4 Space Voyager Mercury

Small and Hot Mercury is a planet. It is in our solar system!

小而热的水星是一颗行星。 它就在我们的太阳系里！

It is closest to the sun. It gets very hot. But it is cold at night.

它离太阳最近。天气变得很热。 但是晚上很冷。

Mercury is small. But it has a big core. It is iron.

水星很小。但它有一个很大的核心。 它是铁。

It is a gray color. It has rocks.

它是灰色的。它有石头。

How do we know? We use a telescope. We look at it.

我们怎么知道的？我们用望远镜。 我们看着它。