日華牧師分享到，《啟示錄》早於2,000年前已預言，
當世界踏入最後七年，後三年半，即世界最後的1,260日裡，
世界會進入大災難時期，而這一場大災難，將會是全球性的。
意思是，世界將不會有任何所謂的「安全區域」，
只要是活在地球上的人類，都會被這場災難牽連。
藉過去十二年間，日華牧師所分享極具前瞻性的「2012信息」，
讓我們得知，這一場1,260日大災難的成因，是Planet X的重臨。
有關Planet X會為地球帶來的災難，其實《聖經》早已記載，
第一次是創世記的挪亞大洪水；
第二次則是出埃及記，發生於古埃及的十災。
於八年前，日華牧師亦曾於「2012信息」之「Planet X」，
分享古埃及人曾以他們的角度，去記載這一場十災，
按他們親眼所見，十災不單單發生在埃及，而是發生於全世界，
並且，這一場普世的災難，是由一顆巨大行星逼近地球所致。
現在，我們已知道，這一顆巨大行星，是近100年，
天文學家不斷尋找其蹤跡的Planet X。
當時，日華牧師已分享，當Planet X逼近地球，
其軌跡與地球和太陽連成一直線的話，
就會令太陽爆發極為巨大的太陽風打向地球，
即遙視者Ed Dames所說的Killshot。
而另一方面，當Planet X逼近地球，其巨大引力，亦會帶來大量隕石，
當中，只要部份隕石擊中地球，都會為地球帶來災難。
事實上，這一種由隕石襲擊所留下的痕跡，其實我們幾乎每天都能看見，
因為，當我們望向月球時，單憑肉眼亦可以看見，月球表面並不平整，
有著大小不同的凹痕，這些，其實正是由隕石撞擊月球表面所引致。
甚至，不用追溯很遠的歷史，近代於27年前的1994年，
發生了「舒梅克 —— 李維九號彗星撞擊木星的事件」，
全人類親眼見證了隕石撞擊的可怕。
舒梅克 —— 李維九號彗星（Shoemaker-Levy 9，簡稱SL9），
臨時編號 D/1993 F2，又譯作舒梅克－李維9號彗星，或舒梅克－李維9。
這顆彗星，於1994年7月中下旬與木星相撞，
這是人類首次直接觀測到太陽系的天體撞擊事件，
引起全球多間主流媒體關注，
及引發各地天文學家與天文愛好者的觀測熱潮。
人們透過這次事件，更加了解木星及其大氣的資料，
以及木星於太陽系內，以強大引力，扮演著清理太空垃圾的清道夫角色，
使地球上的複雜生命，免受頻繁的天體撞擊影響。
這顆彗星，由美國天文學家尤金、卡羅琳‧舒梅克夫婦
（Eugene and Carolyn Shoemaker）及天文愛好者大衛‧李維
（David H. Levy），
於1993年3月24日，於美國加州帕洛瑪天文台共同發現，
是他們發現的第九顆彗星，
因此，根據國際星體命名規則，依照他們的姓氏命名。
這彗星很可能源於火星和木星軌道之間的小行星帶，隨後成了週期彗星，
電腦推算運行軌道的結果顯示，是出自1994年7月8日，
於距離木星表面4萬公里時，因受到強大引力影響而分裂為21個小碎塊。
並於格林尼治標準時間，1994年7月16日20時15分開始，
以每小時21萬公里的速度陸續墜入木星大氣層，
撞向木星的南半球，形成了彗星撞木星的天文奇觀。
在多塊碎片中，以碎片G的撞擊威力最大，
於7月18日7時32分（UTC）撞向木星，威力達6兆噸TNT炸藥，
其當量相當於全球核武器儲備總和的750倍，
造成一條比地球直徑還要長的疤痕。
YouTube片段：
The Lasting Impacts of Comet Shoemaker-Levy 9.
舒梅克 —— 李維九號彗星撞擊的深遠影響。
At the close of the last century, a comet, captured into orbit around a planet traveled too close and was shredded by its gravity into multiple pieces.
上世紀末，一顆彗星受一顆行星牽引而繞其運行，由於距離太近，
彗星被行星的引力分裂成無數碎片。
Some as large as half a mile or 1 kilometer long.
部份碎片長達半英里或1公里，
Those fragments would plunge into the planet’s atmosphere in a series of impacts.
碎片陸續撞向行星的大氣層。
Would the impacts be spectacular?
這次天體撞擊壯觀嗎？
Or would the comet fragments disappear without a trace?
