ByAlana+Semuels+++陳一榛

One day， when earth is destroyed by war or rising seas or a wayward1） asteroid2）， humanity will be extinguished—and along with it reality television， baseball stadiums， and thousands of recipes for guacamole3）， with and without peas.

太空探索技術(shù)公司開發(fā)的名為“Dragon”的宇宙飛船

Unless， that is， weve established a colony somewhere in space.

That idea may sound far-fetched4）， but scientists are working hard to make it a reality. What would it take， and how might we use the resources beyond Earths atmosphere？ I recently talked with aerospace engineers， entrepreneurs， and researchers to find out what our future in space will look like， in the near term and in centuries to come.

Fast Flights高速飛行

Private aerospace companies are developing reusable spacecraft， which will dramatically cut the cost of launches， because we wont need to build a new vessel each time we want to leave Earths atmosphere. Elon Musks SpaceX， for example， is on the brink of5） launching a reusable spaceship. Such vessels may soon make commercial spaceflight possible： Companies such as Virgin Galactic and Xcor are already accepting reservations for suborbital flights.

Such flights will be quick—Xcors will last about half an hour， Bryan Campen， a spokesman for Xcor， told me. Passengers can expect to be in zero gravity within five minutes of takeoff. After floating for another five or so minutes， they will descend back to Earth， experiencing 30 seconds of teeth-gnashing6） 4G reentry—about the same as on an intense roller-coaster ride—before gliding to the ground. These flights will take off and land in the same spot， but within a few decades， spaceflight could become the fastest way to travel internationally—making it possible to get from New York City to Tokyo in 90 minutes， Campen said.

Crowded Skies 擁擠的天空

As the cost of launching rockets comes down， more people will be able to participate in aerospace ventures. Already， universities and research groups can send up CubeSats—satellites about the size of a bread box—for as little as $100，000， a fraction of the tens of millions of dollars a satellite launch usually costs.

As more organizations send satellites into space， however， collisions become more likely. In 1967， 10 years after Sputnik 17）s launch， about 2，500 objects （satellites， used rockets， and debris） were orbiting Earth; now there are more than 20，000， according to Colonel8） John Giles， the commander of the Joint Space Operations Center， which identifies and tracks objects in space. A two-centimeter piece of debris can cause as much damage to a satellite in space as a speeding Jeep would on Earth， Giles told me. The U.S. military is developing a “space fence”—a radar-like system expected to be operational by 2018—to warn of impending collisions and beginning to plan for a time when adversaries might try to take out satellites that are crucial for GPS and communications.

Men on the Moon 人類登月

Though no American has set foot on the moon since 1972， China recently landed a rover there and plans to eventually set up a permanent lunar base. In many ways， the moon is a good place for a colony—it has water， and its soil could be mined for minerals and oxygen. The moon would also make a good jumping-off point9） for exploring the rest of the solar system. Its gravity is about one-seventh that of Earth， so launching spacecraft there would require much less energy.

Chris Impey， an astronomy professor at the University of Arizona and the author of Beyond： Our Future in Space， thinks we may one day build a “space elevator” on the surface of the moon in order to make lunar launches even easier. The idea sounds like something out of a Roald Dahl10） book： A giant tapered11） cable made of superstrong material would reach 35，000 miles into space. Solar-powered elevator cars would climb up the cable， delivering spacecraft into the moons orbit. “Serious engineers have been investigating this for half a century，” Impey said. “We could almost build it right now.”

Missions to Mars … 火星任務(wù)

Many scientists think Mars， which has large underground glaciers， could be our best bet for a permanent colony on another planet. But the obstacles to living there are daunting. Humans cant breathe the air， and the planets frequent dust storms would make farming difficult. Solar radiation is another problem， and sending messages to Earth （via radio waves traveling at the speed of light） can take more than 20 minutes， depending on where the planets are in their orbits.

