Placeholder Image

字幕列表 影片播放

  • How fast are you moving right now?

    「現在你的時速多快?」

  • That seems like an easy question.

    你以為這問題很單純吧。

  • The first tempting answer is,

    對於使用個人電腦看影片的你, 首先閃過的念頭應該是:

  • "I'm not moving."

    我沒移動啊。(除非你在通勤中)

  • Upon further reflection,

    更細深思,

  • you realize that maybe the Earth's motion counts.

    你意會到,說不定 地球的運轉也得考慮進來。

  • So, a second tempting answer is,

    因此,再試一次你答道:

  • "19 miles/second around the Sun."

    平均每秒 29.79 公里繞著太陽轉,對吧 (一月地球通過近日點,高於均速。 七月遠日點則相反)

  • But then you recall learning that the Sun

    但不想則已,一想你又發覺太陽

  • moves around the center of the Milky Way galaxy,

    正繞著銀河系中心運轉,

  • and the Milky Way moves within the Local Group of galaxies,

    而銀河系正在本星系群中運轉,

  • and the Local Group moves within the Virgo Cluster,

    本星系群又是室女座星系團的一部分,

  • and the Virgo Cluster moves within...

    室女座星系團又是室女座超星系團......

  • "How fast are you moving?"

    於是「你正以多快速度運動?」

  • is not an easy question.

    不是個好回答的問題。

  • When Mission Control tells astronauts

    當太空任務控制中心告訴太空人

  • how fast they're going,

    他們火箭的飛行時速

  • there's always an assumed standard of rest.

    總有個默認的「靜止」參考點。

  • At the start of the voyage,

    在發射之初,

  • speeds are given relative to the launchpad.

    火箭速度根據的基準點是發射平台。

  • But later, when the launchpad is

    然而不久之後,

  • just one more arbritrary place

    發射平台就退居 地球快速運轉的表面上

  • down there on Earth's spinning surface,

    一個無關緊要的地點,此時

  • speeds are given relative to

    飛行速度的參考基準點是一個

  • the idealized, non-spinning pinpoint center of Earth.

    理想化的:地球本體的旋轉、質量中心。

  • On their way to the Moon,

    在登月任務中,

  • Apollo astronauts had a hard time

    阿波羅太空人瞭解到

  • answering the question,

    即使問題簡單如 「你們現在飛行得多快?」

  • "How fast are you moving?"

    都很難回答。

  • Speed away from Earth was one thing,

    遠離地球的速度是一回事,

  • and speed toward the Moon was quite another.

    朝向月球的速度 並不見得與前者相同。

  • That's because the Earth and the Moon

    理由是地球與月球 事實上是互相繞轉的系統

  • move relative to one another.

    (地月系統的質量,也是旋轉中心位在地球當中,但距離地心長達地球半徑的3/4,也就是地月的花式溜冰中地球也會相對於此中心搖擺。另外,太陽對月球的引力事實上比地球對月球大兩倍。想想看為何月球沒被太陽吸走。)

  • Ah, of course!

    啊,你恍然大悟。

  • Speed is a relative quantity.

    這影片想要彈 「速度是相對概念」這老調,對吧?

  • When Captain Kirk ask Lieutenant Sulu

    當《星艦迷航記》的寇克鑑長對蘇魯上尉提問 (注:星艦當用海空軍軍階)

  • if the Starship Enterprise has reached a speed of warp 7,

    「星艦企業號是否已達曲速因子7 」 (Star Trek的科幻空想單位, 對應幾倍光速設定很亂, 總之皆為超光速)

  • Sulu should reply,

    假如蘇魯是物理魂,應該回答:

  • "Relative to what, Captain?"

    「艦長,你問多快是相對於什麼?」

  • Such a sassy reply

    即使如此有性格的答案

  • may get subordinate Starfleet officers in trouble,

    八成會讓這位艦隊部屬惹上麻煩,

  • but it is the only good answer

    這卻是唯一有格調的答案,

  • to the question, "How fast are you moving?"

    因為「現在多快?」本身條件並不充足。

  • This is basic relatively talking.

    這是基本的相對性思考。

  • Not fancy Einsteinian relativity,

    不是愛因斯坦那種高級的相對性,

  • but good old fashioned (and still correct)

    而是老忠實,仍然可靠的

  • Galilean relativity.

    加利略式的相對性(運動相對性)

  • Galileo seems to have been the first person

    加利略大概是史上第一人做出

  • to realize that there is no such thing

    「世上無絕對的速度」的洞見

  • as an absolute speed.

    「世上無絕對的速度」的洞見

  • Speeds are relative.

    速度,如前所述,皆相對

  • This means that speeds only have meaning

    亦即在沒有給予參考系 (reference frame)之下

  • when they are referred to a reference frame.

