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。
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。
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 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。
Clouds swirl on Saturn, the second largest planet in our solar system.
云层在土星上打漩涡，土星是太阳系中第二个大行星。
In our solar system, planets for the most part have fairly uniform circular orbits.
在太阳系，大多数的行星都各自拥有统一的圆周轨道。
As in our solar system, vast distances stretch between these stars and their gas giants.
正如在我们的太阳系一样，恒星与其气态巨行星之间相隔甚远。
Among all the planets in our solar system, earth is also one of the most unstable planet.
地球是太阳系中最不稳定的行星之一。
Indeed, an analysis of the magnetic position of the planets in our solar system bear this out.
实际上，对我们太阳系里磁场位置相反的各个行星进行一下分析就可以证明这一点。
Mister Sagan was deeply involved in American efforts to explore the planets in our solar system.
萨根先生积极参与美国对我们太阳系各个行星的探测工作。
Questioner: Are there any people such as you find on Earth on any of the other planets in our solar system?
发问者：你们在我们太阳系之中，除了地球，有没有在其它行星发现如同人类的生物？
The sun is by far the largest object in our solar system, containing 99.8 percent of the solar system's mass.
太阳是我们已知的太阳系内最大的天体，占有太阳系总质量的99.8％。
These primitive meteorites are like time capsules, containing the most primitive materials in our solar system.
这些原始陨石就像时间胶囊，含有太阳系最原始的资料。
In our solar system eight planets circle around the sun. What are they? Can you match the names with the planets?
在我们的太阳系中有八颗行星绕着太阳转。它们是谁？你能把行星和名字匹配起来吗？
Lost in space: Researchers say aliens may be in our solar system (we're just not looking hard enough to see them).
迷失太空：研究人员说在我们的太阳系里可能会有外星人的存在(我们只是不太容易看到他们而已)。
Of all the planets in our solar system, we are now pretty certain the Earth is the only one on which life can survive.
我们目前可以肯定的是，在我们太阳系的所有行星中，地球是生命能存在的唯一行星。
Once classified as a true planet, icy Pluto is now considered one of the more than 40 dwarf planets in our solar system.
它曾一度被划归为行星，冰冷的冥王星目前被认为是我们太阳系的40多个矮行星之一。
Voyager 2 is the only spacecraft that has flown close by to one of the more enigmatic planets in our solar system: Uranus.
旅行者2号是唯一一个接近我们太阳系众多神秘行星之一天王星的一艘航天器。
For instance, five of the six planets orbit closer to their parent star than any planets in our solar system orbit the sun.
比如，其6个行星里有5个围绕其母星的轨道距离比我们太阳系里任何一个行星到太阳的轨道距离都要近。
Without the rocket, it is safe to say we would not only have never gone to the moon or visited every planet in our solar system.
没有了火箭，我们也就不可能到达月球或者任何一个太阳系的星球。
The second asteroid belt lies at about 20 astronomical units from the star, or a position comparable to Uranus in our solar system.
第二个行星带距离它的恒星为20个天文单位，这相当于太阳系中天王星的位置。
It could be that the planet managed to cling onto a moon when all the other gas giants in our solar system had already lost theirs.
可能是因为在我们太阳系的其他气态巨星已经失去自己的卫星的时候土星捕获了一个月亮。
Near the top of the short list of places in our solar system that might harbor extraterrestrial life is Jupiter’s rocky moon Europa.
在短短的外星生命或有星球列表上，接近表上端的位置有一个地点：木星的卫星——巉岩耸峙的欧罗巴。
Each planet in our solar system has a particular influence by which certain lessons are to be learned and for which we are tested on Earth.
我们太阳系中的每颗行星都有一种特殊的影响力，我们通过它得以学会某些课程，为此我们在地球上经受考验。
The main purpose was to use the gravity of the largest planet in our solar system to slingshot Cassini towards Saturn, its ultimate destination.
其主要目的是利用太阳系中最大的一个的行星获得重力推动将卡西尼号弹向其最终目的地——土星。
In that case, "it would be the most unique exoplanet we've found so far," study leader Bean said. "we have nothing like that in our solar system."
万一是那样的话，“她可能是迄今为止我们发现的最为独特的太阳系外行星”首席科学家宾安说：“在我们的太阳系中没有那样的情况。”
In fact, if Betelgeuse replaced the sun in our solar system, its outer layers would extend past Earth and Mars and to nearly the orbit of Jupiter.
实际上，如果让参宿四来代替我们太阳系的太阳，它的外层将会延伸超过地球和火星，并且几乎接近于木星的轨道。
In fact, if Betelgeuse replaced the sun in our solar system, its outer layers would extend past Earth and Mars and to nearly the orbit of Jupiter.
实际上，如果让参宿四来代替我们太阳系的太阳，它的外层将会延伸超过地球和火星，并且几乎接近于木星的轨道。
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