Scientists believe Ceres is made of rock, and covered with ice.

科学家认为谷神星是岩石构成的，上面覆盖着冰。

Ceres is the biggest, at about 900 km across.

谷神星是最大的，直径约900公里。

Scientists want to study whether Ceres was ever home to microbial life.

科学家们想要研究谷神星是否曾经是微生物的家园。

The object was given the name Ceres… but was it really a planet?

这个物体被命名为谷神星… … 但它真的是一颗行星吗？

Hopes were high that Ceres was the wished-for planet between Mars and Jupiter.

谷神星曾被寄予厚望，人们认为它就是预想的火星和木星之间的那颗行星。

But Ceres isn't the only world in our solar system whose development was cut short.

但谷神星并不是太阳系中唯一一个发展中断的星球。

It will also try to discover how Ceres' surface has changed.

它还将试图找出谷神星表面如何变化。

Ceres probably has a rocky core surrounded by a water ice mantle.

谷神星可能有一个岩石内核，被水冻冰块所覆盖。

Almost all asteroids are irregularly shaped, although a few big ones, like Ceres, are nearly spherical.

几乎所有的小行星都是不规则形状的，尽管有几个像谷神星这样的大小行星几乎是球形的。

Originally, asteroids were named after female goddesses; Ceres, Vesta, Juno, and so on.

最初，小行星是以女性女神的名字命名的：谷神星（刻瑞斯）、灶神星（维斯塔）、朱诺，等等。

Small amounts of carbonate minerals have also been found on asteroids, including the near-Earth asteroid Bennu and the dwarf planet Ceres.

在小行星上也发现了少量的碳酸盐矿物，包括近地小行星本努和矮行星谷神星。

Dawn will gather information about Ceres until the middle of 2016. It will then continue to orbit the small planet.

到2016年中旬，曙光号飞船将会收集有关谷神星的信息。然后它会继续环绕这颗小星球运行。

Ceres was removed from the official list of planets after about fifty years as the fifth planet from the sun.

被视为太阳系第五行星的谷神星在大约五十年后被移出行星名单。

Dawn left Earth more than seven years ago on a trip to explore Ceres and another dwarf planet, called Vesta.

曙光号是7年前离开地球的，其旅程是为了探索谷神星和另一颗名叫灶神星的矮行星。

And Ceres was in the right place—the missing spot. Uh, but it was way too faint to be a planet.

谷神星正好在那个空档里。嗯，但作为一颗行星它又太微弱。

What do Ceres, Juno and Vesta have in common?

谷神星、朱诺和灶神星有什么共同点？

As he tracked it each night, the Earth and Ceres moved like this until Ceres was here.

当他每晚追踪它时， 地球和谷神星就这样移动，直到谷神星来到这里。

Water is considered a major necessity for life. Scientists want to study whether Ceres was ever home to microbial life.

水被认为是生命的重要必需品。科学家们想研究谷神星是否曾经有过微生物生命。

When Piazzi first spotted Ceres, it was here, and the Earth was here.

当皮亚齐第一次发现谷神星时，它就在这里，地球就在这里。

But Ceres itself contains about a third of the mass of all of those objects.

但是谷神星本身包含所有这些物体质量的大约三分之一。