Shale gas: Surface water also at risk
Shale gas: Surface water also at risk
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DOI：
10.1038/499154c
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发表时间：
2013-07
期刊：
影响因子：
64.8
通讯作者：
G. Zeng;Ming Chen;Zhuotong Zeng
中科院分区：
文献类型：
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作者：
G. Zeng;Ming Chen;Zhuotong Zeng
Nidhal Guessoum提到的天文学的重大成就早于公元9世纪至16世纪阿拉伯天文学的“黄金时代”（Nature 498, 161-164; 2013）。天文学在公元前4世纪到公元1世纪之间发展起来，尤其是在公元前3世纪。它从观测表中逐渐成熟，从中只认识到一些一般的模式（例如沙罗月食周期），到对太阳系的合理理解。这包括对地球、太阳和月亮的大小以及它们的距离的准确估计，以及对春分岁差的发现。更重要的是，一个宏伟的数学结构可以预测天空中所有可见的主要天体的位置，其精度接近观测的最佳精度（10分弧度）。这些成就是亚历山大天文学的产物，主要是由生活在埃及的希腊人完成的，并由作家克劳狄乌斯·托勒密总结。出于良好的动机，Guessoum列举了阿拉伯人在天文学方面的卓越成就，比如用来测量时间的柱（地晷）（在早期科学不发达的罗马帝国很常见），以及水手们用月亮的弧线来指示东西线（这种技术在几千年前就已经为人所知）。但是，将这些成就美化为成就显示出对当今阿拉伯世界学生的缺乏尊重。此外，阿拉伯天文学的严格宗教动机在亚历山大时代是不存在的，这听起来可能像是宗教控制科学的理由——在许多国家仍然是一种危险。值得赞扬的是，阿拉伯天文学家认识到了
The substantial achievements in astronomy that Nidhal Guessoum refers to occurred earlier than the ‘golden age’of Arab astronomy from the ninth to the sixteenth century ad (Nature 498, 161–164; 2013). Astronomy developed between the fourth century bc and the first century ad, but especially in the third century bc. It matured from tables of observations, from which only a few general patterns were recognized (the saros eclipse cycles, for example), into a sound understanding of the Solar System. This included good estimates for the size of Earth and the sizes of the Sun and the Moon, as well as their distances, and the discovery of the precession of the equinoxes. More importantly, a majestic mathematical construction allowed the prediction of the positions of all of the major bodies visible in the sky, with a precision close to the best available with observation (10 minutes of arc). These achievements were products of Alexandrian astronomy, mostly by Greeks living in Egypt, and were summarized by the writer Claudius Ptolemy. Good intentions motivate Guessoum’s examples of Arab excellence in astronomy, such as columns (gnomons) that were used to measure time (common in the earlier, scientifically illiterate Roman Empire) and of sailors using the arc of the Moon to indicate the east–west line (a technique already known for a couple of millennia). But glorifying these as achievements shows a lack of respect for today’s students in the Arab world. Furthermore, the stated strictly religious motivations of Arab astronomy, absent in Alexandrian times, may sound like a justification for religious control of science—still a danger in many countries. To their credit, Arab astronomers recognized the