了解宇宙是如何运行的（2010）

但这不仅仅是一场数字游戏，即使数百万颗小行星中的任何一颗都可能造成重大撞击
But this isn't just a numbers game, even though any one of the millions of asteroids could result in a major impact
他们都并不相同，这意味着每一种威胁都是不同类型的
They're not identical. This means each one presents a different type of threat.
它的速度、大小和离地球的距离决定了危险的程度
Its speed, size and distance from Earth helps determine the degree of danger.
我们对小行星了解得越多，我们就越能做好防御的准备
The more we can really understand about an asteroid, the better prepared we are to be able to defend against it
这绝对不能称之为敌人
This is definitely a case of no thy enemy.
你知道，我们需要了解这些物体的性质
You know, we need to know something about the about the properties of these objects.
如果我们还有希望，就是有一天把存在的威胁从我们的道路上移开
If we have any hope of of of moving a threatening one uh out of our path one day
但是科学家们意识到小行星的成分可能是最致命的因素
But scientists are realizing that an asteroids composition could be the deadliest factor
知道小行星是由什么组成的可以帮助我们找到防御它们的盔甲的物质
Knowing what asteroids are made of can help us find things in the armor
为此，近东研究中心的玛丽娜·布拉索维奇使用了二战期间开♥发♥的技术
To do so Marina Brasovich which on the Center for Near Eastern Studies uses a technology developed during World War Two
雷达
Radar.
行星雷达与机场雷达非常相似
Planetary radars are very similar to airport radars.
机场雷达追踪飞机，而我们正在追踪小行星
Airport radar also tracks Planes we are tracking down asteroids.
它们离我们有几十万甚至几百万公里远
That is hundreds of thousands away from us And maybe millions of kilometers.
雷达还能告诉我们这颗小行星的样子
Radars also tell us Also what this asteroid looks like.
我们想知道它的大小、形状和化学成分
We want to know its size, shape and chemical composition.
考虑到我们需要在小行星的表面上看到的细节，除了发射航♥天♥器，你无法做到这一点
Considering the detail that we see on the surface short of sending a spacecraft, you cannot achieve that.
所以雷达才是我们这个小太空任务所需要的
So radar is in the way, it's own little space mission
雷达显示小行星可能是由岩石或矿物或它们的混合物形成的
Radars show that asteroids may form Of rocks or minerals or a mix between them.
这是我们如何处理它的重要信息
This is important information for how we deal with it.
金属小行星比一般的岩石小行星密度大得多
Metal asteroids are much denser From the usual rocky asteroids.
和巨大的铁质小行星碰撞产生的能量可能比同样大小的岩石小行星产生的能量要多得多
Collisions from a huge iron asteroid might generate energy Much more than just a rocky asteroid the same size.
它还造成了比同样大小的岩石行星更大的金属外壳损坏
It also caused the metal shell Damage greater than a rock of the same size.
金属小行星可能比岩石小行星更致命
Metal asteroids may be More deadly than rock asteroids.
科学家们现在已经发现，大多数小行星与金属外壳的相似性较低，更像是宇宙子弹
Scientists have now discovered that most asteroids are less similar With metal shells, I resemble the cosmic bullets a lot.
大多数小行星都不是一个致密甚至是砾石集♥合♥体的物体
Most asteroids are not an object One compact and even aggregates of gravel.
它由许多较小的岩石、砾石、颗粒和部分沙子组成
It consists of many smaller rocks Gravel, grains and parts of sand.
它们都被引力紧密地结合在一起
All of them bind gravity together tightly.
砾石小行星，如“itkawa”像一颗豆状药丸，可能是在小行星之间剧烈碰撞形成的
Gravel asteroids, such as "itkawa" in the form of a pill Beans may have formed violent collisions between asteroids.
最初，岩石散射体将这些碰撞分散为碎片
Initially rocky scatterers scatter Such collisions are as fragments.
然后控制彼此的引力将它们再次绑在一起而不是收紧
Then the gravity that controls each other Rocks tie them together again without tightening.
这堆松散的岩石实际上可以重塑卫星的形状，形成我们在许多小行星中看到的有趣形状
它们听起来可能很奇怪
但是这些松散结合的太空岩石构成了我们研究的关键部分
因此，我们对小行星家族的了解是，只要小行星直径在十几英里宽时
我们认为几乎所有这样小行星实际上都是小行星带早期历史巨大碰撞中重新堆积的碎片形成的
小行星的结构对我们的地球保护者来说是一个巨大的挑战
The structure of the asteroid asteroid represents A huge challenge for our planet protectors.
科学英雄们怎么能把我们从一堆石头里救出来？
How can science heroes be Save us from a pile of stones?
如果天体是固体金属，那么它对碰撞或爆♥炸♥的反应将与碎石堆完全不同
If the body had a solid mass of metal it would respond to collision or Blast in a completely different way than if it were piles of gravel.
它们由重力连接在一起，但没有绷紧
They are linked together by gravity without tightening.
他们是非常脆弱的天体，需要特别的照顾
They are very fragile bodies and need special considerations.
