So to talk about where meteorites come from, we need to talk about comets and asteroids.
那么讲到流星体从何而来，我们就需要讨论下彗星和小行星。
I'm not going to go into any depth on comets and asteroids now, but we'll come back later and do that.
我现在不打算深入讨论彗星和小行星了，但是我们稍后会再回到这个点上，讨论这方面的内容。
Don't mix up comets and asteroids.
不要把彗星和小行星搞混了。
For many years comets and asteroids remained hidden to the world.
多年来，彗星和小行星仍然鲜为世人所知。
This cannot be correct unless Unoosa considers aliens to be near-earth objects (like comets and asteroids).
如果外太空司把近地天体(如彗星和小行星)当成“近地物体”的话，那么这个说法才可以说得通。
A: The Earth has always been subject to impacts by comets and asteroids, although big hits are very rare.
答：地球一直受到冲击，慧星和小行星，虽然金矿是非常罕见的。
One theory is that they came from comets and asteroids, which pounded the lunar surface billions of years ago, and later drifted to the poles.
有一种说法是，它们来自于数亿年前撞击月球的慧星和小行星，后来转移到了极点。
We will learn about strange objects called comets and asteroids, and about mysterious places like the asteroid Belt, the Kuiper Belt, and the Oort Cloud.
我们将学习彗星和小行星奇怪物体，以及一些神秘的地方，如小行星带，柯伊伯带和奥尔特云。
The compounds, which include ammonia, carbon dioxide, carbon monoxide, sodium and, surprisingly, silver, could have come from the Earth, from the moon's interior, or from comets and asteroids.
这些物质,包括氨、二氧化碳、一氧化碳、钠时,让人吃惊的是,银,可能来自地球、月亮的内部,还是来自彗星和小行星。
Roids are, for the most part anyway, they are just smaller bits of asteroids and comets.
在很大程度上，Roids只是小行星和彗星的小碎片。
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。
The Sun is the hub of a huge rotating system consisting of nine planets, their satellites, and numerous small bodies, including asteroids, comets, and meteoroids.
太阳是一个巨大的旋转系统的中心，这个旋转系统由九大行星、它们的卫星和无数的小天体组成，包括小行星、彗星和流星体。
The idea isn't that these building blocks are just passengers aboard meteorites, but that the chemistry inside asteroids and comets can actually manufacture the essential building blocks of biology.
该想法并不是认为这些结构单元只是搭乘陨石的乘客，而是小行星和彗星中的化学成分实际上可以制造生物的结构单元。
However, as we've explored our cosmic backyard, hunting for any signs of the building blocks of life, we've found organic chemistry on moons, comets, asteroids and distant exoplanets.
然而，当我们探索自己的宇宙后院，搜寻生命的构筑材料的迹象时，我们在卫星、彗星、小行星和遥远的系外行星上都发现了有机化学。
In addition to the planets and moons seen in this simulated photo, our solar system contains a star, asteroids and comets, and dwarf planets such as Pluto.
除了在此模拟的照片里所看到了行星和卫星外，我们的太阳系统还包含一个恒星、一些小行星和彗星，和像冥王星那样的侏儒行星。
Thousands of near-Earth objects (asteroids and comets) will have been analyzed by telescopes on the Moon and by spacecraft that were launched from the Moon.
将通过设在月球的天文望远镜和由月球发射的宇宙飞船，对数以千计的近地目标星体（小行星和彗星）进行分析研究。
Other particles within the disk collided and stuck together to form asteroid-sized objects named as planetesimals, some of which combined to become the asteroids, comets, moons and planets.
其它在盘状星云中的物质相互碰撞合并，形成小行星尺寸的星体，称为“星子”，一些星子相互结合，形成小行星、彗星、卫星和行星。
When water lands in sunny spots, perhaps carried by comets or asteroids, the water transforms directly into gas; if it lands in shadow, the water freezes and can remain indefinitely.
当彗星或者其他小行星携带的水着陆在阳光明媚的坑点时，水直接气化。如果落在背阴一面，水就会结冰，不清楚什么时候解冻。
Explore an asteroids and comets interactive.
探索一颗小行星和彗星们的相互作用。
The rings—there are thousands—are made up of billions of ice and rock particles, thought to be pieces of comets, asteroids, or shattered moons
这些环，有成千上万个，是由数十亿个冰和岩石的粒子所组成，这些粒子被认为是彗星、小行星和粉碎卫星的碎片。
In the past 2bn years, asteroids and comets have ploughed into the moon, dumping an estimated ten thousand billion tonnes of water onto its surface.
在过去的20亿年来，许多小行星和彗星撞击月球，留下撞痕，并在月球表面上遗留下大约10000亿吨水。
Epsilon eri is also known to be surrounded by a disk of dust, which may be derived from collisions between asteroids and comets, which is an indirect argument for smaller planets also being present.
我们还知道EpsilonEri环绕着一圈尘埃，可能产生于小行星和彗星之间的撞击，这也是存在更小的行星的一个间接证据。
As the comet nears the sun, its ice melts, releasing gas and dust that stream away into space. (Explore an asteroids and comets interactive.)
当彗星靠近太阳时，它的冰层融化，释放的气体和尘埃远远地飘向太空。(探索一颗小行星和彗星们的相互作用。)
Stars would stay fixed, but objects like comets, asteroids, and planets moved.
通过这种方法可以观察到，恒星是固定不动的，而像彗星、小行星和行星这样的物体都在移动。
The mission is designed to uncover objects never seen before, including the coolest stars, the universe's most luminous galaxies and some of the darkest near-Earth asteroids and comets.
该任务计划发现以前从未见过的目标，包括最冷的恒星、宇宙中最明亮的星系和一些最暗的近地小行星和彗星。
The mission is designed to uncover objects never seen before, including the coolest stars, the universe's most luminous galaxies and some of the darkest near-Earth asteroids and comets.
该任务计划发现以前从未见过的目标，包括最冷的恒星、宇宙中最明亮的星系和一些最暗的近地小行星和彗星。
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