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Every week is great for getting excited about planets, but this past one has been especially exciting!
关于行星，每周都有让人激动的新闻，但刚刚发生的这条尤为让人激动！
I mean, planets! What would we do without them? From launching a new satellite, to finding diamonds from a lost world,
我指的是关于行星的新闻哦！毕竟如果没了它们，就没有我们，无论是发射一颗新卫星，还是寻找迷失世界里的钻石，
researchers have been hard at work transforming how we think about our planet, the solar system, and the rest of the universe. It's been a big week.
研究人员一直都在努力工作，想要转变我们对于行星、太阳系乃至整个宇宙的看法，这周是非凡的一周。
First up, earlier this week, NASA launched its Transiting Exoplanet Survey Satellite, or TESS, from the Kennedy Space Center in Florida.
首先，本周早些时候，美国宇航局从加州的肯尼迪航天中心发射了凌日系外行星勘测卫星(TESS)。
Like its name suggests, TESS will hunt for exoplanets using the transit method, which relies on watching a planet cross in front of its star.
顾名思义，凌日系外行星勘测卫星将通过中天法来探寻系外行星，依靠的方法是在某行星围绕的恒星前观测这颗行星。
When that happens, the brightness of the star dims by a certain amount, depending on how big and how close the planet is.
这种观测方法会在一定程度上减弱恒星的亮度，具体程度视恒星与行星之间的距离远近而定。
Over time, if the brightness keeps changing by the same amount at regular intervals, that's a good indication that there's a planet there.
一段时间后，如果亮度规则变化，就表明观测地有恒星。
Researchers can then extrapolate details about the planet's size and orbit based on the magnitude and regularity of that dip.
然后研究人员就可以根据亮度变化的程度以及时间间隔来推断出行星的大小和轨道。
The Kepler Mission, which ran from 2009 to 2013, also used this method.
2009-2013年的开普勒任务也用了这种方法。
It focused in on a small patch of sky, which allowed it to get lots of data from dimmer, farther stars. TESS is gonna do almost the exact opposite:
即专注于某一小块区域，这样就能从更暗、更远的恒星处获得大量信息，而凌日系外行星勘测卫星的工作内容却基本相反：
It'll look at about 85% of the sky and observe over 200,000 targets, focusing only on the brightest stars within 200 light-years of Earth.
该卫星会从天空中大概85%的恒星中选择20多万个恒星为观测目标，主要关注那些距离地球不到200光年的亮度最大的恒星。
But that brightness will allow it to do something Kepler can't.
但这样的亮度可以让凌日系外行星勘测卫星做到开普勒任务做不到的事情。
See, when transiting exoplanets move in front of their stars, they don't just block out light because they're in the way.
这是因为：当恒星前观测系外行星的时候，因为挡在中间而阻隔光线只是其中一个表现而已。
The chemicals in their atmospheres also absorb some of the light.
恒星大气层中的化学物质还会吸收部分光线。
Specific chemicals absorb specific wavelengths of light, and when scientists spread that starlight out into a spectrum, they can see that chemical footprint.
特定的化学物质会吸收特定的光波长，而当科学家将光线投射到光谱中的时候，就能看到其中化学物质的足迹了。
It shows up as a pattern of dark lines at specific wavelengths. Based on this pattern, they can tell what's in that planet's atmosphere.
会在特定波长处呈现出黑线，通过这个模式，他们就能判断出行星大气层的组成。
And based on that, they can figure out some of what's happening on the planet's surface, even maybe assess how habitable the world is.
在此基础上，他们就能得知这颗行星表面发生了什么，甚至可以得知这颗行星是否宜居。
The thing is, if a star is dim, its spectrum is also dim, and the spectral lines aren't well-defined.
问题在于：恒星如果暗度不高，那相应的光谱也会比较暗，那么光谱线就不会很清晰。
And since Kepler focused on dimmer targets, it's really hard to extract that chemical info.
而鉴于开普勒主要专注于亮度不高的目标，所以就很难确定其中的化学物质信息了。
That's not to badmouth Kepler, of course, it did lots of amazing things, lots of great measurements, found tons and tons of planets!
当然，这并无贬低开普勒任务的意思，我们当然肯定开普勒任务所达成的伟大工作，所做的重要测量以及所发现的无数行星了！
But spectrally, it's kind of lacking. We have gotten good spectra from some of its targets, but most of them are just too dim.
但从光谱角度而言，开普勒做的还不够，我们已经从开普勒的观测目标中获得了不错的光谱，但大多数都比较晦暗。
Because TESS will look at super bright stars, we're going to be able to do lots of follow-up using ground-based telescopes,
鉴于凌日系外行星勘测卫星可以观测亮度极高的恒星，所以我们以后就能够通过地面上的望远镜
and when it launches, NASA's James Webb Space Telescope.
来做很多后续工作，比如用詹姆斯·韦伯空间望远镜。
We're going to get much more detailed and complete portraits of the kinds of planets in the galaxy than we did with Kepler.
那时候，我们获得的系外行星的种类和细节都会比开普勒更多。
We'll be able to learn not just their size and orbit, but their compositions, and what kinds of processes are happening on and inside them!
我们可以了解到的不只是行星的大小和轨道运行情况，还会了解到它们的组成、其表面和内部正在发生哪些进程！
So far, TESS is expected to find tens of thousands of new worlds, including at least a few dozen around the size of Earth.
目前来看，凌日系外行星勘测卫星预计可以发现数万个新行星，至少包括一些跟地球差不多大的行星。
And when they do, you can bet we will be here to tell you about them.
