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陨石中含有比地球形成还早25亿年的物质

kira86 于2020-07-17发布
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默奇森陨石上发现地球上已知最古老物质,比地球,其中三分之二的细粒是46到49亿年前的。有些细粒已经有70亿年的历史了。
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资配易Meteorite Contains Material Older Than Earth

陨石含有比地球更古老的物质

Sunday morning, September 28th, 1969, a fireball lit up the skies north of Melbourne, Australia.

资配易1969年9月28日的周日早晨,一个火球照亮了澳大利亚墨尔本北部的天空。

People were getting ready to go to church, and then they heard this loud sonic boom, some of them saw the bright fireball in broad daylight, and people were surprised, they said, what's going on, is there an airplane that came down? It sounded really dramatic. And then suddenly shortly after that there was a smell that was detectable over the whole area. People describe it as methylated spirits--a strong organic smell.

资配易“人们正准备去教堂,然后他们听到了巨大的音爆,其中有些人在大白天看到了明亮的火球,人们很惊讶,他们说,发生了什么事?是有飞机坠毁了吗?听起来十分引人关注。不久之后,整个区域都能闻到一种气味。人们将之描述为甲基化酒精——一种强烈的有机气味。”

Cosmochemist Philipp Heck, of Chicago's Field Museum, describing the spectacular arrival of what's now known as the Murchison meteorite, named for the village where it was found. A portion of the space debris now resides at the Field Museum. And Heck says it's our best source of pre-solar stardust. Meaning stardust older than the solar system, and the Sun itself. "I call it a scientific treasure trove."

芝加哥菲尔德博物馆的宇宙化学家菲利普·赫克描述了现在被称为默奇森陨石到来的壮观场景,默奇森陨石是以发现它的村庄命名的。部分太空碎片现在被存放在菲尔德博物馆。赫克说这些碎片是研究太阳系前星尘的最佳源头。太阳系前星尘的意思是比太阳系和太阳本身还要古老的星尘。“我称之为科学宝藏。”

Inside the meteorite is dusty debris left over from when stars slightly larger than our Sun fizzled out. Over millions of years, those dust grains were battered by cosmic rays, which slightly altered their composition. Atoms of elements got broken down into smaller ones like neon and helium. Then, some of that stardust was swallowed up within rocks - such as the Murchison meteorite - during the formation of our solar system. Those rocks served as time capsules, preserving the material for unimaginable ages.

资配易在陨石内部是一些比太阳稍大的恒星熄灭后留下的尘埃碎片。在数百万年的时间里,这些尘埃颗粒受到宇宙射线的冲击,其组成略有改变。元素的原子被分解成更小的原子,比如氖原子和氦原子。然后,在我们太阳系形成期间,一些星尘被如默奇森陨石的岩石吞噬。这些岩石充当了时间胶囊,将这些物质保存了长到难以想象的时间。

Previous astronomical observations have hypothesized that there was a "baby boom" of stars about seven billion years ago. By studying the Murchison grains' elemental composition, Heck's team was able to date 49 grains, and found that two-thirds of them were 4.6 to 4.9 billion years old.

之前的天文观测已经假设在大约70亿年前有一个恒星的“婴儿潮”。通过研究默奇森细颗粒的元素组成,赫克的研究小组确定了49种细粒的年代,发现其中三分之二的细粒是46到49亿年前的。

资配易And that all makes sense, because the parent stars formed seven billion years ago, took them 2 to 2.5 billion years to evolve and become planetary nebula, and become dust producing.The results are in the Proceedings of the National Academy of Sciences.

“这一切都说得通,因为母恒星形成于70亿年前,花了大约20到25亿年才进化成行星状星云,并产生尘埃。”研究结果发表在《美国国家科学院院刊》上。

资配易Some of the grains are actually up to seven billion years old. Making them the most ancient material on Earth. Delivered here without notice, on a quiet Sunday morning, 50 years ago.

事实上,有些细粒已经有70亿年的历史了。这使它们成为地球上最古老的物质。在50年前一个安静的星期天早上,在没有任何预兆的情况下被送到了这里。

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