宇宙中最極端的爆炸：英語精讀講義

Supernovae are the most powerful explosions in the universe,

超新星是宇宙中最猛烈的爆炸，

unleashing enough energy to outshine galaxies. 文法

釋放出的能量足以讓星系黯然失色。

We have no real metaphor for their power. 片語搭配

我們找不到任何真正貼切的比喻來形容它的威力。

If the sun were to magically go supernova, 文法

如果太陽突然像變魔術一樣變成了超新星，

it would feel like you were being hit by the energy of a nuclear explosion

感覺就像是你被核爆炸的能量擊中了一樣，

every second for weeks.

而且接連幾週每一秒都在承受。

While supernovae are the engines of creation, 文法

雖然超新星是創造的引擎，

forging the elements that enable life,

鍛造出了孕育生命的各種元素，

they also burn sterile whole regions of galaxies.

但它們也會將星系中整片區域燒成不毛之地。

So, what would happen if one hit Earth?

那麼，如果地球被擊中會發生什麼？

There are, roughly speaking, 片語搭配

粗略來說，

two ways to make a supernova.

超新星的形成有兩種方式。

Either the core of a massive star implodes,

一種是大質量恆星的核心發生內爆，

or, less common,

另一種不太常見的情況是，

a white dwarf gains mass to the point 文法

白矮星的質量增加到了一個臨界點，

where it ignites explosive nuclear fusion.

從而點燃了爆炸性的核融合。

The outcome is the same,

結果是一樣的，

a supernova explosion.

都會發生超新星爆炸。

When we think of an explosion on Earth,

當我們想到地球上的爆炸時，

we think of something that happens fast and ends.

我們會覺得它發生得快，結束得也快。

But a supernova is more like a volcanic eruption 表達脈絡

但超新星更像是一場火山爆發，

followed by a tsunami.

緊隨其後的是一場海嘯。

At first, there's a colorful ball of hot expanding gas,

起初，會出現一團色彩斑斕、不斷膨脹的熾熱氣體球，

creating a spectacular cloud that will shine for about a month.

形成一團壯觀的雲，大約會閃耀一個月的時間。

But then, it doesn't stop.

但隨後，它並不會停止。

Hot and dangerous gas rushes outwards at speeds of 10,000 km a second

熾熱而危險的氣體以每秒 10,000 公里的速度向外衝去，

through the near vacuum of space,

穿過近乎真空的太空，

sweeping up the sparse gas of the galaxy. 片語動詞

席捲星系中稀薄的氣體。

This wall of gas expands for tens of thousands of years

這堵氣體牆會持續膨脹數萬年，

and will eventually span up to dozens of light years

最終跨越幾十光年的範圍，

until it finally cools off and disperses its substance back into the galaxy. 片語動詞

直到它完全冷卻下來，並將物質散佈回星系中。

So, what if this star tsunami hits us?

那麼，如果這場恆星海嘯擊中了我們呢？

Well, the damage depends on how far away it is. 片語搭配

嗯，破壞程度取決於它離我們有多遠。

Stage one,

第一階段，

thousands of light years away.

幾千光年外。

Humans have witnessed dozens of supernovae,

人類已經目睹過幾十顆超新星，

but all of them were thousands of light years away.

但它們都在幾千光年之外。

They appeared as new stars,

它們看起來就像是新出現的星星，

some outshining the moon,

有的甚至比月亮還要亮，

twinkling for a few weeks,

閃爍幾週後，

and disappearing.

就會消失不見。

Aside from looking very pretty at this distance, 文法

在這麼遠的距離，除了看起來很漂亮之外，

they don't do much to us.

它們對我們沒有太大的影響。

Stage two,

第二階段，

300 light years away.

300光年外。

Things begin to get a bit icky 用詞

事情開始變得有點糟糕了，

once a supernova occurs around 300 light years away.

一旦超新星發生在距離我們300光年左右的地方。

We can expect one this close to us every few million years.

每隔幾百萬年，我們就能預期一次如此近距離的爆發。

A single star giving the night sky an eerie glow like twilight.

單獨一顆恆星會讓夜空泛起像黃昏一樣的詭異光芒。

And while this is far enough away and dim enough to not do harm to us, 片語搭配

雖然這個距離足夠遠，光度也足夠暗，不會對我們造成傷害，

they can affect the Earth.

