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黑洞图片的意义是什么? – 译学馆
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黑洞图片的意义是什么?

Why this black hole photo is such a big deal

2017年4月4日
On April 4th, 2017,
高山上一组观测行星的
a privileged group of telescopes on mountains across the
特制望远镜同时开启
planet switched on at the same time.
因为它们下周会联合操作
For the next week they danced in unison,
接收银河系中心
collecting radio waves dispatched from the center
和m87星系发出的无线电波
of our Milky Way galaxy and from the galaxy m87.
这些望远镜组合成视界望远镜
Together they makeup the event horizon telescope,
这是一项全球性项目 用来拍摄史上第一张黑洞照片
a global project to capture the first everpicture of a black hole.
不错
That’s right.
几个世纪前 自物理学家们首次假想黑洞以来
Ever since physicists first conceived of black holes centuries ago,
教课书上和航天局发布的都是黑洞假想图
every image of one from our textbooks and our space agencies, they’re all illustrations.
直到现在
Until now.
很高兴 今天要
We are delighted to be able
向大家宣布 我们已经能看到
to report to you today that we have seen
曾经以为看不到的东西
what we thought was unseeable.
几个世纪来 物理学家通过理论推测出
For centuries, physicists have theorized that
如果一个物体的体积和密度足够大
an object with enough mass and
它的引力就会大到连光都无法逃离
density could trap even light in its gravitational field,
正如宇航员离开地球比离开月球
just as you have to travel faster to leave Earth
需要更快的速度一样
than you do to leave the Moon.
可能存在这样一个地方
There could be a place where you’d have to travel faster than
你必须跑得比光快才能逃离
the speed of light to escape.
然而 没什么东西跑得比光快
And nothing moves faster than light.
根据爱因斯坦的
The math from Einstein’s theory
广义相对论 用计算的方式得出了肉眼看不到的区域
of general relativity describes an area completely invisible to us.
里面的边界被称为视界
Within a boundary called the”event horizon”
黑洞的中心是奇点 奇点的密度无限大
and at the center of that black hole is a singularity,a point of infinite density,
以往的物理学定律已不能用来解释奇点
which is where physics as we know it breaks down.
很久以前 奇点在数学中就已很常见
They showed up in the math long ago and they kept reappearing
一直都会出现在数学中
and they sort of persistently would not go away.
但爱因斯坦认为
But Einstein always thought that
一定存在某种物理原理
there must be some physical mechanism that
能阻止恒星坍塌成无穷小的点
prevents stars from collapsing to an infinitely small point,
爱因斯坦的猜想并不是完全没道理
which is actually pretty reasonable.
这听起来很不可思议
I mean, because it sounds insane.
如果黑洞真的存在
Eventually scientists began to
科学家们才能合理解释某些事物
see things that only made sense if black holes were real,
如恒星围绕银河系中心旋转
like the orbits of these stars around the centre of the Milky Way galaxy.
可以看到这些恒星围绕在
You see these stars just slingshotting
一个看不见的地方
around an invisible point
最有可能的解释就是
and a black hole is the most likely explanation
只有黑洞才能将大量的物质吸进
for putting that amount of mass in that
极小的空间里 因此里面一片漆黑
small space, for something that’scompletely dark.
我们能看到发光的物质围绕黑洞呈螺旋状旋转
We can also see the glowing materialthat spirals around black holes.
转动产生的摩擦力让这些物质的温度
Friction heats this matter up tens of millions
达到千万度 高温物质会发出
of degrees and anything that hot emits
X射线 能被地球上空运转的望远镜检测到
X-rays that we can detect with telescopes that orbit above Earth’s atmosphere.
这是一对在同一轨道上运行的恒星
This is a pair of galaxiesthat pass through each other.
据猜测 这里至少有九个黑洞
There are at least nine suspected black holes here,
但只有监测到X射线时
but you can only see them when you look
才能发现这些黑洞
at the X-ray layer.
这些光点就是X射线的光源
These dots are X-raysources linked to suspected supermassive
这些光源是3-10亿光年外银河系中心的猜想黑洞发出的
black holes at the center of galaxies three to ten billion light-years away.
这也是宇宙的冰山一角而已
And that’s just from this small patch ofsky.
一些超级大黑洞还会
Some super massive black holes also
喷射出大量的物质
feature gigantic jets of particles,
从m87星系发出的无线电波数据中可看出来
seen here in radio wave data from the galaxy m87,
那里有一个黑洞
which has a much bigger black hole
比银河系中的还要大
than the one in the center of the Milky Way.
没有哪种已知能量
No other known source of energy
能发出这种电波
could power these things
除了两大黑洞相撞外 没有其他物质能
and nothing we know of besides two black holes colliding
产生2015年监测到的那种引力波
could have produced the gravitational waves we detected in 2015.
科学家认为整个宇宙
Scientists think there are black holes
有无数个大大小小的黑洞
large and small all over the universe.
