科学美国人60秒 SSS 研究证实维京人最早横渡大西洋（在线收听）

This is Scientific American's 60-second Science, I'm Christopher Intagliata.

这里是科学美国人——60秒科学系列，我是克里斯托弗·因塔利亚塔。

Exactly 1,000 years ago, in the year 1021, a Viking or two or three likely wandered around the very northern tip of Newfoundland, cutting down trees ...

整整1000年前的1021年，一两个或三个海盗可能在纽芬兰的最北端游荡，砍伐树木……

... for clearing a particular spot or for gathering wood that might have been used as timber for construction or for boat repair.

…… 用于清出一块特定的地方，或收集可能用作建筑木材或修理船只的木材。

They were very careful to make sure their ships were seaworthy.

他们小心翼翼地确保他们的船只适合航海。

Michael Dee is a geoscientist at the University of Groningen in the Netherlands.

迈克尔·迪伊是荷兰格罗宁根大学的一位地球科学家。

He says it's not news that the Vikings made it to North America around this time.

他说，维京人在这个时候到达北美并不是什么新闻。

Scientists and scholars have surmised as much from archaeological remains in Newfoundland and by scrutinizing ancient texts like the Icelandic sagas.

科学家和学者们从纽芬兰的考古遗迹中，通过仔细研究像冰岛传说这样的古代文本，已经做出了同样多的推测。

One is not really sure how literal one can take the Icelandic sagas.

人们并不确定可以从字面上理解冰岛的传奇故事。

They contain a lot of not only inaccuracies, a lot of things that are obviously fantastical—things like dead people speaking to them, and so on.

它们不仅有很多不准确的地方，还有很多明显很奇异的事情——比如死人对它们说话等等。

But now Dee and his colleagues have been able to come up with a precise date—the year 1021—based on evidence these Norse visitors left behind: specifically, a stump, a log and a branch.

但现在，迪伊和他的同事们已经能够根据这些挪威游客留下的证据得出一个确切的日期——1021年:具体来说，就是一个树桩、一根圆木和一根树枝。

Wood anatomists have determined that certain surfaces of that wood must have been cut by metal blades—a Viking technology the local Indigenous people are not known to have shared.

木材解剖学家已经确定，木材的某些表面一定是用金属刀片切割的——据了解，当地土著居民并不使用维京人的技术。

And Dee’s team was able to use a cosmic occurrence—an extraordinary shower of high-energy particles from space around the year 993—to date the felling of the trees.

迪伊的团队能够利用一次宇宙事件-993年左右来自太空的一场非同寻常的高能粒子阵雨-来确定树木被砍伐的日期。

You see, that shower of cosmic rays created an abundance of radiocarbon.

你看，那阵雨的宇宙射线产生了大量的放射性碳。

When taken up by trees, it left a lasting signature in tree rings—giving the scientists a key to pinpoint the year 993 in the three wood samples using radiocarbon dating.

当它被树木吸收后，它会在树木的年轮上留下持久的印记——这给科学家们提供了利用放射性碳年代测定法确定这三个木材样本中的993年的关键。

And then you see what we have to do is count the rings from there to the edge.

然后我们要做的就是数从这里到边缘的环。

You have to know where the edge is, the bark edge.

你必须知道边缘在哪里，树皮的边缘。

And then you’ll know that was the last growth year of the tree, or the felling date of the tree.

然后你就会知道那是这棵树的最后一个生长年份，或者说是这棵树的砍伐日期。

And it just so happened in all three cases it was exactly the same year: 1021 A.D.

这三种情况都发生在同一年份:公元1021年

The details are in the journal Nature.

详情发表在《自然》杂志上。

The year 1021 therefore marks the first time we know of that Europeans set foot in the Americas.

因此，1021年标志着我们第一次知道欧洲人踏足美洲。

But as the authors write, it also marks “the earliest known year by which human migration had encircled the planet.”

但正如作者所写，它也标志着“已知人类迁徙环绕地球的最早年份”。

Ever since moving out of Africa through Europe and Asia and across the Americas, nobody had got across the Atlantic Ocean, so by this date, we know the Atlantic Ocean was crossed for the first time.

自从人们离开非洲，穿过欧洲和亚洲，穿过美洲，就没有人横渡过大西洋，所以到这个时候，我们知道人们第一次横渡大西洋。

But—as we know—it wouldn’t be the last.

但正如我们所知，这不会是最后一次。

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

谢谢大家收听科学美国人——60秒科学。我是克里斯托弗·因塔利亚塔。