了解宇宙是如何运行的（2010）

All defense against asteroids That we mentioned is technically possible.
可怕的问题是它们还没有准备好
The scary problem is that it is not ready yet.
现在还不是阻止末日灾难的时候
It is not time to stop the end catastrophe yet.
我们已经取得了很大的进步，尤其是在过去的几年里，但我们还没有取得进展
We have made a lot of progress, especially in The past few years, but we haven't achieved it yet.
但我们可能会达到那个阶段也许10年或15年后
But we may reach that stage Maybe after ten or fifteen years.
但不要害怕
But do not be afraid.
地球有一个内置的防御系统，可以在小行星撞击地球表面之前就将其烧毁
The Earth has a built-in defense that can burn Asteroids before they even hit the surface.
亚利桑那州
Arizona.
2016年6月2日
June 2, 2016.
一块五英尺宽的岩石冲向地面
A five-foot-wide rock rushing towards the ground.
它以每小时4万英里的速度移♥动♥
It moves at a speed of about forty thousand miles per hour.
当它掠过头顶时，它照亮了天空
As it rushes over the heads, it illuminates the sky.
清晨，一颗小行星带着一枚炮弹在地面爆♥炸♥了，其速度超过了猎枪
Early in the morning, an asteroid exploded with a shell The Earth quickly far exceeds the shotgun.
晚上有一个火球照亮了我们周围的红色岩石
There was a fireball lit up Red rocks around us at night.
它的光亮足以烧掉NASA在地球上用来观测火球的拍摄机器
It was shiny enough to burn NASA machines to photograph on Earth that we used to observe fireballs.
小行星离碰撞还有几秒钟，重大的破坏似乎不可避免
The asteroid was seconds away from Collision and major damage seemed inevitable.
但是小行星没有到达表面，为什么？
But the asteroid did not reach the surface, why?
我们有抵御冲击的天然屏障，至少对小行星来说是这样
We have a natural inhibitor against shocks At least the small asteroids.
让我暗示一下你
And let me allude to you.
我们周围的空气，它很稀薄，但它能击退来自太空的危险
The air around us appears thin It repels a danger from space.
大气层实际上是小行星面前的另一道防线
But the atmosphere is actually Another line of defense in front of asteroids.
总有一天，我们的行星保护者将准备好从小行星撞击中拯救我们
One day, our planetary protectors will be ready to save us from asteroid strikes.
在此之前，我们必须依靠地球的内置防御系统
Until then we have to rely on the earth's built in defense system.
大气层
Atmosphere.
我们知道，我们的大气层就像一个防护罩
We know for a fact that our atmosphere acts as a protective shield.
因为小行星每天都会来到地球
Because asteroids come to Earth every day.
有些很小，有些稍微大一些
Some are small, some are slightly larger.
但当你高速进入大气层时，摩擦会产生燃烧
But what happens is when you enter the atmosphere At high speed, the friction burns.
虽然上层空气很薄，但与太空中的真空相比，它的密度却是极高的
Although the upper layers are thin, It is extremely dense in comparison to the vacuum of space.
当岩石小行星穿过大气层时
When rock asteroids rush through the atmosphere.
摩擦和气压将其加热到华氏3000度以上
Friction and air pressure heat it up To more than 3000 degrees Fahrenheit.
小行星越大，燃烧的时间就越长
The larger the asteroid, the longer it takes to burn.
对于那些巨大的岩石影响是显著的
For those huge rocks The effects can be significant.
如果里面有块大石头就够了，不要烧得太快
If there was a big rock in it It suffices, do not burn quickly.
我们称它为爆♥炸♥流星，当流星穿过外壳时，我们称它为火球
We call it the explosive meteor, and when the meteor falls across The casing makes a great show we call it Fireball.
2013年2月
In February 2013.
俄♥罗♥斯♥车里雅宾斯克被火球击中
Chelyabinsk in Russia was hit by a fireball.
当一块太空岩石从60英尺的高空坠落
When a space rock went off 60 feet across the sky.
这颗小行星比校车还大
This asteroid was bigger than a school bus.
它的速度是每秒11英里
And it sped off eleven miles per second.
它被高温加热，分解成小块
It was heavily heated, disintegrating into small portions.
然后这些部分进入大气层
Then those parts penetrated the atmosphere.
当所有的动能转化为光和热时岩石爆♥炸♥了
When all that kinetic energy is transferred For that rock to light and heat it exploded.
“车里雅宾斯克”流星是一百多年以来进入大气层的最大的自然天体
The meteor "Chelyabinsk" is the largest natural body has ever been Seeing him enters the atmosphere for more than a hundred years.
它在地面上空12英里处爆♥炸♥了30枚核弹
It exploded twelve above the ground Miles of thirty nuclear bombs.