但它們確實會影響地球。

At these distances,

在這個距離上，

it's like being hit by the last weak waves of the star tsunami.

就像是被恆星海嘯最後微弱的波浪擊中了一樣。

Not strong enough to do real damage,

雖然不足以造成實質性的破壞，

but still noticeable.

但仍然很引人注目。

In fact,

事實上，

we know that over the past 10 million years,

我們知道在過去的一千萬年裡，

multiple supernovae have struck Earth from these distances

有多顆超新星在這樣的距離擊中過地球，

because we can find radioactive isotopes of iron

因為我們可以找到鐵的放射性同位素，

deep in the rocks and sediments at the bottom of the ocean.

它們深埋在海底的岩石和沉積物中。

Amazingly,

令人驚奇的是，

these supernovae around the solar system

太陽系周圍的這些超新星

have cleared a 1,000-light-year wide pocket of space that's called the Local Bubble. 文化背景

清空了寬達1000光年的太空區域，被稱為「本地泡」。

They blew away the interstellar gas and dust,

它們吹散了星際氣體和塵埃，

creating a lumpy wall of gas that's now a cradle for star formation. 慣用語

形成了一堵凹凸不平的氣體牆，如今成了恆星形成的搖籃。

Stage three,

第三階段，

150 light years away.

150光年外。

Once a supernova happens much closer than 300 light years,

一旦超新星發生在距離不到300光年的地方，

we're approaching the zone where it does real damage.

我們就接近了它能造成實質性破壞的區域。

Stars have extremely powerful magnetic fields.

恆星擁有極強的磁場。

When they die,

當它們死亡時，

the tsunami of dead star actually retains a lot of this magnetic energy

死亡恆星的海嘯實際上保留了大量的磁能，

woven through the shock wave that expands outwards.

交織在向外膨脹的衝擊波中。

In this highly magnetized cloud,

在這團高度磁化的星雲中，

we get conditions like in a huge particle accelerator

我們會遇到類似巨型粒子加速器的情況，

that's accelerating charged particles like protons, nuclei, and electrons to immense speeds,

它將質子、原子核和電子等帶電粒子加速到極高的速度，

which means we have an expanding cloud that is shooting deadly radiation in all directions

這意味著我們有一團不斷膨脹的星雲，在四面八方發射致命的輻射，

long after the bright light from the initial explosion has faded away. 文法

哪怕是在最初爆炸的強光褪去很久之後。

If a supernova happens too close by,

如果超新星離得太近，

waves of these cosmic rays will wash over the solar system for thousands of years. 慣用語

這種宇宙射線的波動將沖刷太陽系長達數千年。

While we're mostly protected on Earth's surface by the atmosphere and ozone layer,

雖然我們在地球表面主要受到大氣層和臭氧層的保護，

the influx of extra radiation will still increase cancer and mutation rates.

但額外湧入的輻射仍然會增加癌症和基因突變的發生率。

Not enough to cause a mass extinction,

雖然不足以引起大規模滅絕，

but it will be noticeable.

但影響將是顯著的。

Spaceflight would become impossible in the solar system

在太陽系內，太空飛行將變得不可能，

as astronauts wouldn't survive the waves of radiation for long.

因為太空人無法在這樣的輻射波中長期存活。

We don't know exactly how bad this would be,

我們不確定具體會有多糟糕，

but a supernova that is close enough may trap our species on Earth for generations,

但一顆足夠近的超新星可能會將人類困在地球上幾代人，

maybe thousands of years.

也許長達幾千年。

It only gets worse from here. 表達脈絡

從這往後情況只會更糟。

Stage four,

第四階段，

closer than 100 light years.

距離不到100光年。

Within 100 light years,

在100光年之內，

things get bad as a supernova disrupts our climate in ways that we don't fully understand yet.

情況會變得得很糟糕，因為超新星會以我們尚未完全了解的方式破壞我們的氣候。

There are a few unpleasant things happening all one after another.

一些不好的事情會接二連三地發生。

First, the high-energy photons arrive from the explosion,

首先，爆炸產生的高能光子到達，

followed by many decades of radiation from the radioactive tsunami,

緊接著是來自放射性海嘯長達數十年的輻射，

both of which seriously damage the ozone layer, 文法

這兩者都會嚴重破壞臭氧層，

Earth's shield against harmful radiation.

