英语 英语 日语 日语 韩语 韩语 法语 法语 德语 德语 西班牙语 西班牙语 意大利语 意大利语 阿拉伯语 阿拉伯语 葡萄牙语 葡萄牙语 越南语 越南语 俄语 俄语 芬兰语 芬兰语 泰语 泰语 泰语 丹麦语 泰语 对外汉语

SSS 2011-10-10

时间:2011-11-01 07:55来源:互联网 提供网友:gmeng   字体: [ ]
特别声明:本栏目内容均从网络收集或者网友提供,供仅参考试用,我们无法保证内容完整和正确。如果资料损害了您的权益,请与站长联系,我们将及时删除并致以歉意。
    (单词翻译:双击或拖选)

 This is Scientific American's 60-Second Science. I'm John Matson. Got a minute?

 
Earth's surface is dominated by oceans. But where did all that water come from?
 
Asteroids1 and comets smashing into the early Earth have long been thought to be a promising2 source. But measurements of Halley's Comet and five others threw cold water on the idea that comets provided a large share of the oceans. Because the chemical signatures of the comets did not match the oceans. Specifically, the ratio of heavy hydrogen, or deuterium, to regular hydrogen was too high in the comets.
 
But now astronomers3 have gotten a glimpse of a comet with a different origin, and it matches the oceans much better. They used the Herschel space telescope to examine Comet Hartley 2, which originated in the Kuiper Belt. Halley and its ilk came from a distant swarm4 of comets called the Oort Cloud.
 
At a planetary science meeting last week in France, and in a study in Nature, the researchers announced that Comet Hartley 2 has the same deuterium-to-hydrogen ratio as ocean water. 
 
So maybe comets did play a major role in delivering Earth's oceans. Something to ponder next time you have a day at the beach.
 
Thanks for the minute. For Scientific American's 60-Second Science, I'm John Matson.

点击收听单词发音收听单词发音  

1 asteroids d02ebba086eb60b6155b94e12649ff84     
n.小行星( asteroid的名词复数 );海盘车,海星
参考例句:
  • Asteroids,also known as "minor planets",are numerous in the outer space. 小行星,亦称为“小型行星”,在外太空中不计其数。
  • Most stars probably have their quota of planets, meteorids, comets, and asteroids. 多数恒星也许还拥有若干行星、流星、彗星和小行星。
2 promising BkQzsk     
adj.有希望的,有前途的
参考例句:
  • The results of the experiments are very promising.实验的结果充满了希望。
  • We're trying to bring along one or two promising young swimmers.我们正设法培养出一两名有前途的年轻游泳选手。
3 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》
4 swarm dqlyj     
n.(昆虫)等一大群;vi.成群飞舞;蜂拥而入
参考例句:
  • There is a swarm of bees in the tree.这树上有一窝蜜蜂。
  • A swarm of ants are moving busily.一群蚂蚁正在忙碌地搬家。
本文本内容来源于互联网抓取和网友提交,仅供参考,部分栏目没有内容,如果您有更合适的内容,欢迎点击提交分享给大家。
------分隔线----------------------------
TAG标签:   托福素材  sss
顶一下
(0)
0%
踩一下
(0)
0%
最新评论 查看所有评论
发表评论 查看所有评论
请自觉遵守互联网相关的政策法规,严禁发布色情、暴力、反动的言论。
评价:
表情:
验证码:
听力搜索
推荐频道
论坛新贴