彗星殘骸會消失於無形嗎？
In July 1994, astronomers around the world watched
with bated breath as the fragments of
comet Shoemaker-Levy 9 slammed into the planet Jupiter.
1994 年7月，全球天文學家緊盯著，
舒梅克 —— 李維九號彗星碎片撞向木星。
Dr. Kelly Fast was one of the impact’s observers
and is now manager of NASA’s Near-Earth Object Observations Program.
Kelly Fast 博士是撞擊事件的觀測者，
現為美國太空總署近地天體觀測計劃負責人。
It was just incredible to watch.
真是一場天文奇觀，
Such an impact event had never before been witnessed,
let alone studied.
這類撞擊事件是人類從未見證過，遑論研究。
Ground-based telescopes around the world
and spacecraft like NASA’s Hubble Space Telescope and even
the Galileo orbiter en route to Jupiter were used to
observe the impacts.
世界各地的地面望遠鏡和太空船，如太空總署哈勃太空望遠鏡，
甚至是探測木星的伽利略號探測器， 也被用來觀察這次撞擊。
The discovery of the comet by Carolyn and Gene Shoemaker
and David Levy gave us about a year to plan our observations.
尤金、卡羅琳‧舒梅克夫婦和大衛‧李維發現這顆彗星，
讓我們有一年時間計劃觀測活動。
The impacts proved to be impressive.
這次撞擊確實壯觀，
The fragments, some 21 in all,
plunged into Jupiter’s atmosphere over the course of six days.
21 塊彗星碎片在 6 天內撞向木星大氣層。
At impact, they were traveling at a speed of
about 37 miles per second or 60 kilometers per second
heating the atmosphere to at least 53,000°F or 30,000°C.
撞擊時秒速達每秒 37 英里或 60 公里，
大氣溫度升至華氏 53,000 度或攝氏 30,000 度。
Like the splash from throwing a rock into a pond.
如同往池塘裡扔石頭所濺起的水花，
The impacts created giant plumes of material
from Jupiter’s lower atmosphere which rose
as high as 1,900 miles or 3,000 kilometers
above the cloud tops into the stratosphere.
碎片衝入木星低層大氣，掀起寬闊的塵雲，
塵雲高出雲頂 1,900 英里或 3,000 公里，進入平流層。
In the aftermath, the plume splashback scarred
Jupiter’s atmosphere with dark clouds of impact debris,
which could be seen for months as they were
gradually dispersed by Jupiter’s winds.
塵雲殘骸飛濺於木星大氣層，留下黑色疤痕，
疤痕數月後仍然可見，其間逐漸被木星氣流吹散。
不單月球和木星會受到巨大隕石的襲擊，
其實，地球亦曾多次受隕石襲擊，並帶來可怕的災難。
例如：很多研究恐龍的科學家都認為，
地球上的恐龍之所以被滅絕， 是因為 6,500 萬年前，
有一顆巨大隕石擊中地球， 令地球氣候和環境突變，
最終令所有恐龍絕種。
隕石擊中地球而產生巨大災難的事，更不只出現一次，
地球曾多次受巨大隕石侵襲，
每一次也會在地表上留下隕石坑，成為一個證據，
證明地球曾多次受隕石襲擊。
例如︰地球上最明顯、最為人所熟知的隕石坑，
是位於美國亞利桑那州北部，沙漠裡的巴林傑隕石坑
（英譯：Barringer Crater 或Meteor Crater）。
據推測，形成巴林傑隕石坑的隕石，
是一顆直徑約 50 公尺的鎳鐵質隕石，
其撞擊速度，至少達每秒數公里，撞擊所釋放的能量，
相當於 10 兆噸黃色炸藥。
更加近期的是，2013 年 2 月 15 日，
車里雅賓斯克小行星撞擊事件，
於俄羅斯烏拉爾聯邦管區的車里雅賓斯克市，
一次小行星撞擊事件。
當日約上午 9 時 15 分，隕石進入大氣層時，
直徑約 15 米，質量約 7 千公噸，
在天空中留下約 10 公里長的軌跡，
主要碎片擊中了切巴爾庫爾湖，事件中造成 1,491 人受傷。
YouTube 片段：
On February 15th, 2013, over Chelyabinsk,
Russia an asteroid heavier than the Eiffel Tower slammed
into the atmosphere.
2013 年 2 月 15 日，俄羅斯車里雅賓斯克上空，
一顆比埃菲爾鐵塔還重的小行星穿越大氣層。
And then 30 kilometers above the ground, it exploded.
