Saturn is the second biggest planet in the solar system.

土星是太阳系的第二大的行星。

The picture shows six of the nine planets in the solar system.

这张图片展示太阳系9个行星中的6个行星。

The spacecraft will enable scientists to study some dark corners of 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。

Mars is the lightest planet in the solar system, which makes Mars the second smallest planet in the solar system.

火星是太阳系中最轻的行星，这使得火星成为太阳系中第二小的行星。

Some spaceships have gone beyond the solar system.

一些宇宙飞船已经飞出了太阳系。

Scientists have launched many spaceships to explore other planets in the solar system.

科学家们已经发射了很多宇宙飞船去探索太阳系的其他行星。

Mars's orbit around the Sun is the fourth fastest orbit of all the solar system planets.

在太阳系所有行星中，火星绕太阳的轨道速度第四快。

Mars is one of the four planets in the solar system that is a rocky planet.

火星是太阳系中四颗岩态行星之一。

If the solar system has an underachiever, it has to be Venus.

如果太阳系有一个后进生，那一定是金星。

They're basically made up of debris left over from the origin of the solar system.

它们基本上是由太阳系起源时遗留下来的碎片组成的。

The Moon's spin and tilt are unique among other planetary bodies in 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。

Why do scientists think something could be hidden beyond the edge of our 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？

That makes it the biggest known crater in our solar system and it may well be the oldest.

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。

For more than 300 years, we thought Saturn was the only body in the solar system with rings.

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。

If we want to survive as a species, we have to expand into the solar system and likely beyond.

如果我们希望作为一个物种生存下去，就必须扩张到太阳系之中或超越太阳系。

Second, Jupiter's enormous mass prevents most Sun-bound comets from penetrating the inner solar system.

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。

Other planets in our solar system lack the oxygen atmosphere that helps explain why life exists on Earth.

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。

Our planet Earth, together with other planets, revolve around our Sun in what is called our Solar system.

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。

The solar system also has two analogous classes of objects, smaller than planets—namely, asteroids and comets.

太阳系也有两类类似的物体，比行星还小——即小行星和彗星。

This transformed our view not only of the solar system but also of the importance of sending a spacecraft to Pluto.

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。

In Astronomy, for example, the distinction between the solar system and the universe wasn't clear until modern times.

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。

They will serve as modern Magellans, mapping out the solar system for whatever explorers follow, whether man or machine.

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。

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。这些都是气体行星，是太阳系的四个重量级。但曾经存在第五个行星吗？

The ancient Greeks believed that what we called the solar system was in fact the entire universe, and that the universe was geocentric.

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。

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.

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。

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.

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。

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.

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 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 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.

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。

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.

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。