I looked across the purple landscape to the blue, setting sun. The stars were starting to appear.
"Mom?", I asked. "What are stars?"
"They're bright balls of glowing gas, like our sun, but farther away."
"Could we get to them?", I asked.
"See that faint one over there?", asked the mom, pointing to a star. "That star is called Sun. Legend has it that there are eight planets orbiting that star, and that our ancestors came from a great civilization on one of them. Earth, I believe it was called. It was a blue planet, covered in water, and you could travel outside the domes without a mask."
"Wow! What happened?", I asked.
"Well, the planet got a bit crowded. People could never get along, and there wasn't enough space. People had to leave. When the time came, people were picked randomly to go or stay. Some had to say goodbye to close friends. Some wished they could see their homes again. The next generation, of course, was born on the rocket ship, so they didn't have the memories. Some people didn't pass on the stories of Earth, so as not to disappoint their kids, who would never see it. Others told exaggerated tales of the time they became the president of a country or some such. It's hard to know what's accurate. Some say there were frogs as big as your thumb, or that there were winged creatures flying around everywhere."
"Why can't we go back?"
"Too far. It would take more than one lifetime. And besides, they may have destroyed it in a war by now."