TAKING A JOURNEY

Through the planet’s history

- STEPHEN CHASTAIN

The Earth is really, really old. It’s so old that it’s tough to imagine how old it is. The best we can do is come up with a metaphor that compares it to things we deal with in everyday life. Dinosaurs went extinct around 66 million years ago. That’s a long time ago, about 1,000 times further back than humans have been around. People that looked like us first turned up about 300,000 years ago. But here’s where it gets wild: the Earth itself formed about 4.54 billion years ago. If you could time travel 66 million years in a single step, you’d have to take about 70 steps to get to the first days of the planet! By the time dinosaurs went extinct, almost 99 percent of Earth’s history had already happened.

A Cross-Country Flight