科學(xué)家們說，極罕見的生命成分可能起源于外太空

科學(xué)家們說，極罕見的生命成分可能起源于外太空

Phosphorus, an element that's key in forming DNA and fuelling life on Earth, may have first arrived on the planet via comets from newborn stars.

磷是形成DNA和促進(jìn)地球生命的關(guān)鍵元素，可能是通過新生恒星的彗星首次抵達(dá)地球的。

Since the element is extremely rare in the Universe, its presence on Earth has been a long-standing mystery. But scientists at the European Southern Observatory (ESO) now suggest that phosphorus may have first arrived on Earth in the molecule phosphorus monoxide – phosphorus bonded with one oxygen molecule.

由于這種元素在宇宙中極為罕見，它在地球上的存在一直是個謎。但歐洲南方天文臺(ESO)的科學(xué)家們現(xiàn)在認(rèn)為，磷最早可能是通過一氧化二磷分子(磷與一個氧分子結(jié)合)到達(dá)地球的。

Their research, published in the journal Monthly Notices of the Royal Astronomical Society on Wednesday, reveals that phosphorus monoxide forms amid the birth of new stars.

他們的研究發(fā)表在周三的《皇家天文學(xué)會月刊》(Monthly notice of the Royal Astronomical Society)上。

They also found the molecule in a comet circling Jupiter: a frozen ball of rock and ice called 67P/Churyumov-Gerasimenko, or "67P" for short.

他們還在一顆環(huán)繞木星的彗星上發(fā)現(xiàn)了這種分子:一個由巖石和冰組成的冰凍球體，名為67P/Churyumov-Gerasimenko，簡稱“67P”。

The discovery suggests comets could have carried phosphorus monoxide to Earth.

這一發(fā)現(xiàn)表明彗星可能攜帶了一氧化磷到地球。

Phosphorus is essential for life as we know it, Kathrin Altwegg, an author of the new study, said in a press release.

“正如我們所知，磷是生命所必需的。”這項新研究的作者之一凱瑟琳·阿爾特韋格(Kathrin Altwegg)在一份新聞稿中說。

As comets most probably delivered large amounts of organic compounds to the Earth, the phosphorus monoxide found in comet 67P may strengthen the link between comets and life on Earth.

“由于彗星很可能向地球輸送了大量的有機(jī)化合物，在67P彗星中發(fā)現(xiàn)的一氧化磷可能會加強(qiáng)彗星與地球生命之間的聯(lián)系。”

Phosphorus is rare in the Universe but essential to life (in most cases). It acts as glue that holds together the chains of nucleotides that make up DNA. Phosphorus also helps build cell walls and store cells' energy.

磷在宇宙中很少見，但對生命卻是必不可少的(在大多數(shù)情況下)。它像膠水一樣把組成DNA的核苷酸鏈粘在一起。磷還有助于建造細(xì)胞壁和儲存細(xì)胞的能量。

To figure out how the element arrived on Earth, astronomers turned to the stars.

為了弄清這種元素是如何抵達(dá)地球的，天文學(xué)家們轉(zhuǎn)而研究恒星。

Using the Atacama Large Millimetre/Submillimeter Array (ALMA) in Chile, the scientists behind the new study looked at a star-forming region called AFGL 5142.

利用智利的阿塔卡馬大型毫米/亞毫米陣列(ALMA)，這項新研究背后的科學(xué)家觀察了一個名為AFGL 5142的恒星形成區(qū)域。

Studying the wavelengths of light coming from that distant region allowed them to determine which kinds of molecules interact with that light.

通過研究來自那個遙遠(yuǎn)區(qū)域的光的波長，他們可以確定哪種分子與光相互作用。

They found phosphorus-carrying molecules forming around the new stars.

他們發(fā)現(xiàn)攜帶磷的分子在新恒星周圍形成。

Stars are born when clouds of gas and dust collapse, giving into gravity and coalescing into new cosmic objects. When massive stars are still young, they send out flows of gas that open huge cavities in the clouds of interstellar dust around them.

恒星是在氣體云和塵埃坍縮時產(chǎn)生的，在重力作用下合并成新的宇宙物體。當(dāng)大質(zhì)量恒星還很年輕時，它們會釋放出氣體流，在它們周圍的星際塵埃云中打開巨大的空洞。

Scientists think molecules with phosphorus begin to form on the walls of these cavities as they're pummelled with radiation from the young, massive stars.

科學(xué)家認(rèn)為，在年輕的大質(zhì)量恒星的輻射沖擊下，含磷分子開始在這些空洞的壁上形成。

But even after pinpointing a potential origin for phosphorus-carrying molecules in the Universe, a big question remained: How did those molecules travel to Earth?

但是，即使確定了宇宙中攜帶磷的分子的潛在起源，一個大問題仍然存在:這些分子是如何到達(dá)地球的?

The researchers turned to data from a spacecraft called Rosetta, which orbited the 67P comet from August 2014 to September 2016.

研究人員轉(zhuǎn)向了一艘名為“羅塞塔”(Rosetta)的航天器的數(shù)據(jù)，該航天器在2014年8月至2016年9月期間環(huán)繞這顆67P彗星運(yùn)行。

Astronomers had already found traces of phosphorus in data Rosetta gathered about 67P, but they hadn't determined which molecule the element was part of.

天文學(xué)家已經(jīng)在羅塞塔收集的67P數(shù)據(jù)中發(fā)現(xiàn)了磷的蹤跡，但他們還沒有確定這種元素屬于哪個分子。

Then, Altwegg said, an astronomer at a conference made a suggestion: "She said that phosphorus monoxide would be a very likely candidate, so I went back to our data, and there it was".

然后，Altwegg說，一位天文學(xué)家在一次會議上提出了一個建議:“她說一氧化二磷是一個非?？赡艿暮蜻x者，所以我看我們的數(shù)據(jù)，發(fā)現(xiàn)它就在那里。”

Phosphorus monoxide can end up in comets after the walls of a newborn star's surrounding cavity collapse. The molecule can get trapped in frozen grains of dust that circle the new star, some of which eventually coalesce into comets.

在一顆新生恒星周圍的空腔坍塌后，一氧化磷會在彗星中消失。這些分子會被困在環(huán)繞這顆新恒星的凍結(jié)塵埃中，其中一些最終會合并成彗星。

Astronomers think that comets may have delivered other chemical components of life, such as amino acids and even water, to early Earth as well.

天文學(xué)家認(rèn)為，彗星可能也向早期地球提供了其他生命的化學(xué)成分，如氨基酸甚至水。

Phosphorus seems to be yet another life-giving element that the space snowballs brought when they pummelled the planet.

磷似乎是太空雪球撞擊地球時帶來的另一種生命元素。