我们不一定会与之发生冲突
We cannot necessarily collide with it.
与砾石小行星碰撞，就像一堆树叶被吹散
Colliding with gravel asteroids It is like scattering a pile of leaves.
成千上万的小岩石会向各个方向移♥动♥
Thousands of smaller rocks will push in every direction.
它无法被监测或预测，它可能会继续冲向我们
It will not be monitored or predicted and you may continue to rush towards us.
但我们有个计划
But we have a plan.
我们可以用一点引力来代替蛮力
Instead of using brute force We can use a slight gravitational pull.
我们需要的不是这种笨拙的方法，而是更仔细、更精确的方法
Instead of this clumsy approach to hit and get away We just need something more careful and more precise.
于是就有了“引力火车头”的想法
And here is where the gravity locomotive comes.
可能这堆岩石很小，但也是有引力的
Piles may be rocks Small but attractive.
例如，如果我们发射一个质量为数吨♥的探测器，它也有引力，虽然没有那么大，但它确实存在
For example, if we send a probe that has a mass of tons, it would be It has attraction too, not so big, but it does exist.
如果我们让它靠近小行星，我们可以利用引力相互作用，它们之间的引力就会把小行星推到安全轨道上
If we bring it closer to the asteroid, we can use gravity Mutual, attraction between them, to flatten the asteroid into a safe orbit.
我们只需要在小行星旁边停一辆车然后停在那里
All we need to park a vehicle Next to the asteroid and hover over there.
不要让小行星和宇宙飞船扯在一起
And don't let the asteroid and spacecraft pull together.
让飞行器的重力像绳子一样把小行星拉离轨道
And let the vehicle's gravity work As a rope to pull the asteroid off its path.
这听起来像科幻小说，然而物理学就是这样简单，我们可以做到
It may sound like a science fiction, however That physics is simple and we can do it.
但引力火车头只有在我们精确追踪小行星运动的情况下才能发挥作用
But the gravity locomotive only works if We tracked the movement of those asteroids precisely.
问题是在我们的太阳系中♥央♥有一个巨大的复合体
The problem is having a giant Complex in the middle of our solar system.
太阳
the sun.
地球保护者想要阻止末日灾难
Planet protectors want to stop the end disaster.
他们的任务是保护地球免受小行星的撞击这似乎是不可避免的
Their mission is to protect the earth from collisions Asteroids that seem inevitable.
但要做到这一点，他们就需要预测它们的一举一动
But to do that, they need to predict their every move.
在一个不断变化的太阳系中，这并不容易
In an ever-changing solar system, this is not easy.
我们测量它们的轨道，并绘制出我们今天看到的轨道图
We measure their orbits and can draw Maps of their orbits as we see them today.
但我们知道它不是一个固定的群，而是一个移♥动♥的群，在小行星带中事物总是在不断变化
But we know that it is not a fixed group, but a moving one Things are constantly changing in the asteroid belt.
小行星不仅仅是在于它的尺寸，我们还要了解它们的密度、轨道和速度，直到我们解决它们
Asteroids are not just about size Understanding density, orbit, and speed until we deal with them.
碰撞会使小行星碎片进入新的轨道
Collisions can set asteroid debris off on new orbits
但还有另一个因素，引力巨大的气体巨行星木星
But there is another factor, gravity The colossal gas giant Jupiter.
木星是太阳系中最大的行星
Jupiter is the largest body in the solar system.
他坐落在小行星带外面
He sits outside the asteroid belt.
它的引力可以拉住小行星使它们的轨道变得更椭圆
Its gravity can pull those asteroids And make their orbits more oval.
也会使小行星穿过地球的轨道并掷向太阳
To send it toward the sun, crossing the Earth's orbit.
模拟木星对数百万颗小行星的影响是非常困难的
Simulate Jupiter's impact on millions Asteroids are very difficult.
而且在其影响下，小行星带中的还有一些最大的天体
Then at the influence of some of the asteroid belts the largest objects
530公里宽的岩石，如“灶神星(Vesta)”和“Palace”
530 kilometer wide rocks such as Vesta and palace
这项艰巨的任务变得几乎不可能完成
The difficult task becomes almost impossible.
但引力并不是唯一使轨道混乱的因素
But gravity is not force The only ones to make orbits mess.
这是一颗"pino"小行星，2700年，它可能会撞到地球
This is a "pino" asteroid, and there is an opportunity In the year 2700 he hit the ground.
但是"pino"的轨道一直在变化
But the Pino orbit is constantly changing.
在过去的18年里，它走过了一百多英里
In the past 18 years, acute Its path is more than a hundred miles.
太阳可能就是罪魁祸首
And the sun may be the culprit.
什么可以改变小行星的轨道？
What can change the orbit of an asteroid?
人们很容易认为那些是巨大的岩石，其中一些因为引力而聚集在一起
It's easy to think that those are huge rocks Some of them are pulling together, attractively.
但这会是最大的影响吗？因为阳光这样的东西太微弱了？
But would it be the most powerful effect? Because of something as slight as sunlight?
它的影响可能很小
Its effect may be very slight.