也就是地球抵禦有害輻射的盾牌。

The ozone layer absorbs ultraviolet radiation by breaking apart ozone,

臭氧層吸收紫外線輻射的方式是將臭氧，

O3, into O2 and a free oxygen atom,

也就是O3，分解為O2和一個游離的氧原子，

which later reforms back into another ozone molecule.

稍後它會重新結合成另一個臭氧分子。

But the supernova radiation breaks up nitrogen molecules that gobble up the free oxygen, 片語動詞

但超新星輻射會分解氮分子，進而吞噬游離氧，

breaking the cycle and depleting the ozone layer quickly.

打破循環並迅速消耗臭氧層。

Without a radiation shield,

沒有了防輻射盾，

everybody living on the surface is exposed to very high levels of UV radiation from our sun.

生活在表面的每個人都會暴露在我們太陽產生的極高強度的紫外線輻射下。

Cancer rates would skyrocket,

癌症發生率會飆升，

and just going outside during the day could be life-threatening.

僅僅在白天出門就可能危及生命。

The extra radiation would also kill a lot,

額外的輻射也會殺死大量的，

if not most, 表達脈絡

甚至絕大多數的

of the plankton in the oceans that live near the surface

生活在海洋表面附近的浮游生物，

and are the basis for the marine food chains,

它們是海洋食物鏈的基礎，

leading to a mass extinction. 文法

從而導致大規模滅絕。

Worse still, 表達脈絡

更糟的是，

supernova radiation would ionize gas in the atmosphere,

超新星輻射會游離大氣層中的氣體，

which means that it would punch through molecules and knock electrons off nuclei,

這意味著它會穿透分子並把電子從原子核上擊飛，

leaving them charged.

使其帶電。

These charged nuclei then act as seeds for water vapor to gather 慣用語

這些帶電的原子核隨後就成了水蒸氣聚集的種子，

and form massive global clouds.

從而形成覆蓋全球的巨大雲層。

In the worst case, 片語搭配

在最壞的情況下，

they would reflect enough sunlight to trigger an ice age.

它們會反射足夠的陽光，從而引發冰河時期。

In fact, it's thought that the ice age 2 and 1/2 million years ago 文法

事實上，人們認為250萬年前的冰河時期

was caused by the supernova.

就是由超新星引起的。

Some scientists even think that a supernova about 60 light years away

有些科學家甚至認為，大約60光年外的一顆超新星

might have been the cause of the Devonian mass extinction 350 million years ago. 文法

可能是3.5億年前泥盆紀大滅絕的起因。

But wait, there's more.

但是等等，還有更糟的。

The electrons punched free by the radiation form enormous electric avalanches,

被輻射擊飛的電子會形成巨大的電子雪崩，

or in other words, lightning. 表達脈絡

換句話說，就是閃電。

Earth is hit by some of the worst thunderstorms in millions of years.

地球將遭受數百萬年來最嚴重的雷暴襲擊。

The intense lightning causes global wildfires that consume forests and crops,

強烈的閃電會引發全球性野火，吞噬森林和莊稼，

devastate cities, disrupt our electrical grids,

摧毀城市，破壞我們的電網

and global supply chains.

和全球供應鏈。

All while a decimated ozone layer leaks deadly radiation. 文法

與此同時，千瘡百孔的臭氧層還會漏入致命的輻射。

While in the past the ecosystem may have bounced back from a nearby supernova 片語動詞

雖然在過去，生態系統可能在附近的超新星爆發後

after a few thousand or million years,

幾千或幾百萬年內恢復了過來，

there's no guarantee modern civilization can take a hit of this magnitude. 講解

但無法保證現代文明能夠承受如此巨大規模的打擊。

We would face food shortages,

我們將面臨食物短缺、

skyrocketing prices, and wars

物價飛漲和戰爭，

as nations struggle to not be consumed by chaos.

因為各個國家都在努力不被混亂所吞噬。

So, a supernova this close would,

所以，如此之近的超新星，

at the very least, do significant damage 片語搭配

至少會造成嚴重的破壞，

for hundreds or thousands of years,

這種破壞會持續數百年甚至數千年，

if not end our modern civilization,

甚至可能終結我們的現代文明，

and with it millions or even billions of lives.

