2023考研英語(yǔ)閱讀月球的歷史
Lunar history
月球的歷史
EARTHS moon has a split personality. One half of its surfacethe half which, thanks to thevagaries of orbital mechanics, always faces Earthis dominated by dark, smooth expanses ofancient, frozen lava known as maria . The contrast between the darkness of themaria and the brightness of the surrounding highlands forms a pattern popularly known,depending on the culture of the observer, as the man in the moon, the rabbit on the moon orone of many other optical illusions.
地球的衛(wèi)星---月球有著分裂的人格。其表面的一半 ---由于軌道力學(xué)的變幻莫測(cè)，這一半總是面對(duì)地球---一直處于黑暗之中。這片黑暗的地方被稱為月海，不僅平坦廣闊，而且由古老而凍結(jié)的火山巖形成。根據(jù)觀察者不同的文化，月海的黑暗和周圍群山的明亮對(duì)比形成了一種眾所周知的模式，比如嫦娥，月兔或許多其它視錯(cuò)覺(jué)之一。
When astronomers got their first glimpses of the moons far side, however, they saw astrikingly different landscape. Early lunar probes revealed a surface that was mountainous,rugged, heavily cratered and virtually devoid of maria. To quote Bill Anders, one of theastronauts on Apollo 8 and thus one of the first three people to see the far side of the moondirectly, it looks like a sand pile my kids have been playing in...all beat up, no definition, just alot of bumps and holes.
然而，當(dāng)天文學(xué)家首次瞥見(jiàn)月球較遠(yuǎn)的那側(cè)時(shí)，他們看到了一處截然不同的景觀。早期月球探測(cè)器顯示了這塊多山，崎嶇不平，擁有大量隕石坑以及幾乎毫無(wú)大海的地域的表面。引用阿波羅8號(hào)宇航員之一，也是首次直接看到月球較遠(yuǎn)那側(cè)的三個(gè)人之一的比爾?安德斯的話說(shuō)，那塊地方就像孩子們玩的沙堆一樣到處都是破破爛爛的，無(wú)法解釋，就是很多坑坑洼洼。
Selenologists, as those who study the moon callthemselves, have kicked around many theories toexplain the differences between the moons twofaces: Earth partly shielding the moon frommeteoritic impacts; uneven heating from beneath;the collision that excavated a 2,500km-wide craterat the lunar south pole, one of the biggest in thesolar system. None seems satisfactory. But in apaper just published in Nature Martin Jutzi and ErikAsphaug of the University of California, Santa Cruz,examine yet another idea. This is that the mountainsof the lunar far side may be debris left over from an even bigger collision than the one at thesouth polea collision that left lumps on the lunar surface rather than digging holes in it.
作為研究月球而稱他們自己為月球?qū)W家的那些人已經(jīng)非正式地討論了許多理論來(lái)解釋月球的兩種截然不同表面的區(qū)別：地球部分地保護(hù)了月球免受隕石的碰撞;月球內(nèi)部不均勻的加熱;在月球南極空砸出一個(gè)2500公里寬的隕石坑---太陽(yáng)系最大的隕石坑之一---的那次碰撞。好像沒(méi)人對(duì)些理論滿意。但是，加州大學(xué)圣克魯斯分校的馬丁?徹奇希和埃里克?阿薩福格剛剛在《自然雜志》發(fā)表的一篇論文檢驗(yàn)了迄今為止的另一個(gè)猜想。這個(gè)猜想就是月球較遠(yuǎn)那側(cè)的群山甚至可能是比月球南極那次碰撞更大的碰撞所留下的巖屑---這次更大碰撞在月球表面留下了隆起，而非砸坑。
Moonstruck
沉迷于幻想
The most widely accepted theory of how the moon formed suggests it is the result of a cosmicsmash-up between Earth and an object roughly the size of Mars that happened about 4.5 billionyears ago during the solar systems turbulent youth. This impact would have sprayed hugequantities of material into space, forming a ring around Earth similar to, but much thicker than,those that now adorn Saturn.
月球如何形成的最廣泛接受的理論表明，大約發(fā)生在45億年前的年輕的太陽(yáng)系動(dòng)蕩期間，地球和一個(gè)大約火星大小的物體間的宇宙大碰撞的結(jié)果而產(chǎn)生了月球。這次碰撞已將大量的物質(zhì)散發(fā)到了太空，從而形成了環(huán)繞地球的光環(huán)，類似于那些現(xiàn)在裝飾土星的光環(huán)，但是要厚得多。
The moon is thought to have condensed rapidly from this ring. Computer simulation of theprocess suggests, however, that several smaller moons may have formed at the same time.Some would then have collided with Earth or the moon, while others would have been ejectedfrom the system altogether. But one or more of them often end up, according to thesimulations, in what are known as Trojan orbits, where they followed the proto-moon endlesslyaround Earth.
