对于我们的宇宙学模型来说，最早的恒星形成得太快了

新的证据表明，对于我们的宇宙学模型来说，最早的恒星形成得太快了

When we think about the formation of the entire freaking Universe, one of the biggest questions concerns the birth of the very first stars. It's thought that stars began appearing in the first 100 million years after the Big Bang, and we've seen some really old stars; but the processes that created them from the primordial Universe soup are a big mystery.

当我们思考整个宇宙的形成时，其中一个最大的问题是关于最早的恒星的诞生。人们认为，恒星是在大爆炸后的1亿年开始出现的，我们看到过一些非常古老的恒星;但是从原始宇宙汤中产生它们的过程是一个很大的谜。

But a gas cloud in the distant Universe has just given us a big clue. It's so far away, light from this cloud has taken nearly 13 billion years to arrive, meaning we're seeing the cloud as it was when the Universe was roughly 850 million years old - a mere blip of its current lifespan.

但是遥远宇宙中的气体云给了我们一个重要的线索。它是如此的遥远，来自这片云的光花了近130亿年才到达，这意味着我们看到的这片云和宇宙大约8.5亿年的时候是一样的——只是它目前寿命的一个小点。

That cloud looks rather similar to younger gas clouds filled with elements that were forged in stars and spewed out into space in a series of explosions as those stars died. This indicates there would have been stars around that had already lived and died by 13 billion years ago.

这片云看起来很像年轻的气体云，充满了在恒星中形成的元素，这些元素在恒星死亡时通过一系列爆炸喷射到太空中。这表明在130亿年前就已经存在和死亡的恒星。

Not just one generation, either. Based on the chemical abundances in this ancient gas cloud, at least two generations of stars had to form, live, and die to produce the chemical signature we're seeing.

也不只是一代人。根据这个古老气体云中的化学元素丰度，至少有两代恒星必须形成、生存和死亡，才能产生我们所看到的化学特征。

It's a real dilly of a pickle for our models of star formation, and it was discovered entirely by accident.

对于我们的恒星形成模型来说，这是一个真正的难题，它完全是偶然发现的。

Astronomer Eduardo Bañados of the Max Planck Institute for Astronomy and colleagues were looking at distant quasars - galaxies with extremely bright active nuclei, or cores. When the team noticed something odd about the light from a quasar called P183+05, around 13 billion light-years away, they decided to take a closer look.

马克斯·普朗克天文研究所的天文学家爱德华多·巴纳多斯和他的同事们一直在观察遥远的类星体——拥有极其明亮的活动核或核心的星系。当研究小组注意到一个名为P183+05的类星体发出的光有些奇怪时，他们决定近距离观察。

It didn't take long before they realised that the odd signatures in the light were from a cloud of gas and dust near the quasar, through which some of the quasar's light was being filtered, dampening some of the wavelengths.

没过多久，他们就意识到这些奇怪的信号来自于类星体附近的一团气体和尘埃，通过这些气体和尘埃，一些类星体的光被过滤了，减弱了一些波长。

(Max Planck Institute for Astronomy)

Because different wavelengths of light are blocked by different elements, this also provided clues as to the composition of the cloud.

因为不同的光波被不同的元素阻挡，这也为云的组成提供了线索。

After we were convinced that we were looking at such pristine gas only 850 million years after the Big Bang, said astronomer Michael Rauch of the Carnegie Institution of Science, "we started wondering whether this system could still retain chemical signatures produced by the very first generation of stars."

卡内基科学研究所的天文学家迈克尔·劳赫说:“我们确信，我们是在大爆炸后8.5亿年才观测到这样的原始气体。我们开始怀疑，这个系统是否还能保留第一代恒星产生的化学信号。”

In the very early Universe, there wasn't a lot of variety. Just after the Big Bang, the Universe was mostly filled with hydrogen and helium. It wasn't until the first stars came along that more elements started to proliferate.