在距離地面 30 公里上空爆炸，
This violent event was brighter than the Sun,
but so high up that it was silent for a full 90 seconds after
the blast which only made the devastation worse.
爆炸猛烈得比太陽還要光亮，但因在高空發生，
爆炸後整整 90 秒都是寂靜無聲，使破壞變得更嚴重。
So, you see all these videos, of people.
你看到關於目擊者的影片，
"Look, oh, what was that?"
看！啊！那是甚麼？
They see the smoke trail in the sky.
他們看到天上的煙跡。
"Oh, that's amazing!"
啊！很神奇！
And then, you know, just when you think nothing's gonna happen,
the shockwave hits and it blows out the windows.
正當你以為不會有事發生時，衝擊波就來襲，把窗子震落。
Thousand people got glass in their face and their eyes,
because they're looking through the windows.
玻璃刺進上千人的臉和眼睛，因為他們正往窗外看。
The shockwave damaged thousands of buildings
and injured 1,500 people.
衝擊波損毀了數千座建築物，1,500 人受傷。
What makes the Chelyabinsk incident kind of embarrassing,
is that the very same day, scientists had predicted
that an asteroid would make a close fly-by of Earth.
車里雅賓斯克事件有點尷尬，原因在同一天，
科學家預測一顆小行星將近距離掠過地球。
And they were right.
他們是對的。
16 hours after Chelyabinsk, a similar-sized asteroid known
as Duende came within 27,000 kilometers of Earth's surface.
在車里雅賓斯克事件 16 小時後，
一顆大小相若的小行星 Duende，到達地球表面 2.7 萬公里以內。
That's closer than satellites in geosynchronous orbit.
比地球同步軌道上的人造衛星還要接近。
But while they correctly predicted this close approach,
they completely missed the unrelated asteroid that
exploded over Russia.
雖然科學家準確預測了這顆小行星，
卻完全錯過在俄羅斯上空爆炸的那一顆。
And the truth is, this happens all the time.
事實上，這種情況一直在發生。
We're really not that good at detecting asteroids
before they hit us.
人類真的不擅長於在撞擊前就將小行星探測出來。
Since 1988, over 1,200 asteroids bigger than
a meter have collided with the Earth and of those,
we detected only five before they hit never with
more than a day of warning.
自 1988 年以來，超過 1,200 顆，
大於 1 米的小行星與地球相撞，
當中，只有 5 個在撞擊前就探測出來，
連超過 1 天的預警也沒有。
With all our technology and all the telescopes
across the Earth not to mention the ones in space.
現代科技發達，望遠鏡遍布全地，還有太空望遠鏡在觀測，
why do we struggle to detect dangerous asteroids
before they strike?
為何很難在撞擊前探測出危險的小行星呢？
What are the chances that a big asteroid will hit wiping out most,
if not all, life on Earth?
有沒有可能大顆的小行星撞擊地球，
消滅大部分以至全部的生命？
And if we saw one coming what could we do about it?
若我們預見有一顆逼近，又有何對策？
Asteroids are the leftover debris from when our solar system formed.
小行星是太陽系形成時所殘餘的碎片，
Four and a half billion years ago,
rocks and dust clumped together into molten protoplanets.
45 億年前，岩石和塵埃聚合在一起，形成熔化的原行星。
Inside, heavy elements metals like iron,
nickel and iridium sank into
the core leaving lighter silicate minerals on the surface.
在內部，較重的元素，鐵、鎳及銥等金屬向地心下沉，
較輕的硅酸鹽礦物則殘留在表面。
Some of these protoplanets grew into the planets we know today.
有些原行星漸漸演變成現今所認知的行星，
But many more collided with each other, breaking into pieces.
但許多都互相碰撞，形成碎塊。
These pieces continued orbiting the Sun and smashing into
each other and breaking into even smaller fragments.
碎塊繼續繞著太陽運行，互相撞擊，形成更小塊的碎片。
These became the asteroids,
which is why some of them are rocky loose conglomerates
of gravel-sized rocks called rubble piles.
這些碎片形成小行星，故此有些小行星由岩石構成，
由砂礫大小的碎石鬆散地黏聚而成，稱為「碎
石堆」。
And others, from the cores of planetesimals are mostly metal.
而源自微行星核心的小行星，則主要由金屬構成。
So, this is, this is an iron meteorite.
這是一塊鐵隕石，
And, essentially it's the piece of a core of a small planetary body,
like basically a small planet that formed
4.5 billion years ago.
