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Black Holes Merge Into Unusual Size
Black holes are becoming stranger — even to scientists who study planets and other objects in outer space.
Astronomers recently reported the discovery of the signal from a violent collision of two black holes. The event, which took place long ago, created a new black hole of a size that scientists had never seen before.
California Institute of Technology physicist Alan Weinstein was part of the discovery team. He noted that the finding was the "biggest bang" ever observed by human beings since the Big Bang.
The Big Bang is a term many astronomers use to explain the beginning of the universe.
Black holes are compact areas of space. They are so dense that not even light can escape. Until recently, astronomers had observed them in two general sizes.
There are "small" ones called stellar black holes. These black holes are formed when a star collapses. They are about the size of a small city.
There are also supermassive black holes. These black holes are millions, maybe billions, of times more massive than our sun.
Astronomers' calculations suggest that anything in between the two sizes did not make sense. That was because stars that grew too big before collapse would generally destroy themselves, leaving no black holes.
Nelson Christensen is research director of the French National Centre for Scientific Research. He says scientists thought that star collapses could not create stellar black holes much bigger than 70 times the mass of our sun.
Then in May 2019 two sensors received a signal that turned out to be the energy from two stellar black holes crashing into each other. One was 66 times the mass of our sun. The other was 85 times the mass of the sun.
The result: The first ever discovered intermediate black hole, at 142 times the mass of the sun. The word intermediate suggests being in the middle of a process or development.
In the collision, a large amount of energy was lost. The energy was in the form of a gravitational wave, a ripple in space that travels at the speed of light.
It was that wave that physicists in the United States and Europe, using detectors called LIGO and Virgo, captured last year. After studying the signal and reexamining their work, scientists published the results this week in Physical Review Letters and Astrophysical Journal Letters.
Because the detectors receive the gravitational waves as audio signals, scientists actually heard the collision. For all the violence, the signal lasted only one-tenth of a second.
"It just sounds like a thud," Weinstein said. "It really doesn't sound like much on a speaker."
This crash happened about 7 billion years ago, when the universe was about half its current age. It was only detected now because the collision was so far away.
Black hole collisions have been observed before. But the black holes involved were smaller to begin with. Even after the collision, they did not grow beyond the size of normal stellar black holes.
Scientists still do not know how supermassive black holes at the center of galaxies formed, Christensen said, but this new discovery may offer a clue.
I'm John Russell.
重點解析
1.discovery n. 發現；發覺
Police have made a macabre discovery.
警察有了個可怕的發現。
2.supermassive adj. 特大質量的
Quasars are the very active centers of galaxies though to surround the central supermassive black hole.
類星體是星系中最活躍的中心，儘管他們圍繞著中心特大質量黑洞。
3.current adj.現在的；流通的
Their current protests are motivated purely by self-interest.
他們目前的抗議純粹是受私利驅使的。
4.intermediate adj.中間的，過渡的
Students are categorized as novice, intermediate, or advanced.
學生分為新生、中級生或高級生。
5.Astronomers' calculations suggest that anything in between the two sizes did not make sense.
make sense 有意義
On the face of it that seems to make sense. But the figures don't add up
乍一看，似乎講得通，但這些數字對不起來。
There are some stylistic elements in the statue that just don't make sense.
這座雕像上的一些風格元素讓人完全捉摸不透。
6.It was only detected now because the collision was so far away.
far away 遙遠的
He had gone as far away as possible to build a new life.
他去了儘可能遠的地方開始新的生活。
They came from as far away as Florida.
他們來自遙遠的佛羅裡達州。
參考譯文
人類探測到兩大黑洞碰撞形成超大黑洞
黑洞變得越來越陌生，甚至對於研究外太空行星和其他物體的科學家來說也不例外。
最近，天文學家報告稱，發現了兩個黑洞劇烈碰撞的信號。很久以前發生的這起事件創造了一個新的黑洞，其大小是科學家們從未見過的。
加州理工學院的物理學家艾倫·韋恩斯坦（Alan Weinstein）是研究這一發現的小組成員。他指出，這一發現是「宇宙大爆炸」以來人類觀測到的「最大爆炸」。
「宇宙大爆炸」是許多天文學家用來解釋宇宙起源的一個術語。
黑洞是空間中緊湊的形態。由於過於密集，連光都無處可逃。直到最近，天文學家才觀察到兩個普通大小的黑洞。
較「小」的黑洞被稱為恆星黑洞。這類黑洞是恆星解體時形成的，體積約等於一個小型城市。
還有超大質量的黑洞。這類黑洞的質量是太陽的數百萬倍，甚至數十億倍。
天文學家的計算表明，這兩種尺寸之間不可能存在中間值。因為在解體前變得太大的恆星通常會自我毀滅而不會留下黑洞。
尼爾森·克裡斯滕森（Nelson Christensen）是法國國家科學研究中心的研究主任。他表示，科學家們認為，恆星解體不會產生比太陽質量大70倍的恆星黑洞。
然後，在2019年5月，兩個傳感器接收到兩個恆星黑洞相撞產生的能量發出的信號。其中一個是太陽質量的66倍。另一個是太陽質量的85倍。
結果就是首次發現了質量是太陽142倍的中級黑洞。中級表示其處於發展的過程中。
兩個黑洞碰撞時損失了大量能量。這些能量變成引力波——太空中以光速傳播的漣漪。
去年，美國和歐洲的物理學家利用「雷射幹涉引力波天文臺」（LIGO）和Virgo天文臺探測器捕捉到了這一引力波。在研究該信號並對其結果進行反覆檢驗後，科學家們本周在《物理評論快報》和《天體物理學雜誌快報》上發表了研究結果。
由於探測器接收到的引力波是聲波信號，因此科學家們真實地聽到了碰撞聲。整個碰撞過程發出的信號只持續了十分之一秒。
韋恩斯坦表示：「聽起來像是『砰』的一聲。不像是揚聲器發出的聲音。」
這次撞擊發生在約70億年前，當時宇宙的年齡只有現在的一半。之所以現在才被發現，是因為碰撞發生的距離太遙遠了。
人類以前也觀測到黑洞碰撞，但那些黑洞體積更小。即使碰撞後，它們的體積也沒有超過正常恆星黑洞的大小。
克裡斯滕森表示，科學家仍然不知道星系中心的超大質量黑洞是如何形成的，但這一新發現或許能提供一些線索。
約翰·羅塞爾為您播報。
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