有必要擔(dān)心外星人入侵嗎?

Should We Keep a Low Profile in Space?

有必要擔(dān)心外星人入侵嗎?

MOUNTAIN VIEW, Calif. — For more than a half-century, a small group of astronomers has sought intelligent company among the stars. They’ve done so by turning large radio antennas skyward, hoping to eavesdrop on signals from an advanced society. It’s a program known as SETI, the Search for Extraterrestrial Intelligence.

加利福尼亞山景城——半個(gè)多世紀(jì)以來(lái)，一些天文學(xué)家一直在探尋星際中的智慧生命，探尋我們的同伴。他們?yōu)榇思茉O(shè)朝向天空的大型無(wú)線電天線，以期捕獲來(lái)自科技先進(jìn)的世界的信號(hào)。人們稱這一探索計(jì)劃為“地外文明搜尋計(jì)劃”(Search for Extraterrestrial Intelligence，簡(jiǎn)稱SETI)。

But now some researchers propose that we should do more than simply don headphones and await E.T.’s call: We should make serious efforts to encourage a response from putative aliens by deliberately transmitting our own messages. It’s a simple idea, akin to tossing a bottle into the cosmic ocean. But recent arguments for what’s termed active SETI have loosed a storm of controversy, one that has even washed into the halls of academe.

不過(guò)，現(xiàn)在有一些研究者建議，我們不能只是側(cè)耳傾聽，等待外星人的召喚，而要做更多、更積極的努力，主動(dòng)傳遞出自己的信息，鼓勵(lì)可能存在的外星人做出回應(yīng)。這是個(gè)簡(jiǎn)單的想法，如同向浩瀚的宇宙扔一只瓶子。不過(guò)最近，被稱作“主動(dòng)探尋地外文明”的想法引發(fā)了諸多討論，刮起了一場(chǎng)爭(zhēng)議的風(fēng)暴，甚至蔓延到了學(xué)術(shù)界。

Why is this? Why has the sending of dispatches to worlds many trillions of miles distant suddenly become a hot-button issue? The simple answer is that there’s now a perception that advertising our existence could be a mortal threat to the planet.

這是為什么呢?為什么向遠(yuǎn)在萬(wàn)億英里之外的世界發(fā)送信息會(huì)驟然成為熱點(diǎn)話題?答案很簡(jiǎn)單，因?yàn)楝F(xiàn)在有一種看法認(rèn)為，廣泛宣示人類的存在可能會(huì)對(duì)我們的星球造成致命威脅。

The reasoning is this: While no one has yet offered decisive proof for life beyond Earth, in the past two years astronomers have learned that tens of billions of habitable planets suffuse our galaxy. Consequently, to believe that only Earth has spawned intelligence is to insist that our world is the site of a miracle. That point of view rarely appeals to scientists.

原因在于：盡管尚未有人能給出存在地外生命的確鑿證據(jù)，但過(guò)去兩年間，天文學(xué)家們了解到，我們的銀河系遍布著數(shù)以百億的宜居星球。因此，讓人相信只有地球產(chǎn)生了智慧生命就等于堅(jiān)持認(rèn)為我們生活的世界全然是一塊奇跡之地?？茖W(xué)家不喜歡這種假設(shè)。

The aliens could very well be out there. And that realization has spurred a call by some for broadcasts intended to elicit a communication from at least the nearest other star systems. But we know nothing of the aliens’ possible motives or behavior. Therefore, it’s conceivable that betraying our existence might prompt aggressive action from space.

地球以外很可能存在外星人。這種認(rèn)識(shí)引起一些人呼吁發(fā)出廣播信號(hào)，意在引發(fā)至少與最近星系的交流。不過(guò)，我們對(duì)外星人的動(dòng)機(jī)和行為一無(wú)所知。因此可以想像，泄露人類的存在可能會(huì)激起來(lái)自太空的侵略行動(dòng)。

Broadcasting is likened to “shouting in the jungle” — not a good idea when you don’t know what’s out there. The British physicist Stephen Hawking alluded to this danger by noting that on Earth, when less advanced societies drew the attention of those more advanced, the consequences for the former were seldom agreeable.

向地外發(fā)送廣播信號(hào)就像“在叢林中大聲叫喊”，如果你不知道周圍存在著什么，那么這樣做可能很不明智。英國(guó)物理學(xué)家史蒂芬·霍金(Stephen Hawking)便暗示過(guò)這種危險(xiǎn)——他指出，在地球上，如果較落后社會(huì)引起了較先進(jìn)社會(huì)的注意，那對(duì)前者來(lái)說(shuō)很少是件好事。

It’s a worry we never used to have. Victorian-era scientists toyed with plans to use lanterns and burning pools of oil to contact postulated Martians. In the 1970s, NASA bolted greeting cards onto spacecraft that will leave our solar system and wander the vast reaches between the stars. The Pioneer and Voyager probes carry plaques and records with information about what humans look like and where Earth is, as well as a small sampling of our culture.