Still， scientists， architects， and engineers are brainstorming ways to overcome those obstacles. ZA Architects， a Ukrainian firm， has drawn up plans for structures made out of Martian soil; robots could be sent ahead to build them. Other researchers propose inhabiting Marss lava12） tubes—underground caverns likely formed by volcanoes—since the tunnels also provide protection from solar radiation and dust storms and would keep the temperature relatively constant. And NASA is testing an inflatable13） habitat that could be deployed on the surface of Mars.

If a group of humans were to live on Mars for centuries with little or no contact with Earth， they would likely evolve， eventually becoming a different species， Impey told me. Because Mars has less gravity， scientists believe humans would slowly grow taller and their cardiovascular14） systems would become weaker. Theyd also have less body hair （because theyd have to stay indoors or wear space suits， they wouldnt need the protection from the elements15））， and their controlled diet might result in smaller teeth. But thats assuming， of course， that humans can reproduce in Marss gravity—an untested proposition.

... And Beyond 向深空探索

In or near the moons orbit， there exist a few spots， called Lagrange points16）， where an object is pulled neither to the moon nor to Earth. A space station orbiting one of these points could stay in place for a long time without floating away.

Eventually， Pat Troutman told me， one of those areas could serve as a harbor for ships going out farther into the universe， a sort of Rotterdam of the solar system. Resupplying and refueling would be costly from Earth， but， aided by robots， astronauts could pull a large boulder17） from an asteroid， tow it to a stable area， and mine it for water and oxygen， which could be turned into rocket propellant， Troutman said.

The dwarf planet18） Ceres， the largest object in the asteroid belt， may have big reserves of water， making it a potential base for more refueling， Troutman told me. And if Mars turns out to be uninhabitable， the Jovian19） system—Jupiter and its moons—might be a good alternative， he said. It， too， has water， and is largely protected from the suns radiation.

The universe contains an almost incomprehensible number of stars—our galaxy alone has hundreds of billions， and there exist hundreds of billions of galaxies—and an even greater number of planets. Current technology isnt very good at determining which of those planets might be habitable—or already inhabited， Sara Seager， a professor of planetary science and physics at MIT， told me. But our view of the galaxy could become a little clearer in 2018 with the launch of the $9 billion James Webb Space Telescope20）. It will sit 1 million miles from Earth， where it will search for gases that look out of place in the atmospheres of other planets， signaling vapors that might be produced by other life-forms.

Sending a probe is likely the only way to know for sure whether extraterrestrial species exist. But even traveling at one-tenth the speed of light， which some physicists believe might be possible， getting to the nearest star—25 trillion miles away—would take about 43 years.

Some physicists theorize that humans could one day get to far-off stars faster by warping21） space-time—essentially pushing a spacecraft forward by rapidly expanding the empty space behind it. The theory is unproven， and the process would require massive amounts of energy. Still， many scientists remain optimistic about the possibility of a manned mission beyond our solar system. “I have no doubt its going to happen，” Troutman said. “Just maybe not in my lifetime.”

如果有一天地球由于戰(zhàn)亂、海平面升高或是橫沖直撞的小行星而毀滅，人類也將面臨滅絕，隨之消失的還有真人秀節(jié)目、棒球場以及成千上萬的鱷梨調(diào)味醬食譜——有沒有豌豆的都算上。

除非，也就是說，我們已在太空的某一處建立了一個殖民地。

這一想法也許聽起來不切實(shí)際，但是科學(xué)家們正努力使之成為現(xiàn)實(shí)。實(shí)現(xiàn)這一夢想需要什么？又該如何使用地球大氣層之外的資源呢？最近，我與航空航天領(lǐng)域的工程師、企業(yè)家和研究人員進(jìn)行了交談，試圖弄明白短期內(nèi)以及以后的幾百年里我們太空探索的未來會是怎樣的。

