Can a space rock tell us about long ago?

Think of a smooth stone resting in your hand, cool and heavy. Most stones come from the ground right here. But some rocks have traveled all the way from space!

Let's wonder about those rocks together. Can a space rock tell us about long ago?

Long, long ago, there was no Earth yet. A big cloud of dust and rock swirled around the Sun. Bits of it stuck together and slowly grew into the planets.

Not every bit became part of a planet. Some little rocks were left over. They kept floating through space, all on their own.

Out in space, there is no rain and no wind. Nothing washes these rocks or wears them down. So they stay just as they were, like a toy kept safe in a box.

One day, one of these old rocks drops down to Earth. It streaks across the night sky and lands on the ground. We call a space rock like this a meteorite, which means a rock from space that has landed on Earth.

People who find a meteorite bring it to scientists. Scientists cut it open with great care to peek inside. What do you think they will find in there?

Inside, scientists find tiny round grains and specks of dust. These bits came from that big cloud around the Sun. They are even older than Earth itself!

Scientists look closely at these old bits. They learn what Earth and the other planets grew from. So yes, a meteorite can tell us about long ago!

Let's remember our word: meteorite. Yes, a meteorite is left over from when the planets grew, and nothing changed it.

Sleep tight, and maybe dream of tiny old rocks drifting through the quiet stars.