Sometimes when I'm on a long plane flight,
有时候当我在孤单的长途飞行中，
I gaze out at all those mountains and deserts and try to get my head around how vast our Earth is.
我望向那些山脉与沙漠，然后尝试去理解地球的广袤。
And then I remember that there's an object we see every day that would literally fit one million Earths inside it.
接着就想到，其实我们每天都会看到能装下一百万颗地球的庞然大物。
The sun seems impossibly big, but in the great scheme of things, it's a pinprick,
太阳够大了吧！但若宏观而论，太阳就如针头般渺小。
one of about 400 billion stars in the Milky Way galaxy,
在银河系约四千亿颗恒星中，它也只是其中一员，
which you can see on a clear night as a pale, white mist stretched across the sky.
银河就是在无云的夜晚里可以看到的横跨天空的一条淡淡的白色雾般的光带。
And it gets worse. There are maybe 100 billion galaxies detectable by our telescopes,
更夸张的是，用当今望远镜所观测到的银河系已高达一千亿个。
so if each star was the size of a single grain of sand,
如果把恒星视为一粒细沙，
just the Milky Way has enough stars to fill a 30 foot by 30 foot stretch of beach three feet deep with sand.
那么我们所在的银河系里所有恒星放在一起就是一个长宽各三十英尺、深三英尺的沙坑。
And the entire Earth doesn't have enough beaches to represent the stars in the overall universe.
而地球上所有沙滩的沙粒集合起来还够不上整个宇宙里的恒星的数量呢！
Such a beach would continue for literally hundreds of millions of miles.
大概要有个绵延几亿英里的沙滩才比得上。
Holy Stephen Hawking, that is a lot of stars.
神圣的史蒂芬·霍金啊，真是有太多星星了。
But he and other physicists now believe in a reality that is unimaginably bigger still.
霍金跟其他的物理学家开始相信真相，可能更大, 超乎想象的大。
I mean, first of all, the 100 billion galaxies within range of our telescopes are probably a minuscule fraction of the total.
首先, 我们的望远镜能观察到的一千亿个银河系，可能只是整体的一小块而已。
Space itself is expanding at an accelerating pace.
空间是一直在膨胀扩张的，而且膨胀的速度一直在增加，
The vast majority of the galaxies are separating from us so fast that light from them may never reach us.
绝大部分的银河系都是快速的远离我们，快到它们的光线根本到不了我们这里。
Still, our physical reality here on Earth is intimately connected to those distant, invisible galaxies.
但是，在地球上的物理现象仍与这些看不到的遥远的银河系们紧密关连。
We can think of them as part of our universe.
我们可以把这些银河系当作我们的宇宙的一部分。
They make up a single, giant edifice, obeying the same physical laws
他们整体属于一个巨大的架构，遵循相同的物理定律，
and all made from the same types of atoms, electrons, protons, quarks, neutrinos that make up you and me.
由相同型态的原子、电子、质子、夸克、中微子，组成你跟我。
However, recent theories in physics, including one called string theory,
但是最近发展的一些物理学理论，其中一种叫做弦理论，
are now telling us there could be countless other universes,
推论说可能有无穷多的宇宙存在着
built on different types of particles, with different properties, obeying different laws.
而且每个宇宙是由不同的基本粒子组成的，具有不同的特性，遵循不同的运作规律。

Most of these universes could never support life, and might flash in and out of existence in a nanosecond,
这些宇宙大部分无法演化出生命型态，也许可能只存在一微秒，然后就消失了，
but nonetheless, combined they make up a vast multiverse of possible universes.
但是不管怎么短暂，这些宇宙都是多元宇宙的各种可能性之一。
In up to 11 dimensions, featuring wonders beyond our wildest imagination.
在高达十一种维度里，有着超出我们所能想象之外的奇妙性质。
And the leading version of string theory predicts a multiverse made of up to 10 to the 500 universes.
而目前弦理论的最先进的版本预测说，一个多元宇宙是由10的500次方个单一宇宙组成的。
That's a one followed by 500 zeroes,
这个数字是1后面跟着500个0，
a number so vast that if every atom in our observable universe had its own universe
一个如此大的数字，即使我们可观测的宇宙中，每一个原子都有着它自己的宇宙，
and all of the atoms in all of those universes each had their own universe,
并且所有这些宇宙中的每一个原子都还有自己的宇宙，
and you repeated that for two more cycles, you'd still be at a tiny fraction of the total--namely,
再这样重复两次，你仍然只是这个大数字的一小部分，
one trillion trillion trillion trillion trillion trillion trillion trillion trillion trillion trillion trillion trillion trillion trillionth.
只有一兆，兆，兆，兆，兆，兆，兆，兆，兆，兆，兆，兆，兆，兆，兆分之一而已。
But even that number is minuscule compared to another number: infinity.
而这么大的数字，跟无穷大比起来，仍旧是微不足道的。
Some physicists think the space-time continuum is literally infinite,
有些物理学家认为，所谓的时空连续体基本上就是无穷的，
and that it contains an infinite number of so-called pocket universes with varying properties.
里面包含了无数个所谓的口袋宇宙，各自有不同的特性与物理定律。
How's your brain doing? But quantum theory adds a whole new wrinkle.
你的脑袋还跟的上吗？不过量子力学还要来加一重笔。
I mean, the theory's been proven true beyond all doubt, but interpreting it is baffling.
这个理论的正确性已经被证明是毫无疑问的了，但是如何解读却仍摸不着头绪。
And some physicists think you can only un-baffle it
有些物理学家认为，如果你想真正理解它
if you imagine that huge numbers of parallel universes are being spawned every moment,
你只能想象每一分钟都有巨大数量的平行宇宙在诞生，
and many of these universes would actually be very like the world we're in, would include multiple copies of you.
并且这些宇宙许多都与我们所在的这个世界十分相似，也会包括着你的许多复制版本。
In one such universe, you'd graduate with honors and marry the person of your dreams.
在其中的一个宇宙，你会以很好的成绩毕业，并且与你梦中情人结婚。
In another, not so much. There are still some scientists who would say, hogwash.
在另外一个宇宙中，可能没这么好命了。也有一些科学家认为，这真是鬼话连篇。
The only meaningful answer to the question of how many universes there are is one, only one universe.
这些科学家认为，关于有多少个宇宙这个问题，唯一合理的答案数字是一个，只有一个宇宙。
And a few philosophers and mystics might argue that even our own universe is an illusion.
甚至一些哲学家和神秘主义者认为，我们的宇宙都可能只是一个幻象。
So, as you can see, right now there is no agreement on this question, not even close.
所以，如你所见，现在在这个问题上没有统一甚至接近的答案。
All we know is, the answer is somewhere between zero and infinity.
我们目前只知道，这个答案介于零与无穷大之间。
Well, I guess we know one other thing: This is a pretty cool time to be studying physics.
我想我们还知道另外一件事：这是一个很好的机会来学习物理。
We just might be undergoing the biggest paradigm shift in knowledge that humanity has ever seen.
我们大概正在面对着人类历史上最大的知识理论体系的变化。