實質是一塊小行星體的核心，即是 45 億年前形成的小行星。
Differentiated, so the core material fell out.
在分化過程中，核心物質脫落，
And then this thing was smashed apart by
a collision with another asteroid.
然後與其他小行星撞擊，便散落成這塊東西，
That's the oldest thing you'll ever see.
這是至今所見最古老的東西。
Most of the asteroids have stable orbits between
Mars and Jupiter, in the main asteroid belt.
大多數小行星都有穩定的軌道，
運轉於火星與木星之間的主小行星帶。
But some have made their way closer to Earth.
但有些卻較接近地球，
And these are known as near-Earth objects.
這類小行星稱為「近地天體」。
They are of greatest interest to us
because of the threat they pose.
它們對地球的威脅大大引起我們關注，
In his last book, Stephen Hawking considered
an asteroid impact to be the greatest threat to life on Earth.
霍金在他最後一本書中提及，小行星撞擊，
對地球上的生命構成最大威脅。
But finding asteroids is difficult for several reasons.
但要找出小行星並非易事，原因有幾個，
Most are spotted by ground-based telescopes.
大部分小行星是由地面望遠鏡所發現。
So, what you do is you take a sequence of pictures.
你得拍下一連串照片，
One, two, three.
1、2、3……
One, two, three, four。
1、 2、3、4……
And you look for essentially a moving dot。
從中尋找出移動的小點，
And it’s moving, because it’s orbiting
around the Sun whereas the stuff far away, the stars and galaxies, are not.
移動是因為它正圍繞太陽公轉，而較遠的星體則不會，
如恆星及銀河系。
But you have to look carefully,
不過，你要細看，
Asteroids are not very big.
因為小行星體積不大。
They range from meters up to kilometers in size.
直徑從幾米到幾公里不等。
And in the vast expanse of space, rocks like that just don’t stand out.
在浩瀚的宇宙中，這樣的岩石並不顯眼。
And even the small ones can be damaging.
但體積小的星體同樣極具破壞性，
The Chelyabinsk meteor was only around 20 meters
in diameter roughly the width of two school buses
就像車里雅賓斯克流星，直徑只有約20米，
大概是兩輛校車的長度。
Plus, asteroids are rough and dark,
they only reflect around 15% of the light that hits them。
另外，小行星表面粗糙暗淡，
僅會反射約15%的光。
So, our best chance to see them is when they’re fully illuminated by the Sun.
因此最能觀察到它們的時候，就是完全被太陽照亮時。
And that’s why over 85% of the near-Earth asteroids we’ve detected,
were found in the 45 degrees of sky directly opposite the Sun。
這解釋為何我們發現的近地小行星中，
有超過85%位於與太陽正對的45度天空上。
This is called the opposition effect.
這現象稱為「衝日效應」。
And it means there are likely more near-Earth
and potentially hazardous asteroids that haven’t been detected yet.
意即可能有更多近地及危險的小行星尚未被發現，
Any asteroid approaching from the direction of the Sun just can’t be seen.
任何從太陽方向接近地球的小行星，都無法被觀測，
This is exactly what happened with Chelyabinsk.
車里雅賓斯克事件就是活生生的例子。
So far, we have detected and cataloged a million asteroids.
迄今，我們已觀測到並編目了100萬顆小行星，
The vast majority of which are in the main asteroid belt.
大多數位於主小行星帶。
But 24,000 are near-Earth objects.
當中有2.4萬顆是近地天體，
Ones that we need to keep a particularly close eye on.
須要密切關注。
Because, even once you've detected an asteroid
it's hard to tell if it will hit the Earth.
因為即使探測到一顆小行星，也很難判斷會否撞擊地球。
So, if you just discover an object and
you only have data from a few days then
you can't really tell where it's going to go。
當你發現一個星體，卻只有幾天的數據，
是不可能預計到真正的軌跡。
Because, you're trying to take this little arc
of motionand predict it far into the future.
因為你是試圖利用細小的弧型軌道，去預測未來的軌跡。
So, what you need is observations over years and years.
你需要多年的觀測數據，
But even if you have perfect observations of
an asteroid there's kind of a fundamental limit
to how far in the future you can predict.
但即使你有著非常精確的觀測，在預測未來上仍會受到基本限制。
And that's because of a couple of effects.
當中涉及了多個因素，
But one is that, you know they're not just orbiting
the Sun with no other influence.
其中之一是，小行星環繞太陽運行時，
亦受其他因素影響
All of the planets have gravity and
all of the planets are pulling on near-Earth asteroids
and can change the orbit significantly.
