Narrator: Listen to part of a lecture in an archaeology class.

旁白：请听一段考古学课上的讲座。

Female professor: A popular misconception about archaeology: Some people imagine we just go out into the field with a shovel and start digging, hoping to find something significant.

女教授：对考古学有一个常见的误解：一些人认为我们仅仅带上铲子去荒野，然后开始挖掘，希望能够发现一些重要的事物。

Well, while there is an element of luck involved, we have an array of high-tech tools to help us figure out where to concentrate our efforts.

是的，这里确实有运气的成分，我们有一系列高科技的工具来帮助我们判断哪里值得我们耗费心力。

One of the newer tools actually relies on particle physics.

其中一个较新的工具实际上是基于粒子物理学的。

Talk about interdisciplinary! Here’s a machine that brings together two very different sciences.

说到学科交叉！有一个可以把两个不同的科学联系到一起的机器。

This machine is called a muon detector. Muons are subatomic particles that result from cosmic rays.

这个机器叫做介子探测器。介子是起源于宇宙射线的亚原子粒子。

OK, let me start over. Cosmic rays aren’t actually "rays"--they’re basically protons, zipping through outer space at close to light speed.

好，我重新开始说。宇宙射线不是真正的“射线”。它们实际上是在外太空以接近于光速的速度快速运行的质子。

And when they collide with the atoms in Earth’s atmosphere, they break up into smaller particles—muons.

而当它们和地球大气里的原子撞击的时候，就会分裂成更小的粒子——介子。

Now, these muons are still highly energized, so they can easily pass on down to the Earth’s surface.

现在，这些介子仍然有很高的能量，它们能够很轻易地一直传递到地球的表面。

In fact, they can pass through solid matter, so they can also penetrate deep into the surface.

事实上，它们能够穿过固体物质，所以它们也能深入穿透地球表面。

And it’s this property of muons that archaeologists are taking advantage of.

而考古学家现在利用的正是介子的这一特性。

Let me explain. With the right kind of equipment, scientists can use muons to create a kind of picture of the structures they’re studying.

我来解释一下，有正确的装备，科学家就能够用介子绘出他们正在研究的事物的结构。

Let’s say we’re studying a Mayan pyramid in Central America, and we’re interested in finding out if there are burial chambers or other rooms inside.

比方说我们正在中美洲研究一座玛雅金字塔，我们想知道里面是否有一些墓葬或者其他的房间。

Well, a muon detector will show a greater number of muons passing through the less dense areas inside the pyramid. Yes, Andrew?

是的，一个介子探测器会显示有很多介子穿过金字塔内密度小的地方。安德鲁，你有什么疑问？

Male student: Um, I’m not sure I get how this muon detector works exactly.

男学生：事实上，我不太确定自己理解了介子探测器究竟是如何工作的。

Female professor: Well, muons lose energy as they pass through dense material, like the stone walls of a Mayan pyramid.

女教授：嗯，介子在穿过密度大的物质时会消耗能量，比如说玛雅金字塔的石墙。

So, more muons, and more energetic muons, will be passing through empty spaces.

因此，更多的介子，和更多拥有能量的介子就会穿过空旷的空间。

The muon detector can differentiate the areas where more muons are passing through--the empty spaces---as well as where there are fewer muons--the walls and dense areas.

这个介子探测器能够分辨出哪些地方有更多的介子穿过——空的地方，以及哪些地方有更少的介子穿过——墙壁以及密度大的地方。

These empty spaces will show up as darker.

这些空的地方呈现出暗色。

So, we wind up with a-a kind of picture of the pyramid, and its internal structure.

所以我们最终得到了一种金字塔以及它的内部结构的图片。

Male student: A picture?

男学生：一张图片？

Female professor: Sort of like an x-ray image.

女教授：一种像X射线照片一样的图像。

Male student: OK, so if we see darker areas inside the pyramid, we assume it’s an empty space with more muons.

男学生：哦，所以如果我们看到金字塔内部暗色区域，我们可以认为它是有更多介子穿过的空旷区域。

Female professor: Exactly. With this technology, we can see what’s inside a structure before we dig.

女教授：对的，利用这个技术，我们在挖掘之前，就能够看到它的内部结构是什么样的。

So we know exactly where to explore, and we can minimize the damage excavation can cause—even a little damage could result in our losing vital information forever.

所以我们能准确地知道去探索哪块区域，并且能把挖掘过程中带来的损坏最小化——甚至一点小的损坏都可能导致我们永远地错失重要信息。

Now, muon detectors have been around for some time, but they’ve been improved upon since archaeologists started using them.

现在，介子探测器诞生已经有一段时间了，但是从考古学家开始使用它们，它们才得到了改进。

In 1967, a physicist placed a muon detector beneath the base of one of the Egyptian pyramids at Giza.

在1967年，一个物理学家把一个介子探测器放在埃及的吉萨大金字塔的地基下面。

And he was looking for burial chambers.

他正在寻找一个墓葬。

Now, it happened that the muon detector found none, but he did demonstrate that the technique worked.

现在，介子探测器没有发现任何东西。但是，他确实证明了这个技术是可行的。

Unfortunately, the machine he used was so big that many archaeologists doubted muon detection could be practical.

不幸的是，他用的这个机器太大了，以至于许多考古学家怀疑介子探测器的实用性。

How could they get a massive piece of equipment into, say, uh, the jungles of Belize?

他们怎样让这么大的一个设备用在，比方说伯利兹的雨林呢？

Then there was the issue of range.

这就谈到范围的问题了。

The machine used in 1967 could only scan for muons directly above it, not from the sides, so it actually had to be put underneath the pyramid so it could look up.

1967年的机器仅仅能够扫描在它正上方的介子，而不能是来自四面八方的。所以，为了它能够向上扫描，就不得不把它放在金字塔的正下方。

That meant, if you wanted to find out what was inside an ancient structure, you’d first have to bury the detector beneath it.

这就意味着，如果你想要发现古老的建筑里有什么，首先你必须把探测器埋在它下面。

There’s been a lot of work on these machines since then, and these problems have been solved by and large.

从那个时候开始，人们对这些机器做了很多的研究，并且这些问题大体上已经解决。

That’s not to say the technology is perfect.

这并不是说这项技术是完美的。

It-it would be nice, for example, to have a system that didn’t take six months to produce an image.

举个例子，如果有个系统不需要6个月去生成一个图形就太好了。

I suppose that’s better than the year it took for the 1967 study to get results, but still...

我认为它比1967年时花一年去等结果的情况要好。但是仍然……

Well, there’s good reason to believe that with better equipment, we’re going to see muon detectors used much more frequently.

仍然有理由相信会有更好的设备，我们将会看到介子探测器更频繁的使用。

They’re already being used in other areas of science--uh, for example Japanese scientists studying the interiors of volcanoes and there are plenty of archaeologists who would love to use this technology.

它们已经被用在科学界的其它领域，举个例子，日本科学家用它研究火山内部，还有很多考古学家也非常愿意使用这项技术。