The Truth About Pluto

THEN ONE DAY IT WASN'T A PLANET. THE END.

- Charles C. Hofer

Once upon a time, Pluto was a planet. Then one day it wasn't a planet. The end. That might be the world's worst bedtime story. But it's also 100 percent true.

Following its discovery in 1930, little Pluto captured the imagination of anyone who looked skyward and wondered about the farthest edges of our solar system. Some people preferred Pluto to the ringed beauty of Saturn or the galactic girth of Jupiter. The man who discovered Pluto went from a small-town hero to a national legend nearly overnight. Pluto, the smallest of planets, became a loveable symbol for any underdog.

Then in 2006, astronomers stripped Pluto of its "planet" status and labeled it a "dwarf planet" whatever that was. Pluto's 76-year run as a planet was over.

The story of Pluto is about how things change. Specifically, it's about how things change in light of new evidence. Pluto's story is a story about science.

The Dawn of Science

Today, we take it for granted, but science, as we know it, has thrived in the Western world for only a little more than 300 years. Prior to that, people often guessed at how the natural world worked. The reason the Sun rises and sets, why birds disappear during the winter months, how we sicken, how we heal-educated guesses, traditions, and religious faiths explained all these natural phenomena. No rigorous way existed to test new ideas about our world.

Then stargazers started to notice that heavenly objects didn't behave the way tradition said they should. In the early 1500s, Polish astronomer Nicolaus Copernicus proposed an idea that shook the world. He suggested that the Earth and all the other planets revolve around the Sun, instead of the other way around. Many refused to accept Copernicus's ideas.