A flash in the sky won't always produce ancient space rocks on the ground.Meteorites are a rare find.As the Lyrid meteor shower thrills early risers this week in Colorado, the chances aren't very good that you'll find a piece of the show in your backyard.According to a Planetary Geologist at the Fiske Planetarium on the C.U. Boulder campus, only one out of 100 "finds" is a true meteorite.They're heavier than a normal rock, usually dark in color with a shiny, possibly criss-cross interior."You can hold it in your hand. And it can fall in your horse pasture. And it's a real deal," the geologist said.But, if you can find one, you'll be holding something older than anything in your house - guaranteed."All meteorites date from the origin of the solar system which is 4.5 billion, with a "B" billion years ago," said Dr. Suzanne Metlay.If you're awake between two and four in the morning over the next couple of days, look to the southwest part of the horizon.You'll want to relax and try not to focus on one section of the sky.Look for brief, bright flashes of light in the corners of your eye.