百科知識視頻之煎蛋小學堂03 小行星來襲，人類如何是好

We've all witnessed the beauty of a shooting star,but what would happen if an asteroid was on a collision course for earth?

我們都曾目睹過流星雨的美景，但如果小行星要撞地球 會發(fā)生什么?

Could we detect it ahead of time?

我們能提前察覺到它嗎?

And more importantly could we stop it?

更重要的是 我們能阻止它嗎?

I believe I have an answer.

我相信我有個答案

Now you see,asteroid impacts are serious business,When I was in second grade Ms.McGonigal told us that the dinosaurs the ancient dinosaurs died out because they had small brains may be like my old boss.

你也知道 行星撞地球可不是件小事,當我上二年級時 McGonigal女士告訴我們說,恐龍 古代的恐龍之所以滅絕,是因為他們的大腦太小，就像我的老上司一樣

But even she knew that was kinda lame ,that theory was nothing. It turns out in my lifetime pelple found this crater,off Chicxulub,Mexico，This crater was so big. How big was it? It was so big that an asteroid hit the earth (or impactors hit the earth),Threw so much stuff into the Earth's sky it was bigger in diamete than the earth itself so the earth was surrounded by red hot rock weeks at a time.

但也也知道這說法站不住腳，這個理論什么也不是,結果在我在世時，人們在墨西哥希克蘇魯發(fā)現(xiàn)了這個隕石坑。隕石坑特別大，有多大呢?它是如此地大，當小行星擊中地球(或物體擊中地球).它將極多東西拋向地球空中，形成碎石圈直徑比地球更大，因面地球在數(shù)周內都將被熾熱的紅色巖石包圍著。

It cooked everything .And just the animals that lived in burrows and caves. our ancestors lead to us so serious business you may recall Valentine's Day 2013?

它烤熟了一切，除了那些住在洞穴和山洞里的動物,比如說我們的祖先，還記得2013年情人節(jié)那件事嗎?

Chelyabinsk Russia (boorn) air burst. See it you are an asteroid ,and you are going 10 km/s or 20 km/s. And you hit the Earth's atmosphere,the atmosphere is like concrete. you can't get out of the way so the asteroid just explodes in air burst.So these asteroids are serious ,most of them are evey small.

俄羅斯車里雅賓斯克上空的爆炸,看到了嗎，如果你是個小行星 以10km/s 或20km/s 的速度前進，你碰上地球的大氣，大氣就像水泥一樣，你躲不過去，所以小行星只能在半空中爆炸.因此這些小行星得嚴肅對待，它們絕大多數(shù)都很小.

If you're under 10 meters in diameter you hit the Earth's atmosphere.you burn up all Big Blue streak,green street white streak and then humans make wishes upon you (I don't know how efficacious these wishes are but people do that).

如果你的直徑小于10米，在擊中地球大氣層后，你就會燒毀，形成藍色大條紋、綠色條紋和白色條紋之后藍星人會對著你許愿，我不知道這么許愿有沒有用，但是人們就這么干.

Alright,so,if their asteroid starts to get bigger,Starts to get into the 25 meters and the 45 meters in diameter.then you get Meteor Crater Arizona (wham)huge thing.That would be like a city killer,or a county killer.And then when they get to be a 100 meters /140 meters now you're into a country killer.and then they get bigger than that and it's a continent killer.much bigger than that and you're taking out whole races of ancient species.

好的 那么如果行星再大一點呢，直徑開始變成25米到45米的了,那么結果就是巴林杰隕石坑那樣的大家伙，這就像是一個屠城者或者一個毀郡者之后，當直徑到達100/140米之后，你就會變成一個滅國者,當直徑繼續(xù)增大，你就成了洲際殺手，比前面的大多了，所有古代物種都會因你而斷子絕孫。

So,what if we found an asteroid that was headed our way,how would we find it? How would we find an asteroid headed our way?

那么，如果我們發(fā)現(xiàn)沖向地球的行星呢，我們要怎么發(fā)現(xiàn)它? 我們該怎么發(fā)現(xiàn)撞向我們的行星呢?

That's a good question,well,you can use telescopes.Skilled people can point the cameras at the sky and look for fast-moving objects.Objects that are crossing the Earth's orbit,but we're missing perhaps a hundred thousand of these things ,of these country killers,city killers and country killers.

問的好，那么你可以用望遠鏡.有經驗的人可以將相機對著天空，尋找快速移動的物體.那些穿過地球軌道的物體，但是我們可能會錯過成百上千的行星，這些屠城者，毀郡者和滅國者們。

So,what we want to do is build a spaceraft called The Sentinel.and as we say "it's like looking for a charcoal briquette in the dark".these things are hard to find.They are tiny compared to the vastness of space.

那么我們想做的是造一架飛船 取名為“哨兵”,正如我們所說“這就像在黑暗里找炭團”，行星很難被發(fā)現(xiàn)，和宇宙之廣大相比，它們太渺小了。

But infrared light/heat bounces off them so what you will do? You are a satellite,you are a surveying spacecraft,you get your back to the Sun and look out from about the orbit of Venus.Any try to find all these asteroids,And then you find one,what do you do?Do you run in circies screaming,"AH"No,No,No,we've got to deflect it ,just a little just a tiny amount.

