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

旁白：请听一段环境科学课的节选片段。

Professor: Now last week when we discussed the serious energy challenges we are going to face as the world's population continues to grow and we place more stress on our finite supply of fossil fuels, especially natural gas and oil, well, maybe it's not all doom and gloom.

教授：上一周当我们讨论到严重的能源危机时说道，我们要准备面对世界人口持续增长的现实，人口膨胀对于现有有限的化石燃料供应形成了更大的压力，尤其是天然气和石油。不过未必这就是前景不妙。

In a number of areas, scientists are thinking outside the box and trying to come up with unusual, novel solutions to the energy question.

在很多领域，科学家在努力跳出定式思维，试着去想出不寻常的、新颖的解决能源问题的方案。

Not that a positive outcome is inevitable by any means, but well, let's take a look at one of these creative ideas involving a gas - helium-3.

并不是说好的结果是无论如何都不可避免的，但是，我们先来看看这些创造性的办法之一，关于一种气体——氦3。

Helium-3 is an isotope of helium that has tremendous potential for use in practical energy applications.

氦3是一种氦气的同位素，它在实际的能源应用上有巨大的潜力。

Remember, an isotope is a form of a chemical element that has the same number of protons in its atomic nucleus but a different number of neutrons.

记得吗，同位素是化学元素的多种形式之一，它和其他元素有相同的质子数，但有不同的中子数。

The most common isotope of helium on Earth is helium-4, which does not have any known or potential uses as an energy source.

最常见的氦气的同位素是氦4，氦4目前我们并不知道它有什么可以用作能源来源的潜力。

Helium-3, in comparison, is extremely rare.

相比之下氦3就很罕见了。

There isn't very much of it on Earth.

在地球上氦3很稀少。

Plus, the, um, the main source of helium-3 in our solar system is solar wind, a stream of lethal radiation and particles pouring off of sun.

另外，氦3在太阳系的主要来源是太阳风，这是一股致命的来自太阳的辐射和粒子。

And Earth's magnetic field fortunately prevents that wind from reaching us.

幸运的是，地球的磁场为我们抵挡了这种太阳风。

So why is helium-3 so exciting?

所以为什么氦3这么另人激动呢？

Well, it seems a sure bet that helium-3 is available in abundant quantities on the moon.

看起来已经确定氦3在月球上储备充足。

Since the moon doesn't have a magnetic field, the solar wind must have been depositing helium-3 there for billions of years.

因为月球没有磁场，太阳风带来的氦3肯定已经在月球上积累了上十亿年。

In fact, Apollo astronauts have already discovered it in the moon's dust.

实际上，阿波罗号的宇航员已经在月球的尘埃中发现了氦3。

Some estimates hold that there may be over a million tons of helium-3 buried on the lunar surface.

一些人估计，在月球地表下可能埋着一百亿吨的氦3。

And one ton is more than enough energy for a city of ten million people for a whole year.

一吨氦3足够给一座千万人的城市供能一年。

So you can see this would certainly solve most of our energy problems.

所以你看，这可以解决大部分的能源问题。

But how could this be possible?

但是具体要怎么使这个设想变为可能呢？

Well, we think helium-3 would have to be used in nuclear fusion reactors.

我们认为氦3会被用在核聚变反应堆里。

Keep in mind that a nuclear fusion reactor is completely different from our existing nuclear fission reactors.

记住，核聚变反应堆和核裂变反应堆有很大不同。

Basically a nuclear plant powered by nuclear fission derives its energy from the splitting of atoms.

一般来说核工厂是靠着核裂变，也就是原子分裂的过程来产能的。

While a plant based on nuclear fusion utilizes the energy produced when atoms are fused together.

然而一个靠着核聚变的核反应堆是利用原子聚合在一起时放出的能量。

Fusion is the same nuclear reaction that fuels stars, which as you know, produces unfathomable amounts of energy.

核聚变也是恒星产能的方式之一，像你所知道的，可以产生超级大量的能源。

Researchers have identified two isotopes of hydrogen as the most promising fuel sources for fusion power plants.

研究者已经确定了两种氢气的同位素作为核聚变工厂可以使用的最被看好的能源来源。

However, there is a real drawback.

然而，事情遭遇了一些不妙。

They both produce large amounts of radioactive material in the fusion reaction.

它们都会在聚变过程中产生放射性物质。

But helium-3 fusion produces no radioactive material.

但是氦3并不会产生放射性物质。

In fact, one proponent stated you could safely build a helium-3 power plant in the middle of a city.

实际上，有一个支持者甚至说就是把氦3聚变工厂建在市中心，也是安全的。

A clean, safe source of power almost sounds too good to be true, doesn't it?

一个清洁安全的能源听起来太好，以至于不真实，不是吗？

Well, of course, this is all very theoretical.

当然了，这都是很理论化的。

And there are issues that have to be addressed.

还有几件事我们需要强调一下。

For one thing, we still haven't created a single nuclear fusion plant despite decades of research and development.

第一件事，尽管经过了几十年的研究和发展，我们也还不能创造出一个单一的核聚变工厂。

An often heard joke about fusion is that a nuclear fusion plant has been just decades away from being created for several decades now.

我们经常能听到一个这样的笑话，还有短短几十年又几十年我们就可以创造出来核聚变工厂啦。

Nuclear fusion research is still ongoing, as strong as ever, in fact, but we still don't have a full- scale fusion plant to point to.

核聚变的研究还在继续，实际上研究力度与以往一样强，但是我们还是造不出全规模的核聚变工厂。

And there's a rather big logistical problem as well.

另一个问题是，还存有一个巨大的逻辑问题。

How to get the helium 3 off the moon?

我们要怎么从月球上获得氦3呢？

Digging the stuff up is challenging because the distribution of helium-3 is so diffused across the lunar surface.

直接挖掘是很困难的，因为月球上氦3分布太分散了。

One estimate is you'd need to heat a million tons of lunar soil to about 800 degree Celsius to yield about 70 tons of helium-3 gas.

有人估计说，你需要加热一百万吨月球上的土到800摄氏度来生产大约70吨的氦3气体。

It's kind of liking digging out a crater with a spoon to find the single nugget of gold. Kind of ridiculous, right?

这就好像是一个人手持一把勺子，翻遍一个巨坑来找一块小金子。听起来有点荒诞，对吗？

There's a camp that believes it'll take more energy to extract helium-3 gas than the gas itself would provide.

有一个阵营的人认为，提取氦3所需要的能量比其能产生的能量还要多。

So there are concerns, but given the lure of the possibilities and the pressing nature of our energy difficulties, it's possible that helium-3 could be a significant driver of future exploration of the moon.

所以这就有顾虑了，但是考虑到这种可能性带来的诱惑以及越来越紧迫的能源危机，氮3就可能成为以后探索月球的重要驱动力。

And it certainly could ease the pressure on the demand for fossil fuels if and when the numerous challenges, and not just the ones we've talked about, are solved.

它当然可以减轻人类对于化石燃料的需求，如果真的可以被用作能源而不是仅仅留作谈资的话，能源问题就可以解决了。