    速度是無法定義的。

  • Presumably that reference frame is itself at rest.

    一開始你似乎能假定這個參考點靜止。

  • But then we have to ask again,

    然而追究起來,

  • "At rest relative to what?"

    「你說靜止是對於什麼靜止?」 (這裡忘了提,沒有絕對速度也代表 沒有絕對空間、或者絕對座標)

  • Because even the concept of rest

    因為,即使靜止(也就是速度為零)

  • has lost any hint of absolute meaning.

    也是速度,因此 也不能獨立於系統定義出來。

  • Speed is relative, and rest is relative.

    速度是相對的,靜止也是相對的。

  • Earth's speed is 19 miles/second relative to the Sun.

    地球的每秒29.79公里是相對於太陽。

  • The Enterprise's speed is warp 7

    企業號的曲速 7

  • relative to the center of the Milky Way galaxy.

    是相對於銀河系中心。

  • Your speed is zero relative to your easy chair.

    你的速度是零,相對於你的椅子。

  • But depending on where you sit,

    但取決於你所在地的緯度,

  • it is hundreds of miles/hour relative to Earth's center.

    你與地心的相對速度可以介於每秒 463 公尺,和 0 公尺之間(各強國的衛星發射站首選低緯地區,為什麼?)

  • When we furrow a brow and ask,

    當我們皺眉尋思:

  • "But how fast is Earth really moving?"

    「那地球本身究竟是以什麼速度移動呢?」

  • we imagine Spaceship Earth

    我們想像中的宇宙太空船「地球號」

  • plowing through the ocean of space

    正在宇宙廣袤的空間中一面破浪而進

  • as it orbits the Sun.

    一面繞行太陽。

  • But space is not an ocean.

    但空間可不是海洋,

  • It has no substance as water does.

    空間不存在水那樣靜止的介質(沒有以太)

  • Space is not a thing;

    空間本身不是物質 (Michelson-Morley 實驗說明以太不存在)

  • space is nothing.

    空間什麼都沒有。

  • Space is no thing.

    空間是空無一物。

  • You can move between two points in space,

    你從空間中的一點運動到另一點,

  • say between Earth and Mars,

    例如從地球到火星,

  • but you can't move through space.

    然而實際上你不能「穿過空間」,

  • There's nothing to move through.

    空間就像影子一樣無物可穿。

  • It's like trying to say how much a hole weighs.

    就好像問「洞有多重」一樣。 (譯:倘若 Vsauce 有這標題的影片我也不會驚訝XD)

  • A hole weighs exactly nothing

    洞的重量什麼的根本沒有,

  • because a hole is nothing.

    因為洞是一個概念,不是實體。

  • It's a void, and so is space.

    洞只是「空無一物」的概念,而空間也一樣。

  • To move relative to nothing is meaningless.

    相對於「什麼都沒有」而動, 不是什麼有用的概念。

  • The concepts of speed and of rest

    速度,或靜止,如同加利略的灼見

  • have only relative meaning.

    天生就得有外在的參考物, 一個巴掌拍不響。

  • They are absolutely meaningless.

    宇宙也不懂你說的速度是怎麼一回事。

  • They mean something

    因為速度總是附帶著隱藏前提,

  • only with respect to arbitrarily chosen,

    一個自由設置

  • artificial frames of reference.

    全然是人為概念的參考框架(參考系)。

  • If, someday, you are buckled into your spaceship,

    設想,有一天,你在 你的太空座椅上繫著安全帶

  • and you see from the side window, say,

    望向窗外看到,舉例而言,

  • a space station whizz by at constant speed,

    一個等速移動的太空站,

  • there is no way to know which of you is really moving.

    你和對方,在荒涼的宇宙中沒有任何實驗能證明誰真的在動,或者兩者都在動。

  • Neither of you is really moving

    又,某種程度來說你們的移動都沒有意義

  • because there is no deep reality about constant speed.

    因為等速本身的實在性完全無法確認,

  • Constant speed in a straight line

    等速運動永遠有可能只是種表象

  • has only relative meaning,

    永遠需要藉由外在現象而定義 (注:這傢伙台詞文采差,還跳針,翻譯火大)

  • a kind of relative reality.

    某種相對現實。

  • Does this mean that all motion is relative?

    所以,你已被我說服 「所有運動都是相對」了嗎? (是啊,感謝你的洗腦)

  • No! Some motions have only relative meaning,

    哈,事情不是憨人所想得那麼簡單。 有些動作只有純粹相對下的意義,

  • but some motions have absolute meaning,

    然而確實存在絕對意義的運動 (感謝你的拖拖拉拉現在才說)

  • are absolutely real.

