How fast are you moving right now?
此时此刻你移动得有多快？
That seems like an easy question. The first tempting answer is, 'I'm not moving.'
这似乎是个简单的问题。第一反应得到的答案是“我并没有移动。”
Upon further reflection, you realize that maybe the Earth's motion counts.
经过更一步的思考后，你意识到可能地球的运动要算进去。
So, a second tempting answer is, '19 miles/second around the Sun.'
所以，第二个容易想到的答案是“以19英里每秒的速度围绕太阳运动。”
But then you recall learning that the Sun moves around the center of the Milky Way galaxy,
但是马上你又回想起曾经学过太阳绕着银河系的中心运动，
and the Milky Way moves within the Local Group of galaxies, and the Local Group moves within the Virgo Cluster,
银河系在本星系群中运动，而本星系群又在室女座星系团中运动，
and the Virgo Cluster moves within...
室女座星系团运动在……
'How fast are you moving?' is not an easy question.
“你移动得有多快？”不是一个简单问题。
When Mission Control tells astronauts how fast they're going, there's always an assumed standard of rest.
当太空航行地面指挥中心告诉宇航员他们的运动速度时，总会有个关于静止的假定标准。
At the start of the voyage, speeds are given relative to the launchpad.
在航行的一开始，速度是以发射台作为参照给出的。
But later, when the launchpad is just one more arbritrary place down there on Earth's spinning surface,
但随后，当发射台只不过是在地球旋转表面上的又一个任意的地点时，
speeds are given relative to the idealized, non-spinning pinpoint center of Earth.
速度的给出是根据理想状态下的停止运转的地球的中心。
On their way to the Moon, Apollo astronauts had a hard time answering the question, 'How fast are you moving?'
在驶向月球的旅途中，阿波罗号宇航员们发现很难回答“你移动得有多快”这个问题。
Speed away from Earth was one thing, and speed toward the Moon was quite another.
从地球出发是一个速度，驶向月球又是另一个速度。
That's because the Earth and the Moon move relative to one another.
这是因为地球和月球相对于彼此运动。
Ah, of course! Speed is a relative quantity.
理所当然的！速度是一个相对量。
When Captain Kirk ask Lieutenant Sulu if the Starship Enterprise has reached a speed of warp 7,
当Krik舰长询问Sulu中尉企业号星舰是否达到曲速7级的速度时，
Sulu should reply, 'Relative to what, Captain?'
Sulu本应该回答“相对于什么而言，舰长？”
Such a sassy reply may get subordinate Starfleet officers in trouble,
如此无礼的回答只怕会让星际舰队的下级官员们惹上麻烦，
but it is the only good answer to the question, 'How fast are you moving?'
但它却是“你移动得多快？”这个问题唯一的好答案。
This is basic relatively talking.
这是基本的相对说法。
Not fancy Einsteinian relativity, but good old fashioned (and still correct) Galilean relativity.
不是大名鼎鼎的爱因斯坦相对论，但也是守旧的（而且至今仍然是正确的）伽利略相对性原理。
Galileo seems to have been the first person to realize that there is no such thing as an absolute speed.
伽利略似乎是第一个认识到绝对速度是不存在的人。
Speeds are relative. This means that speeds only have meaning when they are referred to a reference frame.
速度是相对的。这就意味着当速度与参考系联系起来时它们才具有意义。
Presumably that reference frame is itself at rest.
假定这个参考系自身是静止的。
But then we have to ask again, 'At rest relative to what?'
但我们又要问，“静止相对于什么？”
Because even the concept of rest has lost any hint of absolute meaning.
因为即使静止这个概念已经失去了任何绝对的意义。
Speed is relative, and rest is relative.
速度是相对的，静止也是相对的。
Earth's speed is 19 miles/second relative to the Sun.
地球以19英里每秒的速度的绕太阳公转。
The Enterprise's speed is warp 7 relative to the center of the Milky Way galaxy.
企业号飞船相对于银河系的中心的速度是曲速7级。
Your speed is zero relative to your easy chair.
你的速度相对于你坐的椅子为零。
But depending on where you sit, it is hundreds of miles/hour relative to Earth's center.
但是根距你坐的地方，相对于地球中心，你的速度是几百英里每小时。
When we furrow a brow and ask, 'But how fast is Earth really moving?'
当我们皱着眉毛然后问“那么地球究竟移动得有多快？”
we imagine Spaceship Earth plowing through the ocean of space as it orbits the Sun.
我们想象中的宇宙飞船“地球号”正在宇宙广袤的空间中一面破浪而进，一面绕行太阳。
But space is not an ocean. It has no substance as water does.
但宇宙不是海洋。它不像水一样由物质构成。
Space is not a thing; space is nothing. Space is no thing.
宇宙不是一个事物，宇宙什么都不是。宇宙没有事物。

You can move between two points in space, say between Earth and Mars, but you can't move through space.
