You probably already know everything is made up of little tiny things called atoms
你也许已经知道所有的东西都是由微小的原子组成。
or even that each atom is made up of even smaller particles called protons, neutrons and electrons.
你可能还知道每一个原子是由更小的叫做质子，中子和电子的微粒组成
And you've probably heard that atoms are small.
也许你听说过原子很小。
But I bet you haven't ever thought about how small atoms really are.
但我打赌，你从未想过它究竟有多小。
Well, the answer is that they are really, really small.
答案是，它们非常非常非常小。
So you ask, just how small are atoms?
你提出问题了，到底原子有多小呢?
To understand this, let's ask this question: How many atoms are in a grapefruit?
为了去理解它，让我们先提出一个问题：一个柚子包含多少原子？
Well, let's assume that the grapefruit is made up of only nitrogen atoms,
首先我们假设柚子完全由氮原子构成，
which isn't at all true, but there are nitrogen atoms in a grapefruit.
虽然不准确，但柚子中确实有氮原子。
To help you visualize this, let's blow up each of the atoms to the size of a blueberry.
为了便于观察，我们把原子放大到一个蓝莓大小。
And then how big would the grapefruit have to be?
那总体柚子又会是多大呢？
It would have to be the same size of -- well, actually, the Earth.
它会跟地球的个头差不多。
That's crazy! You mean to say that if I filled the Earth with blueberries,
天啊！难道地球装满蓝莓的数量
I would have the same number of nitrogen atoms as a grapefruit?
会和柚子中的氮原子一样多？
That's right! So how big is the atom?
的确如此！那么原子究竟有多小？
Well, it's really, really small! And you know what? It gets even more crazy.
它真的非常非常小，小到超出了你的想象。
Let's now look inside of each atom -- and thus the blueberry, right? What do you see there?
现在让我们看看原子内部，也就是蓝莓。你看到了什么？
In the center of the atom is something called the nucleus,
你会发现原子有一个核心，叫原子核。
which contains protons and neutrons, and on the outside, you'd see electrons. So how big is the nucleus?
其中包含着质子和中子，外围的是电子。那么原子核有多大？
If atoms are like blueberries in the Earth, how big would the nucleus be?
如果原子是地球中的蓝莓，那么原子核又有多大呢？
You might remember the old pictures of the atom from science class,
你可能在物理书上看过原子的描绘，
where you saw this tiny dot on the page with an arrow pointing to the nucleus.
原子核是箭头所指的小点。
Well, those pictures, they're not drawn to scale, so they're kind of wrong. So how big is the nucleus?
这些图不是按比例画的，所以并不准确。那么真实的原子核多大呢？
So if you popped open the blueberry and were searching for the nucleus
如果你在蓝莓的内部搜索原子核，结果是一无所获。
You know what? It would be invisible. It's too small to see!
知道为什么吗？因为我们看不到它！它太小了，我们看不到！
OK. Let's blow up the atom -- the blueberry -- to the size of a house.
因此我们把原子，也就是蓝莓，放大到房子的尺寸。
So imagine a ball that is as tall as a two-story house.
想象一下有两层房屋那么高。
Let's look for the nucleus in the center of the atom.
然后在寻找原子中央的原子核，
And do you know what? It would just barely be visible.
你知道吗？原子核还是几乎不可见。
So to get our minds wrapped around how big the nucleus is,
所以想要直到原子核到底有多大，
we need to blow up the blueberry, up to the size of a football stadium.
我们必须把蓝莓放大到橄榄球场那样大。

So imagine a ball the size of a football stadium,
然后想象一下橄榄球场大小的球。
and right smack dab in the center of the atom, you would find the nucleus, and you could see it!
原子不偏不倚的中央一小点，你就会找到原子核，而且你可以看得到它。
And it would be the size of a small marble.
而它只有玻璃弹珠大小。
And there's more, if I haven't blown your mind by now.
不仅仅如此，如果现在你都没有被震撼到，
Let's consider the atom some more. It contains protons, neutrons and electrons.
我们来更详尽地了解原子。原子中包含了质子，中子，电子。
The protons and neutrons live inside of the nucleus, and contain almost all of the mass of the atom.