所有行星都有引力，會牽引地球附近的小行星，
大幅度地改變小行星的軌道。
So, there is something called dynamical chaos.
這就是所謂的動態混沌。
Which basically means after a certain amount of time,
you don't know where the asteroid is going to be
簡單來説，經過一定時間後，
就無法預測小行星的軌跡，
And in practice, what that means is
we can't do any work more than 100 years in the future.
在實踐上，意味著人類無法預測100年後的情況。
So, the maximum time you can predict with any accuracy at all,
where a body will be is about 100 years.
所以要準確預測天體位置，最遠預測期為100年。
And this is pretty important.
這是非常重要的，
Because, we know with certainty, if one does hit, the results will be dramatic.
因為我們非常肯定，如果有一顆來襲，
結果將會是災難級。
This is Barringer Crater in Arizona.
這是亞利桑那州的巴林傑隕石坑，
It's named after a mining engineer,
Daniel Barringer who was the first to suggest
it was formed by a meteorite impact.
命名來自採礦工程師Daniel Barringer，
他是首位提出這坑是由隕石撞擊而成的人。
The prevailing view even up until the 1950s,
was that it was created by volcanic activity.
直到1950年代，普遍認為是由火山活動造成，
But Barringer was convinced it was the site of an iron meteorite impact.
但Barringer 確信這是鐵隕石撞擊的地點。
So, in 1903, he staked a mining claim
and began drilling for the metallic meteorite
which he believed to be worth more than a billion 1903 dollars.
所以他於1903年取下了採礦權，
開始鑽探尋找金屬隕石，認為於1903年其市值超過10億美元。
Yeah, So, people are motivated by money, right?
是的，人都會受金錢所激勵，對吧？
So, they thought, "Hey, we can get some iron for free!" basically.
當時的人認為「嘿，我們可以得到免費鐵材！」。
So, they started to drill in the bottom of the crater and found nothing.
他們開始往坑內鑽探，但一無所獲，
And then they started to do other exploratory drills.
然後開始了一系列勘察式鑽探，
And this went on for years and decades.
鑽探工作持續了數十年。
They started to drill sideways.
他們開始往兩側鑽探，
Somebody said, you know, maybe it came in from an angle, which it did.
有人認為或許隕石是斜著進來，的確如此。
And maybe the iron is not under the middle,
but maybe it’s over there under the wall.
或許鐵不在中間，而是坑洞兩側。
So, he was doing drilling.
所以他一直鑽探。
If you go there, you can see the drills now.
如你到那裡，你會看見不同鑽孔，
He was drilling around the wall, he found nothing.
他在兩側鑽探，但沒有任何發現。
So, what they didn’t realize is when you have an impact at high speed,
it’s not like you’re throwing a stone into a brick wall.
他們沒有意識到，當物件以高速撞擊時，
並不如你將石頭擲向磚牆。
You know, and it makes a hole and sticks in there, or just bounces off.
留下一個洞和貼在牆上，或反彈回來。
It’s explosive, it’s like totally explosive.
卻會爆炸，並且非常劇烈，
So, the kinetic energy of the projectile
comes in maybe 30 kilometers per second.
隕石以秒速30公里的動能滑行，
The kinetic energy of the projectile is big enough
to completely vaporize the projectile.
龐大的動能足以把隕石氣化掉。
It turns it into a gas.
隕石變為氣體。
And that gas is super hot and super high pressure
and it explodes and it blows out the crater.
溫度、氣壓極高，爆炸後形成極大的坑洞。
So, the projectile doesn’t really exist after the impact.
因此，隕石在撞擊後是不復存在。
I mean, little pieces can survive
我指只會留下碎件。
But this 50-meter body was basically obliterated.
而這50米大的星體就此灰飛煙滅，
So, he was looking for something that did not exist.
故此他當時在尋找不存在的東西。
He spent 27 years mining the crater drilling down
to a depth of over 400 meters,
but what he was searching for had vaporized on impact 50,000 years earlier.
他花了27年鑽探隕石坑，鑽頭深入地底達400米，
但所尋找的於5萬年前撞擊時已氣化。
The 50-meter asteroid,
not that much bigger than
Chelyabinsk released the energy equivalent of 10 megatons of TNT.
這50米小行星，比車里雅賓斯克隕石大不了多少，
釋放了相當於1,000萬噸爆炸當量。
That’s over 600 times the energy of the Hiroshima bomb.
威力比廣島原子彈大600倍。
So, the thing that most closely resembles a meteorite impact
is a very large nuclear explosion
因此隕石撞擊可比巨型核爆.