但只能看到黑洞一圈圈的环形边缘
We can see their fingerprints but we didn’t
无法一窥真容
have the mug shot.
要直接拍摄洞黑洞 简直就是天方夜谭
Directly imaging ablack hole has been impossible
因为它们要么太小 要么太远 或既小又远
because they’re either too small, too far away, or both.
黑洞人马A*
Sagittarius A*, the black hole
位于银河系中心 有400百万个太阳那么大
at the center of our galaxy has the mass of four million Suns.
但却和水星运行的轨道一样大
But it would fit inside the orbit of Mercury.
从地球拍摄人马A* 就像是从地球拍摄
Imaging it from Earth is like taking a picture of a
月球表面上的一张小光碟一样
DVD on the surface of the Moon,
中间还隔着大量的云层 尘埃和气体
with huge clouds of dust and gas in between.
所以要有天时地利人和的条件才能拍到照片
So many things had to go right for this image to exist,
首先要刚好有光线从
so the first thing that has to happen is there has to be some slice
从黑洞周围散发出来
of light that travels all the way from the edge of the black hole
光线不在传播的过程中中断
without getting knocked off course or absorbed
不被途中的气体等物质削弱
by any of the gas or anything in between,
其次还要穿透地球大气层
and then it also has to make it through
许多频率的光都没能穿透地球大气层
the Earth’s atmosphere which a lot offrequencies of light don’t.
许多到达地球的光线波长都是1.3毫米
They landed on a wavelength of 1.3 millimeters
是电磁波普高频端中频率最低的光线
at the high frequency end of the radio spectrum.
有了能穿透大气层的波长和
With that wavelength and
全世界的八个观测台
with eight observatories across the world, the
在有利的天气条件下
event horizon telescope had a chance at seeing a black hole,
视界望远镜就能观测到黑洞
as long as the weather cooperated.
地球转动到这个位置时
You have to have clear weather in all of those places at a time
八个观测台位于的地点必须同时是晴天
when the Earth is oriented in such a way that all of
所有的望远镜同时进行观测 才能监测到黑洞
those telescopes can see the black hole simultaneously.
每年只能进行一次观测
They can really only observe once a year.
得到的观测数据非常庞大
There was so much data involved
需要飞机在各个站点收集数据
that it had to be flown on airplanes.
因冬季南极站点关闭 要经过六个月的漫长等待
They waited six months for the hard drives to arrive from the South Pole,
才能得到从南极送来的数据
which closes during winter time.
这种用多台望远镜的方法叫“甚长基线干涉测量法”
This multi-telescope method is calledvery long baseline interferometry.
能将千里之外的望远镜的时间戳
it correlates timestamped data from
联合起来 加强信号 消除噪音
distant telescopes to boost the signaland quiet the noise.
每组望远镜只提供了黑洞合成图的部分数据
Each pairing of telescopes contributes a piece of the puzzle,
但数据收集完后 还不能立刻得到黑洞图
but the image doesn’t just pop out after that.
四组望远镜要运行数月来合成
They had four groupsworking for months to generate the image
这张能更好阐述数据的黑洞图
that best represents the data.
每组望远镜单独冲洗黑洞图
Each group was working individually and like in
但每组望远镜的数据都是一样的
isolation from the other groups, working with the same data,
以便观察每组望远镜合成的黑洞图是否一致
to see that each group came up with the same image or not.
最后得出的黑洞图是这样的
And the result of all that work is this.
发光的部分是光和其他物质
The bright parts are the matter
在围绕着黑洞旋转
and lights swirling around the black hole
地球接收到的光线就是更亮的那部分发出的
and it’s brighter on the side that’smoving toward us.
暗的那部分就是
And the dark part is
黑洞的藏身之处
the black hole’s shadow,
其中包括视界和
which includes the event horizon plus a region where
连光都无法逃脱的区域
light could escape, but doesn’t.
黑洞图的大小和形状
The size and shape of the shadow appear to
印证了广义相对论
confirm the theory of general relativity ,
如今 广义相对论通过了另一项重要的验证
Today, general relativity has passed another crucial test,
验证的范围从视界到宇宙恒星
this one spanning from horizons to the stars.
人类拍出的第一张
Humanity’s first image
黑洞图虽然不像书本中的插图或
of a black hole isn’t crisp and beautiful like the illustrations or
《星际穿越》中的那么精美漂亮 但更像是黑洞
the movie Interstellar. It’s better.
我们这周看到的黑洞图
The picture we see this week is made of
是由望远镜接收穿越宇宙的零散光线
scraps and bits of light that’s been traveling
拼凑而成的
across the universe and collected by these.
如你所见 高山上的铝制望远镜接收这些光
You know, aluminum dishes on top of mountaintops and then
然后由超级计算机合成黑洞图
combined in a supercomputer to make this image.
所以黑洞图是真的
So that’s why it’s real.

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视频概述

人类第一张黑洞图印证了爱因斯坦相对论的正确推论

听录译者

收集自网络

翻译译者

Nacy廖

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审核员 AF

视频来源

https://www.youtube.com/watch?v=pAoEHR4aW8I

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