SpaceKids on Space.com

Buzz Aldrin set foot on the moon, and his new book encourages kids to take the first steps onto Mars.

Asteroids are space rocks.

Even the smartest scientists in the world don't know what dark matter is. But they know it’s out there.

The sun is mostly composed of the elements hydrogen and helium.

The planet Mercury looks a little bit like Earth's moon.

Mercury is the closest planet to the sun.

A lot of kids are led to believe this idea.

Our Milky Way galaxy looks like a huge milky haze in the night sky, which is where its name comes from.

The first footprints put on the moon will probably be there a long, long time.

Gravity is everywhere, even in space.