This is the actual size of the T-Rex skull.
這是暴龍頭骨的大小。
And I thought, this is such a cool thing, I got to have it.
我覺得這麼酷的東西，我得擁有 。
So, I bought the T-Rex.
所以買了下來。
The dinosaurs were wiped out by a 10-kilometer size asteroid,
that hit about 65 million years ago.
恐龍滅絕是因為一顆直徑10公里的小行星，
撞擊大約在6,500萬年前發生。
So, above a critical size, which is probably a couple of kilometers.
當隕石超過臨界體積，即大概兩公里，
An impactor delivers so much energy that it has a global effect.
所釋出的能量足以影響全球。
So essentially, it launches a whole bunch of debris into suborbital trajectory.
一大堆碎片因而進入亞軌道。
So, the ejecta goes around the Earth, falls back into the Earth, all over.
碎片環繞地球，再掉落到遍地，
Even on the other side of the planet from where the impact occurred.
甚至是地球未受到撞擊的一邊。
And what that means is the whole sky lights up with wall-to-wall meteors.
整個天空因而亮了起來，鋪滿流星。
So, you can imagine the sky turning from,
you know, a nice blue day like today into essentially a red,
hot glow like being inside a toaster oven。
可以想像天空，從今天那樣美好的藍色，
變成紅色，發出熾熱光芒，
就像在多士爐裡一樣。
So, the first effect of this impact apart from
the initial blast near where the actual impact occurred,
the first effect is the sky turns into a great source of heat and
it cooks everything on the ground.
所以撞擊的第一個影響，除了附近發生爆炸外，
就是天空變成了巨大的熱源，把地上一切都烤熟。
So, these guys were basically cooked.
所以恐龍基本上都是被烤死的。
Cooked alive.
活活被烤死。
Cooked alive, as they were walking around.
就在四處走動時，活活被烤死。
The only animals that had a chance,
were the ones living in tunnels under the ground or maybe in the water.
唯一生存下來的動物，就是那些住在地底或水中的。
And they were able to come back and
take over without having to deal with the dinosaurs as a major obstacle.
後來牠們回來接管全地，再不用面對恐龍的威脅。
What are our chances that Earth gets hit
by another 10-kilometer or bigger asteroid?
可能性有多大？地球被另一顆10公里或更大的小行星撞擊？
In your lifetime, assuming you live to be 100 years old.
假設你活到100歲，
You have a 10-kilometer impactor like the K-T extinction event.
遇上物種滅絕事件中的10公里小行星。
Every hundred million years or something like that.
機會是大概每1億年1次。
So, the probability of getting it in one year is one in a hundred million.
即每年發生的或然率是億分之一。
So, you have one in a million chance of dying from a 10-kilometer impact.
即你有百萬分之一機會死於10公里的撞擊物。
But, because we know that there are no 10-kilometer impactors
with a path that intersects the Earth for the next hundred years.
但是我們預計沒有10公里的撞擊物會在未來百年，
與地球的軌跡相遇。
Your chance of dying from that is actually zero.
因此死亡的機率是零。
So, work done already has reduced that down you know,
from one in a million to nothing.
所以我們已做好了預測，把機率從百萬分之一降至零。
So, the good news is there won't be another dinosaur-style extinction
event in our lifetimes.
好消息是，我們有生之年不會遇上滅絕恐龍級數的事件。
But, there are exponentially more asteroids of smaller sizes.
但較小的小行星卻是數倍之多。
For every 10-kilometer asteroid,
there are roughly a thousand one-kilometer asteroids
and they're still capable of doing a lot of damage.
每一顆10公里小行星，就會有大約1,000顆1公里小行星，
足以造成大量破壞。
One or two kilometers is capable of causing local but massive damage.
1到2公里小行星，會造成局部的巨大破壞。
So that means, you know,
instead of wiping out the entire world
you would wipe out the equivalent of some European country
like France or Germany, to mention two of my favorites.
意即雖不會造成全球滅絕，卻足以毀滅等同一個歐洲國家的區域，
例如我最喜愛的法國或德國。
So, you would obliterate those countries
with the impact of a one or two kilometer size body.
毀滅這些國家只需要1或2公里的隕石。
Do we know about all the one to two kilometer bodies that could hit us?
我們掌握了所有可能來襲的1至2公里隕石嗎？
We think that we know 90-something percent.
我們認為掌握了90%以上，
Maybe 98% of those bodies have been identified and
we have their orbits and we can make reasonable predictions
for the next 10 years of something about where they'll be.
