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  • Just now, somewhere in the universe, a star exploded.

    剛剛宇宙中的某個角落裡一顆恆星爆炸了。

  • There goes another one.

    接著又一顆恆星爆炸了。

  • In fact, a supernova occurs every second or so in the observable universe,

    實際上,在觀察到的星系中每分每秒都都有超新星誕生,

  • and there is one on average every 25 to 50 years

    平均每25到50年有一個

  • in a galaxy the size and age of the Milky Way.

    像銀河系那麼大那麼年老的恆星誕生

  • Yet we've never actually been able to watch one happen

    然而,我們還沒有看到過一顆恆星

  • from its first violent moments.

    自它誕生爆炸之初的過程

  • Of course, how would we?

    當然,我們怎麼會看到呢?

  • There are hundreds of billions of stars close enough

    有無數的恆星距離我們相當的近

  • that we could watch the supernova explosion

    近到我們幾乎能看見超新星爆炸

  • break through the surface of the star.

    打破恆星的表面的現象。

  • But we'd have to have our best telescopes focused on the right one

    但是我們一定要將最好的望遠鏡在精確的時機對準正確的恆星

  • at precisely the right time to get meaningful data.

    來獲取有用的數據。

  • Suffice it to say, the odds of that happening are astronomically low.

    簡單地說,這種情況在天文學上發生的可能性很低。

  • But what if we could anticipate a supernova before its light reached us?

    但是如果我們能在恆星的光到達之前預測超新星的誕生呢?

  • That may seem impossible.

    這似乎是不可能的。

  • After all, nothing travels faster than the speed of light, right?

    畢竟沒有比光速更加快的東西,不是嗎?

  • As far as we know, yes.

    據我們所知,是的。

  • But in a race, fast doesn't matter if you take a detour

    但是比賽中,如果你繞遠路那麼速度快也是沒有用的

  • while someone else beelines it for the finish line.

    而別人直走走已經到達終點了。

  • For exactly that reason,

    對於確切的原因,

  • photons don't win the supernova race to Earth.

    從超新星到地球的比賽,光子並沒有贏。

  • Neutrinos do.

    而微中子贏了。

  • Here's why.

    原因是:

  • There are two types of supernova.

    超新星有兩種。

  • Type 1 is when a star accumulates so much matter from a neighboring star,

    第一種是當一顆恆星從隔壁的恆星積累很多的物質,

  • that a runaway nuclear reaction ignites and causes it to explode.

    一個失控的核反應點燃並且讓恆星爆炸了。

  • In type 2, the star runs out of nuclear fuel,

    第二種,恆星的核燃料快用光,

  • so the gravitational forces pulling in

    地心引力造成向心力就

  • overwhelm the quantum mechanical forces pushing out,

    壓倒了向外拉出的量子力,

  • and the stellar core collapses under its own weight in a hundredth of a second.

    在百分之一秒間,恆星核被自己的重量拉了出來

  • While the outer reaches of the star are unaffected by the collapsed core,

    然而恆星外部區域並沒有受到內部崩潰的影響,

  • the inner edges accelerate through the void,

    內部邊緣加速通過空間

  • smash into the core, and rebound to launch the explosion.

    粉碎恆星的核心,並反彈產生爆炸;

  • In both of these scenarios,

    在兩種情況下,

  • the star expels an unparalleled amount of energy,

    恆星噴出巨大的能量,

  • as well as a great deal of matter.

    還有大量的物質。

  • In fact, all atoms heavier than nickel, including elements like gold and silver,

    實際上,從超新星爆炸說產生的所有原子都比鎳重, 包括像金和銀這些元素。

  • only form in supernova reactions.

  • In type 2 supernovae,

    在第二類型的超新星,

  • about 1% of the energy consists of photons,

    大約有百分之一的輻射裡面包含光子,

  • which we know of as light,

    也就是我們所說的光,

  • while 99% radiates out as neutrinos,

    百分之九十九的輻射是微中子,

  • the elementary particles that are known for rarely interacting with anything.

    我們知道微中子是很少與其他東西相互影響的。

  • Starting from the center of the star,

    從恆星的中心開始,

  • the exploding matter takes tens of minutes, or even hours,

    爆炸物質需要數十分鐘,甚至幾小時,

  • or in rare cases, several days, to reach and break through the surface of the star.

    或是少數情況下的幾天,到達和通過恆星的表面。

  • However, the neutrinos, thanks to their non-interactivity,

    然而,由於微中子間的互不影響性,

  • take a much more direct route.

    他們走了更直接的路線。

  • By the time there is any visible change in the star's surface,

    在恆星表面沒有任何變化的時間裡面,

  • the neutrinos typically have a several hour head start over the photons.

    微中子比光子走了好幾小時。

  • That's why astronomers and physicists

    這就是為什麼天文學家和物理學家

  • have been able to set up a project called SNEWS,

    成立一個叫SNEWS的項目,

  • the Supernova Early Warning System.

    超新星即早預報系統。

  • When detectors around the world pick up bursts of neutrinos,

    當世界各地的偵察器偵測到微中子的爆發時,

  • they send messages to a central computer in New York.

    他們會對紐約的中央電腦發出信息。

  • If multiple detectors receive similar signals within ten seconds,

    如果數台偵測器在十秒內收到類似信號,

  • SNEWS will trigger an alert warning that a supernova is imminent.

    SNEWS就會發出警報,超新星即將來臨。

  • Aided by some distance and direction information from the neutrino detectors,

    借助微中子偵測器的一些距離和方向信息,

  • the amateur astronomers and scientists alike

    業餘天文學家和科學家

  • will scan the skies and share information

    將會掃描天空和分享信息

  • to quickly identify the new galactic supernova

    來快速的去搜尋新的超新星

  • and turn the world's major telescopes in that direction.

    並將世界主要的天文望遠鏡對準那個方向。

  • The last supernova that sent detectable neutrinos to Earth was in 1987

    上一個發送微中子的超新星是在1987年被偵察到

  • on the edge of the Tarantula Nebula

    在狼蛛星雲的邊緣

  • in the large Magellanic Cloud, a nearby galaxy.

    在麥哲倫星雲裡面,一個很近的銀河系

  • Its neutrinos reached Earth about three hours ahead of the visible light.

    微中子比可見光快3小時到達地球。

  • We're due for another one any day now, and when that happens,

    我們未來的任何一天,都很可能遇到超新星爆炸的現象,

  • SNEWS should give you the opportunity to be among the first to witness something

    SNEWS給了你們一個機會去見證

  • that no human has ever seen before.

    其他人類之前無法看到的東西。

Just now, somewhere in the universe, a star exploded.

剛剛宇宙中的某個角落裡一顆恆星爆炸了。

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B2 中高級 中文 TED-Ed 恆星 新星 爆炸 光子 到達

【TED-Ed】如何探測超新星--薩曼莎-庫拉 (【TED-Ed】How to detect a supernova - Samantha Kuula)

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    SylviaQQ 發佈於 2021 年 01 月 14 日
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