    擁有非常真實的效應。

  • For example, constant speed is relative,

    簡言之,常速是相對的,

  • but change in speed is absolute.

    但【加速度是絕對的】。

  • Calling something absolute in science

    科學上,說某物是絕對的,

  • means that arbitrary standards are not used

    代表測量的基準

  • in its measurement.

    無法任意選擇。

  • It is unambiguously measurable.

    而且對於實驗觀測只有唯一解讀方式。

  • When your spaceship fires its engines,

    當你的太空船引擎點火,

  • your change in speed is beyond doubt.

    加速度的效應無庸置疑, 你會被 G 力壓到椅子裡。

  • You feel it in your stomach,

    連你的內臟都測量得到,

  • and your ship's sensors can measure it.

    當然,飛船上的力學儀器也能輕鬆分辨。

  • Outside your window,

    看出你的窗口,

  • the passing space station

    現在太空站與你的相對速度,

  • may seem to be changing speed,

    似乎也在改變加速,

  • but the beings inside the station will not feel it.

    然而在太空站裡的人 會繼續飄浮毫無感覺,

  • And no sensors can measure it.

    並且他們的儀器並不會感到加速。

  • You are really changing speed,

    真正的在改變速度的是你,

  • and they are really are not.

    而非你觀察的太空站。

  • There's something absolutely real

    與恆速運動(慣性運動)不同的是,

  • about changes in speed.

    變速運動(加速運動) 是貨真價實測量得到的。

  • The same goes for rotation.

    同樣的理由,旋轉運動也是絕對的。

  • If your spaceship is spinning,

    若你的太空船正在旋轉,

  • you can feel it,

    你絕對感覺得到

  • and your ship's sensors can measure it.

    你飛船的感應器也可以。 (加速座標必有假力,旋轉座標中 是離性力、柯氏力)

  • The space station outside

    在你看來你窗外的太空站,

  • may seem to be going around you,

    也在用與你一樣的角速度旋轉,

  • but it is you who feels queasy,

    但唯一會暈得亂七八糟的是你,

  • not the folks in the space station.

    他們不會(繼續飄浮)。

  • You are really spinning,

    你在轉而對方沒在轉,

  • and they really are not.

    可以透過扎實的實驗分辨出來。

  • There's something absolutely real about rotation.

    旋轉,很神奇的,具有一個獨立的實在性。

  • So, some motions are relative, and some are not.

    總結本集,有純粹相對的運動, 也有純粹絕對的運動。

  • There is no deep reality about constant speed,

    慣性/恆速運動永遠不能 以實驗確定為實在, 總是有只是表象的可能

  • but changes in speed are deeply real,

    但加速度本身是實在的,

  • and so are rotations.

    旋轉也是。

  • We have to be thoughtful

    在平凡的日常經驗中,

  • in our analysis of everyday experience

    你得要萬分謹慎,並且「想太多」

  • in order to identify what is deeply real.

    才能分辨實在與否。

  • Since we can be fooled by perceptions

    因為即使簡單如速度的概念

  • as basic as speed,

    都會為我們的感官所混淆,

  • maybe every perception deserves careful scrutiny.

    那或許所有感覺都值得審慎檢驗。

  • This is what inspired Einstein

    這個思想實驗啟發了愛因斯坦

  • to his incredible insights

    去寫下不朽的真知灼見

  • about the speed of light and forward time travel.

    關於光速,與加速座標系的時間膨脹 --向未來的時間旅行。

  • Knowing how to identify

    對於鑑別各種

  • what is deeply real

    「究竟真實」

  • is tough and important work.

    是重要而艱難的工作。

  • If a police officer ever pulls you over for speeding

    下次若被警察路邊攔檢,說,

  • and asks, "Do you know how fast you were going?"

    「這位先生,你知道剛才你開多快嗎?」

  • an insightful, though perhaps unwise, reply

    你可以報以一個深刻,也許有點不智,的回答:

  • would be, "Relative to what?"

    「那要看相對於什麼而言啊。」

  • And then, as you sit in the backseat of the police car

    於是乎,你就可以在警車的後座

  • and feel it accelerate toward jail,

    感受那朝向拘留所的加速度,

  • you can add,

    並且補充說

  • "But some things are absolute!"

    「啊,但還是有些運動是絕對的啊。」

How fast are you moving right now?

「現在你的時速多快?」

字幕與單字

影片操作 你可以在這邊進行「影片」的調整,以及「字幕」的顯示

B1 中級 中文 TED-Ed 速度 運動 靜止 地球 太空站

【TED-Ed】你現在的移動速度有多快?- 塔克-希亞特 (【TED-Ed】How fast are you moving right now? - Tucker Hiatt)

  • 1114 116
    阿多賓 發佈於 2021 年 01 月 14 日
影片單字