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宇宙大爆炸的画面(最古老的光) – 译学馆
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宇宙大爆炸的画面(最古老的光)

Picture of the Big Bang (a.k.a. Oldest Light in the Universe)

当你从任何一个位置抬头看夜空
If you look up at the night sky in any direction
穿过所有的恒星 星系以及超级星团
past all the stars and more stars and galaxies and superclusters of galaxies
你会看到那走了137亿年后到达地球的光
you will see light that has been traveling for 13.7 billion years to reach earth.
这是宇宙中最古老原始的光
It’s the oldest and most primeval light in the universe
描绘了我们宇宙年轻时的样子
a picture of our cosmos in its hot younger years
它被称为“宇宙背景辐射”
and it’s called the “Cosmic Background Radiation”.
当然你不可能用你的肉眼看到这道光
Of course you can’t really see this light with your naked eyes
因为它属于电磁波谱里的微波波段
because it’s in the microwave band of the electromagnetic spectrum.
但是收音机和无线电望远镜能接收到它
But it is visible to radios and radio telescopes
它甚至是模拟电视的“雪花点”中的一部分
and even makes up a small portion of the ‘salt and pepper’ on an analog TV.
那么宇宙中这个发着光的背景从何而来呢?
Where does this luminescent background come from?
在宇宙大爆炸初期 宇宙还很小
Well, just after the big bang, the entire universe was still so small.
宇宙的密度很大并且十分炎热
It would have been very dense, scorchingly hot
因为还没来得及变得粗糙 不均匀
and, because it hadn’t yet had time to get rough and uneven
宇宙还十分的光滑
it would also have been scrumptiously smooth.
在那个时候 由于温度很高
For a while, things would have been so sweltering
电子没有稳定下来成为原子或分子的一部分
that electrons didn’t settle down as parts of atoms or molecules
而是在像热汤一样的宇宙中自由地游荡
but instead roamed freely in a kind of red-hot cosmic soup.
宇宙“汤”中也到处闪着光
That soup would have had lots of light bouncing around it, too
散射着质子和电子 像一个满是镜子的礼堂
scattering off of electrons and protons, like a hall of mirrors.
然而 随着宇宙的膨胀
However, as the universe expanded
每个点具有的能量都越来越少
there was less and less energy to be had in any one place.
当物质冷却至低于太阳的温度时
And when things had cooled to just below the temperature of the sun
成对的电子和质子再也没有能量相互排斥
pairs of electrons and protons no longer had the energy to resist each other
他们组合在一起 形成了氢原子
and they fell into the electromagnetic embrace-we call the hydrogen atom.
这些电子太过迷恋自己的新伴侣质子
These electrons were so enamored by their new proton love interests
以至于开始忽略周围闪动的光
that they effectively began to ignore all the light bouncing around them.
越来越少的电子和光发生反应
So, with fewer free electrons for light to interact with
宇宙突然变得透明 而所有被阻挡的光
the universe suddenly became transparent and all the pent-up light
都向着它最后一次散射的方向前进
was sent forth in whatever direction it had been headed after its last scattering
它们注定要默默前行 穿过宇宙
doomed to travel alone and unnoticed through the cosmos.
直到撞上固体
That is, until it bumps into something solid
当我们最终在地球上见到它时
When we finally see it here on earth
它已被130亿年的空间延伸拉长了太多
this light has been stretched so much by the thirteen-billion-year expansion of space
就如慢下来的录音 它的频率和颜色
that, like a record slowing down, its frequency and color
从最初的白光变成了冷调的微波
have shifted from the original sunlight white all the way to cool microwaves
因此 它通常被叫做“宇宙背景辐射”
Thus, it’s often called the ‘cosmic microwave background radiation’, or CMB.
正如我们能从铁的发热状态
And just as we can tell the temperature of
红色或白炽色 推测出它的温度
a red or white-hot iron from its glow
这束光告诉我们真空的温度
this light tells us the temperature of empty space:
目前大约是2.725开尔文 -270摄氏度
currently around 2.725 Kelvin, or minus 270 degrees Celsius.
然而 不是宇宙中每个地方的温度都是2.725K
However, the universe isn’t exactly 2.725 Kelvin in every direction.
仔细观察 会看到一些微小但明显的凸起物
If we look closely, there are small and seemingly random but noticeable bumps
似乎是随机分布的 有点像开始凝固的牛奶
all over the place, kind of like milk that’s starting to curdle.
最佳解释是:这些宇宙“凝乳”形成了量子波动
Our best understanding is that these cosmic curds formed as quantum fluctuations
另一方面 初期宇宙是乳脂状
in the otherwise creamy infant universe
然后随着不断冷却和膨胀 宇宙也开始凝结
and then began to coagulate as the universe cooled and expanded.
很难说开始时温度的波动有多小
It’s hard to overstate just how small, or un-bumpy
或者各处的密度有多均匀
these fluctuations of temperature and density were to begin with.
因为那些较热(冷)的地方只比它周围
The hot or cold spots were only hotter or colder than their surroundings
热(冷)大约1/100,000
by a factor of about one in a hundred thousand
-就如同注意到细菌让一个沙滩球变得更大一样
-that’s like noticing that a bacteria makes a beach ball bigger.
但是 由于这些小块最初导致了
But, while this clumping of the universe initially resulted in
些许的不同 就像我们在CMB上看到的
small variations like the ones we see in the CMB
随后 在原始的宇宙中 这些物块由于引力相互吸引
later on, the chunky curds of primordial soup attracted each other gravitationally
最终凝结成我们现在
and they ultimately coagulated and coalesced
在太空中看到的那些巨大结构的物体
to form all of the massive structures in the universethat we see today
如行星 恒星 星系以及超级星团
like planets, stars, galaxies, and superclusters of galaxies.
所以当我们仰望星空 穿过星系
So when we look up at the night sky past those galaxies
看到那宇宙背景辐射下的古老的光时
and see the ancient light of the cosmic microwave background radiation
我们确实看到了宇宙起点 也就是最初的“奶油”
we’re literally seeing the starting point, the proverbial cream, if you will
从那以后 遍布乳脂的宇宙开始凝结
from which the starry curds of the universe congealed.
简单地说 就是月亮的确由奶酪做成的证据
Or quite simply, proof that the moon really is made of cheese.
为了让你更完整地体验 宇宙背景辐射有多精彩
To give you a more complete experience of how awesome the cosmic background radiation is
我们制作了一个冒险地图来展示它
we’ve made an adventure map showing it
看起来就像是你幻想世界中那个不存在的地方一样
as if it were the out-of-this-world geography of your favorite fantasy series
只不过它真的是我们宇宙婴儿时期拍的第一张照片
– except it’s really the first picture taken of our universe as a baby
地图包括了星系和星座的图片
We’ve included pictures of constellations and galaxies with the map
加上一个通过红外线看到的天空的的样子
plus an overlay of what the sky looks like in infrared
如果你想要体验坐拥江山的感觉 你可以试着给地图上的高山和海洋命名
And if you’re feeling imperial, you can help name the oceans and mountains on our map.
去bigbangregistry.com开始探索吧!
Head over to bigbangregistry.com to start exploring!

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遇见最原始的光 了解宇宙形成初期的故事

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