听力课堂TED音频栏目主要包括TED演讲的音频MP3及中英双语文稿，供各位英语爱好者学习使用。本文主要内容为演讲MP3+双语文稿:月球是怎么形成的？这里有一个新理论，希望你会喜欢！
【演讲者及介绍】Sarah T. Stewart
莎拉·斯图尔特——行星科学家，专门研究太阳系中的碰撞。
【演讲主题】一个解释月球起源的新理论
【中英文字幕】
Translation by Cissy Yun. Reviewed by Carol Wang.
00:13
Nobody likes to make a mistake. And I madea whopping one. And figuring out what I did wrong led to a discovery thatcompletely changes the way we think about the Earth and Moon.
没人喜欢犯错。而我却犯了个惊天大错。但弄清误点的过程则让我有了一个发现，它完全改变了我们对地球和月球的看法。
00:29
I'm a planetary scientist, and my favoritething to do is smash planets together.
我是一个行星科学家，我最爱做的事是：让行星相撞。
00:35
（Laughter）
（笑声）
00:36
In my lab, I can shoot at rocks usingcannons like this one.
在我的实验室中，我可以用这样的大炮击射岩石。
00:43
（Cannon shot）
（大炮射击）
00:44
（Laughter）
（笑声）
00:46
In my experiments, I can generate theextreme conditions during planet formation. And with computer models, I cancollide whole planets together to make them grow, or I can destroy them.
在实验中，我能模拟行星形成时的极端环境。借助电脑模型，我可以让所有的行星互相撞击，让它们重生，也可让它们毁灭。
01:00
（Laughter）
（笑声）
01:02
I want to understand how to make the Earthand the Moon and why the Earth is so different from other planets.
我想弄明白地球和月球是如何形成的，而且地球为何与其他行星如此不同。
01:11
The leading idea for the origin of theEarth and Moon is called the "giant impact theory." The theory statesthat a Mars-sized body struck the young Earth, and the Moon formed from thedebris disk around the planet. The theory can explain so many things about theMoon, but it has a huge flaw: it predicts that the Moon is mostly made from theMars-sized planet, that the Earth and the Moon are made from differentmaterials. But that's not what we see. The Earth and the Moon are actually likeidentical twins. The genetic code of planets is written in the isotopes of theelements. The Earth and Moon have identical isotopes. That means that the Earthand Moon are made from the same materials.
有关地球月球起源的主流观点是“大碰撞理论”。该理论认为，一个火星大小的天体撞击了年轻的地球，而环绕行星周围的碎屑盘形成了月球。该理论能解释有关月球的许多事，但它有一个巨大的瑕疵：它预言月球的大部分构成来自那个火星大小的行星，即地球和月球是由不同物质组成的。但这与我们的发现大相径庭。地球与月球其实像一对孪生子。行星的基因秘钥写在它们的元素同位素中，而地球与月球拥有相同的同位素。这说明地球和月球是由相同物质构成的。
02:03
It's really strange that the Earth and theMoon are twins. All of the planets are made from different materials, so theyall have different isotopes, they all have their own genetic code. No otherplanetary bodies have the same genetic relationship. Only the Earth and Moonare twins.
地球和月球竟然是孪生子？这太怪了。所有行星都由不同的物质构成，所以它们都有不同的同位素，它们的基因秘钥也不一样。没有任何其他行星天体有同样的基因关系。只有地球和月球是孪生子。
02:23
When I started wong on the origin of theMoon, there were scientists that wanted to reject the whole idea of the giantimpact. They didn't see any way for this theory to explain the specialrelationship between the Earth and the Moon. We were all trying to think of newideas. The problem was, there weren't any better ideas. All of the other ideashad even bigger flaws. So we were trying to rescue the giant impact theory.
当我开始研究月球起源时，已经有科学家尝试摈弃“大碰撞理论”。他们认为，该理论完全无法解释地球与月球之间的特殊关系。我们都在尝试找到新的想法。但问题是，没有什么更好的想法，所有其他的想法漏洞更大。因此，我们试图去拯救“大碰撞理论”。
02:53
A young scientist in my group suggestedthat we try changing the spin of the giant impact. Maybe making the Earth spinfaster could mix more material and explain the Moon. The Mars-sized impactorhad been chosen because it could make the Moon and make the length of Earth'sday. People really liked that part of the model. But what if something elsedetermined the length of Earth's day? Then there would be many more possiblegiant impacts that could make the Moon. I was curious about what could happen,so I tried simulating faster-spinning giant impacts, and I found that it ispossible to make a disk out of the same mixture of materials as the planet. Wewere pretty excited. Maybe this was the way to explain the Moon.
