听力文本

Fortunately, there is another way to travel in time,
所幸还有另外一种穿越时间的方法
and this represents our last and best
它是我们建造真正时间机器的
hope of building a real time machine.
最后也是最有望实现的一丝希望
Traveling through the fourth dimension
通过第四维空间进行时间旅行
will never be a walk in the park.
永远不会像在公园散步那么简单

But it turns out there is a surprisingly
但事实上存在一个惊人的
straightforward way to do it.
直通途径
You just have to travel very very fast,
你只需以极快极快的速度移动
much faster than even the high speed required
甚至要快于能够
to keep out of the supermassive black hole.
避免被吸入特大质量黑洞的高速度
This is because of another strange fact about the universe.
其中的奥妙在于另一个奇妙的宇宙事实
There's a cosmic speed limit --
世界上存在宇宙速度极限
186,000 miles per second,
186000英里/秒
also known as the speed of light.
即人们熟知的光速
Nothing can exceed that speed.
这是世间最快的速度
I realize this sounds weird, but trust me.
我知道这听起来有些奇怪，但请相信我
It's one of the best established principles in science.
这是最具权威的科学定理之一
Believe it or not,
信不信由你
traveling at near the speed of light
以接近光速的速度移动
transports you to the future.
你就能穿越至未来
To explain why,
为弄清原委
let's dream up a science-fiction transportation system.
我们来想象一个科幻的运输系统
Imagine a track that goes right around the earth.
试想有一条紧绕地球的轨道
A track for a superfast train.
一条极速列车专用轨道
We're going to use this imaginary train to get as close as possible
假定这列虚幻列车无限接近光速
to the speed of light and see how it becomes a time machine.
看它如何变成时间机器
On board are passengers with a one-way ticket to the future.
列车上的乘客手持通向未来的单程票
The train begins to accelerate faster and faster.
列车开始不断加速，越来越快
Soon it's circling the earth over and over again.
很快它便开始一圈又一圈绕地球行驶
To approach the speed of light means circling the earth pretty fast.
无限接近光速意味着飞速环绕地球
Seven times a second.
达到每秒7圈

视频及简介

《与霍金一起了解宇宙》纪录片耗时3年多制作，期间霍金曾多次坚持对剧本作大幅修改。霍金指出外星生物在消耗尽自己星球上的资源后便会乘坐大型飞船到他们能够到达的星球掠夺资源，并将那里开拓成为他们的殖民地；如果有外星生物到访地球，那将会像当年意大利航海家哥伦布登陆美洲大陆一样，最后给人类带来毁灭性的灾难。