月球被認(rèn)為是從這個(gè)光環(huán)的氣體凝聚而成。然而，計(jì)算機(jī)模擬的過(guò)程表明，這次大碰撞可能在同一時(shí)間形成了幾個(gè)更小的衛(wèi)星。然后，有些衛(wèi)星就與地球或月球相撞，而其它衛(wèi)星則完全被太陽(yáng)系噴射出來(lái)。但，根據(jù)計(jì)算機(jī)多次模擬，其中的一個(gè)或多個(gè)衛(wèi)星往往停留在被稱為特洛伊星座的軌道上而終結(jié)。這些衛(wèi)星在那兒伴隨著永無(wú)休止地圍繞地球的原月。
Or, rather, almost endlessly. For the hypothesis of Dr Jutzi and Dr Asphaug is that a largemoonlet did eventually catch up and collide with the proto-moonat a relatively low speedgiven that they shared an orbitand produced the highlands on its far side as a result.
或者，更確切些，幾乎是沒(méi)有休止的。因?yàn)閺仄嫦２┦亢桶⑺_福格博士的假說(shuō)就是一個(gè)大的小衛(wèi)星最終趕了上來(lái)并與這個(gè)原月發(fā)生了碰撞---考慮到它們共享一條軌道，是以相對(duì)低的速度碰撞---結(jié)果，就在月球較遠(yuǎn)的那側(cè)產(chǎn)生了那些群山。
To test their theory, the two researchers simulated such a collision on a computer. They foundthat, assuming the second moon was indeed smaller than the main one, and was made ofsimilar stuff , then a comparatively low-speed collision at around 2.4 kilometres asecond would mean that much more material from the moonlet was deposited on the lunarsurface than was blasted off by the impact. Most of the excess rock, moreover, would havestayed near the point of impact, covering about half of the moon with a thicker,mountainous layer of crustjust what is seen on the real moon.
為了測(cè)試他們的理論，這兩位研究者在計(jì)算機(jī)上模擬了這樣一次大碰撞。他們發(fā)現(xiàn)，假設(shè)第二個(gè)月球確實(shí)比最大的月球要小，并且由相似的物質(zhì)組成。然后，以大約每秒2.4公里的相對(duì)低速碰撞意味著，小衛(wèi)星上更多的物質(zhì)被沉積在月球表面而不是因碰撞而噴射出來(lái)。此外，過(guò)多的巖石將留落在碰撞點(diǎn)附近，且以更厚、多山的外殼層占了月球約為一半的面積 ---正如真正月球上所見(jiàn)到的一樣。
Of course, computer simulations can say only whatcould have happened, not what did. For that,physical evidence is required. Some suggestiveevidence does exist, though. For a start, the cruston the far side of the moon is indeed much thickerthan that on the nearside. Also, because the secondmoon would have been smaller than the main one, itwould have cooled and solidified more quickly,meaning that its rocks would be older. Sure enough,different parts of the present moons crust,recovered by various missions to the lunar surface,differ in age by up to 200m years, a fact that has long puzzled selenologists but which theimpact theory neatly explains. Moreover, such a huge collision on the far side would haveshifted much of the magma ocean that then underlay the moons surface to the near side,which led to the formation of the maria.
當(dāng)然，計(jì)算機(jī)模擬只能估計(jì)已經(jīng)發(fā)生的情形，而不是確實(shí)發(fā)生的情況。為此，實(shí)物證據(jù)是需要的。雖然，某些提示性的證據(jù)確實(shí)存在。因?yàn)閺囊婚_(kāi)始，較遠(yuǎn)那側(cè)的月球外殼確實(shí)比較近側(cè)的外殼要厚實(shí)的多。此外，因?yàn)檫@第二個(gè)月球應(yīng)該比最大的月球要小的多，所以這個(gè)月球應(yīng)該冷卻、凝固要快得多。這也意味著這個(gè)月球的巖石要年久的多。果真如此，現(xiàn)在月球外殼的不同部分，各次去月球表面的探測(cè)任務(wù)發(fā)現(xiàn)，這些巖石年代的不同達(dá)到 2億年之久。一個(gè)長(zhǎng)期困擾月球?qū)W家的客觀事實(shí)被碰撞理論巧妙地解釋了。此外，在月球較遠(yuǎn)那側(cè)如此巨大的一次碰撞應(yīng)該迅速移動(dòng)很多巖漿洋，然后在月球表面一直鋪到近地側(cè)，這就導(dǎo)致了月海的形成。
More evidence may surface when the Gravity Recovery and Interior Laboratory mission, anAmerican spacecraft designed to map the moons gravitational field, arrives in lunar orbit inaround six months time. That should yield a detailed map of the lunar crust, and how itsthickness varies from place to place. But the best way to check the new hypothesis would befor selenologists to get their hands on rocks from the far side.