在非常早期的宇宙中，没有太多的多样性。大爆炸后不久，宇宙主要由氢和氦组成。直到第一批恒星出现，更多的元素才开始增殖。

In their cores, stars fused hydrogen into helium, then helium into carbon, and so forth, with the more massive stars able to fuse nuclei all the way up to iron. When such stars reach the end of their lives and go supernova, the extreme conditions of these explosions can, in turn, create heavier elements.

在它们的核心中，恒星将氢聚变成氦，然后氦聚变成碳，以此类推，质量更大的恒星能够将原子核一直聚变到铁。当这些恒星到达生命的尽头并变成超新星时，这些爆炸的极端条件反过来会产生更重的元素。

These are taken up into new generations of stars - thus, the more metals there are in a star, the younger its generation is likely to be. And those signatures can also be used to tell the age of the gas between the stars - the interstellar medium.

这些元素被吸收到新一代的恒星中——因此，一颗恒星中的金属元素越多，它的新一代可能就越年轻。这些特征也可以用来判断恒星间气体的年龄——星际介质。

Which brings us back to that super-old gas cloud. Something of a holy grail in cosmology is finding the chemical fingerprints of the very first generation of stars, known as Population III. The team thought that their gas cloud might have them.

这让我们回到了那个超级古老的气体云。找到第一代恒星的化学指纹是宇宙学中的圣杯，也就是我们所知的第三种群。研究小组认为，他们的气体云可能会把它们带走。

So, they analysed the metallicity and relative chemical abundances in the cloud, based on spectra separated out from the light of the quasar.

因此，他们根据从类星体中分离出的光谱分析了云团中的金属丰度和相对化学丰度。

As expected, the cloud had low metallicity, consistent with its age. But the relative chemical abundances had no evidence of being enriched by Population III stars. Rather, they were startlingly similar to those of much younger gas clouds enriched by Type Ia supernovae.

不出所料，这片云的金属丰度很低，与它的年龄相符。但相对的化学元素丰度并没有被星族III丰富的证据。相反，它们与Ia型超新星丰富的年轻气体云惊人地相似。

What that means is that another generation of stars separates the cloud from Population III stars - and, since Type Ia supernovae generally take around a billion years… well. We have a discrepancy.

这意味着新一代的恒星会将星云与第三类恒星分开——而且，由于Ia型超新星一般需要大约10亿年的时间……我们有分歧。

That puts a curious constraint on the life cycles of early stars, which is going to be an interesting puzzle to solve. But there's other evidence to suggest that the early Universe is a pretty precocious place - such as a whole bunch of supermassive black holes that we don't think could have formed so quickly.

这给早期恒星的生命周期带来了一个奇怪的限制，这将是一个需要解决的有趣难题。但也有其他证据表明，早期宇宙是一个相当早熟的地方——比如一大堆我们认为不可能这么快就形成的超大质量黑洞。

If this finding checks out, maybe it's time to give the cosmological models a do-over.

如果这一发现得到证实，也许是时候对宇宙学模型进行重新研究了。

Meanwhile, the team is continuing to search for clues.

与此同时，调查小组仍在继续寻找线索。

It is exciting that we can measure metallicity and chemical abundances so early in the history of the Universe, but if we want to identify the signatures of the first stars we need to probe even earlier in cosmic history, Bañados said.

Banados说:“我们能够在宇宙早期历史中测量金属丰度和化学丰度是令人兴奋的，但是如果我们想要确定第一批恒星的特征，我们需要在宇宙历史中更早的时候进行探测。”

I am optimistic that we will find even more distant gas clouds, which could help us understand how the first stars were born.

“我很乐观地认为，我们将发现更远的气体云，这将有助于我们了解第一批恒星是如何诞生的。”

The research is due to be published in The Astrophysical Journal, and is available on arXiv.

这项研究将发表在《天体物理学杂志》(Astrophysical Journal)上，可以在arXiv上找到。