過(guò)去，我們從來(lái)沒有這種擔(dān)心。維多利亞時(shí)代的科學(xué)家設(shè)想過(guò)用點(diǎn)亮燈盞和大量燃油的方式與設(shè)若存在的火星人取得聯(lián)系。到了20世紀(jì)70年代，美國(guó)國(guó)家航空航天局將問(wèn)候賀卡栓牢在航天器上，并隨航天器離開太陽(yáng)系、在恒星之間的廣闊空間漫游。“先驅(qū)者”號(hào)和“旅行者”號(hào)探測(cè)器則攜帶鍍金鋁板和鍍金銅質(zhì)唱片，承載著人類長(zhǎng)什么模樣和地球位于何方的信息，還包括一個(gè)人類文化的小樣本。

Those messages move at the speed of rockets. But in 1974, a three-minute encoded pictogram was transmitted using the large radio antenna at Arecibo, Puerto Rico. It moves at the speed of light, 20,000 times faster. More recent radio transmissions include a Beatles song beamed by NASA to the North Star, a Doritos advertisement launched to a planetary system in the Big Dipper, and a series of broadcasts sent to nearby stars using an antenna in Crimea.

上述這些信息的傳遞速度與火箭相同。不過(guò)1974年，波多黎各的阿雷西博天文臺(tái)(Arecibo)用大型無(wú)線電天線發(fā)送了一個(gè)3分鐘的編碼圖片符號(hào)，運(yùn)行速度已達(dá)光速，比之前的信息快2萬(wàn)倍。更近期發(fā)送的無(wú)線電信息有：美國(guó)宇航局向北極星傳送的一支甲殼蟲樂(lè)隊(duì)的歌，向北斗星座一個(gè)行星系發(fā)送的一段 “立體脆”食品廣告，以及通過(guò)在克里米亞的一部天線向近地恒星發(fā)送的一系列無(wú)線電信號(hào)。

When most people believed that aliens were no more than easy black hats for Hollywood, the idiosyncratic nature of these messages could be easily dismissed. But if cosmic company is a legitimate possibility, shouldn’t we offer up something more edifying than pop music and snack food? A deliberate transmission should represent all of humanity — not short-circuit the important question of who will speak for Earth.

在大多數(shù)人認(rèn)為外星人不過(guò)是好萊塢的噱頭的時(shí)代，人們很容易對(duì)這些怪怪的選擇不以為然。但如果真的有可能存在外星生命，我們難道不應(yīng)當(dāng)發(fā)送比流行音樂(lè)和小吃零食更有助益的信息嗎?深思熟慮后發(fā)送的信息應(yīng)當(dāng)能代表全體人類——而不能回避誰(shuí)可以代表地球這一重要問(wèn)題。

Consequently, recent conferences on the merits of active SETI have sought the advice of social scientists. Among their worries is whether to be up front about humanity’s seamy side: Should we tell the extraterrestrials about war and injustice?

所以，最近就“主動(dòng)探尋地外文明”的好處方面，有討論會(huì)開始向社會(huì)科學(xué)家尋求意見。諸多擔(dān)憂中有一條，是否要誠(chéng)實(shí)展現(xiàn)人類丑陋的一面。我們需要告訴地外文明我們有戰(zhàn)爭(zhēng)和不公正現(xiàn)象嗎?

Personally, I think this concern is overwrought. Any society that can pick up our radio messages will be at a level of development at least centuries beyond our own. They would be no more incensed by our bad behavior than historians who learned that Babylonians attacked one another with spears. It seems naïve to imagine that, by shielding aliens from the less flattering aspects of humanity, we would somehow lessen any incentive to do us harm. If there’s a danger, mincing words is unlikely to eliminate it.

就個(gè)人而言，我認(rèn)為這種擔(dān)憂過(guò)慮了。能接收到地球無(wú)線電信息的社會(huì)必定處在比我們先進(jìn)至少幾世紀(jì)的發(fā)展水平。他們對(duì)人類的不良行為產(chǎn)生的憤怒不會(huì)比歷史學(xué)家發(fā)現(xiàn)巴比倫人自相殘殺更嚴(yán)重。認(rèn)為只要對(duì)他們掩蓋我們不光彩的一面，就可以降低他們加害我們的動(dòng)機(jī)，這種想法似乎太天真。如果確有危險(xiǎn)存在，我們不太可能通過(guò)文過(guò)飾非把這種危險(xiǎn)消除。

A better approach is to note that the nearest intelligent extraterrestrials are likely to be at least dozens of light-years away. Even assuming that active SETI provokes a reply, it won’t be breezy conversation. Simple back-and-forth exchanges would take decades. This suggests that we should abandon the “greeting card” format of previous signaling schemes, and offer the aliens Big Data.

