Name: 黑洞（What is a Black Hole? -- Black Holes Explained）
Uploaded: 2021-04-11T06:49:01.000Z
Duration: 10 min 57 s

From far away, stars are tiny points of light. But up close, stars are massive, seething,

從遠處看，恆星是微弱的光點。 但近距離，恆星是巨大的，沸騰的，

情態副詞

fiery balls of burning gas. This fierce display does not last forever. Eventually, the nuclear

燃燒氣體的火熱球。這種激烈的展示 不會永遠持續下去。最終，核

fusion which powers the star will burn all its fuel. Gravity then collapses the remaining

為星星供電的融合將燃燒所有 它的燃料。重力然後折疊剩餘的

matter together. For very large stars, what happens next is a display of extremes. First,

在一起。對於非常大的星星，什麼 接下來發生的是極端的顯示。第一，

the star explodes in a supernova, scattering much of its matter throughout the universe.

這顆恆星在超新星中爆炸，散射 整個宇宙中的大部分問題。

For a brief moment, the dying star outshines its entire galaxy. But once the light fades

短暫的一瞬間，這位瀕臨死亡的明星將會熠熠生輝 它的整個星系。但是一旦光線消失

and darkness returns, the remaining matter forms an object so dense that anything that

和黑暗回歸，剩下的事情 形成一個如此密集的物體

gets too close will completely disappear from view. THIS is a black hole…

太靠近會完全消失 視圖。這是一個黑洞......

The idea of a black hole originated hundreds of years ago. In 1687, Isaac Newton published

黑洞的想法起源於數百人 多年前1687年，艾薩克·牛頓出版

his landmark work known as The Principia. Here he detailed his laws of motion and the

他的標誌性作品稱為The Principia。 在這裡，他詳細闡述了他的運動定律和

universal law of gravitation. Using a thought experiment involving a cannon placed on a

普遍萬有引力定律。用一個想法 實驗涉及放置在大砲上的大砲

very tall mountain, Newton derived the notion of escape velocity. This is the launch speed

非常高的山，牛頓得出了這個概念 逃逸速度這是發射速度

required to break free from the pull of gravity. In 1783, the English clergyman John Michell

需要擺脫重力的拉力。 1783年，英國牧師約翰·米歇爾

found that a star 500 times larger than our sun would have an escape velocity greater

發現一顆恆星比我們大500倍 太陽的逃逸速度會更大

than the speed of light. He called these giant objects “dark stars” because they could

比光的速度。他稱這些巨人 對象“黑暗的星星”，因為他們可以

not emit starlight. This idea lay dormant for more than a century.

不發出星光。這個想法處於休眠狀態 一個多世紀以來。

Then, in the early 20th century, Albert Einstein developed two theories of relativity that

然後，在20世紀初，阿爾伯特愛因斯坦 發展了兩種相對論

changed our view of space and time: the special theory and the general theory. The special

改變了我們對空間和時間的看法：特殊的 理論和一般理論。特別的

theory is famous for the equation E=mc2. The general theory painted a new and different

理論以等式E = mc2而聞名。該 一般理論描繪了一個新的和不同的

picture of gravity. According to the general theory of relativity, matter and energy bend

引力圖。據將軍說 相對論，物質和能量彎曲

space and time. Because of this, objects which travel near a large mass will appear to move

空間和時間。正因為如此，對象當中 大質量附近的旅行似乎會移動

along a curved path because of the bending in spacetime. We call this effect gravity.

由於彎曲，沿著彎曲的路徑 在時空。我們稱這種效應為引力。

One consequence of this idea is that light is also affected by gravity. After all, if

這個想法的一個結果是光 也受到重力的影響。畢竟，如果

spacetime is curved, then everything must follow along a curved path, including light.

時空是彎曲的，然後一切都必須 沿著彎曲的路徑行進，包括光線。

Einstein published his general theory of relativity in 1915. And while Newton's theory of gravity

愛因斯坦發表了他的廣義相對論 在1915年。而牛頓的引力理論

could be expressed using a simple formula, Einstein's theory required a set of complex

可以用一個簡單的公式來表達， 愛因斯坦的理論需要一套複雜的理論

equations known as the “field equations.” Only a few months after Einstein's publication,

被稱為“場方程”的方程式。 愛因斯坦出版後僅幾個月，

the German scientist Karl Schwarzschild found a surprising solution. According to the field

德國科學家Karl Schwarzschild發現 一個令人驚訝的解決方根據該領域

equations, an extremely dense ball of matter creates a spherical region in space where

方程式，一個非常密集的物質球 在空間中創建一個球形區域

nothing can escape, not even light. A curious result, but did such things actually exist?