但阳光的确对我们的身体施加了轻微的压力
But sunlight on our bodies exerts a slight pressure.
事实上，当你的一边比另一边更热时，你可能会移♥动♥
The fact that one of your sides is hotter From the other it is a batch that may move.
阳光由一束称为光子的少量能量组成
Sunlight consists of bundles A small amount of energy called photons.
当光子与小行星碰撞时，它们被传送了少量的驱动力和热量
When photons collide with the asteroid, they are transported A small amount of driving force and heat.
想象一下这种情况
Imagine this situation here.
这是我们的小行星
Here is our asteroid.
它可能真的只是一个10英里左右或类似大小的范围
It may really be a showcase Ten miles or miles or the like.
这是我们的小行星，这是太阳
Here is our asteroid, and here is the sun.
小行星以这种方式围绕太阳旋转
The asteroid revolves around the sun in this way.
小行星的这张脸被加热是由太阳的热量引起的
This face heats up from The asteroid is caused by heat from the sun.
这里的背面是因为寒冷的空间更凉爽
Here the back face is Because the cold space is cooler.
我真的用自己的双手感受到了
I really feel it with my own hands.
温暖的脸从太阳吸收光线，使它将热量分配到红外光谱段
The warm face that draws light from the sun restores it Distribute that heat in the infrared spectral segment.
所有这些辐射都来自红外线小行星的侧面就像火箭发动机一样
All of this radiation is from infrared The side of the asteroid somehow acts as a rocket motor.
他推着小行星
He pushes the asteroid.
这就是众所周知的雅科夫斯基影响
This is known as the Yarkovsky influence.
这是一个缓慢的过程
It is a slow process.
推动小行星的这个力量同样也在推动地面上的那些葡萄
The asteroid is propelled with equal force Weighed a few grapes on the ground.
但是当“Pino”绕着太阳转时，它的一面会被加热
But when Pino turns Around the sun, it heats one side.
是什么驱使它进入不同的轨道
What drives it to a different orbit.
雅科夫斯基的效应是个问题
Yarkovsky influence is a problem.
如果仅靠引力就能影响这些小行星我们就能知道所有小行星和行星的位置
If gravity alone affects those asteroids We would have expected the location of all asteroids and planets.
在未来的许多年里，我们知道了小行星的运行轨迹
We got to know the course of that Asteroids for many years to come.
但在雅科夫斯基效应的影响下，情况发生了变化，这使得预测变得困难
But this changes with the influence of Yarkovsky In a way that makes it difficult to predict.
这取决于小行星的某些不透明度的程度，即使知道它在旋转，它的形状是什么
It depends on the extent of the opacity The asteroid, even though it rotates and what its shape is.
这使得小行星的轨道在遥远的未来难以预测
It makes the orbit of the asteroid difficult Prediction in the distant future.
亚尔科夫斯基效应使得像“Pino”这样的小行星的运动预测更加困难
The Yarkovsky Effect makes movement predictions Asteroids like "Pino" are more difficult.
但我们星球的保护者很熟练
But the protectors of our planet are adept.
他们试图利用雅科夫斯基效应制♥造♥一种新的武器
And they try to use the Yarkovsky effect To create a new weapon in their arsenal.
知道了雅科夫斯基效应改变了小行星的轨道
Know that the effect of Yarkovsky It changes the orbits of asteroids a lot.
这是一种我们可以让小行星自己移♥动♥的效果
It is an effect that we can use To move the asteroid by ourselves.
如果我们能改变太阳温暖小行星的方式改变它的颜色或形状以特定的方式加热
If we could change the way the sun warms the asteroid Change its color or change its shape to heat in a specific way.
我们就可以用这种方法改变它的轨道
We can change its orbit in this way.
如果科学家能向小行星发射卫星
If scientists could send Satellite to the asteroid.
他可以使用黑色或白色涂料来增加或减少加热效果
He can use black paint or White to increase or decrease the heating effect.
在南加州大学
But at the University of Southern California.
一组科学家正在研究一种高科技的解决方案
A team of scientists is working on a high-tech solution.
他们想要摆脱雅科夫斯基的影响，使用一种叫做“D-Star”的太空激光
They want to outrun the influence of Yarkovsky Using a space laser called "D-Star.".
想象一下看到一颗小行星朝地球飞来
Imagine seeing an asteroid heading towards Earth.
我们可以用太空激光撞击小行星
We can use a space laser to hit the asteroid.
我们使表面物质汽化，使其变成迅速膨胀的气体
We vaporize the surface material that is Turn into a rapidly expanding gas.
这就像导弹一样所以我们可以用它把小行星推到更安全的轨道上
This works as a missile so we can use it To push the asteroid onto a safer path, too.
太空激光是哈马的另一个强大武器，我们的星球正在与小行星作战
Space lasers are another powerful weapon for Hama Our planet who are fighting asteroids.
结合了“引力火车头”
It joins the gravity locomotives.
运动学
Kinematics.
以及核武库中的核武器
And nuclear weapons in the arsenal.
但这里有一个大问题
But there is a big problem.
所有我们提到的防御小行星的方法在技术上是可行的