团队中的一位年轻科学家建议我们尝试改变大碰撞中的自转：也许将地球自转的速度提高后，岩屑盘可以混入更多物质，并解释月球的成因。选中火星大小的撞击物是因为它能够形成月球，并形成地球上一天的时长。人们非常喜欢模型的这一部分。但是，倘若地球一天的时长是由其他因素导致的呢？那么，很多其他可能的大碰撞都有可能生成月球。我很好奇会发生什么情况，所以，我模拟了行星转速加快后的大碰撞实验，发现的确有可能产生与行星物质相同的岩屑盘。我们都非常兴奋，也许，这可以解释月球起源。
03:48
The problem is, we also found that that'sjust not very likely. Most of the time, the disk is different from the planet,and it looked like making our Moon this way would be an astronomicalcoincidence, and it was just hard for everyone to accept the idea that theMoon's special connection to Earth was an accident. The giant impact theory wasstill in trouble, and we were still trying to figure out how to make the Moon.
问题是，我们也发现这种可能性极小，因为多数情况下，岩屑盘与行星的物质是不一样的，若如此形成了月球，看起来像是天文巧合。大家很难接受月球和地球的特殊关系仅仅是一个巧合。“大碰撞理论”依然无法解释，我们仍在尝试搞清月球的成因，
04:21
Then came the day when I realized mymistake. My student and I were looking at the data from these fast-spinninggiant impacts. On that day, we weren't actually thinking about the Moon, wewere looking at the planet. The planet gets super-hot and partially vaporizedfrom the energy of the impact. But the data didn't look like a planet. Itlooked really strange. The planet was weirdly connected to the disk. I got thatsuper-excited feeling when something really wrong might be something reallyinteresting.
直到有一天，我发现自己弄錯了。我和学生在研究行星高速自转时大碰撞所产生的数据。那一天，我们其实没思考有关月球的事，我们在观察那个行星。因为碰撞所产生的能量，那个星球会变得超级热，并会部分蒸发。但数据显示，不像是行星，它看起来十分奇怪。行星以一种奇怪的方式与岩屑盘联结着。我忽然有了那种超级兴奋的感觉：当某件事看起来很不对劲时，极有可能是个有趣的发现。
05:00
In all of my calculations, I had assumedthere was a planet with a separate disk around it. Calculating what was in thedisk as how we tested whether an impact could make the Moon. But it didn't lookthat simple anymore. We were making the mistake of thinking that a planet wasalways going to look like a planet. On that day, I knew that a giant impact wasmaking something completely new.
在所有的计算中，我都假设行星被一个分离的岩屑盘所环绕。把计算岩屑盘的成分作为测试大碰撞是否生成月球的方法。但它看起来却不再那么简单，我们犯的错在于认为行星总是其终极状态的样子，直到那天，我才意识到大碰撞创造出一种全新的天体。
05:33
I've had eureka moments. This was not oneof them.
我有过很多次“恍然大悟”的时刻，但这次却不是。
05:37
（Laughter）
（笑声）
05:38
I really didn't know what was going on. Ihad this strange, new object in front of me and the challenge to try and figureit out. What do you do when faced with the unknown? How do you even start?
我完全不知道到底发生了什么。在我面前的是这个奇怪的新型天体, 我的挑战则是弄清它是什么。当你面对未知物時，你会怎么做？你该如何着手？
05:55
We questioned everything: What is a planet?When is a planet no longer a planet anymore? We played with new ideas. We hadto get rid of our old way of thinking, and by playing, I could throw away allof the data, all of the rules of the real world, and free my mind to explore.And by making a mental space where I could try out outrageous ideas and thenbring them back into the real world to test them, I could learn. And byplaying, we learned so much. I combined my lab experiments with computer modelsand discovered that after most giant impacts, the Earth is so hot, there's nosurface. There's just a deep layer of gas that gets denser and denser withdepth. The Earth would have been like Jupiter. There's nothing to stand on. Andthat was just part of the problem. I wanted to understand the whole problem. Icouldn't let go of the challenge to figure out what was really going on ingiant impacts. It took almost two years of throwing away old ideas and buildingnew ones that we understood the data and knew what it meant for the Moon.
我们质疑所有事情：什么才是行星？什么情况下，行星就不再是行星了？我们玩索各种脑洞大开的新想法。我们得摒弃旧的思考方式，因为“玩”的性质，我可以忘却所有数据、扔掉所有现实中的条条框框、让我的思想去自由地探索。我先在大脑中创建一个让自己任意遐想的空间，然后再在现实世界中去测试这些想法，并从中学习。通过玩索，我们受益匪浅。我把实验与电脑模型结合起来，发现在多数大碰撞之后，地球会变得滚烫，没有地表。地球只有一层厚厚的气体，愈深密度愈高，这时的地球其实像木星一样，表面没有任何固体。但这只是问题的一部分，而我想搞清整个问题。我放手不了这个弄清大碰撞到底 发生了什么的挑战，为此，我花了大约两年的时间 去摒弃老思维，并筑建新理论，这些理论基于理解实验数据、 和弄清它对月球的影响。
07:17
I discovered a new type of astronomicalobject. It's not a planet. It's made from planets. A planet is a body whoseself-gravity is strong enough to give it its rounded shape. It spins around alltogether. Make it hotter and spin it faster, the equator gets bigger and biggeruntil it reaches a tipping point. Push past the tipping point, and the materialat the equator spreads into a disk. It's now broken all the rules of being aplanet. It can't spin around together anymore, its shape keeps changing as itgets bigger and bigger; the planet has become something new.
