(Probably Not A) Giant Alien Antenna
By Christopher Intagliata on March 12, 2017


The Earth is studded(嵌釘) with telescopes, listening for electromagnetic radiation(電磁輻射) from the great beyond. And a decade ago, astronomers stumbled upon(偶然發現、撞見) a mysterious signal: a powerful pulse of radio waves just a few thousandths of a second(幾千之一秒) long. Mysterious because: “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 (百億倍) more than the brightest radio sources we know about." 
地球最近戴上幾隻望遠鏡耳釘(stud),用來聽遠在外面的(from the great beyond)電磁輻射(electromagnetic radiation)。十年前天文學家偶然發現(stumbled upon)一個神祕信號:幾千之一秒 (thousandths of a second)強力無線電波脈衝。之所以神秘是因為:「來源的本質是甚麼」?Avi Leob,哈佛理論天體物理學家,不管來源是什麼,他說: 「它比我們現在所知最強的無線信號強幾百億倍。」

The radio pulses are known as ‘fast radio bursts(高速無線電爆發)’—and Loeb says you‘d need something tens of billions of times brighter than a pulsar(脈衝星:中子星的一種,為會週期性發射脈衝信號) 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(收音機天線)."
無線脈衝被稱為高速無線電爆發,Leob說只有比脈衝星(pulsar)強幾百億倍才有可能產生這種信號,所以他和他的同事Manasvi Lingam著手研究調查(investigated)另一種可能性:「我們對簡單的方法產生強力無線電波有些了解(know of),就是用收音機天線。」

A radio antenna built and controlled by extraterrestrials(外星生物), 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(道理站得住腳) from an engineering standpoint—like would it melt under its own heat?
更精確地說(to be more precise),一個由外星人(extraterrestrials)建造和操控的無線電天線,Loeb和Lingam內心盤算(did the math 做算術),計算那樣大的星際驅動無線電天線該多大,才足夠發射這樣的快速無線電脈衝,姑且不論從工程的角度看(from an engineering standpoint)是否站得住腳(hold up) – 比方說被自己所發的熱給熔化。

Using those energy and engineering constraints(限制), they found that the radio beam emitter(發射器) would have to be twice the diameter of Earth. Pretty big—for us. But at least theoretically possible, he says, for more advanced civilizations(更先進的文明). The study is in The Astrophysical Journal Letters.
考量能量和工程上的條件限制(constraints),他們發現無線電光束發射器(emitter)的直徑必須有地球的兩倍大,這相當大,對我們人類而言,但是至少在理論上是講得通的,Loeb這麼說道,更先進的文明(more advanced civilizations)可能做得到。這份研究報告發表在天文物理期刊上。

To be clear: this is definitely not proof that intelligent aliens exist. It‘s just proof-of-concept(概念證明), 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(帆) that is pushing on the sail, such that eventually the sail will reach a fraction of(一小部分的) 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.
在此澄清(To be clear):這絕不是外星人存在的證明,這只是一種概念性的證明,說明可能有比人類聰明的人建了這樣的東西,然而未建這樣的東西幹啥?「這個概念是,某個先進技術的文明製作一個無線電波光束,集中打擊在一張帆上推動這艘帆,最終這艘帆將會接近一部份的(a fraction of)光速」,我們只需看哪個先到:無線電波推過來的外星水手?還是技術上的進步讓我們人類自己能夠建出這樣的東西。


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