外星生命也许是紫色的

时间:2018-12-26 08:12:20

(单词翻译:单击)

Alien life might be purple.
 
外星生命也许是紫色的。
 
That's the conclusion of a new research paper that suggests that the first life on Earth might have had a lavender hue1. In the International Journal of Astrobiology, microbiologist Shiladitya DasSarma of the University of Maryland School of Medicine and postdoctoral researcher Edward Schwieterman at the University of California, Riverside, argue that before green plants started harnessing the power of the sun for energy, tiny purple organisms figured out a way to do the same.
 
Alien life could be thriving in the same way, DasSarma said.
 
"Astronomers2 have discovered thousands of new extrasolar planets recently and are developing the capacity to see surface biosignatures" in the light reflected from these planets, he told Live Science. There are already ways to detect green life from space, he said, but scientists might need to start looking for purple, too. 
 
The idea that the early Earth was purple is not new, DasSarma and his colleagues advanced the theory in 2007. The thinking goes like this: Plants and photosynthesizing algae3 use chlorophyll to absorb energy from the sun, but they don't absorb green light. That's odd, because green light is energy-rich. Perhaps, DasSarma and his colleagues reasoned, something else was already using that part of the spectrum4 when chlorophyll photosynthesizers evolved.
 
That "something else" would be simple organisms that captured solar energy with a molecule5 called retinal. Retinal pigments6 absorb green light best. They're not as efficient as chlorophylls in capturing solar energy, but they are simpler, the researchers wrote in their new paper.
 
Retinal light-harvesting is still widespread today among bacteria and the single-celled organisms called Archaea. These purple organisms have been discovered everywhere from the oceans to the Antarctic Dry Valley to the surfaces of leaves, Schwieterman told Live Science. Retinal pigments are also found in the visual system of more complex animals.
 
The appearance of the pigments across many living organisms hints that they may have evolved very early on, in ancestors common to many branches of the tree of life, the researchers wrote. There is even some evidence that modern purple-pigmented salt-loving organisms called halophiles might be related to some of the earliest life on Earth, which thrived around methane7 vents8 in the ocean, Schwieterman said.

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1 hue qdszS     
n.色度;色调;样子
参考例句:
  • The diamond shone with every hue under the sun.金刚石在阳光下放出五颜六色的光芒。
  • The same hue will look different in different light.同一颜色在不同的光线下看起来会有所不同。
2 astronomers 569155f16962e086bd7de77deceefcbd     
n.天文学者,天文学家( astronomer的名词复数 )
参考例句:
  • Astronomers can accurately foretell the date,time,and length of future eclipses. 天文学家能精确地预告未来日食月食的日期、时刻和时长。 来自《简明英汉词典》
  • Astronomers used to ask why only Saturn has rings. 天文学家们过去一直感到奇怪,为什么只有土星有光环。 来自《简明英汉词典》
3 algae tK6yW     
n.水藻,海藻
参考例句:
  • Most algae live in water.多数藻类生长在水中。
  • Algae grow and spread quickly in the lake.湖中水藻滋蔓。
4 spectrum Trhy6     
n.谱,光谱,频谱;范围,幅度,系列
参考例句:
  • This is a kind of atomic spectrum.这是一种原子光谱。
  • We have known much of the constitution of the solar spectrum.关于太阳光谱的构成,我们已了解不少。
5 molecule Y6Tzn     
n.分子,克分子
参考例句:
  • A molecule of water is made up of two atoms of hygrogen and one atom of oxygen.一个水分子是由P妈?f婘??妈?成的。
  • This gives us the structural formula of the molecule.这种方式给出了分子的结构式。
6 pigments 90c719a2ef7a786d9af119297e63a36f     
n.(粉状)颜料( pigment的名词复数 );天然色素
参考例句:
  • The Romans used natural pigments on their fabrics and walls. 古罗马人在织物和墙壁上使用天然颜料。 来自辞典例句
  • The original white lead pigments have oxidized and turned black. 最初的白色铅质颜料氧化后变成了黑色。 来自辞典例句
7 methane t1Eyx     
n.甲烷,沼气
参考例句:
  • The blast was caused by pockets of methane gas that ignited.爆炸是由数袋甲烷气体着火引起的。
  • Methane may have extraterrestrial significance.甲烷具有星际意义。
8 vents 3fd48768f3da3e458d6b73926735d618     
(气体、液体等进出的)孔、口( vent的名词复数 ); (鸟、鱼、爬行动物或小哺乳动物的)肛门; 大衣等的)衩口; 开衩
参考例句:
  • He always vents his anger on the dog. 他总是拿狗出气。
  • The Dandelion Patch is the least developed of the four active vents. “蒲公英区”在这四个活裂口中是发育最差的一个。

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