了解宇宙是如何运行的（2010）

How the Universe Works S08E08

Part 7 Jan. 30, 2022, 2:59 p.m.

钛44是一种高放射性元素
Titanium-44 is a highly
radioactive element.
这意味着它想要衰变成
That means that
it wants to decay
其他类型的原子核
into other types of nuclei.
当钛44衰变时
Narrator:
When titanium-44 decays,
会释放反物质
it gives off antimatter.
但要产生在星系核心看到的反物质
But to produce the antimatter
seen in the galaxy's core,
就需要大量的钛-44
you would need
a lot of titanium-44.
它可以在罕见的高能事件中产生
It could be created
in rare energetic events,
在两颗死亡恒星——白矮星的碰撞中产生
in the collision of two dead
stars -- white dwarfs.
白矮星是一颗在死亡后质量不足以
A white dwarf star is a star
that didn't have enough mass
成为超新星的恒星
when it died
to actually become a supernova.
它就像一堆死渣一样冷却了
It just sort of cools off
as a dead little cinder.
但如果有两颗白矮星
But what if you have
two white dwarfs
互相围绕彼此旋转
that are orbiting
around each other,
随着它们越来越近并发生碰撞时
and as they come closer
and closer and collide,
突然之间，就有足够的质量
all of a sudden now,
you have enough mass
来引发超新星爆♥炸♥了
to actually kick
a supernova explosion off.
♪
这些特殊类型的超新星
these particular kinds
of supernovae
非常善于产生钛-44
are very good
at producing titanium-44.
所以这类超新星
So these kinds of supernovas
are very, very good
非常擅长制♥造♥♥反♥物质
at making antimatter.
这些超新星每2000年
Narrator: These supernovas
erupt in the core of the galaxy
在星系中心喷发一次
once every 2,000 years.
但在星系核心的外♥围♥
But outside of the core
in the disk of the galaxy
也就是太阳系运行的地方……
where our solar system orbits...
……这些超新星发生的频率是以前的三倍
...These supernovas happen
three times as often.
所以伽马射线观测是错误的
So the gamma ray observations
were wrong.
在银河系中心已经没有更多的反物质了
There isn't more antimatter
in the heart of the galaxy.
反而是我们太阳系所处的区域
It's our region of the galaxy
含有的反物质是银河中最多的
that contains
the most antimatter.
问题是，我们有危险吗？
Question is, are we in danger?
普莱特:如果你将一盎司的物质
Plait:
If you take an ounce of matter
和一盎司的反物质碰撞
and an ounce of antimatter
and collide them,
就会产生一百万吨♥的能量
<之所以会爆发这么强大的能量，是因为当正反物质>
<接触时，所有的物质全部转化为了能量，这个能量>
<比核聚变产生得更多，而后者只损失了小部分物质>
you're generating
a megaton of energy,
相当于一百万吨♥tnt爆♥炸♥的能量
<之所以会爆发这么强大的能量，是因为当正反物质>
<接触时，所有的物质全部转化为了能量，这个能量>
<比核聚变产生得更多，而后者只损失了小部分物质>
the equivalent of a million tons of tnt exploding.
所以你不需要太多的反物质
<之所以会爆发这么强大的能量，是因为当正反物质>
<接触时，所有的物质全部转化为了能量，这个能量>
<比核聚变产生得更多，而后者只损失了小部分物质>
So you don't need much antimatter to generate
就能产生大量的能量
<之所以会爆发这么强大的能量，是因为当正反物质>
<接触时，所有的物质全部转化为了能量，这个能量>
<比核聚变产生得更多，而后者只损失了小部分物质>
a vast amount of energy.
但你必须记住的是我们生活在
But the thing you have
to remember is we live
一个更大的宇宙中的这个奇妙而充满戏剧性的
in this wonderful,
dramatic environment
环境中
of a larger universe.
它没有危险
It's not dangerous.
它离我们很远，而且很迷人
It's very far away from us,
and it's fascinating.
但所有这些反物质都是在我们的星系中产生的
But all of this antimatter
is being produced in our galaxy,
所以坐下来享受烟花吧
so just sit back
and enjoy the fireworks.
银河系的中心是
Narrator: The center
of the milky way
暴♥力♥和极端的
is violent and extreme,
但事情可能会变得更糟
but things could get
a whole lot worse.
流氓超大质量黑洞
Rogue supermassive black holes
可能潜伏在我们的星系附近
could be
lurking near our galaxy,
它们有我们所知道的终结生命的能力
and they have the power
to end life as we know it.
♪
银河系大约有10万光年宽
narrator:
The milky way is around
100,000 light-years across,
是至少2000亿颗恒星的家园
and it's home to at least
200 billion stars,
但它并不总是这么大
but it hasn't
always been this large.
我们知道我们的银河系是通过吞噬其他星系
We know that our milky way
galaxy grew to the size
才发展到现在这么大的规模
it is now, which is huge,
by eating other galaxies.
其中一些星系的中心
And some of these galaxies
would've had
会有超大质量的黑洞
supermassive black holes
in their centers.
当银河系的引力
Narrator:
When the milky way's gravity
吸引较小的星系时
pulled in smaller galaxies,
它们的大部分物质与银河系合并
most of their material
merged with the milky way,
但有一些物质，如恒星
but some material like stars,
可能会被抛到银河系
could've been slung tens
of thousands of light-years
数万光年之外
out of the milky way.
这可能发生在一个较小星系的
This could've happened
to a smaller galaxy's
超大质量黑洞上
super massive black hole.
普莱特:完全有可能
Plait: It is entirely possible
存在超大质量黑洞
there are supermassive
black holes
但不是在中心
wandering around out there,
not in the center.
塞勒:那么，为什么会有一个
Thaller: So how could it be
possible that there's actually
超大质量的黑洞在我们附近徘徊
a supermassive black hole
close to us wandering around,
但我们从来没有看到过它呢？
but we never even see it?
好吧，再次强调，黑洞意味着它非常非常黑
Well, remember black hole
means it's really, really black.
它实际上吸收辐射和任何能量
It actually absorbs radiation
and any energy.
所以除非有东西落入黑洞
So unless something is falling
into a black hole
或绕黑洞运行，否则你是看不到的
or orbiting around it,
you're not going to see it.
特伦布雷:所以，如果假设这个超大质量黑洞
Tremblay: And so, if this
supermassive black hole
在我们星系的外♥围♥游荡
were hypothetically wandering
the outskirts of our galaxy,
那么，那里可供黑洞
well, there's a lot less
gas there
吞噬的气体就会少得可怜
for that black hole to run into.
如果黑洞周围
And if there's no gas around
没有气体，我们就看不到它
that black hole,
we will not see it.
这个凶猛的超大质量黑洞可能
Narrator: The rogue supermassive
black hole may not stay
不会永远呆在银河系的外♥围♥
in the outskirts
of the galaxy forever.
引力的作用慢慢地把它
Gravitational interactions
slowly pull it back
拉回银河系
into the milky way.
数十亿年后
Billions of years later,
这个超大质量黑洞可能会到达中心
the supermassive black hole
could arrive in the center.
当这个巨大的超大质量黑洞
When this rogue supermassive
black hole meets up with
与人马座a星♥相♥遇时，引线就被点燃了
sagittarius a-star,
the fuse is lit.
这一对螺旋形地向对方靠近……
The pair spiral