Moon

The Moon is Earth's only natural satellite. It travels around Earth all the time. The Moon stays about 384,399 kilometers away from us. That's about 30 times wider than Earth itself. The Moon takes 29 and a half days to go all the way around Earth.

Earth and the Moon pull on each other with invisible forces. This pulling creates the tides in our oceans. The Moon always shows us the same side. We never see the other side of the Moon. This happens because Earth's pull has slowed down the Moon's spinning.

The Moon is much smaller than Earth. It is only about one-quarter as wide as Earth. You could fit the Moon across the United States. If you weigh 60 pounds on Earth, you would weigh only 10 pounds on the Moon. The Moon is covered in gray dust and rocks. There are many holes called craters all over it. Long ago, the Moon had volcanoes that erupted hot lava. This lava cooled and made dark flat areas we call lunar seas.

Scientists think a giant space rock hit Earth billions of years ago. This crash threw pieces into space. Those pieces came together and formed the Moon. We can see the Moon change shape in the night sky. Sometimes it looks round, sometimes it looks like a thin line. When the Moon moves in front of the Sun, we see a solar eclipse. The Moon looks just as big as the Sun in our sky.

Humans have traveled to the Moon. In 1969, people first walked on the Moon. Twelve people total have been there. They stayed for a few days and brought back rocks. Scientists want to send more people to the Moon soon.