當(dāng)引力恢復(fù)和室內(nèi)實(shí)驗(yàn)任務(wù)時(shí)，更多的證據(jù)可能會(huì)出現(xiàn)。一架設(shè)計(jì)用來(lái)勘測(cè)月球引力場(chǎng)的美國(guó)航天器，大約會(huì)在六個(gè)月內(nèi)到達(dá)月球軌道。這次探測(cè)任務(wù)應(yīng)該會(huì)產(chǎn)生出一份詳細(xì)的月球外殼圖，以及各個(gè)地方的厚度如何變化。但是，對(duì)月球?qū)W家來(lái)說(shuō)，檢查這個(gè)新假說(shuō)的最好方式就是找到月球較遠(yuǎn)那側(cè)的巖石。
Sadly, that is unlikely to happen soon. Neither America nor Russia has any sample-recoverymissions planned for the moon. China does . But, like the American andSoviet missions of the 1960s and 1970s, the Chinese are expected to opt for the safety of alanding on the near side. Selenologists may therefore have to wait a long time before they cantest the Jutzi-Asphaug model properly.
可嘆的是，這種情況不可能很快發(fā)生。無(wú)論是美國(guó)還是俄羅斯都沒(méi)有任何計(jì)劃去月球恢復(fù)取樣的任務(wù)。中國(guó)倒有一個(gè)。但是，像20世紀(jì)60年代和70年代的美國(guó)和蘇聯(lián)的任務(wù)一樣，中國(guó)人選擇在近地側(cè)安全著陸。因此，月球?qū)W家可能需要等待很長(zhǎng)一段時(shí)間才能夠真正測(cè)試徹奇希-阿薩福格模型。
Lunar history
月球的歷史
EARTHS moon has a split personality. One half of its surfacethe half which, thanks to thevagaries of orbital mechanics, always faces Earthis dominated by dark, smooth expanses ofancient, frozen lava known as maria . The contrast between the darkness of themaria and the brightness of the surrounding highlands forms a pattern popularly known,depending on the culture of the observer, as the man in the moon, the rabbit on the moon orone of many other optical illusions.
地球的衛(wèi)星---月球有著分裂的人格。其表面的一半 ---由于軌道力學(xué)的變幻莫測(cè)，這一半總是面對(duì)地球---一直處于黑暗之中。這片黑暗的地方被稱為月海，不僅平坦廣闊，而且由古老而凍結(jié)的火山巖形成。根據(jù)觀察者不同的文化，月海的黑暗和周圍群山的明亮對(duì)比形成了一種眾所周知的模式，比如嫦娥，月兔或許多其它視錯(cuò)覺(jué)之一。
When astronomers got their first glimpses of the moons far side, however, they saw astrikingly different landscape. Early lunar probes revealed a surface that was mountainous,rugged, heavily cratered and virtually devoid of maria. To quote Bill Anders, one of theastronauts on Apollo 8 and thus one of the first three people to see the far side of the moondirectly, it looks like a sand pile my kids have been playing in...all beat up, no definition, just alot of bumps and holes.
然而，當(dāng)天文學(xué)家首次瞥見(jiàn)月球較遠(yuǎn)的那側(cè)時(shí)，他們看到了一處截然不同的景觀。早期月球探測(cè)器顯示了這塊多山，崎嶇不平，擁有大量隕石坑以及幾乎毫無(wú)大海的地域的表面。引用阿波羅8號(hào)宇航員之一，也是首次直接看到月球較遠(yuǎn)那側(cè)的三個(gè)人之一的比爾?安德斯的話說(shuō)，那塊地方就像孩子們玩的沙堆一樣到處都是破破爛爛的，無(wú)法解釋，就是很多坑坑洼洼。
Selenologists, as those who study the moon callthemselves, have kicked around many theories toexplain the differences between the moons twofaces: Earth partly shielding the moon frommeteoritic impacts; uneven heating from beneath;the collision that excavated a 2,500km-wide craterat the lunar south pole, one of the biggest in thesolar system. None seems satisfactory. But in apaper just published in Nature Martin Jutzi and ErikAsphaug of the University of California, Santa Cruz,examine yet another idea. This is that the mountainsof the lunar far side may be debris left over from an even bigger collision than the one at thesouth polea collision that left lumps on the lunar surface rather than digging holes in it.
