SSS 2012-03-06
时间：2019-01-08 作者：英语课 分类：Scientific American(三)月
英语课
This is Scientific American 60 Second Science, I am Cynthia Graber, this will just take a minute~
How can we search for life on exoplanets? Step one: examine the Earth as if it were an exoplanet. That’s the idea behind a recent look at earthshine.
Researchers aimed what’s officially called the Very Large Telescope, housed at the European Southern Observatory 1, at the moon. They measured earthshine: sunlight that reflects off the Earth, hits the moon and bounces back.
The scientists are looking for hints of life in the light—such as evidence of the gases associated with organic life. Such gas signatures are generally tough to find, because any planetary light is swamped by the light of its host star.
But in this effort, the research team also took into account polarized light. Because light reflected off a planet is polarized. But light from the star is not.
The analysis of earthshine correctly revealed that the planet it came from has a partly cloudy atmosphere and is covered with oceans and some vegetation. The researchers could even ascertain 2 changes in cloud cover and vegetation as the Earth turned. The research was published in the journal Nature.
Similar scrutiny 3 of actual exoplanets may one day reveal the first good suspects for harboring life—via their light.
Thanks for the minute for Scientific American 60 Second Science, I'm Cynthia Graber.
n.天文台，气象台，瞭望台，观测台
- Guy's house was close to the observatory.盖伊的房子离天文台很近。
- Officials from Greenwich Observatory have the clock checked twice a day.格林威治天文台的职员们每天对大钟检查两次。
vt.发现，确定，查明，弄清
- It's difficult to ascertain the coal deposits.煤储量很难探明。
- We must ascertain the responsibility in light of different situtations.我们必须根据不同情况判定责任。