私營航天公司正在研發(fā)可重復(fù)利用的航天器，這樣會極大地降低發(fā)射成本，因?yàn)槲覀儗⒉挥妹恳淮蜗胍x開地球大氣層時都造一個新的飛船。例如，埃隆·馬斯克的太空探索技術(shù)公司（SpaceX）即將推出可重復(fù)使用的宇宙飛船。有了這樣的飛船，商業(yè)太空旅行很快就可能成為現(xiàn)實(shí)：維珍銀河公司和Xcor航天公司等都已經(jīng)接受亞軌道旅行的預(yù)訂。

Xcor航天公司的發(fā)言人布萊恩·坎彭對我說，此類飛行的速度會很快，Xcor公司的飛船將飛半個小時左右。乘客有望在起飛后五分鐘內(nèi)體驗(yàn)到失重狀態(tài)，之后漂浮五六分鐘，然后下降返回地球，在重返大氣層時要體驗(yàn)咬緊牙關(guān)承受四倍重力的感覺，仿佛坐在飛馳的過山車上一般，最后滑翔落地。這樣的飛行會在同一個地點(diǎn)起飛和降落，但是要不了幾十年，太空旅行將會成為國際旅行最快捷的方式——從紐約到東京只需90分鐘是有可能實(shí)現(xiàn)的，坎彭說道。

隨著火箭發(fā)射成本的降低，越來越多的人可以參與到太空探索中來。各個大學(xué)和研究機(jī)構(gòu)已經(jīng)可以發(fā)射魔方衛(wèi)星——只有面包盒大小的衛(wèi)星——花費(fèi)低至十萬美元，只是發(fā)射一個普通衛(wèi)星所花費(fèi)的成千上百萬美元成本的皮毛。

然而，由于越來越多的組織發(fā)射衛(wèi)星到太空，衛(wèi)星發(fā)生碰撞的幾率也隨之增大。1967年，“斯普特尼克1號”發(fā)射升空十年后，大約2500個物體（包括衛(wèi)星、火箭殘骸、碎片）在地球軌道運(yùn)行。而按照聯(lián)合太空作戰(zhàn)中心的指揮官約翰·吉爾斯上校的說法，如今這一數(shù)量已達(dá)到20000個。該中心負(fù)責(zé)確認(rèn)并追蹤太空中的物體。吉爾斯告訴我，太空中兩厘米大小的碎片撞擊衛(wèi)星所造成的破壞與地球上一輛高速行駛的吉普產(chǎn)生的破壞相當(dāng)。美軍正在研發(fā) “太空籬笆”，這是一種類似雷達(dá)的系統(tǒng)，有望在2018年前運(yùn)行，其目的在于對即將發(fā)生的碰撞發(fā)出警告。另外，軍方也開始制定計劃，以便在敵人試圖擊落對GPS系統(tǒng)和通信極為重要的衛(wèi)星時予以應(yīng)對。

自1972年之后就沒有美國人登陸過月球，但中國近期卻把探測車送到了月球上，并計劃最終建立永久的月球基地。從很多方面來講，月球都是個建立殖民地的好地方——那里有水，那里的土壤中含有可供開采的礦物質(zhì)和氧。月球也可作為探索太陽系其他星球的一個很好的出發(fā)點(diǎn)，其重力僅為地球的七分之一，因此在那里發(fā)射宇宙飛船所需的能量要少很多。

克里斯·殷匹是亞利桑那大學(xué)的天文學(xué)教授，也是《地球之外：我們在太空的未來》一書的作者，他認(rèn)為有一天我們會在月球表面建一個“太空電梯”，以使在月球上發(fā)射宇宙飛船更容易。這個想法聽起來像是出自羅爾德·達(dá)爾的書：一條由超強(qiáng)材料制成的巨型錐形電纜通往35000英里深處的太空。太陽能驅(qū)動的電梯轎廂沿著電纜爬升，將航天器運(yùn)送入月球軌道。“正兒八經(jīng)的工程師們研究這個都有半個世紀(jì)之久了，” 殷匹說，“我們眼下幾乎都能把它造出來了?！?/p>

