SSS 2009-12-22
时间：2018-12-02 作者：英语课 分类：Scientific American(十二)月
In 2008 astronomers 1 discovered surprising amounts of water molecules 2 where planets were forming near young stars. But how, they wondered, could those molecules survive? They should have been destroyed by ultraviolet radiation. In theory, planetary dust could block out UV rays, but the dust was bound up in the creation of those young planets. So what's protecting the water? Now researchers at the University of Michigan believe they have the answer, which they published in the December 18th edition of the journal Science.
The regions where planets are being created are incredibly chemically productive, rapidly generating new compounds. According to the researchers, some water molecules surround the almost-planet dust and act as almost a sacrificial layer. The water molecules absorb the ultraviolet rays—and, though those molecules are destroyed, the embryonic 3 planet is shielded. And the region is producing water faster than the protective layer is being destroyed.
The scientists say this action is similar to our ozone 4 layer, which blankets us with protective shielding from UV radiation. They tested this idea in computer models and found that the results mirrored the observations. Seems that having water when a planet’s finished requires sacrificing some in the process.
- 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》
- 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。