了解宇宙是如何运行的（2010）

How the Universe Works S09E07

Part 3 March 16, 2022, 8:55 a.m.

surface temperature
剧烈的变化
if it were about to explode.
那么，如果参宿四没有冷却很多
So, if
Betelgeuse wasn't cooling
是什么让它变暗了呢？
much, what was making it dim?
为了更近距离地观察，我们使用了一个非常大的望远镜
To take a closer look, we
used a very large telescope
和一个叫做 SPHERE 的系外行星搜寻设备
and an exoplanet
hunting instrument
并得到了一幅非凡的图像
called SPHERE and came up
with an extraordinary image.
当我第一次看到参宿四的这张照片时，我被震撼了
When I first saw this image
of Betelgeuse, it blew me away.
我几乎喘着粗气
I almost gasped.
我可能说了一句我不能在电视上说的话
I may have said a
word I can't say on TV.
这太令人兴奋了
That was very exciting.
这张照片显示，参宿四的上半部分
The image reveals
that, while the upper part
仍然很亮，但下半部分
of Betelgeuse was
still bright, the lower
明显变暗了
part was noticeably dimmer.
我们有以前拍摄过的参宿四的照片
We had images of
Betelgeuse from before,
我们能够将这些新照片与它进行比较
and we were able to compare
the new ones with it.
所以你可以看到参宿四的一半
And so you could see
that half of Betelgeuse
看起来和以前几乎是一样的
looked pretty much the same.
但另一半则明显变暗了
But the other half was
significantly dimmer.
是什么让一颗恒星这么快变暗？
And what could make a
star dim that quickly?
记住这颗恒星有多大
And remember how
big this star is.
参宿四上不会发生很快的事件
Nothing happens on
Betelgeuse quickly.
所以这一定是在表面上发生的事情
So this must be something
happening right on the surface.
当像硅这样较重的物质
As heavier
material like silicone
从参宿四表面出现时
emerges from the
surface of Betelgeuse,
它会冷却并凝结
it cools and condenses.
这就像把软管插错了
It's kind of like sticking
the hose in the wrong end
吸尘器的头
of your vacuum cleaner.
它不是把东西拉进来，[模仿爆♥炸♥]
Instead of pulling stuff
in, [imitates explosion]
它把所有的尘埃都吹到太空中
it blows all this
dust out into space.
参宿四患有宇宙消化不良
Betelgeuse
has cosmic indigestion
正在喷发尘埃，这使得这颗恒星看起来很暗
and is belching dust, which
makes the star seem dim.
但这还没有结束
But it's not over.
整个2020年，参宿四先是变亮
All through 2020,
Betelgeuse first brightened
然后又变暗
and then dimmed again.
所以天文学家们正在屏息注视着这颗巨大的恒星
So astronomers are watching this
massive star with bated breath.
它会爆♥炸♥
It's going to explode.
问题是，什么时候？
The question is, when?
可能是在未来十万年的某个时候
It's probably sometime
in the next 100,000 years.
但也可能是明天
But it could be tomorrow.
它可能已经爆♥炸♥了，我们就等着
It could have already
exploded and we're
看到闪光吧
just waiting to see the light.
如果幸运的话，参宿四的爆♥炸♥会让我们
With luck, if
Betelgeuse blows, all we'll see
看到一场美丽的光影秀
is a beautiful light show.
在550光年的距离
At a distance of
550 light years,
它可能太远了，不会造成严重的破坏
it's probably too far
to do serious damage.
但是还有其他恒星值得我们担心吗？
But is there another star
we should worry about?
一颗近一点的恒星，距离地球只有150光年
A closer star, just 150
light years from Earth,
可能会对我们造成重大伤害，这颗恒星就是飞马座 IK
could do us some major
damage, a star like IK Pegasi.
但威胁并不是我们在夜空中
But it isn't this star which
we can see in our night
看到的这颗恒星
sky that's the threat.
主恒星的质量只有太阳的1.6倍
The main star is only about
1.6 times the mass of the sun.
这还远远不够形成超新星
That's nowhere near enough
mass to go supernova.
然而，我们认为它是超新星的前身
And yet, we think it is the
progenitor for a supernova.
这怎么可能呢？
How can that be?
主角并不是只有一个
The main
star isn't alone.
它有一个更危险的同伙
It has a more
dangerous accomplice.
还有另一颗恒星围绕着这个大的恒星运行
There's another star there
orbiting the larger star.
菲尔·普莱特:这就是我们所说的双星系统——
PHIL PLAIT: And this is what
we call a binary system--
两颗恒星围绕彼此运行
Two stars orbiting each other.
现在，系统是稳定的
Right now, the system is stable.
但事情不会总是像现在这样
But things aren't always going
to be the way they are now,
在未来的某个时候
and sometime in
the future, things
事情会发生很大的变化
are going to change a lot.
飞马座 IK 实际上是由
IK Pegasi
is really made up
飞马座A(一颗巨大的白色恒星)和它的同伴——
of IK Pegasi A, a large white
star, and its accomplice,
一颗被称为飞马座B的白矮星组成的
a white dwarf called IK
Pegasi B. This tiny star
这颗小的才是对地球的真正威胁
is the real threat to Earth.
你可以把白矮星想象成僵尸
You can think of a
white dwarf as a zombie.
你知道，这是一颗死星，但它们可以吃活星
You know, it's a dead star,
and they can eat living stars.
如果白矮星附近有一颗像太阳一样的正常恒星
If there's a normal star like
the sun near a white dwarf,
白矮星就会有非常非常强的引力
the white dwarf has very,
very intense gravity.
它可以把物质从正常的恒星上拉下来
It can literally pull
material off that normal star,
然后这些物质会堆积在
and that material will
then pile up on the surface
白矮星的表面
of the white dwarf.
所以它真的是在吃一颗活着的恒星
So it really is
eating a living star.
这些恒星之间的轨道距离
These stars
orbit each other just
只有1850万英里
18.5 million miles apart.
这比水星和太阳的距离还要近
That's closer than
Mercury is to our sun.
但它们还没有相互作用
But they're not interacting
with each other, yet.
问题是，在未来的某个时候
The problem is,
sometime in the future,
普通的恒星会耗尽燃料
that normal star is
going to run out of fuel.
到那时，它会膨胀成一颗红巨星
And when it does, it's going
to expand into a red giant.
当飞马座A生命结束时
When it gets
to the end of its life,
它会冷却并膨胀成一颗红巨星
IK Pegasi A will cool and
swell up to become a red giant.
就这样，没有大爆♥炸♥
And that's it, no big explosion.
它不会变成超新星
It won't become a supernova.
但它只是帮凶，飞马座B
But that's just when it's
accomplice, IK Pegasi B,
开始进食
will start to feed.
大量的物质会被白矮星的引力吸引
A lot of that material
will gravitationally
并落在其表面之下
be attracted to the white dwarf
and fall under the surface.
随着白矮星从它膨胀的
As the white
dwarf pulls material
红巨星邻居那里吸收物质
from its bloated
red giant neighbor,
它的质量越来越大
it gets more and more massive.
它的引力增大
It's gravitational
pull increases,
所以它进食的速度更快
so it feeds even faster.
最终，它无法支撑自己的重量
Eventually, it can no longer