很多科學(xué)家認(rèn)為，火星地表下含有大量的冰川，會成為我們在另一個星球建立永久殖民地的最佳選擇。但是在火星上生活面臨的障礙之大令人畏懼。人類無法呼吸那里的空氣，火星上頻繁發(fā)生的沙塵暴會使農(nóng)業(yè)耕作困難重重。太陽輻射也是個問題。向地球傳送消息（通過無線電波以光速傳送）要超過20分鐘，時間的長短還要取決于這兩顆行星處在各自軌道的什么地方。

然而，一些科學(xué)家、建筑師以及工程師們正在集思廣益，想辦法克服這些障礙。烏克蘭的ZA建筑師事務(wù)所已經(jīng)起草了用火星土壤建造房屋的方案，人類會率先發(fā)射機(jī)器人去建造。其他研究人員提出在火星熔巖管道——可能是火山噴發(fā)形成的地下洞穴——里面居住，因?yàn)檫@些管道也能保護(hù)人類不受太陽輻射和沙塵暴的侵害，并且能保持相對恒定的溫度。此外，美國宇航局正在測試一種充氣式居所，可部署到火星表面上。

殷匹還告訴我，如果一群人在火星上居住長達(dá)幾個世紀(jì)，與地球毫無聯(lián)系或者聯(lián)系甚少，那么他們很有可能進(jìn)化，最終成為不同的物種。由于火星的重力更小，科學(xué)家認(rèn)為人類會慢慢長得更高，心血管系統(tǒng)功能會變得更弱。他們的體毛也會越來越少（他們因?yàn)椴坏貌淮谑覂?nèi)或穿著太空服，所以就不需要體毛來保護(hù)自己不受周圍環(huán)境的傷害），同時受控的飲食也會導(dǎo)致他們的牙齒變小。當(dāng)然這只是建立在人類能夠在火星的重力環(huán)境中繁衍后代的假設(shè)上——這是個未被驗(yàn)證的設(shè)想。

在近月軌道上或附近，有幾個點(diǎn)叫拉格朗日點(diǎn)，在這些點(diǎn)上的物體既不會被拉向地球，也不會被拉向月球。圍繞這樣一個點(diǎn)運(yùn)行的空間站可以長時間停留在合適的位置，而不會漂移到其他地方。

帕特·特勞特曼對我說，最終這些區(qū)域中的某個可以作為飛船深入宇宙的港灣，相當(dāng)于太陽系中的鹿特丹港。從地球上對飛船再次提供補(bǔ)給和補(bǔ)充燃料的花費(fèi)會很大，但是在機(jī)器人的協(xié)助下，宇航員能從小行星上搬走一塊巨石，將之牽引至穩(wěn)定地帶，從中開采水和氧氣，這些物質(zhì)可以進(jìn)而轉(zhuǎn)化成火箭的推進(jìn)燃料。

谷神星這一矮行星是小行星帶中最大的一個星球，可能有豐富的水儲備，這使其可能成為一個補(bǔ)給燃料的基地，特勞特曼告訴我。他說，如果最終發(fā)現(xiàn)火星不適合人居住，那么木星系統(tǒng)，也就是木星及其衛(wèi)星，也許是另一個不錯的選擇。木星上同樣有水，而且很大程度上不受太陽輻射的影響。

宇宙里恒星的數(shù)量多到幾乎無法想象，光是銀河系就有上千億顆恒星，而星系又有上千億個，行星的總量就更多了。麻省理工學(xué)院的行星科學(xué)與物理學(xué)教授薩拉·西格爾告訴我，目前的技術(shù)手段還不太能夠確定哪一個星球適宜居住，或是已經(jīng)有生命定居。但是隨著2018年耗資90億美元的詹姆斯·韋伯太空望遠(yuǎn)鏡的發(fā)射，我們對銀河系的觀測會更加清晰一些。這臺太空望遠(yuǎn)鏡會坐落在與地球相距100萬英里的地方，在那里探測其他星球上看起來與其本身的大氣格格不入的氣體，這可能就是由別的生命體產(chǎn)生的氣體在向我們發(fā)信號。

