Hello Bill, my name is Alicia, what I would like to know is, do you think time is real?
你好比尔! 我叫艾丽西娅 我想知道 你认为时间是真实的吗
For example, sometimes an hour can feel very short and sometimes it can feel very long depending on your perception.
比如 有时候我们会感觉一个小时很短 有时候我们会感觉一个小时很长
So then is time subjective?
所以那么时间是主观的吗
If it's a measurement of something what is it a measurement of?
如果它是一个计量单位 那么它衡量的是什么东西
I'd really like to know your thoughts about time. Thank you.
我真的很想知道您对这个问题的看法 谢谢!
Alicia, that is fantastic.
艾丽西娅 这个问题很好

Notice that in English we don't have any other word for time except time. It's unique.
首先要注意 在英语里我们除了“time”没有别的词语来表达“时间” 这说明它很独特
It's this wild fourth dimension in nature.
它是大自然中自由的第四维度
This is one dimension, this is one dimension,this is one dimension and time is the fourth dimension.
这是一个维度 这是另一个维度 这是第三个维度 而时间正是第四个维度
And we call it the fourth dimension not just in theoretical physics but in engineering.
我们不仅在理论物理学里称时间为第四维度 在工程学里也是如是称谓
I worked on four dimensional auto pilots so you tell where you want to go
我以前研究四维自动驾驶仪 你可以指挥去哪里
and what altitude it is above sea level and then when you want to get there.
海拔是多少 以及你什么时候想到达那里
Like you can get there at any time.
你想什么时候到都可以
We have a whole bunch of other words. We have appointments.
我们有一大堆词语可以形容某段时间 比如预约
We have morning, afternoon, evening, noon time.
我们有早晨 下午 晚上或中午时间
We have a whole bunch of words describing periods of time,
我们有这么多词形容时段
but when it comes to actual time we just have this one word it's a strange and surprising thing.
但当我们要表达“时间”本身时 却独独这么一个词 那是很奇怪和令人惊讶的事实
So along this line, in my opinion, which as you know is correct, I'm kidding, in my opinion time is both subjective and objective.
所以在这个问题上 我的看法就是 你知道我肯定是对的 开个玩笑 我的看法是时间既主观又客观
What we do in science and engineering and in life, astronomy, is measure time as carefully as we can
我们在科学 工程学 生命科学 天文学里的做法是 尽量精确地计量时间
because it's so important to our every day world.
这对我们日常生活太重要了
You go to plant crops you want to know when to plant of them. You want to know when to harvest them.
例如你要种植谷物 你想知道什么时候开始播种 什么时候开始收获
If you want to have a global positioning system that enables you to determine which side of the street you're on from your phone
如果你想用你手机上的全球定位系统来确定你在街道的哪个位置
you need to take into account both the traditional passage of time that you might be familiar with watching a clock here on the earth's surface
你既需要考虑平常那种时间的推移就是我们在地球上看钟表得知的那个时间
and the passage of time as it's affected by the speed of the spacecraft and the passage of time
还要考虑受航天器速度影响的时间 以及
as it's affected by the gravity of the earth itself, both special and general relativity. It's astonishing.
受地球引力影响的时间 无论是狭义相对论还是广义相对论意义上的 这太惊人了
So, we work very hard to measure time with all sorts of extraordinary clocks,
所以我们得用各种神奇的钟表来计量时间
but there is no question with our brains, which are wet chemical computers, we lose track of time.
但毫无疑问 对于人脑这种湿化学“电脑” 我们弄乱了时间
Sometimes it feels short, sometimes it feels long and it's just the nature I think of being constrained by measuring time with our brains.
有时觉得很短暂 有时候很漫长 我觉得问题本质就在于用人脑衡量时间是受限的
This is why we build instruments to measure time outside of ourselves externally. But it is a great question.
这也是为什么我们人类要制造各种仪器来衡量处于我们身外的时间 但这真是个好问题
And then the whole idea of science really started with this thing people used to call natural philosophy.
整个科学的理念都起源于人们过去称之为自然哲学的东西
And when you throw in the word philosophy for me you start asking this question like can you know anything,
当你跟我用了“哲学”这个词 你其实就开始问这个问题:你能知道所有事情吗
let alone what time it is or how long it's been since something happened
更不用说时间是什么 这东西存在多久了
or when something will happen in the future or whether or not it will happen at all, these are philosophical questions.
以后会发生什么 或者会不会发生 这些都是哲学问题
I feel that you can get yourself pretty spungup in saying to yourself there's no way to know anything.
我觉得 当你对自己说“人无法知道所有事”就够让你自己纠结的了
Philosophically you can't know anything.
从哲学上来讲 你不可能无所不知
On the other hand, it seems to me we can know a great deal objectively about nature and that includes time and it's passage.
另一方面又似乎是 我们能很客观地了解大自然的很多事情包括时间以及它的变化推移
One last thought Alicia, when I think about my grandfather he had no idea, no understanding of relativity.
最后艾丽西娅我想到我爷爷 他不知道 也根本不懂相对论
Not because he was a bad person, because no one had discovered it yet.
并不是因为他是坏人 而是那时人们还未发现它
And so I just wonder what else it is about the nature of time
所以我在想 关于时间的本质
or the nature of what physicists, astrophysicists like to call space time where you talk about these four dimensions at once
或是物理学家 天文物理学家所谓的“时空”(X,Y, Z, T四维的合称)的本质 还有些什么其他发现
X, Y, Z, and T. I cannot help but wonder there is something else undiscovered about time
我不禁地想 关于时间也许有其他尚未发现的事实
and perhaps you and I will be alive, not much more time will have passed before this discovery is made.
也许用不了太久 这个发现就会被揭示而你我都还健在
Carry on. Excellent question. Thank you.
继续努力吧 很棒的问题 谢谢你