What is the only terrestrial planet on this list?

以下哪一个是唯一的类地行星？

And this will really help us understand how terrestrial planets are made.

这将真正帮助我们理解类地行星的形成过程。”

But the long era of the four terrestrial planets will be over.

但是四颗类地行星的漫长时代将会结束。

Instead of a mantle, like terrestrial planets, Jupiter has a huge region made up of liquid metallic hydrogen.

不想类地行星有地幔，木星有一大块区域由液态等离子氢构成。

Unlike the other three terrestrial planets, Earth has something very important: Water.

与其他三个类地行星不同，地球有一个非常重要的东西：水。

After earth, Venus is the second largest terrestrial planet, meaning it has a solid rocky surface and an atmosphere.

地球之后，金星是第二大类地行星，这意味着它有着坚固的岩石表面和大气层。

Up in the corner, the terrestrial planets, Mercury, Venus, Earth and Mars.

在角落里，类地行星水星、金星、地球和火星。

The Earth is the largest of the terrestrial planets, the four smaller, denser, rocky worlds orbiting close in to the Sun.

地球是类地行星中最大的一个（距太阳较近的四颗更小、密度更大的岩石行星）。

In the long term, nothing is stopping humanity from constructing a zero-propellent transport network for the terrestrial planets, centered on the Martian moons.

从长远来看，没有障碍会阻挡人类建立一个零推进剂的运输网络，连接着以火星卫星为中心的陆地行星。

Though natural disasters have rocked our terrestrial planet, life on Earth has survived, evolved, and flourished for billions of years.

尽管自然灾害震撼了我们的地球，但地球上的生命已经生存、进化并繁荣了数十亿年。

Now get this: a lot of Europa's material is silicate rock, like on Earth and other terrestrial planets, located in a layer under the ocean.

和地球及其他类地行星一样，木卫二的海洋底下的主要成分是硅酸盐矿石。

Mars is the fourth planet from the Sun, and the outermost of the terrestrial planets; that is, ones that are rocky and similar in size to Earth.

火星是太阳的第四颗行星，是类地行星中最外层的一颗；类地行星就是指岩石质并且尺寸接近地球的行星。

Because people had thought the moon had formed cold, so it completely changed our idea how the moon formed, how the terrestrial planets formed, like the Earth as well.

因为人们认为月球是冷形成的，所以它完全改变了我们对月球是如何形成的， 类地行星是如何形成的， 地球也是如此。

One of the interests in bodies like Ceres and other icy bodies in the outer solar system is that when objects like that impacted the terrestrial planets, they brought a lot of water.

她说，" 人们对谷神星和其它冰壳星球之类的外太阳系星球感兴趣的一点在于，当这类星球撞击类地行星时，它们会带来大量的水。

The first robotic missions may launch from Earth or Mars to one  of the millions of terrestrial planets in our galaxy, making preparations for human  colonies outside of our solar system.

第一个机器人任务可能从地球或火星发射到我们银河系中数百万颗类地行星中的一颗，为我们太阳系外的人类殖民地做准备。

" Now we have the technology to extend this methodology to another terrestrial planet, Mars, which hosts an ancient sedimentary rock record which extends even further back in time than our own, " McMahon said in a statement.

" 现在我们拥有了将这种方法推广到另一个类地行星—火星的技术，火星上保存着一份古老的沉积岩记录，其时间甚至比我们地球的记录还要久远。"