中文导读 一块在沙漠里捡到的石头,能告诉我们火星 40 多亿年前的样子吗?文章介绍 10 月 29 日发表在《科学》期刊上的研究:2022 年在撒哈拉沙漠发现的陨石 Teghaza 001 是一块形成于 41 亿多年前的火星岩石。先交代发现经过和它的特别之处——多数火星陨石只有几亿年历史;再讲研究者如何一步步确认它的来源和年龄,包括让第一作者差点拒绝研究的“普通”第一印象,以及能精确定年的锆石晶体;接着说明岩石中水的迹象意味着什么、不意味着什么;最后介绍可能的来源地点和“只有一块样本”的局限。阅读时可留意 However、so、Still 如何表达转折与因果,以及 suggest、may、could 等词如何为结论划定边界。
正文 In 2022, a rose-colored rock was found on a salt plain in the Sahara Desert , in Mali . Nobody knew how old it was or where it had come from . Now scientists say it is a piece of Mars that formed more than 4.1 billion years ago . Their study , published on 29 October in the journal Science , describes the rock as a rare sample of the planet’s earliest crust .
本段译文 2022 年,人们在马里境内撒哈拉沙漠的一片盐滩上发现了一块玫瑰色的岩石。当时没人知道它有多古老,也不知道它从哪里来。如今科学家表示,它是一块形成于 41 亿多年前的火星碎片。他们的研究于 10 月 29 日发表在《科学》期刊上,称这块岩石是这颗行星最早期地壳的珍稀样本。
The meteorite is called Teghaza 001, after the place where it was found . Its eight stones together weigh nearly 800 grams . About 435 meteorites from Mars have been found on Earth . All were thrown into space when something hit the planet . However , most of them are only a few hundred million years old , so they tell us little about the planet’s early history .
本段译文 这块陨石以发现地命名,叫作 Teghaza 001。它的八块石头加起来重近 800 克。地球上已发现约 435 块来自火星的陨石。它们都是在有物体撞击火星时被抛入太空的。然而,其中大多数只有几亿年的历史,因此很难告诉我们这颗行星早期的历史。
At first , researchers at the University of New Mexico had shown that it came from Mars by checking its oxygen , which works like a fingerprint for different planets . Carl Agee , who leads the university’s meteorite institute , noticed unusual textures and minerals . When Yang Liu of NASA’s Jet Propulsion Laboratory , the lead author , was asked to study it , she almost said no . Then her team found tiny zircon crystals , which can be used to date rocks very exactly .
本段译文 起初,新墨西哥大学的研究人员通过检测它的氧确认它来自火星,氧就像不同行星的“指纹”。领导该校陨石研究所的 Carl Agee 注意到了不寻常的纹理和矿物。当美国国家航空航天局(NASA)喷气推进实验室的 Yang Liu(论文第一作者)被邀请研究它时,她差点拒绝。随后,她的团队发现了微小的锆石晶体,可以用来非常精确地测定岩石年代。
The results surprised them . The tests showed that water had changed the rock around 4.1 billion years ago , so the rock itself must be even older . A method developed at Caltech allowed the team to study single grains on a piece smaller than a fingernail . This kept most of the rare sample safe for future research .
本段译文 结果让他们吃惊。测试显示,大约 41 亿年前水改变过这块岩石,所以岩石本身一定更古老。加州理工学院开发的一种方法让团队能够在一块比指甲还小的碎片上研究单个颗粒。这样,这份珍稀样本的大部分都得以保留,供今后研究。
The rock also carries signs of water . Its oxygen and its changed minerals suggest that it was once in contact with fluids . Agee also found areas rich in manganese oxide , a substance that rovers on Mars search for as a sign of places that may have suited life . These clues support the idea that early Mars was warmer and wetter than the cold , dry planet we see today . They do not show that life existed there .
本段译文 这块岩石还带有水的迹象。它的氧和发生变化的矿物表明,它曾与流体接触。Agee 还发现了富含氧化锰的区域——火星车在火星上寻找这种物质,把它当作某些地方可能曾适合生命存在的迹象。这些线索支持这样一种看法:早期火星比我们今天看到的寒冷干燥的星球更温暖、更湿润。不过,它们并不能证明那里存在过生命。
The scientists compared the rock’s chemistry with data from spacecraft . They found 13 places on Mars that could match it , several of them in the ancient southern highlands , where no rover has explored . Liu said one reviewer called the rock “a Rosetta Stone for Mars ”. Still , it is only one stone , and no one will ever know exactly where it came from . “We’ve only scratched the surface ,” Liu said .
本段译文 科学家还把这块岩石的化学成分与航天器获得的数据进行比较。他们找到了火星上 13 个可能与之相符的地点,其中几个位于古老的南部高地,那里还没有火星车探索过。Liu 说,一位审稿人称这块岩石是“火星的罗塞塔石碑”。尽管如此,它毕竟只有一块,而且没有人能确切知道它来自哪里。“我们才刚刚触及表面。”Liu 说。
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