沒有什麼可以逃脫，甚至沒有光。好奇 結果，但這樣的事情確實存在嗎？

At first, the idea of a black sphere in space from which nothing could escape was considered

首先，在空間中的黑色球體的想法 考慮到沒有任何東西可以逃脫

purely a mathematical result, but one which would not really happen. However, as the decades

純粹是一個數學結果，但其中一個 不會真的發生。然而，就像幾十年

passed, our understanding of the lifecycle of stars grew. It was observed that some dying

通過了，我們對生命週期的理解 星星長大了。有人觀察到有些人死亡

stars became pulsars, another exotic object predicted by theory. This suggested that dark

恆星變成了脈衝星，另一個奇異物體 理論預測。這表明黑暗

stars could actually be real as well. These strange spheres were named “black holes,”

明星實際上也可能是真實的。這些 奇怪的球體被稱為“黑洞”

and scientists began the hard work of finding them, describing them and understanding

科學家們開始努力尋找 他們，描述他們和理解

But how do you find an object in space that is completely black? Luckily, because black

但是你如何在太空中找到一個物體呢？ 完全黑了？幸運的是，因為黑色

holes have a large mass, they also have a large gravitational field. So while we may

孔的質量很大，它們也有一個 大引力場。所以儘管我們可能

not be able to SEE a black hole, we can observe its gravity pulling on its neighbors. With

我們無法觀察到黑洞 它的引力拉近了它的鄰居。同

this in mind, astronomers looked for a place where a visible star and a black hole were

考慮到這一點，天文學家尋找一個地方 那裡有一顆可見的恆星和一個黑洞

in close proximity to one another. One such place is binary stars.

在彼此附近。一個這樣的 地方是二元星。

A binary star is a system of two stars orbiting one another. We can spot them in several ways.

雙星是由兩顆恆星軌道運行的系統 另一個。我們可以通過幾種方式發現它們。

You can look for stars that change position back and forth ever-so-slightly. Alternatively,

你可以尋找改變位置的星星 來回如此輕微。或者，

if you observe a binary star from the side, the brightness will change when one star passes

如果你從側面觀察到一個雙星， 當一顆星通過時亮度會改變

behind the other. So it's possible that somewhere in space, there's a binary star

在另一個之後。所以有可能 在太空的某個地方，有一個雙星

consisting of a black hole and a visible star. In fact, such binary systems have been observed!

由黑洞和可見星組成。 事實上，已經觀察到了這樣的二元系統！

Astronomers have found stars orbiting an invisible companion. From the size of the visible star

天文學家發現恆星繞著無形的軌道運行 伴侶。從可見星的大小

and its orbit, astronomers calculated the mass of its invisible neighbor. It fit the

天文學家計算了它的軌道 它看不見的鄰居的質量。它適合

Since we can't see a black hole, is there a way to find its size? From Einstein's

既然我們看不到黑洞，那就是 有辦法找到它的大小？來自愛因斯坦

field equations, we know that given the mass of a black hole, we can determine the size

場方程，我們知道給定質量 一個黑洞，我們可以確定大小

of the sphere that separates the region of no escape from the rest of space. The radius

分離區域的球體 沒有逃離其餘的空間。半徑

of this sphere is called the Schwarzschild radius in honor of Karl Schwarzschild. The

這個領域被稱為Schwarzschild 為紀念Karl Schwarzschild而設的半徑。該

surface of the sphere is called the event horizon. If anything crosses the event horizon,

球體的表面稱為事件 地平線。如果有什麼東西穿過事件視界，

it's gone forever — hidden from the rest of the universe.

它永遠消失了 - 隱藏在其他地方 宇宙

This means, once you know the MASS of a black hole, you can compute its SIZE using a simple

這意味著，一旦你知道了黑色的MASS 孔，你可以用簡單的方法計算它的SIZE

formula. And it's actually quite easy to measure the mass of a black hole. Just take

式。它實際上很容易 測量黑洞的質量。拿走吧

a standard issue space probe and shoot it into orbit around the black hole. Just like

一個標準的問題空間探測器並拍攝它 進入黑洞周圍的軌道。就像

any other system of orbiting bodies — like the Earth orbiting the Sun, or the Moon orbiting

任何其他軌道運動系統 - 如 地球繞太陽運行，或繞月球軌道運行

the Earth — the size and period of the orbit will tell you the mass of the black hole.

地球 - 軌道的大小和周期 會告訴你黑洞的質量。

If you don't have a space probe handy, then compute the mass and orbit of a companion

如果你沒有方便的太空探測器，那麼 計算伴侶的質量和軌道

star and use that to find the Schwarzschild radius.

明星並用它來尋找Schwarzschild 半徑。

Black holes come in many sizes. If it was made from a dying star, then we call it a

黑洞有多種尺寸。如果它是 由垂死的恆星製成，然後我們稱之為

“stellar mass” black hole, because its mass is in the same range as stars. But we

“恆星質量”黑洞，因為它 質量與恆星的範圍相同。但我們

can go bigger - much bigger. And to do so, we are going to visit the center of a galaxy.