作為研究月球而稱他們自己為月球?qū)W家的那些人已經(jīng)非正式地討論了許多理論來(lái)解釋月球的兩種截然不同表面的區(qū)別：地球部分地保護(hù)了月球免受隕石的碰撞;月球內(nèi)部不均勻的加熱;在月球南極空砸出一個(gè)2500公里寬的隕石坑---太陽(yáng)系最大的隕石坑之一---的那次碰撞。好像沒(méi)人對(duì)些理論滿意。但是，加州大學(xué)圣克魯斯分校的馬丁?徹奇希和埃里克?阿薩福格剛剛在《自然雜志》發(fā)表的一篇論文檢驗(yàn)了迄今為止的另一個(gè)猜想。這個(gè)猜想就是月球較遠(yuǎn)那側(cè)的群山甚至可能是比月球南極那次碰撞更大的碰撞所留下的巖屑---這次更大碰撞在月球表面留下了隆起，而非砸坑。
Moonstruck
沉迷于幻想
The most widely accepted theory of how the moon formed suggests it is the result of a cosmicsmash-up between Earth and an object roughly the size of Mars that happened about 4.5 billionyears ago during the solar systems turbulent youth. This impact would have sprayed hugequantities of material into space, forming a ring around Earth similar to, but much thicker than,those that now adorn Saturn.
月球如何形成的最廣泛接受的理論表明，大約發(fā)生在45億年前的年輕的太陽(yáng)系動(dòng)蕩期間，地球和一個(gè)大約火星大小的物體間的宇宙大碰撞的結(jié)果而產(chǎn)生了月球。這次碰撞已將大量的物質(zhì)散發(fā)到了太空，從而形成了環(huán)繞地球的光環(huán)，類似于那些現(xiàn)在裝飾土星的光環(huán)，但是要厚得多。
The moon is thought to have condensed rapidly from this ring. Computer simulation of theprocess suggests, however, that several smaller moons may have formed at the same time.Some would then have collided with Earth or the moon, while others would have been ejectedfrom the system altogether. But one or more of them often end up, according to thesimulations, in what are known as Trojan orbits, where they followed the proto-moon endlesslyaround Earth.
月球被認(rèn)為是從這個(gè)光環(huán)的氣體凝聚而成。然而，計(jì)算機(jī)模擬的過(guò)程表明，這次大碰撞可能在同一時(shí)間形成了幾個(gè)更小的衛(wèi)星。然后，有些衛(wèi)星就與地球或月球相撞，而其它衛(wèi)星則完全被太陽(yáng)系噴射出來(lái)。但，根據(jù)計(jì)算機(jī)多次模擬，其中的一個(gè)或多個(gè)衛(wèi)星往往停留在被稱為特洛伊星座的軌道上而終結(jié)。這些衛(wèi)星在那兒伴隨著永無(wú)休止地圍繞地球的原月。
Or, rather, almost endlessly. For the hypothesis of Dr Jutzi and Dr Asphaug is that a largemoonlet did eventually catch up and collide with the proto-moonat a relatively low speedgiven that they shared an orbitand produced the highlands on its far side as a result.
或者，更確切些，幾乎是沒(méi)有休止的。因?yàn)閺仄嫦２┦亢桶⑺_福格博士的假說(shuō)就是一個(gè)大的小衛(wèi)星最終趕了上來(lái)并與這個(gè)原月發(fā)生了碰撞---考慮到它們共享一條軌道，是以相對(duì)低的速度碰撞---結(jié)果，就在月球較遠(yuǎn)的那側(cè)產(chǎn)生了那些群山。
To test their theory, the two researchers simulated such a collision on a computer. They foundthat, assuming the second moon was indeed smaller than the main one, and was made ofsimilar stuff , then a comparatively low-speed collision at around 2.4 kilometres asecond would mean that much more material from the moonlet was deposited on the lunarsurface than was blasted off by the impact. Most of the excess rock, moreover, would havestayed near the point of impact, covering about half of the moon with a thicker,mountainous layer of crustjust what is seen on the real moon.