那时候，我们一定会再来跟大家分享消息的。
Speaking of planets, scientists published a paper this week in Nature Communications describing the first evidence of a whole new planet in our solar system.
提到行星，本周，一些科学家在《自然-通讯》杂志上发表了一篇论文，提到了首次发现太阳系中某新行星的证据。
Or rather, one that used to be around here billions of years ago.
这颗新发现的行星在数十亿年前就有了。
This isn't, like, a sneaky Planet 9 announcement, you probably would've heard about that.
这颗行星不像隐晦宣布的第九颗行星那样，所以大家可能早就有所耳闻了。
For a while, researchers believed that the early solar system was full of protoplanets.
科学家曾经一度认为，早期的太阳系到处都是原行星。
These were bodies around the size of Mars or Mercury that smashed into each other to form today's planets and moons, including Earth's Moon.
原行星大小跟火星或者水星差不多，它们通过彼此撞击来形成如今的一些行星和卫星，比如地球的卫星月球。
We think they should exist based on what we can see around us, but we haven't really had any tangible proof, at least, not until this new paper.
我们根据自己在周围的所见所闻就会认为他们应该是存在，但我们其实并没有切实的证据，直到这篇论文发表。
Now, researchers have announced they've found concrete evidence for a lost protoplanet in the Almahata Sitta meteorite, which exploded over Sudan in 2008.
如今，研究人员宣布，他们发现了具体证据，可以证明六号站陨石中含有消失的原行星，而2008年的时候，该陨石在苏丹上空消陨。
Specifically, this rock is a ureilite, which is a kind of meteorite that's been exposed to intense pressures and temperatures,
这颗陨石是橄辉无球粒陨石，这种陨石要暴露于高压高温下才能形成，
and has lots of magnesium, iron, and carbon. We think all ureilites came from one original parent body, but we're not totally sure.
其中含有大量的镁、铁和碳，目前我们认为橄辉无球粒陨石来自一种原始的母体，但我们还不完全确定是什么。
Either way, they definitely formed under some extreme conditions, like the kind of conditions on par with the inside of Earth.
无论如何，这种陨石一定是在极端条件下形成的，有点像地球内部的那种环境。
Now, we've found this kind of rock before, but Almahata Sitta is special.
虽然我们现在发现了这种陨石，但六号站依然是特殊的。
Because when scientists took a close look at some of its fragments, they found diamonds inside, which is not actually the special part.
因为当科学家仔细观测其组成部分后，他们竟然在里面发现了钻石！但这还不是真正特殊之处。
We know diamonds form inside the Earth, and since ureilites formed in similar environments, the presence of diamonds wasn't a huge surprise.
我们都知道地球内部是有钻石存在的，所以既然橄辉无球粒陨石也是在类似环境里形成的，那么发现钻石也就不足为奇了。
But the information contained in them was. Diamonds are minerals, which means they have regular, repeating crystalline structures.
真正特殊的其中包含的信息，钻石是矿物质，也就是说，钻石是由无数个规则的晶体结构组成的。
And that structure reflects the pressure and temperature conditions under which the mineral formed.
从这个结构可以得知钻石形成时的压力和温度。
Analysis of the diamonds in this meteorite showed that its parent body formed under pressures that exceeded 20 gigapascals, which is a whole lot;
通过分析陨石中含有的钻石可以得知，其母体是在20多个吉帕斯卡的压力下形成的，这个压力就厉害了；
the kind of pressures seen in the Earth's upper mantle.
因为这么大的压力在跟地球上地幔的压力差不多。
That means that the rocks must have originally formed in a body big enough to have sustained a mantle like the Earth,
这就意味着，这些陨石的母体一定非常大，大到可以经受住地球地幔那么大的压力，
something about the size of Mercury or Mars, but with a different composition.
其大小应该跟水星或者火星差不多，只不过组成不尽相同。
The problem is, there isn't a direct match anywhere in our solar system. But there probably used to be.
问题在于：太阳系里找不到对应的物体，或许以前是有的。
Based on its composition, scientists now think Almahatta Sitta came from a Mercury- or Mars-sized protoplanet that existed billions of years ago.
根据其结构，科学家现在认为，六号站陨石是来自跟水星或者火星差不多大的系外行星，这种系外行星存在于几十亿年前。
That means the diamonds in these rocks are some of the last remains of a world that no longer exists, at least, not in the way it used to.
也就是说，这些陨石中的钻石是已经消失的世界中留下的残余物，而且存在的方式也与过去不同了。
These days, it might just be a bunch of asteroids.
现在，他们可能以小行星的方式存在着。
We already knew that ureilites happen under extreme conditions, but now, we have some pretty clear pointers to their origin: protoplanets.
我们已经知道，橄辉无球粒陨石是在极端条件下形成，但现在，我们有一些非常清晰的源头指向了，那就是许多原行星。
Or maybe even just one protoplanet. As always, it would be helpful to do more research to look for supporting evidence.
或者某一颗原行星，老规矩：做更多的研究来获取更多的证据是有益无害的。
But one way or another, these rocks are telling a pretty great story. Thank you for watching this episode of SciShow Space!
但无论如何，这些陨石中蕴藏着不少信息，感谢收看本期的《太空科学秀》！
Scientists are learning new stuff about the universe every week,
每一周，科学家对于宇宙都有新发现，
and if you want to keep learning about that and getting excited about it with us, you can subscribe at youtube.com/scishowspace.
如果大家热衷于了解宇宙的话，就请订阅youtube.com/scishowspace吧！
