了解宇宙是如何运行的（2010）

How the Universe Works S08E01

Part 13 Jan. 30, 2022, 2:57 p.m.

这个东西肯定来自灶神星，我们已经证明了
This thing is definitely
from vesta, and we proved it.
那么灶神星碎片是如何来到地球的呢？
Narrator: So how did bits of
vesta end up here on earth?
大约在2200万年前，一些非常大的撞击物
22 million years ago,
some very large impactor
撞击了灶神星，形成了一个巨大的陨石坑
struck vesta,
made a huge crater,
陨石坑中的一些岩石
and some of the rocks
from that crater actually
脱离了灶神星的引力被送入太空
escaped from vesta's gravity
and were lofted into space.
一些来自灶神星的岩石
Narrator: Some of these rocks
from vesta went into orbits
进入了与地球相交的轨道
that intersected with earth.
2200万年后，萨里切克上空发生了爆♥炸♥
22 million years later,
one blew up over saricicek.
这颗萨里切克流星表明小行星带
This saricicek meteor shows
that the asteroid belt
是一个不稳定的环境
is an unstable environment.
小行星经常撞击其他小行星
Asteroids frequently strike
other asteroids.
兰扎:事实上，这种情况一直在发生
Lanza: That's actually
happening all the time.
在我们的太阳系里
Things are running
into each other
天体正在相互碰撞
in our solar system right now.
这让我们很难追踪所有这些物体
And so that makes it
really hard for us
因为我们不知道
to track all of those objects
because we don't actually know
它们相互碰撞后会发生什么
what happens after they collide
with each other.
现在情况完全不同了
Now things are
totally different.
这就改变了整个系统
And that changes
the whole system.
每次碰撞都会产生更多的小行星
Narrator: Each collision
makes more asteroids.
奥卢塞伊:小行星碰撞会发生什么
Oluseyi: There's many
different possibilities
有很多不同的可能性
of what could happen
when asteroids collide.
想象一下轮滑比赛的场景
Imagine a roller derby
situation.
如果你有两组玩家
If you have two
groups of players
相互碰撞
that run into each other,
这可能就像两颗小行星♥相♥互碰撞
that could be like two asteroids
running into each other.
一个可能的结果是
And one possible outcome
is that one stays intact
一个完好无损，而另一个则完全破碎
while the other
is completely blown apart.
这使得碎片在主小行星带中飞行
That sends fragments flying all
through the main asteroid belt,
然后有一小块小行星碎片
and then there's
a little asteroid fragments
在它们自己独♥立♥的轨道上围绕太阳运行
are on their own independent
orbits around the sun.
小行星撞击的一个问题是
A problem with
asteroid impacts is that
总是在制♥造♥新的小行星
we're always making
new asteroids.
外面有很大的小行星
There are big asteroids
out there,
它们会被其他小行星撞击
and they get hit
by other asteroids,
然后就会有碎片
and then you get shrapnel.
现在已经不是一个大的和一个小的
And now you've got not one
big one and one smaller one,
而是有一个大的，一个小的
you've got one big one,
one smaller one,
和数百万个小的
and millions of little ones.
现在，大多数都不是很大，但有些
Now, most of these aren't very
big, but some of them might be
可能更大，可能有潜在的危险
bigger and could be
potentially hazardous.
随着太阳系的老化
Narrator:
As the solar system ages,
小行星的数量也会增加
the number of
asteroids increases.
每一块新的太空岩石
Each new space rock
travels on a new course
都有可能在新的轨道上与地球相交
which could intersect
with earth.
所以我们会不断地和
So we're constantly producing
new asteroids
在主小行星带中产生新的小的和大的小行星进行碰撞
and big collisions
in the main asteroid belt.
这些小行星最终
And these are producing
the small asteroids
会向太阳系内部漂移
that will eventually drift
inward in the solar system.
追踪这些不断进化的小行星
Narrator: Tracking this
constantly evolving population
让科学家们非常头疼
of asteroids gives scientists
a huge headache.
如果它们分开了，就会有
If they break apart,
then that gives you
更多的小行星碎片需要追踪
even more pieces
of the asteroid to track.
追踪和预测小行星的轨道
It's not a simple thing
to track and predict
和它们的运动并不是一件简单的事情
the orbits of asteroids
and their movements,
因为一个微小的变化
because one tiny little change
可能会对其未来产生巨大的戏剧性影响
can have huge dramatic impacts
for its possible future.
布洛克:弄清楚他们要去哪里
Bullock: Figuring out exactly
where they're going to go
并记录他们彼此之间的互动
and keeping track of how
they interact with each other,
这是一个巨大的挑战
this is a huge endeavor.
小行星的巨大体积
Narrator: The sheer volume
of asteroids can affect
会影响其他小行星
the behavior of other asteroids
在引力作用下的行为
as they gravitationally
interact.
想象一下轮滑选手在打转
Think about your roller derby
player skating in circles.
当更多的人走上这条轨道
The path they're going
to follow would evolve
他们就会开始
the more people you plop down
on the track
与他人互动
they start interacting
with each other,
他们的轨迹就会改变
and their trajectory
will change.
太阳系越拥挤
The more crowded you make
the solar system,
改变小行星轨道的东西
the more things are
to change your orbit
就越多
of your individual asteroid.
它不像空中交通管制
It's not like
air traffic control,
那里有已知数量的飞机
where there's a known
amount of airplanes
它们都按照一个计划飞行
and they all follow a plan.
这种情况更加复杂，因为小行星轨道
Narrator: This situation is
further complicated because
可能会受到其他更微妙的力量的影响
asteroid orbits can be affected
by other more subtle forces.
其中一种被称为雅科夫斯基效应或约普效应
One of these is called the
yarkovsky or the yorp effect.
老实说，约普效应说起来更有趣
Honestly yorp
is more fun to say.
约普效应是由阳光
Narrator: The yorp effect is
caused by sunlight
击中小行星引起的
hitting an asteroid.
光是由正在传播的光子组成的
Light is made up of photons
that are traveling,
这些光子实际上有动量
and these photons
actually have momentum.
所以当光线照射到某物上时
So when light shines
on something,
它实际上是在推动它
it actually pushes on it.
当阳光照射到小行星时
Narrator: When sunlight
hits an asteroid,
光子会给它一个微小的推力……
the photons give it
a tiny push...
……足以改变太空岩石的轨迹
...Enough to change
the space rock's trajectory.
♪
当我们知道有一颗小行星正朝我们飞来
when we know an asteroid
is really heading our way,
是时候反击了
it's time to fight back.
有一颗小行星正朝我们飞来
So we've got an asteroid
that's headed at us.