CASSIE loves to camp. So do her parents. Every summer, the three of them, plus Orion the dog, go camping far from the city lights.
Dark skies mean bright stars -- thousands of them. Cassie loves to look at the stars and think about the stars. So do her parents. As a matter of fact, they named Cassie for the constellation Cassiopeia. And Cassie named her dog for a constellation too -- Orion the Hunter.
Now, at last it's dark in the campground. Campfires are out. All is quiet.
From her sleeping bag, Cassie gazes up. The night is so dark she sees nothing but thousands of twinkling stars floating silently in the blackness. A white band of light splashes across the sky. It is the glow of our own Milky Way galaxy seen from our home on its edge.
"Mom?"
"Yes, Cassie," her mother answers.
"I feel like I'm floating out in space all by myself. It feels lonely -- and scary!"
"I know the feeling. It makes you feel very small, huh?" says her dad.
"Yeah. But in a good way. Dad, do you think there are other people or planets like Earth out there?"
"I think so, Cassie," her dad replies thoughtfully. "The universe is very, very big. And even though we see more stars than we can count, our eyes are still very poor."
"What do you mean?" Cassie protests. "I see 20-20!"
Her mom laughs. "Cassie, even with perfect vision, we see only a tiny slice of the starlight. It's as if there's a whole rainbow of colors, but sadly we can see only one shade of green."
"Really?" Cassie marvels. "Wow, what if we could see all the starlight colors? What would the sky look like then?"
"Even more spectacular!" her dad answers. "Actually, we do have telescopes in space that can see colors of light our eyes can't see. These telescopes send back awesome pictures of a universe we never saw before."
"Really? What do they show?" Cassie asks.
"Oh, my!" says Cassie's mom excitedly. "You wonder about other planets like Earth? Well, one telescope, NASA's Spitzer Space Telescope, can see new solar systems forming around stars and -- "
"Yes!" her dad interrupts. "This telescope sees not only bright stars but also much cooler stuff that doesn't shine in visible light. It has found disks of cool dust and debris around many stars. New planets form inside these dusty disks. Our own planet formed from a dusty disk that surrounded our own sun."
"Really? From dust? How can this telescope see this cool dust?" Cassie asks.
