科學(xué)家們剛剛發(fā)現(xiàn)了地球上最古老的物質(zhì)——它聞起來很有趣

科學(xué)家們剛剛發(fā)現(xiàn)了地球上最古老的物質(zhì)——它聞起來很有趣

Fifty years ago a meteorite landed on Earth near Murchison, a rural village located in Victoria, Australia. Over the years, scientists have studied each crevice of the celestial rock.

50年前，一顆隕石降落在澳大利亞維多利亞州的默奇森村附近。多年來，科學(xué)家們研究了天體巖石的每一個(gè)裂縫。

Recently, a new team of researchers discovered stardust on the meteorite that dated back 7 billion years, making it the oldest known material on Earth.

最近，一個(gè)新的研究小組在這塊70億年前的隕石上發(fā)現(xiàn)了星塵，這使它成為地球上已知的最古老的物質(zhì)。

This is part of the Murchison meteorite, a famous rock discovered on Sept. 28, 1969. (Photo: James St. John [CC by 2.0]/Flickr)

"This is one of the most exciting studies I've worked on," said Philipp Heck, lead author of the paper? describing the findings in? PNAS?. "These are the oldest solid materials ever found, and they tell us about how stars formed in our galaxy."

這篇論文的主要作者菲利普·赫克說：“這是我研究過的最令人興奮的研究之一。“這些是迄今為止發(fā)現(xiàn)的最古老的固體材料。關(guān)于我們星系中的恒星是如何形成的。”

Stardust forms when stars burn out and pitch their particles into space, creating new planets, moons and meteorites.

當(dāng)恒星燃燒殆盡并將它們的粒子拋入太空，形成新的行星、衛(wèi)星和隕石時(shí)，星塵就形成了。

Heck and his colleagues found presolar grains on the meteorite, which are minerals formed before the sun was born. And they are tiny — about 100 presolar grains would fit on the period at the end of this sentence.

赫克和他的同事們在這塊隕石上發(fā)現(xiàn)了太陽系前的顆粒，這些顆粒是在太陽誕生之前形成的礦物質(zhì)。它們很小，大約100個(gè)前摩爾的顆粒適合在這句話的最后。

This is a scanning electron micrograph of a presolar grain. It may not look like much, but it's rare — only found in about 5% of the meteorites on Earth. (Photo: Janaina N. Avila/Australian National University)

The stardust has remained trapped and unchanged for billions of years, making it a time capsule of space before our solar system was born.

數(shù)十億年來，星塵一直被困在宇宙中，沒有改變，這使它成為了我們太陽系誕生之前的一個(gè)時(shí)空膠囊。

Presolar grains are rare; they've only been found in 5% of the meteorites on Earth.

前胚乳顆粒很少;它們只在地球上5%的隕石中被發(fā)現(xiàn)。

A large chunk of the Murchison meteorite was given to the Field Museum about 30 years ago, and since then University of Chicago researchers have isolated some of the solar grains.

大約30年前，默奇森隕石的一大塊被捐贈(zèng)給了菲爾德博物館，從那以后，芝加哥大學(xué)的研究人員分離出了一些太陽顆粒。

"It starts with crushing fragments of the meteorite down into a powder," said Jennika Greer, a graduate student at the Fi?eld Museum and the University of Chicago. "Once all the pieces are segregated, it's a kind of paste, and it has a pungent? characteristic — it smells like rotten peanut butter."

菲埃爾德博物館和芝加哥大學(xué)的研究生Jennika Greer說：“首先是將隕石碎片粉碎成粉末。“一旦所有的碎片都分開了它是一種糊狀物，而且有一種刺激的特性——聞起來像腐爛的花生醬。”

The paste was then dissolved with acid until only the presolar grains remained and Heck and his team were able to determine their age and origin.

然后用酸溶解糊狀物，直到只剩下前胚乳顆粒，赫克和他的團(tuán)隊(duì)才能確定它們的年齡和來源。

"We have more young grains that we expected," Heck said. "Our hypothesis is that the majority of those grains, which are 4.9 to 4.6 billion years old, formed in an episode of enhanced star formation. There was a time before the start of the Solar System when more stars formed than normal."

赫克說:“我們有比預(yù)期更多的新谷物。我們的假設(shè)是，這些49到46億年前形成的大部分顆粒，是在一次恒星形成增強(qiáng)過程中形成的。在太陽系形成之前，有一段時(shí)間形成的恒星比正常情況下要多。”

Stardust is the next best thing to taking samples directly from stars, allowing us to learn more about the history of our galaxy. Heck hopes the methods used in his team's research will help other scientists as well.

“星塵”是直接從恒星上取樣的下一個(gè)最佳選擇，它能讓我們更多地了解銀河系的歷史。赫克希望他團(tuán)隊(duì)研究中使用的方法也能幫助其他科學(xué)家。

"With this study, we have directly determined the lifetimes of stardust," Heck said. "We hope this will be picked up and studied so that people can use this as input for models of the whole galactic life cycle."

“通過這項(xiàng)研究，我們直接確定了星塵的壽命，”赫克說。“我們希望這將被研究，這樣人們就可以把它作為整個(gè)銀河系生命周期模型的輸入。”