Astrophysicists propose that mysterious “fast radio bursts” could, in very speculative theory, be produced by an antenna twice the size of Earth. Christopher Intagliata reports.

天体物理学家们指出，经理论推测，神秘的“快速射电爆”，可能是由一个两倍地球大小的天线发出的。克里斯托弗·因塔利亚塔报道。

撰文/播音：克里斯托弗·因塔利亚塔(Christopher Intagliata)

翻译：郭鑫鹏

审校：杨枭

The Earth is studded with telescopes, listening for electromagnetic radiation from the great beyond. And a decade ago, astronomers stumbled upon a mysterious signal: a powerful pulse of radio waves just a few thousandths of a second long. Mysterious because:

地球上有大量望远镜监视着外太空的电磁辐射。十年前，天文学家们偶然发现了一个神秘的信号：一个只有几千分之一秒长的强大无线电脉冲。它神秘的原因在于：

“What is the nature of the sources?” Avi Loeb, a theoretical astrophysicist at Harvard. Whatever the sources are, he says, “they seem to be brighter by 10 of billions of times more than the brightest radio sources we know about.”

“它的发射源是什么？”哈佛大学理论天文学家阿维·勒布（Avi Loeb）说。无论发射源是什么， “它们看起来比我们已知的射电源还要亮一百亿倍。”

The radio pulse are known as “fast radio bursts”-and Loeb says you’d need something tens of billions of times brighter than a pulsar to produce them. So he and his colleague Manasvi Lingam investigated another possibility: “We know of one simple way to produce very powerful radio waves, and that’s using a radio antenna.”

勒布说，这个无线电脉冲被称为“快速射电爆”，你需要一个一百亿倍脉冲星亮度的东西才能产生它。所以他和同事马纳斯维·林加姆（Manasvi Lingam）研究了另一可能性，“我们知道一些简单的产生强大无线电脉冲的方法，比如使用无线电天线。”

A radio antenna built and controlled by extraterrestrials, to be more precise. Loeb and Lingam did the math on how big that stellar-powered radio antenna would have to be, to transmit signals like fast radio bursts. And whether it would even hold up from an engineering standpoint-like would it melt under its own heat?

更准确地说，一个由外星人制造并控制的无线电天线。勒布和林加姆计算了天线的尺寸要多大，才能发射像快速射电发这样的超强信号。并且从工程角度出发判断它是否可以实现——比如它是否会被它自身产生的热量融化？

Using those energy and engineering constraints, they found that the radio beam emitter would have to be twice the diameter of Earth. Pretty big-for us. But at least theoretically possible, he says, for more advanced civilizations. The study is in The Astrophysical Journal Letters. [Manasvi Lingam and Abraham Loeb, Fast Radio Bursts from Extragalactic Light Sails]

在这些能量和工程的限制下，他们发现这个无线电脉冲发射器所需尺寸是地球直径的两倍。这对我们来说太大了。但是至少理论上可行，他说，至少对某些更加先进的文明来说是如此。这项研究发表在《天体物理学杂志通讯》上。

To be clear: this is definitely not proof that intelligent alien exist. It’s just proof of concept, that someone, smarter than us, could in theory build such a thing. And why you might build it? “The idea is that an advanced technological civilization could produce a beam of radio waves focused on a sail that is pushing on the sail, such that eventually the sail will reach a fraction of the speed of light.” We’ll just have to see what arrives first: alien sailors, pushed by radio waves? Or the technological advances to allow us humans to build such a thing ourselves.

需要澄清的一点是：这并不是外星智慧生物存在的证据。这只是说明，如果有某些比我们聪明的生物，他们在理论上可以制造这样一个东西。但是为什么要制造这个呢？“一个观点是先进科技文明可以产生一束无线电脉冲来推动飞船航行，使它的速度最终将达到光速的几分之一。”我们可以看看谁先会出现在地球上：是无线电脉冲推动的外星飞船，还是科技进步使我们可以自己制造出一个这样的装置。

-Christopher Intagliata