土星是太阳系的第二大的行星。
这张图片展示太阳系9个行星中的6个行星。
The picture shows six of the nine planets in the solar system.
太空船使得科学家可以研究太阳系中一些不为人知的角落。
The spacecraft will enable scientists to study some dark corners of the solar system.
如果太阳系有一个后进生，那一定是金星。
If the solar system has an underachiever, it has to be Venus.
它们基本上是由太阳系起源时遗留下来的碎片组成的。
They're basically made up of debris left over from the origin of the solar system.
月球的自转和倾斜在太阳系的其他行星体中是独一无二的。
The Moon's spin and tilt are unique among other planetary bodies in the solar system.
为什么科学家认为某些东西可能隐藏在我们太阳系的边缘之外？
Why do scientists think something could be hidden beyond the edge of our solar system?
太阳系也有两类类似的物体，比行星还小——即小行星和彗星。
The solar system also has two analogous classes of objects, smaller than planets—namely, asteroids and comets.
大多数已知的太阳系外行星都居住在高度拉长而非圆形的轨道上。
Most known extrasolar planets reside in highly elongated, not circular, orbits.
例如，在天文学中，太阳系和宇宙两者的区别直到现代才被弄清楚。
In Astronomy, for example, the distinction between the solar system and the universe wasn't clear until modern times.
这使它成为太阳系中已知最大的陨石坑，也可能是最古老的陨石坑。
That makes it the biggest known crater in our solar system and it may well be the oldest.
其次，木星的巨大质量阻止了大多数与太阳结合的彗星穿透太阳系内部。
Second, Jupiter's enormous mass prevents most Sun-bound comets from penetrating the inner solar system.
在300多年的时间里，我们一直认为土星是太阳系唯一拥有光环的天体。
For more than 300 years, we thought Saturn was the only body in the solar system with rings.
人们发现，在一些保存着太阳系原始化学成分的陨石中，铱元素的含量很高。
Ir is found in high concentrations in some meteorites, in which the solar system's original chemical composition is preserved.
我们的行星地球，连同其他行星，围绕我们的太阳旋转，这就是我们的太阳系。
Our planet Earth, together with other planets, revolve around our Sun in what is called our Solar system.
他们将作为现代麦哲伦人，绘制出太阳系的蓝图，无论探险者是人类还是机器。
They will serve as modern Magellans, mapping out the solar system for whatever explorers follow, whether man or machine.
我们太阳系的其他行星缺乏氧气大气层，这有助于解释为什么地球上存在生命。
Other planets in our solar system lack the oxygen atmosphere that helps explain why life exists on Earth.
古希腊人坚信，我们所谓的太阳系实际上就是整个宇宙，并且宇宙以地球为中心。
The ancient Greeks believed that what we called the solar system was in fact the entire universe, and that the universe was geocentric.
这不仅改变了我们对太阳系的认识，也使我们意识到向冥王星发射飞船的重要性。
This transformed our view not only of the solar system but also of the importance of sending a spacecraft to Pluto.
我将介绍陨石的不同类型，以及我们能够从中了解到的有关地球和太阳系的形成的知识。
I wanna go over the different types of meteorites, and what we've learned from them about the formation of Earth, and the solar system.
当然，我们现在知道，包括地球在内的行星都围绕太阳公转，而太阳系只是宇宙的一小部分。
Of course, we now know that the planets, including Earth, revolve around the Sun, and that the solar system is only a tiny part of the universe.
太阳占据了太阳系总质量的大约99.85%，而在剩余的0.15%中，行星占据了大部分。
An estimated 99.85 percent of the mass of our solar system is contained within the Sun, while the planets collectively make up most of the remaining 0.15 percent.
受哈雷提出的确定太阳系大小的方法启发，英国和法国天文学家团队开始在印度和西伯利亚等地考察。
Inspired by Halley's suggestion of a way to pin down the scale of the Solar System, teams of British and French astronomers set out on expeditions to places as diverse as India and Siberia.
在远离太阳的外太阳系，在木星轨道之外，温度低到足以使冰从水以及甲烷和二氧化碳等气体中形成。
Far from the sun, in the outer solar system, beyond Jupiter's orbit, temperatures are low enough to permit ices to form out of water and out of gases like methane and carbon dioxide.
火星表面显示出广泛的地质特征，包括巨大的火山——太阳系中已知的最大的火山——和广阔的撞击坑。
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.
在火星和我们太阳系的其他行星上没有氧气，这意味着这些行星也缺乏保护地表生物免受紫外线辐射的臭氧层。
The absence of an oxygen atmosphere on Mars and other planets in our solar system means that these planets also lack an ozone shield that would protect surface-dwelling life from UV radiation.
在我们的太阳系中，行星的轨道几乎是圆形的，这使得科学家们预测，其他恒星周围的行星也会位于圆形轨道上。
The nearly circular orbits of planets in our solar system led scientists to expect that planets around other stars would also reside in circular orbits.
我们太阳系的有序特性使大多数天文学家得出结论，这些行星基本上在同一时间形成，且物质来源和太阳的一样。
The orderly nature of our solar system leads most astronomers to conclude that the planets formed at essentially the same time and from the same material as the Sun.
目标是测量AU；随后，当我们知道了所有围绕太阳的其他行星的轨道速度，对太阳系的规模就有充分的认识了。
The goal was to measure the AU; then, knowing the orbital speeds of all the other planets around the Sun, the scale of the Solar System would fall into place.
1977年发射的“旅行者一号”太空探测器发回了木星和土星的壮观图像，然后飞出太阳系，执行前往恒星的单程任务。
The space probe, Voyager I, launched in 1977, had sent back spectacular images of Jupiter and Saturn and then soared out of the Solar System on a one-way mission to the stars.
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