科学美国人60秒：隐藏在早期宇宙中的尘埃

Christopher Intagliata: This is Scientific American’s 60-Second Science. I’m Christopher Intagliata.If you’ve ever looked up at the Milky Way, you’ve seen what’s known as cosmic dust.

Christopher Intagliata：这是《科学美国人》的 60 秒科学。我是克里斯托弗·英塔利亚塔。如果你曾经仰望过银河系，你就会看到所谓的宇宙尘埃。

Pascal Oesch: When you see this band of the Milky Way, you can see these dark patches. So that’s really just dust that is obscuring the stars behind it.

帕斯卡·奥什：当你观察银河系带时，可以看到这些黑色斑块。事实上是这些尘埃掩盖了它后边的恒星。

Intagliata:Pascal Oesch is an associate professor at the University of Geneva. He points out that cosmic dust isn’t exactly the kind of dust you or I might be familiar with.

雕刻：帕斯卡·奥什是日内瓦大学的副教授。 他指出宇宙尘埃并不是你我所熟悉的那种尘埃。

Oesch: Cosmic dust is not quite the same as dust we know from the apartment. Cosmic dust is really just very small particles in the universe that are consisting of just a few molecules, often containing carbon or silicate.

奥什：宇宙尘埃与我们从公寓里的尘埃不太一样。宇宙尘埃实际上只是宇宙中非常小的粒子，由几个分子组成，通常含有碳或硅酸盐。

Intagliata:And—as in that Milky Way example—that cosmic dust absorbs the light of stars behind it, making it harder for us to see those stars with instruments like the Hubble Space Telescope.

雕刻：而且——就像银河系的例子一样——宇宙尘埃吸收了它背后恒星的光，使我们更难用哈勃太空望远镜等仪器看到这些恒星。

But there is one way around that: Astronomers can observe the sky with longer wavelengths—using telescopes like the Atacama Large Millimeter/submillimeter Array in Chile, or ALMA.

但是有一种方法可以解决这个问题：天文学家可以用更长的波长观测天空——使用智利阿塔卡马大型毫米波天线阵(ALMA)这样的望远镜。

With ALMA, astronomers can see even the dust bunnies hiding up in the sky—because as the dust absorbs photons from the stars behind it, it heats up.

有了 ALMA，天文学家甚至可以看到隐藏在天空中的尘埃——因为当尘埃吸收了它背后恒星的光子时，会变热。

Oesch: And so then, with ALMA, we can directly see the emission of this heated up dust even in the very early universe.

奥什：因此，有了 ALMA，我们甚至可以在非常早期的宇宙中直接看到这种被加热的尘埃的排放。

Intagliata:Oesch and his team have now stumbled upon two previously obscured galaxies using ALMA observations. The galaxies date back to the very earliest days of the universe, 13 billion years ago.

雕刻：奥什 和他的团队现在使用 ALMA 观测，偶然发现了两个以前被遮蔽的星系。这些星系可以追溯到130亿年前的宇宙最早期。

Oesch: So those are the first building blocks, right, of the galaxies that we see around us in the universe today. So these are the first kind of Lego stones. And apparently we have been missing some of those Lego stones.

奥什：所以这些是我们今天在宇宙中看到的星系的第一个组成部分。如果这些是第一批乐高积木。显然我们已经错过了很多。

Intagliata:In fact, the scientists estimate that up to one in five galaxies may be missing from our current census of the early universe. The results appeared recently in the journal Nature. [Y. Fudamoto et al., Normal, dust-obscured galaxies in the epoch of reionization]

雕刻：事实上，科学家们估计，我们目前对早期宇宙的普查可能会丢失多达五分之一的星系。结果最近发表在《自然》杂志上。

Hubble's successor, the James Webb Space Telescope, is set to sail off the planet later this month. And with its more powerful ability to probe long wavelengths, Oesch is hoping it might bring our galactic census a little closer to completion.

哈勃的继任者詹姆斯韦伯太空望远镜将于本月晚些时候离开地球。凭借其更强大的探测长波长的能力，奥什 希望它可以让我们的银河系普查更进一步。

Thanks for listening for Scientific American's 60-second Science. I'm Christopher Intagliata.

以上是《科学美国人》的 60 秒科学。克里斯托弗·英塔利亚塔报道。