这次爆♥炸♥造成一千五百人受伤，七千幢建筑物受损
The explosion caused one thousand five hundred Injured and damaged seven thousand buildings.
如果我们的保护罩不存在，结果会更糟
If the protective shield does not exist for our cover The results would be worse.
问题是，这个保护层只能保护我们不受岩石小行星和碎石堆的伤害
The problem is that the cover will only protect us From rocky asteroids and rubble heap.
最多大约100英尺宽
Up to about a hundred feet wide.
还有一件更危险的事情需要记住
And there is something more dangerous to bear in mind.
金属小行星
Metal asteroids.
如果我们被小行星撞到，小石子是无法到达地面的
If we were hit by a rock asteroid or Pebble will not reach the ground.
100英尺宽的小行星，它几乎在天空中爆♥炸♥
The asteroid is one hundred feet wide It almost explodes in the sky.
如果一颗100英尺宽的金属小行星与我们相撞
If a metal asteroid collided with us a hundred feet wide.
它一开始就不会警告我们
It will not warn us in the first place.
它会撞到最上面的一层，然后一秒钟后它会撞到地面
It will hit the top layer Then it hits the ground a second later.
会引起巨大的爆♥炸♥，会炸开一个火山口，大约有一英里宽
Causing an enormous explosion that would open up a crater. It would be about a Mile across.
建筑物会被夷为平地，数百万人会死于冲击波的传播
Buildings will be razed to the ground and millions die By the shock wave propagating.
在接下来的几分钟和几个小时内落下一层层的灰尘
A layer of dust falls again on The next minutes and hours.
这颗金属小行星穿透大气层
The metal asteroid penetrates into the atmosphere.
很难产生摩擦并完全压缩空气
Difficulty to make friction And compress the air completely.
它会在灾难性的爆♥炸♥中击中地面
It hits the ground in a catastrophic explosion.
金属小行星可能是地球保护者最致命的敌人
Metal asteroids may be The deadliest enemies of the planet's protectors.
但很明显，地球还有另一种紧密的防御
But it is clear that the Earth has another compact defense.
我们知道有一颗小行星穿过大气层并灭绝了恐龙
We know that an asteroid penetrated the atmosphere and annihilated dinosaurs.
但研究表明，我们的地球差点拯救了它们
But research shows that our planet may have saved them.
只是恐龙非常不幸
Dinosaurs were totally unlucky.
即使天体确实穿过了大气层，我们还有另一道防线
Even the object does make it passed our atmosphere, we still have another line of defense
小行星的成分并不总是有区别的
It's not always what an asteroid is made of that makes the difference
有时，还要看它撞击在哪里?
Sometimes it's all about where it hits
我们星球的保护者正在创造技术来改变灾难性小行星的运行轨迹
Our planet's protectors are creating technologies To change the course of a catastrophic asteroid.
但在他们的武器库建成之前地球有自己的防御方法
But until their arsenal is complete The Earth has its own defense methods.
可以肯定的是，总有一天我们会再次被一颗或几颗小行星击中
One of the sure things is that an asteroid or asteroid will shock us again.
也许在数百万年内不会发生，但它总会发生的
It may not happen for millions of years, but it will happen.
在这一天，是非常糟糕的一天还是全球性的灾难？什么会导致区别呢？
On this day, what will differentiate between that It is a hard day or a global catastrophe.
就是位置，位置，位置
Its location, location, location.
地球的某些区域可以减少致命小行星造成的损害
Some regions of the Earth can reduce From the damage caused by the deadly asteroid.
我们怎么知道的？
How do we know that?
恐龙
Dinosaurs.
六千五百万年前
65 million years ago.
恐龙的运气不好，它们很“幸运”地被小行星撞击而灭绝
The luck of the dinosaurs was bad, it was They were lucky to be annihilated by an asteroid collision.
我们以为我们知道整个故事
We thought we knew the whole story.
但研究人员发现了一些惊人的东西
But the researchers showed something amazing.
如果小行星再晚一分钟撞击地球，恐龙可能今天还会在地球上游荡
If the asteroid had hit the earth just a minute later, Dinosaurs may still be roaming the planet today
但怎么会？
but how?
这个小行星在尤卡坦半岛相撞
This body collided On the Yucatan Peninsula.
最大的大海啸淹没了北美
The latest giant tsunami flooded North America.
而且它还向空气中扔了很多硫磺
But he also threw a lot of sulfur in the air.
将小行星降落在浅海中，宽度为6英里
Land the asteroid with a width Six miles in shallow seas.
即现在是墨西哥湾
Which is now the Gulf of Mexico.
他蒸发了大♥陆♥架海底的岩石
He evaporated rocks on the sea floor of the continental shelf.