可以變得更大 - 更大。要這樣做， 我們要去參觀銀河系的中心。

Galaxies can contain billions and billions of stars, all orbiting a central point. Scientists

星係可以包含數十億甚至數十億 所有的恆星，都圍繞著一個中心點。科學家們

now believe that in the center of most galaxies lives a black hole which we call a “supermassive

現在相信在大多數星系的中心 生活在一個我們稱之為“超大質量”的黑洞

black hole,” because of its tremendous mass. The size can vary from hundreds of thousands

黑洞，“因為它的巨大質量。 大小可以從幾十萬不等

to even billions of solar masses. For example, at the center of our own Milky Way galaxy

甚至數十億太陽質量。例如， 在我們銀河系的中心

is a supermassive black hole with a mass 4 million times that of our sun.

是一個質量為4的超大質量黑洞 我們太陽的百萬倍。

Black holes have another property we can measure - their spin. Just like the planets, stars

黑洞還有另一種我們可以測量的屬性  - 他們的旋轉。就像行星，恆星一樣

rotate. And different stars spin at different speeds. Imagine we can adjust the size of

旋轉。不同的星星旋轉不同 速度。想像一下，我們可以調整大小

this star but keep the mass constant. If we increase the radius, the spinning slows down…

這顆恆星但保持質量不變。要是我們 增加半徑，旋轉速度減慢......

If we decrease the size, the spinning speeds up. But while the rotational speed can vary,

如果我們減小尺寸，旋轉速度 起來。但是雖然轉速可以變化，

the angular momentum never changes - it remains constant. Even if the star were to collapse

角動量永遠不會改變 - 它仍然存在 不變。即使明星崩潰了

into a black hole, it would still have angular momentum. We could measure this by firing

進入一個黑洞，它仍然會有角度 動量。我們可以通過射擊來衡量這個

two probes into opposite orbits close to the black hole. Because of their angular momentum,

兩個探針進入相對的軌道靠近 黑洞。由於他們的角動量，

black holes create a spinning current in spacetime. The probe orbiting along with the current

黑洞在時空中產生旋轉電流。 探測器隨著電流軌道運行

will travel faster than the one fighting it, and by measuring the difference in their orbital

比戰鬥的人旅行得更快， 並通過測量它們的軌道差異

periods we can compute the black hole's angular momentum.

我們可以計算黑洞的時期 角動量。

This spacetime current is so extreme it creates a region called the ergosphere where nothing,

這個時空電流非常極端 一個叫做ergosphere的地區，什麼都沒有，

including light, can overcome it. Inside the ergosphere, nothing can stand still. Everything

包括光，可以克服它。在 - 的里面 ergosphere，沒有什麼可以停滯不前。一切

inside this region is dragged along by the spinning spacetime. The event horizon fits

在這個區域裡面被拖著 旋轉時空。事件視界適合

inside the ergosphere, and they touch at the poles. So in one sense, black holes are like

在ergosphere裡面，他們觸摸到了 極。所以從某種意義上說，黑洞就像

whirlpools of spacetime. Once inside the ergosphere, you are caught by the current. And after you

時空的漩渦。一旦進入ergosphere， 你被當前抓住了。在你之後

One final property of black holes we can measure is electric charge. While most of the matter

我們可以測量黑洞的最後一個屬性 是電荷。雖然大部分事情都是如此

we encounter in our day-to-day lives is uncharged, a black hole may have a net positive or negative

我們在日常生活中遇到的是不收費的， 黑洞可能有淨正面或負面

charge. This can easily be measured by seeing how hard the black hole pulls on a magnet.

收費。這很容易通過觀察來衡量 黑洞在磁鐵上的拉力有多大。

But charged black holes are not expected to exist in nature. This is because the universe

但預計不會出現帶電的黑洞 存在於自然界中。這是因為宇宙

is teeming with charged particles, so a charged black hole would simply attract oppositely

充滿了帶電粒子，所以充電 黑洞只會吸引人

charged particles until the overall charge is neutralized.

帶電粒子直到整體充電 被中和了。

There are 3 fundamental properties of a black hole we can measure - mass, angular momentum,

黑色有3個基本屬性 我們可以測量的孔 - 質量，角動量，

and electric charge. It is believed that once you know these three values, you can completely

和電荷。據信一次 你知道這三個值，你可以完全

describe the black hole. This result is humorously known as the “no hair theorem,” since

描述黑洞。這個結果很幽默 自從被稱為“無毛定理”

other than these 3 properties, black holes have no distinguishing characteristics. It's

除了這三個屬性，黑洞 沒有區別特徵。它的

We now have a good idea of a black hole from the outside, but what does it look like on

我們現在很好地了解了一個黑洞 在外面，但它看起來像什麼

the inside? Unfortunately we can't send a probe inside to take a look. Once any instrument

裡面？不幸的是我們無法發送 在裡面探測一下。一旦任何儀器