Saturn is the second biggest planet in the solar system.(土星是太陽系的第二大的行星。)

The solar system also has two analogous classes of objects, smaller than planets—namely, asteroids and comets.(太陽系也有兩類類似的物體，比行星還小——即小行星和彗星。)

If we want to survive as a species, we have to expand into the solar system and likely beyond.(如果我們希望作為一個物種生存下去，就必須擴張到太陽系之中或超越太陽系。)

"And what is the Solar System?" asked the librarian.(“那么什么是太陽系呢？”管理員又問。)

At the heart of the solar system is our sun.(位于太陽系中心的是我們的太陽。)

In Astronomy, for example, the distinction between the solar system and the universe wasn't clear until modern times.(例如，在天文學中，太陽系和宇宙兩者的區別直到現代才被弄清楚。)

The spacecraft will enable scientists to study some dark corners of the solar system.(太空船使得科學家可以研究太陽系中一些不為人知的角落。)

Jupiter, Saturn, Uranus, and Neptune. Those are the gas giants, the four heavyweights of the solar system. But was there once a fifth?(木星、土星、天王星和海王星。這些都是氣體行星，是太陽系的四個重量級。但曾經存在第五個行星嗎？)

The surface of Mars shows a wide range of geologic features, including huge volcanoes—the largest known in the solar system—and extensive impact cratering.(火星表面顯示出廣泛的地質特征，包括巨大的火山——太陽系中已知的最大的火山——和廣闊的撞擊坑。)

Complex life evolved on the Earth's surface, but not on Mars or other planets in the solar system because on those planets, early surface life was killed by UV radiation.(復雜的生命在地球表面進化，而不是在火星或太陽系的其他行星上，因為在那些行星上，早期的地表生命被紫外線殺死了。)