万物简史 第416期:生命的起源(10)

 The Murchison meteorite¹ was found to be 4.5 billion years old, 人们发现，默奇森陨石的年代已达45亿年，

and it was studded with amino acids—seventy-four types in all, eight of which are involved in the formation of earthly proteins. 上面星星点点地布满着氨基酸——总共有74种之多，其中8种跟地球上的蛋白质有关。

In late 2001, more than thirty years after it crashed, 2001年底，在陨石坠落30多年以后，

a team at the Ames Research Center in California announced that the Murchison rock also contained complex strings² of sugars called polyols,  加利福尼亚的埃姆斯研究中心宣布，默奇森陨石里还含有一系列复杂的糖，名叫多羟基化合物。

which had not been found off the Earth before. 这类糖以前在地球之外是没有发现过的。

A few other carbonaceous chondrites have strayed into Earth's path since, 自1969年以来，又有几块碳质球粒陨石进入地球轨道，

one that landed near Tagish Lake in Canada's Yukon in January 2000 was seen over large parts of North America, 有一块于2000年1月坠落在加拿大育空地区的塔吉什湖附近，

and they have likewise confirmed that the universe is actually rich in organic compounds. 北美许多地方的人都亲眼目睹了那个景象——它同样证明，宇宙里实际上存在丰富的有机化合物。

Halley's comet, it is now thought, is about 25 percent organic molecules³. 现在认为，哈雷彗星大约25%是有机分子。

Get enough of those crashing into a suitable place—Earth, for instance—and you have the basic elements you need for life. 要是这类陨石经常坠落在一个合适地方——比如地球，你就有了生命所需的基本元素。

There are two problems with notions of panspermia, as extraterrestrial theories are known. 胚种说——即生命源来天外的理论——的观点有两个问题。

The first is that it doesn't answer any questions about how life arose, but merely moves responsibility for it elsewhere. 第一，它没有回答生命是如何产生的这个问题，只是把责任推给了别的地方。

The other is that panspermia sometimes excites even the most respectable adherents⁴ to levels of speculation⁵ that can be safely called imprudent. 第二，连胚种说的最受人尊敬的支持者有时候也到了猜测的地步。肯定可以说，这是很轻率的。

Francis Crick, codiscoverer of the structure of DNA⁶, and his colleague Leslie Orgel have suggested that Earth was "deliberately⁷ seeded with life by intelligent aliens," DNA结构的两个发现者之一弗朗西斯·克里克和他的同事莱斯利·奥格尔认为“聪明的外星人故意把生命物种子”播在了地球。

an idea that Gribbin calls "at the very fringe of scientific respectability", 格里宾称这个观点“处于科学地位的最边缘”，

or, put another way, a notion that would be considered wildly lunatic if not voiced by a Nobel laureate. 换句话说，假如这个观点不是一位诺贝尔奖获得者提出的，人家会认为它简直荒唐透顶。

1 meteorite   

n.陨石；流星

参考例句：

• The meteorite in Jilin Exhibition Hall is believed to be the largest in the world.吉林展览馆的陨石被认为是世界上最大的。
• The famous Murchison meteorite smashed into the Australian ground in 1969.1969年著名的默奇森陨石轰然坠落在澳大利亚。

2 strings   

n.弦

参考例句：

• He sat on the bed,idly plucking the strings of his guitar.他坐在床上，随意地拨着吉他的弦。
• She swept her fingers over the strings of the harp.她用手指划过竖琴的琴弦。

3 molecules   

分子( molecule的名词复数 )

参考例句：

• The structure of molecules can be seen under an electron microscope. 分子的结构可在电子显微镜下观察到。
• Inside the reactor the large molecules are cracked into smaller molecules. 在反应堆里，大分子裂变为小分子。

4 adherents   

n.支持者，拥护者( adherent的名词复数 )；党羽；徒子徒孙

参考例句：

• He is a leader with many adherents. 他是个有众多追随者的领袖。 来自《简明英汉词典》
• The proposal is gaining more and more adherents. 该建议得到越来越多的支持者。 来自《简明英汉词典》

5 speculation   

n.思索，沉思；猜测；投机

参考例句：

• Her mind is occupied with speculation.她的头脑忙于思考。
• There is widespread speculation that he is going to resign.人们普遍推测他要辞职。

6 DNA   

(缩)deoxyribonucleic acid 脱氧核糖核酸

参考例句：

• DNA is stored in the nucleus of a cell.脱氧核糖核酸储存于细胞的细胞核里。
• Gene mutations are alterations in the DNA code.基因突变是指DNA密码的改变。

7 deliberately   

adv.审慎地；蓄意地；故意地

参考例句：

• The girl gave the show away deliberately.女孩故意泄露秘密。
• They deliberately shifted off the argument.他们故意回避这个论点。