5 The Solar System

The Solar System

太阳系

In space. The Earth is a planet. It's a huge, round lump of rock floating in space. The Earth is one of eight planets that travel around the Sun. The Sun and the planets are called the Solar System. This is what the Earth looks like from space.

在太空中。地球是一个行星。 它是一块巨大的圆形岩石，漂浮在太空中。 地球是围绕太阳运行的八颗行星之一。 太阳和行星被称为太阳系。 这是从太空看地球的样子。

What's out there? The planets in the Solar System move around the Sun. Pieces of rock, called asteroids, travel around the Sun, too.

外面有什么？太阳系中的行星围绕太阳运行。 被称为小行星的岩石碎片也围绕太阳运行。

The planets are shown close together on these pages. Really, they are very, very far apart. As well as planets, there are lots of other things that move around the Sun, from specks of dust to 'dwarf planets' such as Pluto.

这些行星在这几页上挨得很近。 真的，它们相距非常非常远。 除了行星，还有很多其他的东西围绕太阳运行，从尘埃到冥王星这样的“矮行星”。

How it started. Scientists think that the Solar System formed millions and millions of years ago. It began as a huge cloud of gas and dust in space, like this one. The swirling cloud of gas and dust slowly got thicker and thicker. Part of the cloud heated up, making a hot ball of gas. This became the Sun.

它是如何开始的。科学家们认为太阳系形成于数百万年前。 它起源于太空中巨大的气体和尘埃云，就像这个一样。 旋转的气体和尘埃云慢慢地变得越来越厚。 云的一部分被加热，形成一个热的气体球。 这就是太阳。

Over millions of years, the gas and dust spun around the Sun. Gradually, the dust and gas joined together to make the planets.

数百万年来，气体和尘埃围绕着太阳旋转。 渐渐地，尘埃和气体结合在一起，形成了行星。