碰撞引爆了数万亿吨♥的气体进入大气层
The collision detonated trillions of tons From gases to the atmosphere.
引发灾难性的气候变化
To provoke a catastrophic climate change.
包括恐龙在内的70%的生命都灭绝了
Seventy percent of all are extinct Live on Earth, including dinosaurs. three hundred fifty
有点悲剧的是，如果撞击发生时，地球自转再多旋转一点
The thing that's kind of tragic is that if the earth had rotated just a little bit more when that impact hit
它就会掉在更深的海洋中，就不会蒸发所有的岩石和硫磺
it would have been in deeper ocean and there wouldn't have been all of that vaporized rock and sulfur
我们的星球以每小时一千英里的速度旋转
Our planet rotates at a thousand miles per hour.
海洋覆盖了地球表面的70%
Oceans cover seventy percent of the Earth's surface.
如果运气好的话，恐龙毁灭者可能会袭击更深的水域
A little luck that Dinosaurs destroyer could have struck in deeper water
地球上没有一个好地方可以承受5英里宽的小行星撞击，没有这样好地方
There's no good place on the earth to take a 5 Mile wide asteroid strike. There's just no good place.
有些地方比其他地方更糟
Some places are worse than others
硫含量如此之高的尤卡坦半岛是最糟糕的区域之一
And the Yucatan peninsula with that much sulfur was one of the worst possible
这不是一个好日子
It was not a good day.
导致恐龙灭绝的小行星让我们的哺乳动物主宰了地球
The asteroid that killed the dinosaurs was allowed Ours - mammals - dominate the Earth.
幸运的是，这些小行星每几百万年才会撞击一次巨人星
Fortunately, those asteroids are hitting Giant once every few million years.
但每两千年，就会有一块A级足球场大小的岩石砸在地上
But every 2000 years, you make a rock of a size A soccer field crashing to the ground.
当其中一颗小行星与海洋发生碰撞时会发生什么？
What happens when one of these asteroids does Smaller common colliding with the ocean?
如果你想象太平洋，那里有很长的海岸线
If you envision the Pacific Ocean, there is a long coastline.
因此有很多人处于危险之中
Thus there are many people at risk.
地球表面的大部分是海洋
Most of the Earth's surface is oceans.
有可能这颗小行星会坠入海洋
The possibility is that the asteroid will crash into the ocean.
问题是随之而来的海啸有多危险？
The question is how dangerous is the resulting tsunami?
科学家们模拟了如果一颗小行星与海洋的不同区域相撞会发生什么
Scientists have simulated what would happen if An asteroid collided with various regions of the ocean.
用3D研究不同类型的结构，不同的海洋深度和不同的进入角度
Study in 3D with different types of structures And different depths of the ocean and different entry angles.
我们意识到大♥陆♥架已经拯救了我们
And we realized that the continental shelf was already saving us.
大♥陆♥架是一个水下的地面块，它从海岸延伸近50英里
The continental shelf is an underwater ground block It stretches nearly fifty miles off the coast.
当一颗小行星撞击到几百英尺深的海洋时
When an asteroid hits a width Hundreds of feet deep into the ocean.
大♥陆♥架形成的浅海海啸在登陆前可能会减弱
The shallow sea made by the continental shelf The tsunami may weaken before it hits land.
看起来海洋有我们的防御机制
It looks like the ocean has our defense.
至于海洋的深度，我们认为小行星直径小于400英尺，虽然还是相当大，但已不存在海啸风险
For the deep ocean, we think that asteroid is smaller than 400 feet across, which is quite large, uh are not a tsunami risk
因此我们不需要像我们想象的那样担心它
And so we don't need to worry as much as we thought we did about it.
这浅水区实际上缓冲了任何可能到来的海啸波
That shallow part of the water actually buffers any tsunami wave that might be coming in
Nina Lanza在演示
让我们想象一下，这块岩石就是我们的小行星
向着地球飞去，它可能会撞到大海，当它撞到的时候，它会产生一个巨大的波浪
但是随着波的传播，向外的距离会越来越小
因此，当波浪冲击短波时，它并不比拍打在我脚下的较小波浪大
这不会给海洋带来多大的冲击，所以这样的活动风景可能并不像你想象的那么糟糕
所以我们的星球有防御机制
So our planet has defensive mechanisms.
我们的科学家正在制定计划，旨在打击危险的小行星
And our scientists are devising plans aiming to combat the dangerous asteroids
他们只需要时间
They only need time.
我们可以拯救世界，因为我们正在寻找所有有一天可能与地球相撞的小行星
Well can save the world because we're on the lookout for all the asteroids that may someday collide with earth
如果我们找到它们，我们就能避免文明的毁灭
And if we find them, we can Avoid the annihilation of civilization.