VOA Special English - Researchers Detect Ancient Energetic Burst

VOA Special English - Researchers Detect Ancient Energetic Burst

研究人员发现古代能量爆发

【原文听力】

　　By John Russell

　　26 October 2023

　　Astronomers have detected radio waves coming from what looks like a joining of galaxies from about 8 billion years ago. The discovery is the oldest-known example of an event that is difficult to explain: a fast radio burst.

　　In less than a millisecond, this burst released the amount of energy our sun releases in thirty years, scientists said.

　　The Australian SKA Pathfinder, a radio telescope in the state of Western Australia, detected the burst. And the European Southern Observatory's Very Large Telescope in Chile, one of the most powerful telescopes, found the location of the burst.

　　This artist's impression, not to scale, illustrates the path of a fast radio burst from the distant galaxy where it originated all the way to Earth in this handout picture obtained on October 20, 2023. (ESO/M. Kornmesser/Handout via REUTERS)

　　A fast radio burst, or FRB, is a kind of radio-frequency electromagnetic radiation. It lasts less than a millisecond but outshines most other sources of radio waves in the universe. Radio waves have the longest wavelengths in the electromagnetic spectrum.

　　Ryan Shannon, an astronomer at Swinburne University of Technology in Australia, was a co-leader of the study published recently in Science.

　　He said radio waves in FRBs are similar to those used in microwave ovens. And he added that this FRB had the same amount of energy needed to microwave "a bowl of popcorn twice the size of the sun."

　　Until now, the oldest-known such burst dated to 5 billion years ago, making this one 3 billion years older. The universe is about 13.8 billion years old. For comparison, Earth is about 4.5 billion years old.

　　In seeing objects and events from long ago, researchers look across large distances, making this burst also the farthest of any FRB ever detected.

　　"We now know that fast radio bursts have been around for more than half the age of the universe," said study co-leader Stuart Ryder of Macquarie University in Australia.

　　Researchers first discovered fast radio bursts in 2007.

　　The most likely source is a special kind of "neutron star, called a magnetar. These stars ... are some of the most extreme objects in the universe, which you would need to produce such extreme bursts," Shannon said.

　　"There are more energetic events in the universe, associated with stellar explosions or a black hole shredding a star apart. But FRBs are unique in that they produce all their energy in radio waves, with nothing seen in other bands - optical light or X-rays for example - and that the signals are so short," Shannon added.

　　They also are more common, Shannon explained, with around 100,000 thought to happen somewhere in the universe daily. Far fewer have been detected, Shannon said, and only around 50 - including this one - have been traced back to the galaxy where they began.

　　The scientists said that studying these bursts can help to detect and measure the large amount of matter believed to populate the large distances of space between galaxies.

　　I'm John Russell.

　　Will Dunham reported on this story for Reuters. John Russell adapted it for VOA Learning English.

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　　作者:约翰·拉塞尔

　　2023年10月26日

　　天文学家已经发现来自80亿年前星系结合处的无线电波。这一发现是难以解释的事件的最古老的例子:快速无线电爆发.

　　不到一年毫秒科学家说，这次爆发释放的能量相当于我们的太阳30年释放的能量。

　　澳大利亚SKA探路者是西澳大利亚州的一架射电望远镜，它探测到了这次爆发。欧洲南方天文台在智利的超大型望远镜，最强大的望远镜之一，发现了位置爆发的时候。

　　在这张2023年10月20日获得的讲义图片中，这位艺术家的印象(不按比例)展示了一个快速射电爆发从遥远的星系一直到地球的路径。(ESO/m . Kornmesser/路透社发布)

　　快速射电爆发，简称FRB，是一种射频电磁辐射。它持续时间不到一毫秒，但比宇宙中大多数其他无线电波源都要亮。无线电波在电磁波谱中波长最长。

　　澳大利亚Swinburne科技大学的天文学家Ryan Shannon是最近发表在《科学》杂志上的这项研究的共同领导者。

　　他说，FRB中的无线电波类似于微波炉中使用的无线电波。他补充说，这种FRB的能量相当于微波“一碗两倍于太阳大小的爆米花”

　　到目前为止，已知的最古老的一次爆发可以追溯到50亿年前，这一次比这次早了30亿年。宇宙大约有138亿岁。相比之下，地球大约有45亿岁。

　　在观察很久以前的物体和事件时，研究人员跨越了很长的距离，这使得这次爆发也是有史以来探测到的最远的FRB。

　　“我们现在知道，快速射电爆发已经存在了超过宇宙年龄的一半，”澳大利亚麦考瑞大学的研究合作者斯图尔特·赖德说。

　　研究人员在2007年首次发现了快速射电爆发。

　　最有可能的来源是一种特殊的“中子星称为磁星。这些星星...是宇宙中一些最极端的物体，你需要它们来产生如此极端的爆发，”香农说。

　　“宇宙中有更多的高能事件，与主要的爆炸或黑洞切碎相隔一星。但是FRB是独一无二的因为它们产生的所有能量都是无线电波，而在其他波段看不到任何东西——例如可见光或X射线——而且信号非常短，”香农补充道。

　　Shannon解释说，它们也更常见，据认为在宇宙的某个地方每天都会发生大约10万次。香农说，发现的数量少得多，只有大约50只——包括这只跟踪回到他们开始的星系。

　　科学家们表示，研究这些爆发有助于检测和测量大量物质，这些物质被认为填充了星系之间的巨大距离。

　　我是约翰·拉塞尔。

　　威尔·邓纳姆为路透社报道了这个故事。约翰·拉塞尔将其改编为美国之音英语学习节目。

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　　这个故事中的词语

　　detect - v。发现或注意到某物的存在

　　burst–n。突然开始的生产或做某事的短时间

　　millisecond –n。千分之一秒

　　location - n。一个地方或位置

　　neutron star –n。一种小而密度很高的星体

　　stellar –adj。属于或关于星星的

　　shred –v。将(某物)切成或撕成长片

　　unique - adj。用来表示某物或某人不同于任何事物或任何人

　　trace- v。追踪某物回到它的原因或开始