發(fā)射探測器很可能是確定是否有外星生命存在的唯一途徑。但即使以一些物理學(xué)家認(rèn)為可行的光速的十分之一的速度飛行，到達(dá)最近的恒星——25萬億英里之外——也需要花費(fèi)大約43年。

一些物理學(xué)家從理論上推測，總有一天，人類可以通過扭曲時空的方式以更快的速度到達(dá)遙遠(yuǎn)的星球。扭曲時空本質(zhì)上就是通過快速擴(kuò)大飛船身后的空間而促使其前行。這一理論并未得到證實(shí)，而這一過程會需要極大的能量。然而，還是有很多科學(xué)家樂觀地認(rèn)為，太陽系之外的載人飛行是可能的。“這一定會發(fā)生，對此我深信不疑，” 特勞特曼說，“只是我在有生之年可能無法看到了?！?/p>

1. wayward [?we?w?（r）d] adj. 難以控制的;不穩(wěn)定的;不規(guī)則的

2. asteroid [??st??r??d] n. [天]小行星

3. guacamole [?ɡwɑ?k??m??li] n. 鱷梨調(diào)味醬。本文在鱷梨調(diào)味醬之后加了句“有沒有豌豆的都算上”，這源于2015年《紐約時報》（The New York Times）的“鱷梨調(diào)味醬門”事件。2015年該報在自己的推特賬號上發(fā)布了一個講述做鱷梨調(diào)味醬時加入豌豆的食譜的鏈接，并配文字說明“Add green peas to your guacamole. Trust us”。這遭到很多讀者的負(fù)面評論，連奧巴馬都發(fā)推特說豌豆與鱷梨調(diào)味醬不搭。

4. far-fetched [?fɑ?（r）?fet?t] adj. 牽強(qiáng)的，靠不住的

5. on the brink of：瀕于，即將發(fā)生

6. gnash [n??] vi. 咬牙

7. Sputnik 1：“斯普特尼克1號”，蘇聯(lián)于1957年發(fā)射的人類第一顆人造地球衛(wèi)星

8. colonel [?k??n（?）l] n. （陸軍、空軍或海軍陸戰(zhàn)隊(duì)的）上校

9. jumping-off point：起點(diǎn)，出發(fā)點(diǎn)

10. Roald Dahl：羅爾德·達(dá)爾（1916～1990），挪威籍的英國杰出兒童文學(xué)作家、劇作家和短篇小說作家，代表作品有《查理與巧克力工廠》（Charlie and the Chocolate Factory）等。

11. tapered [?te?p?（r）d] adj. 錐形的

12. lava [?lɑ?v?] n. [地]熔巖

13. inflatable [?n?fle?t?b（?）l] adj. 可吹脹的，可充（或打、吹）氣的

14. cardiovascular [?kɑ?（r）di???v?skj?l?（r）] adj. 心血管的

15. element [?el?m?nt] n. （人或物的）自然環(huán)境

16. Lagrange point：拉格朗日點(diǎn)，指在兩大物體引力作用下能使小物體穩(wěn)定的點(diǎn)，于1772年由法國數(shù)學(xué)家拉格朗日推算得出。

17. boulder [?b??ld?（r）] n. 巨礫;漂礫;（由于氣候或水侵蝕而形成的）卵石

18. dwarf planet：矮行星，太陽系外圍較小的天體，體積介于行星和小行星之間，目前發(fā)現(xiàn)的矮行星包括谷神星、冥王星、鬩神星、鳥神星和妊神星。

19. Jovian [?d???vi?n] adj. [天]木星的

20. James Webb Space Telescope：詹姆斯·韋伯太空望遠(yuǎn)鏡，是哈勃太空望遠(yuǎn)鏡的繼任者，將在2018年10月發(fā)射。

21. warp [w??（r）p] vt. 使翹曲