為了測(cè)試他們的理論，這兩位研究者在計(jì)算機(jī)上模擬了這樣一次大碰撞。他們發(fā)現(xiàn)，假設(shè)第二個(gè)月球確實(shí)比最大的月球要小，并且由相似的物質(zhì)組成。然后，以大約每秒2.4公里的相對(duì)低速碰撞意味著，小衛(wèi)星上更多的物質(zhì)被沉積在月球表面而不是因碰撞而噴射出來(lái)。此外，過(guò)多的巖石將留落在碰撞點(diǎn)附近，且以更厚、多山的外殼層占了月球約為一半的面積 ---正如真正月球上所見(jiàn)到的一樣。
Of course, computer simulations can say only whatcould have happened, not what did. For that,physical evidence is required. Some suggestiveevidence does exist, though. For a start, the cruston the far side of the moon is indeed much thickerthan that on the nearside. Also, because the secondmoon would have been smaller than the main one, itwould have cooled and solidified more quickly,meaning that its rocks would be older. Sure enough,different parts of the present moons crust,recovered by various missions to the lunar surface,differ in age by up to 200m years, a fact that has long puzzled selenologists but which theimpact theory neatly explains. Moreover, such a huge collision on the far side would haveshifted much of the magma ocean that then underlay the moons surface to the near side,which led to the formation of the maria.
當(dāng)然，計(jì)算機(jī)模擬只能估計(jì)已經(jīng)發(fā)生的情形，而不是確實(shí)發(fā)生的情況。為此，實(shí)物證據(jù)是需要的。雖然，某些提示性的證據(jù)確實(shí)存在。因?yàn)閺囊婚_(kāi)始，較遠(yuǎn)那側(cè)的月球外殼確實(shí)比較近側(cè)的外殼要厚實(shí)的多。此外，因?yàn)檫@第二個(gè)月球應(yīng)該比最大的月球要小的多，所以這個(gè)月球應(yīng)該冷卻、凝固要快得多。這也意味著這個(gè)月球的巖石要年久的多。果真如此，現(xiàn)在月球外殼的不同部分，各次去月球表面的探測(cè)任務(wù)發(fā)現(xiàn)，這些巖石年代的不同達(dá)到 2億年之久。一個(gè)長(zhǎng)期困擾月球?qū)W家的客觀事實(shí)被碰撞理論巧妙地解釋了。此外，在月球較遠(yuǎn)那側(cè)如此巨大的一次碰撞應(yīng)該迅速移動(dòng)很多巖漿洋，然后在月球表面一直鋪到近地側(cè)，這就導(dǎo)致了月海的形成。
More evidence may surface when the Gravity Recovery and Interior Laboratory mission, anAmerican spacecraft designed to map the moons gravitational field, arrives in lunar orbit inaround six months time. That should yield a detailed map of the lunar crust, and how itsthickness varies from place to place. But the best way to check the new hypothesis would befor selenologists to get their hands on rocks from the far side.
當(dāng)引力恢復(fù)和室內(nèi)實(shí)驗(yàn)任務(wù)時(shí)，更多的證據(jù)可能會(huì)出現(xiàn)。一架設(shè)計(jì)用來(lái)勘測(cè)月球引力場(chǎng)的美國(guó)航天器，大約會(huì)在六個(gè)月內(nèi)到達(dá)月球軌道。這次探測(cè)任務(wù)應(yīng)該會(huì)產(chǎn)生出一份詳細(xì)的月球外殼圖，以及各個(gè)地方的厚度如何變化。但是，對(duì)月球?qū)W家來(lái)說(shuō)，檢查這個(gè)新假說(shuō)的最好方式就是找到月球較遠(yuǎn)那側(cè)的巖石。
Sadly, that is unlikely to happen soon. Neither America nor Russia has any sample-recoverymissions planned for the moon. China does . But, like the American andSoviet missions of the 1960s and 1970s, the Chinese are expected to opt for the safety of alanding on the near side. Selenologists may therefore have to wait a long time before they cantest the Jutzi-Asphaug model properly.
可嘆的是，這種情況不可能很快發(fā)生。無(wú)論是美國(guó)還是俄羅斯都沒(méi)有任何計(jì)劃去月球恢復(fù)取樣的任務(wù)。中國(guó)倒有一個(gè)。但是，像20世紀(jì)60年代和70年代的美國(guó)和蘇聯(lián)的任務(wù)一樣，中國(guó)人選擇在近地側(cè)安全著陸。因此，月球?qū)W家可能需要等待很長(zhǎng)一段時(shí)間才能夠真正測(cè)試徹奇希-阿薩福格模型。