並隨之奪走數百萬甚至數十億人的生命。

Still, humanity would likely survive and could recover.

不過，人類很可能還是能生存下來，並能夠恢復。

Stage five,

第五階段，

closer than 25 light years.

距離不到25光年。

A supernova closer than 25 light years

一顆距離不到25光年的超新星

means that we're in its kill radius,

意味著我們進入了它的殺傷半徑，

where a mass extinction is all but guaranteed. 慣用語

大規模滅絕幾乎是不可避免的。

Probably about half of the ozone layer would be destroyed,

大約一半的臭氧層將被破壞，

and massive climatic disruption on a scale we've never witnessed

規模前所未見的巨大氣候劇變

would ravage Earth.

將肆虐地球。

Entire ecosystems would swiftly be wiped out by radiation 片語動詞

整個生態系統將迅速被輻射抹除

as global wildfires envelop the planet.

全球性野火將席捲整個星球。

All the things described before happen,

之前描述的所有事情都會發生，

but way more intensely and much faster. 用詞

但強度更大，速度也快得多。

A few people might survive for years in bunkers if they have food supplies,

少數人如果擁有食物儲備，也許能在碉堡裡倖存幾年，

but the world they return to will be devastated

但當他們重返地表時，世界將滿目瘡痍，

and hostile to life for hundreds of thousands of years.

並在幾十萬年內都不適宜生命生存。

Human extinction is extremely likely.

人類滅絕的可能性極大。

Final stage,

最終階段，

four light years.

4光年。

Being any closer to a supernova is very unlikely

距離超新星再近一點的可能性微乎其微，

because space is big.

因為宇宙非常大。

But the effects would be extreme.

但其影響將是極端的。

Even from four light years away,

即使是在4光年外，

the distance to Alpha Centauri,

也就是到半人馬座阿爾法星的距離，

a supernova would be almost as bright as the sun in the sky. 文法

超新星在天空中的亮度也幾乎與太陽相當。

While casting two shadows could be fun for a few hours,

雖然能投下兩個影子也許在頭幾個小時內挺有趣，

within days the Earth's surface gets as hot as a sauna,

但幾天之內，地球表面就會變得像桑拿房一樣熱，

baking the surface for weeks until the explosion fades.

地表會被連續烘烤數週，直到爆炸的光芒減弱。

The surface of Earth burns,

地球表面將會燃燒，

scoured of life.

生命被洗劫一空。

Even the oceans aren't safe.

就連海洋也不安全。

The massive amount of radiation that follows

隨後而來的海量輻射

burns away the ozone layer,

將會燒毀臭氧層，

killing everything that sees sunlight.

殺死所有暴露在陽光下的生物。

It would be the largest extinction event in history,

這將成為歷史上最大規模的滅絕事件，

reducing life to a few survivors in the deep sea 片語搭配

讓生命只剩下深海中的極少數倖存者，

and critters in the deep soil.

以及深土中的小生物。

Life basically has to start over. 片語動詞

生命基本上不得不重新來過。

Conclusion.

結論。

How worried do you need to be?

你需要有多擔心？

So, should you worry?

那麼，你應該擔心嗎？

No.

不用。

Fortunately,

幸運的是，

there are only a handful of stars that may explode 片語搭配

距離地球1000光年內，

within 1,000 light years of Earth,

可能發生爆炸的恆星寥寥無幾，

and none are close enough to be a serious threat.

而且沒有一顆近到足以構成嚴重威脅。

Even better,

更好的是，

these stars will probably not go supernova for many millions of years. 片語搭配

這些恆星可能在未來幾百萬年內都不會變成超新星。

So, you are safe.

所以，你是安全的。

But there's no guarantee for the far future.

但對於遙遠的未來，這可沒有保證。

As stars orbit the galaxy,

隨著恆星在星系中運行，

our descendants may find themselves dangerously close to a supernova. 文法

我們的子孫後代可能會發現自己離超新星近得危險。

But by then,

但到那時，

a far more advanced and wiser humanity

一個更先進、更明智的人類社會

will hopefully be able to just move out of the way. 片語動詞

有望能夠直接避開。

In any case, 表達脈絡

無論如何，

you can sleep well tonight

今晚你可以睡個好覺，

under the beautiful night sky.

就在這美麗的夜空下。