但它們會放射出紅外線輻射，所以你要怎么做?你是一個衛(wèi)星，是個調查用的航天器，你跑到太陽后面在金星軌道附近四處張望，試圖找到所有的這些行星，你找到了一個 腫么辦 畫著圈圈四處尖叫，不不不 我們得讓它走偏一點 一點就行 只要一點點。

Asteroid might be going 10km/s,we want to change its speed about 2 mm/s.So ten kilometers,that's ten times a thousand meters,that's 10,000 meters. A millimeter that's a thousandth of a meter so that you take the one over the thousand its a thousand times ten thousand,that's 10 million,You want to change its speed a 10 millionth of its total.

行星可能以10km/s 的速度運行，我們要讓它的速度改變2mm/s, 10千米就是10*1000米，也就是10,000米。一毫米是千分之一米，那么你在取出這一千分之一，所占比例就是1000*10,000 也就是一百萬,你想改變總速度的一百萬分之一.

That's not very much,but if you're an asteroid that comes in at 10,000 tons/100,000tonnes.it does take quite a bit force to change it a 10 millionth of its speed.Okay,how do we do that?Well,the easiest way is to get a rocket ,just a big rocket.just go out there and smack into it.Except as an outer space so it ,just goes (silence)like that.

似乎不多 但如果你是那個撞向地球的萬噸/十萬噸的小行星。想要讓速度改變一百萬分之一的確需要很大的力。好的，那么怎么辦?最簡單的方法是弄一個火箭 要大大的一個。 飛到那里一頭裝進去，只不過這是在外太空 所以效果是這樣的(靜音)。

Okay,that would change its speed a little,now notice everybody,what if its not just a rock?What if its a pile of rocks just loosely held together by primordial gravity? And so if you hit them they will just spread out and you will have a shower of rocks,That would be bad So,how about this?

好的 這會將它的速度改變一點點 現(xiàn)在各位看官注意，如果撞的不是巖石呢?如果那只是被原初引力聚焦在一起的一堆松垮巖石呢?如果你擊中它們 它們就會分散開來 給你下場石頭雨。好悲催的樣子 那么怎么辦呢?

We will get a big space craft that is massive,a massive sapacecraft will go out there and just get nearer to the asteroid,Just get near it,and then the mutual gravity of the you the asteroid and me the spacecraft will tug the asteroids just a little bit，just a tiny amount or maybe get on the other side and tug this way.That might work but here's the problem

我們讓一艘碩大的宇宙飛船飛過去 讓它靠近行星，靠近它 之后你(小行星)的和我(宇宙飛船)的相互引力會將行星拉近一點點 就那么一點點 或者到這邊來 這么拉,這也可能有用 不過現(xiàn)在有個問題。

We need a huge amount of fuel for days ans weeks and months and years.And what if it stops working you can't go out there and fix it.Okay,how about this?The Laser Bees?A swarm of sunlight powered lasers that are zapping the surface of the asteroid,for days,and weeks,and months,and years ZAP ZAP ZAP.So some asteroids,some rock is vaporized.

我們需要大量的燃料 得準備數(shù)天 數(shù)星期 數(shù)月甚至數(shù)年的，如果它停止工作了 你沒法跑到那修理它，好 那這么辦 激光小密蜂怎么樣?一群太陽能激光器射向行星的表面，就這么嗞嗞嗞地照上幾天 幾周 幾個月甚至幾年。一部分行星 一部分巖石會蒸發(fā)。

So the ejecta,or the stuff ejected has momentum just like rocket fuel,just like standing on a skateboard and playing catch with a bowling ball.the way you do.And so it would then cause the asteroid to change its speed,

從物體上拋出的東西和火箭燃料一樣 都有動量，就像你站在滑板上用保齡球玩接球游戲一樣，就像你做的那樣，之后 這會致使小行星改變運行速度。

And so you send a swarm of these laser spacecraft,so that if one of them stops working you can use the other one,Or you can have them come in from all different angles,And what if the asteroid is irregularly shaped (like this).you could beam it when the thing is smooth,and then when there's a pit or an inefficient place to be beaming you turn off,you wait for the asteroid to turn,then you turn it back on.

另外你送去了一群這樣的激光航天器，如果一個停止工作了 你還可以使用另一個，或者你可以讓它們從不同角度切入，如果小行星的形狀不規(guī)則(像這樣),你可以把表面烤到光滑，當出現(xiàn)一個坑或者有照射不足的地方時 你把激光關掉，你等著行星轉一圈之后再把激光打開。

You see everybody,just beacuse it's unlikely doesn't mean its not a big deal.You know if it only happens once every few thousand years,Well if it happens on my watch it would as the kids say "suck". Okay,so we don't want that to happen,we want to avoid that.

你們看到了嗎 事情不太可能發(fā)生并不意味著它不重要,你知道 即使它幾千年才會發(fā)生一次，如果在我們觀察時這事發(fā)生了 我會和孩子一樣說“擦”,好的 我們不想讓這事發(fā)生 我們要躲著它。