Name: 【TED-Ed】如何探測超新星--薩曼莎-庫拉 (【TED-Ed】How to detect a supernova - Samantha Kuula)
Uploaded: 2021-01-14T05:42:24.000Z
Duration: 4 min 42 s

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。

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

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

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

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.

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？

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？

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。

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。

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，

overwhelm the quantum mechanical  forces pushing out,

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,

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

粉碎恆星的核心，並反彈產生爆炸；

the star expels an unparalleled amount of energy,

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。

about 1% of the energy  consists of photons,

大約有百分之一的輻射裡面包含光子，

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。

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，

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.

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,

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

will scan the skies and share information

to quickly identify  the new galactic supernova

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

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

其他人類之前無法看到的東西。