaurs roaming the Earth, but the Earth itself looked very different. South America was not connected to North America. North America was somewhere over close to Europe. Australia was connected to Antarctica.

15. It really is quite wonderful to be so close to such an ancient cycle of life. I can hear breathing, actually. So, a remarkable experience. I mean, it really is beautiful to see that. On one night of many hundreds of millions of nights stretching back into the past. And she's gone. To witness a moment like this is to open up a connection to the deep past and to experience timespans far longer than the history of our own species.