甚至辨識了98%的隕石，而且掌握其軌跡，可以合理地預測未來10年的去向。
And we seem to be okay at the moment but you know,
what about the ones that are just a little bit less than a kilometer?
現在大致上沒有問題，但那些比1公里小一點的隕石呢？
What about the ones that are 800 meters?
直徑只有800米的小行星呢？
That's still pretty, pretty savage if it hits.
如果撞向地球，後果同樣嚴峻。
And this is possibly where the greatest threat of asteroids remains.
也許是這類隕石，對人類構成最大威脅，
A few hundred meters is large enough to obliterate a large city.
幾百米的隕石，足以毀滅一座大城市。
But, small enough that we haven't detected them all yet.
但體積太小，人類難以全部偵察。
We're missing a lot of hundred-meter size projectiles.
大量以百米計的星物是偵察不到的，
And those guys are big enough to
cause substantial damage on the Earth depending on where they hit.
其體積卻足以對地球造成嚴重破壞，視乎擊中的地區，
So, it could destroy a city.
可以毀滅一座城市。
Yeah, it would knock down the buildings in the city.
是的，足以摧毀城市的建築物。
It would cause citywide fire.
引發全市火災。
And if it hit the ground, it would throw up ejecta
that would come back down that would obliterate
a hundred kilometer zone around it.
如果擊中地面，就會產生大量碎片射向天，
再從天而降。碎片高速墜落，如同下雨一樣，毀滅方圓100公里內的區域。
And this could happen tomorrow.
明天便可能發生。
Well, it could, yeah.
嗯，可能，是的。
If we saw a big one coming, what's our best bet for I mean,
could we do anything about it? What would we do about it?
假若預見大隕石逼近，最好的對策是甚麼，有對策嗎？該怎麼辦？
No.
沒有。
Is there anything we can do actively?
我們可否主動出擊？
No, there's nothing we can do.
沒有，我們束手無策。
I was on a committee that looked at that, okay, like 10 years ago,
like, what could we do.
10年前，我是研究對策的委員之一，
One option would be to try and bomb it. It's a standard thing.
方案之一是炸毀它，這是標準做法，
We don't know how that would work out.
可是不知道結果會如何。
Even when you got it there, and even if you could explode it
on the surface or in the surface.
即使你引爆隕石表面或裡面，
It's not clear what you would do.
你仍是不肯定該怎麼辦。
Because, typically what happens is you blow up a body
and the fragments move out.
因為一般而言，當你爆破一個星體，碎片會向外移動。
They expand out, but not very quickly.
向外擴散，但速度不是很快，
And then gravity pulls them back together again.
然後重力又再把碎片聚合，
So, it would reform as a rubble pile.
重新形成「碎石堆」。
If it was not already a rubble pile to begin with
which it probably would be because of past impacts.
即使起初時不是碎石堆，但很可能會是，因為以往受過撞擊，
So, blowing up a rubble pile is something that we don't really know about.
因此，爆破碎石堆並非我們懂得操作的。
Another idea is you could attach.
另一個方案是，
You could be all gentle, and attach a rocket to the asteroid.
緩緩地將火箭附在小行星上，
And just try to push it aside.
嘗試把它推到一邊。
Just nudge it aside, instead of trying to blow it up.
只是輕輕推開，而不是炸毀，
Let's just push it gently aside.
只是輕輕地推到一邊。
So that it deflects it, and it doesn't hit the Earth
令其偏移，而不會擊中地球。
The trouble is, when you work out the numbers none of the rockets
that we have can push it around enough.
問題是，當你計算出相關數值時，人類的火箭都不足以把它推開。
You would have to keep the rockets attached to the surface
which we don't know how to do.
你必須把火箭固定在表面，但就此無法可施。
Remember, it's a rotating body for centuries
to have a significant effect on the motion of the asteroids.
別忘了，這是自轉的星體，需要幾個世紀，
才能對小行星的運動帶來顯著影響，
So, forget bombs, forget attaching rockets.
所以炸彈、附加火箭也不行。
Ablating the surface, basically you boil the surface with a laser.
至於消融其表面，就是用激光煮沸表面，
We don't have any lasers powerful enough.
我們沒有激光具備足夠強度，
And probably can't make lasers powerful enough to do that from the Earth.
也不可能從地球發射如此強烈的激光，
We would have to take the lasers to the object which is even more difficult.
只能把激光帶到星體上，這是更加困難的。
The idea that you could wrap an asteroid in cooking foil.