质子和中子是在原子核之内，且占了原子大部分的重量。
Way on the edge are the electrons. So if an atom is like a ball the size of a football stadium,
在原子边缘的是电子。如果原子像一个橄榄球场那样大的话，
with the nucleus in the center, and the electrons on the edge, what is in between the nucleus and the electrons?
原子核在中央，而电子在边缘，那么两者之间的东西又是什么呢？
Surprisingly, the answer is empty space. That's right. Empty!
相当令人惊讶，答案是什么都没有。没错，空无一物！
Between the nucleus and the electrons, there are vast regions of empty space.
在原子核和电子之间，存在着大片的空洞区域。
Now, technically there are some electromagnetic fields, but in terms of stuff, matter, it is empty.
严格的说来那里存在着电磁场，但就本质而言，那里是空的。
Remember this vast region of empty space is inside the blueberry,
记得这一大片空间，是位于和组成地球的蓝莓一样大的原子之中
which is inside the Earth, which really are the atoms in the grapefruit.
组成地球的蓝莓就好比是葡萄柚里的原子。
OK, one more thing, if I can even get more bizarre.
另外还有一件事是更难以想象的
Since virtually all the mass of an atom is in the nucleus
既然事实是原子的全部质量集中在原子核，
now, there is some amount of mass in the electrons, but most of it is in the nucleus
当然电子也有一定质量，但是可以忽略。
how dense is the nucleus? Well, the answer is crazy.
那么原子核的密度是多少？你会觉得不可思议。
The density of a typical nucleus is four times 10 to the 17th kilograms per meter cubed.
一般而言，原子核的密度是4乘以10的17次方千克/立方米。
But that's hard to visualize. OK, I'll put it in English units.
但数字是难以想象的，那么换作英制单位是
2.5 times 10 to the 16th pounds per cubic feet.
2.5乘以10的16次方磅/立方英尺。
OK, that's still kind of hard to figure. OK, here's what I want you to do.
当然这还是难以理解的，不如我告诉你怎么做。
Make a box that is one foot by one foot by one foot.
做一个各边都是1英尺长的盒子，
Now let's go and grab all of the nuclei from a typical car. Now, cars on average weigh two tons.
然后集合一堆重量相当于一辆汽车的原子。车子一般而言重约两吨。
How many cars' nuclei would you have to put into the box to have your one-foot-box have the same density of the nucleus?
要在盒子里放多少辆车子的原子才能让这个每边1英尺盒子的密度等同于原子核呢？
Is it one car? Two? How about 100? Nope, nope and nope.
一辆，两辆，还是一百辆？都不是。
The answer is much bigger. It is 6.2 billion. That is almost equal to the number of people in the Earth.
答案是不止如此。需要62亿辆。这差不多是世界人口总数。
So if everyone in the Earth owned their own car and they don't, and we put all of those cars into your box.
所以假设地球上每个人都拥有一辆车，当然并非如此，我们把这些车都装进你的盒子里，
That would be about the density of a nucleus.
就差不多相当于一个原子核的密度。
So I'm saying that if you took every car in the world and put it into your one-foot box,
我的意思是你把世界上每一辆车都装进一个每边1英尺长的盒子中，
you would have the density of one nucleus. OK, let's review. The atom is really, really, really small.
你才得到原子核的密度。我们回顾一下。原子极其渺小的。
Think atoms in a grapefruit like blueberries in the Earth. The nucleus is crazy small.
柚子中的一粒原子就相当于地球上的一颗蓝莓。原子核更是出奇的小。
Now look inside the blueberry, and blow it up to the size of a football stadium,
把蓝莓放大到足球场一边大，
and now the nucleus is a marble in the middle.
原子核就是其中央的一颗弹珠。
The atom is made up of vast regions of empty space. That's weird.
原子的组成是一大片空间。这是很不寻常的。
The nucleus has a crazy-high density. Think of putting all those cars in your one-foot box. I think I'm tired.
原子核有极高的密度。这好比把所有的车放进每边为1英尺的盒子中。我想我累了。