So we think that the inner planets didn't naturally form with a lot of water.

我们认为内行星中大量的水并不是自然形成的。

Over 4 billion years, the inner planets bound enough interstellar debris to become rock solid.

在40亿年里这些近日行星在太阳系内各种杂乱物质的碰撞与结合下形成了各自的固体结构。

For example, the inner planets — Mercury, Venus, Earth, and Mars — are all relatively small and rocky.

比如水星、金星、地球和火星这类内行星都相对较小，且多是岩石质地。

The inner planets, Mercury and Venus, move so rapidly you can see their motion after a single night.

水星和火星这种内行星的移动速度很快，以至于一个晚上就能看出变化。

And around 500 smaller planets collided with each other to form the inner planets we know today, including your home, Earth.

大约500颗较小的行星相互碰撞，形成了我们今天的内行星，包括我们的家，地球。

The Sun will fry the inner planets and...even though the Sun will become red and cooler, the Earth will be much hotter.

太阳将煎熬着内部的行星，尽管太阳会变得更红和更冷，但是地球会变得更热。

An asteroid belt runs between the inner and outer planets.

小行星带在内行星和外行星之间运行。

The four inner planets--Mercury, Venus, Earth, and Mars--are termed 'rocky' because of their solid surfaces.

四颗内行星——水星、金星、地球和火星——因其固体表面而被称为“岩石行星”。

Iron and rock make up most of the four smaller inner planets of our solar system.

铁和岩石构成了我们太阳系四颗较小的内行星的大部分。

And this does a good job of explaining why the inner planets are younger than the outer gas giants.

这很好地解释了为什么内行星比外行星更年轻。

This alone makes it extremely anomalous; it means that our planetary system consists of four rocky inner planets, four gassy outer giants, and a tiny, solitary iceball.

光这一点就使它显得极其反常，这说明，我们的行星系统是由4颗稳固的内行星、4颗气态的外行星和1颗孤独的小冰球组成的。

Despite the harsh conditions on Mercury and on Venus, a close look around our own backyards reveals the good, the bad and the ugly of the inner planets.

尽管水星和金星环境恶劣，进一步的观察显示，其不如古代想象般美好，只是又糟又丑的近日行星。

Coalescing out of a flat disk of material around the Sun, the inner planets were warmer, smaller, and rocky, while the outer planets were in a region that was colder, and grew huge.

内行星由围绕太阳的扁平物质盘凝聚而成，它们温度更高、体积更小且多岩石状构成，而外行星则位于温度更低的区域，它们体积更大。

Most likely, the sun will expand into a into a red giant star, and vaporize the inner planets of our solar system including the earth as it collapses and dies.

最有可能的是， 太阳会膨胀成一颗红巨星，并在地球坍缩和死亡时蒸发我们太阳系的内行星， 包括地球。

The very least we can do is try to keep this planet in as best shape as possible until the Sun eventually turns into a red giant, incinerating the inner planets and turning Earth from a watery wonderland into a scorched wasteland.

我们至少能做的就是尽量让这颗行星保持最佳状态，直到太阳最终变成一颗红巨星， 焚烧内行星，将地球从一片水汪汪的仙境变成一片焦土。