我发现了一种新型天文物体，它不是行星，但它来自于行星。行星，是受强大自引力作用而呈球状的星体。它作为一个整体进行自转。温度越高，自转速度就越快，赤道会越变越大，直至到达临界点。一旦过了临界点，在赤道附近的物质会向外扩散形成岩屑盘，此时，它也不再遵循行星的所有规律。它再也无法自转，随着不断变大，其形状也会不断变化，行星变成了一种全新的天体。
08:00
We gave our discovery its name: synestia.We named it after the goddess Hestia, the Greek goddess of the hearth and home,because we think the Earth became one. The prefix means "alltogether," to emphasize the connection between all of the material. Asynestia is what a planet becomes when heat and spin push it over the limit ofa spheroidal shape.
我们给这个发现起了个名字：索内斯蒂亚（synestia），用女神赫斯提亚来命名它，她是古希腊神话中的家炉之神，因为我们认为地球就变成了这样的角色。词首“syn”意味着“一起”，强调了所有物质之间的联结。当热量和转速将行星推越了球型天体的极限后，行星就变成了索内斯蒂亚。
08:27
Would you like to see a synestia?
你们想看看索内斯蒂亚吗？
08:30
（Cheers）
（欢呼）
08:33
In this visualization of one of mysimulations, the young Earth is already spinning quickly from a previous giantimpact. Its shape is deformed, but our planet would be recognizable by thewater on its surface. The energy from the impact vaporizes the surface, thewater, the atmosphere, and mixes all of the gases together in just a few hours.We discovered that many giant impacts make synestias, but these burning, brightobjects don't live very long. They cool down, shrink and turn back intoplanets. While rocky planets like Earth were growing, they probably turned intosynestias one or more times.
这是其中的一个模拟视频，因为之前的一次碰撞，年轻的地球在快速自转。地球有些变形，但根据地表的水，我们还认得出它是地球。大碰撞带来的能量让地球表层、水、大气层完全蒸发，在短短几小时中，所有的气体混合起来。我们发现许多大碰撞会产生索内斯蒂亚，但这些燃烧着的炽热天体寿命不长。它们会降温，缩小，并再次变回行星。在类似地球这样的岩石行星在成长过程中，可能会一次或数次变成索内斯蒂亚。
09:19
A synestia gives us a new way to solve theproblem of the origin of the Moon. We propose that the Moon formed inside ahuge, vaporous synestia. The Moon grew from magma rain that condensed out ofthe rock vapor. The Moon's special connection to Earth is because the Moonformed inside the Earth when Earth was a synestia. The Moon could have orbitedinside the synestia for years, hidden from view. The Moon is revealed by thesynestia cooling and shrinking inside of its orbit. The synestia turns intoplanet Earth only after cooling for hundreds of years longer. In our newtheory, the giant impact makes a synestia, and the synestia divides into twonew bodies, creating our isotopically identical Earth and Moon. Synestias havebeen created throughout the universe. And we only just realized that by findingthem in our imagination: What else am I missing in the world around me? What ishidden from my view by my own assumptions?
索内斯蒂亚为我们解决月球起源提供了新途径，我们提出，月球形成于一个巨型、气化的索内斯蒂亚内部。月球形成于岩石蒸汽凝结而产生的岩浆雨。月球与地球间的特殊联系是因为月球形成于地球内部，那时，地球还是一个索内斯蒂亚。月球在索内斯蒂亚内部可能已公转了许久，但我们无法观察到它。而当索内斯蒂亚冷却缩小到月球公转轨道以内时，月球才出现在我们的视线中，只有经历了几百年的冷却后，索内斯蒂亚才会变成地球。在我们的新理论中，大碰撞形成了索内斯蒂亚，而索内斯蒂亚分成两个新天体，就是同位素相同的地球与月球。索内斯蒂亚在宇宙各处都在发生，通过想象他们的存在，我们才刚刚意识到这个现象：在我周围的世界中，我还遗漏了什么？我自己的臆测 还妨碍我看到什么其他信息？
10:51
The next time you look at the Moon,remember: the things you think you know may be the opportunity to discoversomething truly amazing.
下一次你赏月时，请记住: 你认为自己知道的事，也许正是让你发现真正令人惊讶事情的好机会。
11:05
（Applause）
（掌声）