你能在宇宙中的两个点之间任意移动，比如说在地球和火星之间，但你不能穿过宇宙。
There's nothing to move through. It's like trying to say how much a hole weighs.
没有什么可以穿过的。就好像是在说一个洞有多重。
A hole weighs exactly nothing because a hole is nothing. It's a void, and so is space.
一个洞是没有重量的，因为一个洞什么也不是。它是空的，宇宙也是。
To move relative to nothing is meaningless.
没有参照系的移动是毫无意义的。
The concepts of speed and of rest have only relative meaning. They are absolutely meaningless.
加速和静止的概念只有相对意义。它们从绝对意义上说是无意义的。
They mean something only with respect to arbitrarily chosen, artificial frames of reference.
它们的意义只存在于任意选中的人工参照系中。
If, someday, you are buckled into your spaceship,
如果有一天，你坐在宇宙飞船中，
and you see from the side window, say, a space station whizz by at constant speed,
你从舷窗看到一个宇宙空间站匀速飞过，
there is no way to know which of you is really moving.
没有办法确定你们中的哪一个是在真正移动。
Neither of you is really moving because there is no deep reality about constant speed.
你们都没有在真正运动，因为关于匀速并没有深刻的现实意义。
Constant speed in a straight line has only relative meaning, a kind of relative reality.
在一条直线上的匀速只有相对意义，就好像是一种相对的现实。
Does this mean that all motion is relative?
这意味着所有运动都是相对的吗？
No! Some motions have only relative meaning, but some motions have absolute meaning, are absolutely real.
不是！一些运动有相对意义，但是一些运动有绝对意义，是绝对真实的。
For example, constant speed is relative, but change in speed is absolute.
比方说，匀速运动是相对的，但速度的改变是绝对的。
Calling something absolute in science means that arbitrary standards are not used in its measurement.
在科学上，把一件事称作为绝对意味着任意的标准没有被运用在它的测量上。
It is unambiguously measurable. When your spaceship fires its engines, your change in speed is beyond doubt.
它是完全清晰可量的。当你的宇宙飞船发动时，你在速度上的变化是毫无疑问的。
You feel it in your stomach, and your ship's sensors can measure it.
你感受到你的胃在翻腾，而且你的飞船感应器可以测量出这一变化。
Outside your window, the passing space station may seem to be changing speed, but the beings inside the station will not feel it.
在你的窗外和你擦肩而过的宇宙空间站，看起来可能也在发生速度变化，但置身于空间站之内不会感受到。
And no sensors can measure it. You are really changing speed, and they are really are not.
而且也没有任何感应器可以测量它。你是真的在发生速度变化，它们确实没有。
There's something absolutely real about changes in speed. The same goes for rotation.
关于速度变化，有些东西是绝对真实的。飞船的旋转也一样。
If your spaceship is spinning, you can feel it, and your ship's sensors can measure it.
如果你的飞船在旋转，你是能感受到的，飞船上的感应器也可以测量。
The space station outside may seem to be going around you, but it is you who feels queasy, not the folks in the space station.
在空间站外面的一切看起来在围着你转，但你却是感到头晕眼花的那一个，而不是空间站里的人们。
You are really spinning, and they really are not.
你确实在旋转，他们真的没有。
There's something absolutely real about rotation.
这就是旋转里面的绝对真实。
So, some motions are relative, and some are not.
所以，有些运动是相对的，有些不是。
There is no deep reality about constant speed, but changes in speed are deeply real, and so are rotations.
对于匀速，并没有深刻的现实性，但速度的变化却再真实不过了，旋转也是。
We have to be thoughtful in our analysis of everyday experience in order to identify what is deeply real.
在日常经历的分析中，为了确定什么是有深刻真实性的，我们必须考虑周全。
Since we can be fooled by perceptions as basic as speed, maybe every perception deserves careful scrutiny.
由于我们会被知觉所迷惑，比如基本的速度，也许对每一个知觉都应该加以仔细的审查。
This is what inspired Einstein to his incredible insights about the speed of light and forward time travel.
这启发了爱因斯坦提出了关于光速和到未来旅行的不可思议的见解。
Knowing how to identify what is deeply real is tough and important work.
知道如何分辩什么是深刻的真实是一个艰难而且重要的工作。
If a police officer ever pulls you over for speeding and asks, 'Do you know how fast you were going?'
如果你因为超速被警察拦下，然后被问“你知道你开的有多快吗？”
an insightful, though perhaps unwise, reply would be, 'Relative to what?'
一个有深刻见解的、尽管可能不明智的回答会是，“相对于什参照系？”
And then, as you sit in the backseat of the police car and feel it accelerate toward jail,
然后，当你坐在警车的后座上，感受到正在加速前往拘留所的时候，
you can add, 'But some things are absolute!'
你可以再说一句，“但是有些事是绝对的！”