In 2017, NASA celebrated 20 consecutive years of Mars exploration — the longest humankind has continuously monitored another planet. But there’s a key phrase in that statement that’s easy to overlook: another planet. Even as planetary scientists strive to understand the fellow planets circling our Sun, it’s worth remembering that we have the perfect scientific testbed right at our fingertips.
As the most familiar planet — and perhaps the strangest — Earth gives us insight into the forces that shaped our solar system, revealing clues about how rocky planets form and evolve. Studying Earth lets us walk before we run, testing techniques and technologies in a familiar setting before sending them to other worlds.
But the more we learn, the more we see that our planet is one of the weirdest places we’ve ever encountered, uniquely shaped and forever altered by the life-forms it sustains.