有人提倡用鋁箔紙包裹小行星，
Aluminium cooking foils, another nice one.
鋁箔紙也是個不錯的主意，
It may be a good one, the best one.
可能是最好的一個。
But it still doesn't really work, because we don't know how to do that.
但仍是不可行，因為不知道如何操作。
We don't have a way to launch enough cooking foil
to wrap up an asteroid and change its radiative properties
which would itself move the asteroid around.
我們無法發射足夠的鋁箔紙來包裹小行星，
以改變它的輻射特性，致使其改變軌道。
So, the truth is, to be honest
we do not have a way now to deflect a kilometer size
asteroid at all that could destroy a country.
所以，說實話，我們暫無方法轉移1公里大小的小行星，
而它卻能毀滅一個國家。
Yeah, we just don’t have a way.
是的，我們無能為力。
And 10 kilometers?
那10公里大小呢？
10 kilometers is absolutely a thousand times more hopeless.
10公里就更是1,000倍無望了，
So, when we discuss this, you know, we had all these grand ideas.
我們在討論中想出許多很棒的主意。
Oh, we could do this and this, and none of them worked.
這樣行、那樣行，不過都行不通，
We came down to the most basic idea,
well maybe if we could figure out where
the asteroid is gonna hit like which city is it gonna explode over,
we can evacuate that city.
我們回歸到最基本的想法，就是如果預測到小行星會撞擊哪裡，
哪座城市將受災，我們便及早撤離。
And then we looked at the history of city evacuations.
我們翻查了撤離城市的歷史記載，
And we looked at cases, you know where,
for example you have like a week’s warning
where some hurricane system is gonna come in and flood the city.
翻閱了個案，例如，提前一週預警颶風來襲並淹沒城市。
And evacuation just doesn't work either, and the reason is very, very simple.
但撤離也行不通，原因非常簡單，
Like going into a city, there are not that many freeways.
出入城市的高速公路其實不多，
If you have millions of people trying to get on a freeway
the first time a car breaks down, you block that freeway.
如果數百萬人突然湧上高速公路，一旦有壞車，交通就會堵塞，
So instantly, you have millions of people trying to
get out of the target zone and they won’t be able to
because all of the roads will be instantly blocked.
換言之，數百萬人嘗試撤離，卻辦不到，因為所有高速公路都立刻堵塞了。
So again, even that, even evacuation of a city is probably
the most hopeful thing that we could try to do.
話雖如此，撤離仍是最有希望的措施，
Even that’s really, really difficult
because of the large numbers of people involved.
雖然牽涉人數眾多，執行起來困難重重，
What I think all reasonable people would conclude is.
我認為所有明理的人會得出結論，
Let’s do the thing that we can do first.
就是先做可以做的事。
So, let’s look for them.
找出應做的事情來，
Let’s do the surveys, let’s build the telescopes.
我們得做些調查、得建造望遠鏡，
Let’s put this telescope in space.
把望遠鏡放在太空，
That will be a major contribution to understanding
the threat from the asteroids.
這對了解小行星的威脅，有著重大貢獻，
And then when we find a particular object
that looks especially dangerous then we can focus on it.
假若發現看似特別危險的小行星時，就專注在它身上。
We can focus everything we have on it.
到時候可以集中精力，
And we can begin to think seriously
and with real motivation about ways to deflect it.
認真思考，有著真正的動力設法將其轉移。
就正如《啟示錄》所預言，
在大災難最後的1,260日，地球至少將會受到兩次巨大隕石襲擊，
而這兩次隕石襲擊，極可能正如上述影片提及，
大小約一公里，甚或是更大型的隕石，
直接擊中地球的陸地和海洋，引起巨災。
啟示錄 8章5至11節：
「天使拿著香爐，盛滿了壇上的火，倒在地上；
隨有雷轟、大聲、閃電、地震。
拿著七枝號的七位天使就預備要吹。
第一位天使吹號，就有雹子與火攙著血丟在地上；
地的三分之一和樹的三分之一被燒了，一切的青草也被燒了。
第二位天使吹號，就有彷彿火燒著的大山扔在海中；
海的三分之一變成
血，海中的活物死了三分之一，船隻也壞了三分之一。
第三位天使吹號，就有燒著的大星，好像火把從天上落下來，
落在江河的三分之一和眾水的泉源上。
這星名叫茵蔯。
眾水的三分之一變為茵蔯；因水變苦，就死了許多人。」
Ref：錫安日報 2012 榮耀盼望 vol. 608 (20211003)
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