一種更好的做法，是先認(rèn)識(shí)到離我們最近的地外智慧生命可能至少也隔著幾十光年的距離。即使主動(dòng)SETI的行為引起了一個(gè)回應(yīng)，那也不會(huì)是順暢的聊天。簡(jiǎn)單的一問(wèn)一答也要幾十年。這意味著，我們要放棄以前那種“問(wèn)候卡”式的信號(hào)發(fā)送模式，向外星人發(fā)送大數(shù)據(jù)。

For example, we could transmit the contents of the Internet. Such a large corpus — with its text, pictures, videos and sounds — would allow clever extraterrestrials to decipher much about our society, and even formulate questions that could be answered with the material in hand. Sending the web on its way would take months if a radio transmitter were used. A powerful laser, conveying bits much like an optical fiber, could launch these data in a few days.

比如，我們可以發(fā)送互聯(lián)網(wǎng)內(nèi)容。文本、圖片、視頻和音頻匯編的大型數(shù)據(jù)庫(kù)可以讓聰明的外星人破解更多有關(guān)人類社會(huì)的信息，甚至思考出一些用手頭資料能夠解答的問(wèn)題。采用無(wú)線電廣播發(fā)射機(jī)傳送網(wǎng)絡(luò)信息需要幾個(gè)月時(shí)間;而用強(qiáng)激光傳送這些數(shù)據(jù)只需幾天，很像用光導(dǎo)纖維傳輸。

Sending messages — even big ones — is technically feasible. However, there’s still the highly controversial matter of whether to broadcast at all. Who decides? One could simply let the public weigh in, but doing so wouldn’t address the security issue. Even if a majority is comfortable with a transmission, how does that mitigate the possible danger?

向地外傳送信息乃至大量信息，從技術(shù)角度來(lái)講是可行的。不過(guò)，要不要向地外發(fā)送信息還是一個(gè)爭(zhēng)議極大的問(wèn)題。誰(shuí)來(lái)做這個(gè)決定?我們完全可以讓公眾參與決策，但這并不能解決安全問(wèn)題。即便多數(shù)人愿意發(fā)送信息，那就能消除潛在危險(xiǎn)了嗎?

The inability to gauge this peril prompts some critics to argue that, given the possibly existential threat posed by active SETI, we should choose the side of caution. We should simply forbid powerful transmissions to the skies. Indeed, a small consortium of academics in California has drafted a petition urging this.

由于無(wú)法測(cè)量這種危險(xiǎn)，一些批評(píng)者提出，考慮到主動(dòng)尋找地外文明可能造成的威脅，我們寧可慎重，應(yīng)當(dāng)禁止向外太空進(jìn)行大功率傳輸。事實(shí)上，加州一小部分學(xué)者已經(jīng)就此起草了請(qǐng)?jiān)笗?，呼吁這么做。

It’s a wary approach. It’s also poor insurance. Any extraterrestrials with technology advanced enough to threaten us will surely have antennas larger than our own, instruments that can pick up the television and radio signals broadcast willy-nilly since World War II. We are already shouting into the jungle, albeit with less volume than a deliberate signal. But the dangerous creatures may have good hearing.

這種做法雖謹(jǐn)慎，卻也不是萬(wàn)無(wú)一失。技術(shù)發(fā)達(dá)程度足以威脅我們的地外文明必定擁有比我們更大的天線等強(qiáng)大設(shè)備，能夠接收二戰(zhàn)以來(lái)人類發(fā)送的雜亂的電視信號(hào)和無(wú)線電信號(hào)。我們已經(jīng)在對(duì)著叢林大喊了，只不過(guò)音量沒有主動(dòng)發(fā)送的信號(hào)那么大。但危險(xiǎn)生物的耳朵也可能很尖。

Additionally, if we forbid high-powered transmitters aimed at the sky, we shut out such obvious future technologies as better radars for aviation and tracking dangerous asteroids. Do we really want to hamstring our descendants this way?

此外，如果禁止高功率設(shè)備向天空發(fā)射信號(hào)，我們顯然就阻斷了未來(lái)技術(shù)的發(fā)展，研制不出在航空飛行及追蹤危險(xiǎn)小行星領(lǐng)域性能更加優(yōu)越的雷達(dá)。我們真的要就此束縛后世兒孫的發(fā)展嗎?