What’s a “shooting star”?

Every once a while, you might see a streak of light shoot across the sky at night. These streaks are often called “shooting stars,” but they occur in our own atmosphere and are more technically called meteors. Meteors occur when bits of rock from space — usually no larger than a pebble — enter our atmosphere and burn up. Because these pebbles were previously orbiting the Sun, they enter our atmosphere at very high speeds (up to about 250,000 kilometers per hour), which is why they can heat up the air enough for it to glow with a visible streak of light. Most meteors burn up completely, so that nothing reaches the ground. Occasionally, an unusually large meteor may be caused by a rock large enough that it does not burn up completely, in which case pieces of rock from space — called meteorites — may hit the ground.