Clyde had finished his farm chores. Now he was free to spend the rest of the evening doing his favorite thing: stargazing. He got out his telescope and he looked up into the night sky. While he looked at the moon and the stars he wondered about the universe.
(Leader: Pause and invite participants to suggest questions Clyde might have had as he looked at the sky. Possibilities include:
Does any other planet have life? Are there aliens out there somewhere? If there are, are they friendly or dangerous? How could we communicate with them? What are they like?
How far away are stars and planets? Will anyone ever be able to travel in space?
Could we live on another planet? What would it be like to walk on the moon?
Why does Mars look reddish? What makes a shooting star streak across the sky? Why do the planets circle around the sun?)
Clyde was filled with curiosity and questions. The telescope he had wasn't strong enough to get him answers. He wanted to see more, to see things more clearly. He decided to build his own telescope.
He searched his parents' farm for old pieces of machinery that he could use. He painstakingly ground mirrors for their reflective powers. His father let him have a shaft from his car. With these materials, Clyde made himself a powerful telescope.
Now he could see much detail when he watched the planets. He drew pictures of what he saw. But, he still wanted to know more. So he sent his drawings of Jupiter and Mars to some astronomers. He hoped they would give him some information. Instead, they were so impressed with his pictures that, even though Clyde had not gone to college yet, they offered him a job.
Another scientist, Percival Lowell, was sure there was another planet, farther away from the Earth than Neptune. But, so far, no one had been able to find it. Clyde went to New Mexico. He spent every night in an unheated observatory, looking through the telescope for Planet "X" and taking pictures of the sky. Through the long, cold nights, Clyde tried to glimpse a new planet. Later in his life he liked to say, "I've really had a tour of the heavens."
Finally, when he was twenty-four years old, Clyde took a photograph of the night sky that showed a strange shifting of light. There was a planet beyond Neptune! He had found Planet "X." The new planet was named Pluto, for the Roman god of the underworld.
All his life, Clyde loved learning about the universe. Over the years he discovered more than one hundred asteroids, a comet, and a supercluster of galaxies. He thought exploring and learning were so important that he became an astronomy teacher. He helped other people investigate the sky, sometimes using the huge, two-story telescope he built in his own backyard.
And, he loved learning so much that he and his wife helped to start a Unitarian Universalist church where they lived in New Mexico. Clyde knew a congregation, like an observatory, could be a very good place for seeking truth.
Clyde died, a very old man, in 1997, but our story does not end there. You see, now scientists have decided Pluto isn't really a planet, after all. New telescopes see much more detail than even Clyde's most powerful telescope could ever see. We now know there are many objects in space about the same size as Pluto. Could there really be dozens and dozens more planets? Or are these smaller objects something else? The scientists voted and agreed on three rules to determine whether an object in space is a planet. It has to orbit around the sun. It must be large enough that its surface becomes smooth and round. And it must be large enough to clear other objects out of its orbit. Pluto does not meet these new rules — it's too small.
Percival Lowell had been curious to find Planet "X." Because of his questions, Clyde Tombaugh was hired to search the night sky. When Clyde discovered Pluto, everyone thought it was a planet. Then, new telescopes showed us many other objects in space like Pluto, and scientists made a new category: dwarf planet.
Clyde's wife, Patricia, said Clyde would have been disappointed about the vote, but as a scientist he would have understood. When we seek the truth, it feels good to make discoveries and find answers. But Clyde knew what's most important is to keep asking questions.