The study recommends that in the mid-sixth century, the earth suddenly become cooler for the dimming of the sun. The study also assumes that a huge volcanic eruption or a large meteorite colliding with erath could have created a large dust cloud so as to block enough sunlight then lower the global temperatures, and some survive records mentioned a loud boom that would consistent with a volcanic eruption. However, the study relies on a series of unsubstantiated assumptions, which render it unconvincing as it stands.
First of all, the author assumes that few historical records which founded in Asia and Europe which mention a dimming of sunlight and extremely cold temperature could reflect the whole earth under the same changes. However, the author provides no evidence that this is the case. Without additional records from other places, I cannot accept the author's sweeping generalization about the the temperatures decline in mid-sixth century globally.
In the second place, the author gives two reasons about why the sunlight dimed and then cause the temperatures cool down. The author overlooks other possibilities. Perhaps large scale forest fire cause circumstance destroyed , or perhaps the recorders forced to change their cities to north. In either event, the author could not justifiably rely on the mere fact that just volcanic eruption and meteorite collide are the reasons of temperatures decline.
In the third place, the author claims a large meteorite collide would probably create a sudden bright flash of light, and no extent historical records of the time mention such a flash, so the author exclusive the possibility of meteorite collide. But the author provides no evidence to substantiate this assumption. It is entirely possible that in the recorder's observation scale is too far beyond the place where meteorite collided. Therefore, the mere fact that no records mention such a flash lends scant support to the recommendation.
Finally, in asserting that some Asian historical records of the time mention a loud boom that would be consistent with a volcanic eruption, the author believes the cooling was probably caused by a volcanic eruption. But the author provides no evidence to substantiate the assumption. It is possible that the loud boom happened behind the cooling. And it is also possible that the loud boom is not associated with volcanic eruption. Without ruling out these possible scenarios, the author cannot convince me that the volcanic eruption is the cause of cooling.
In conclusion, the other causes of temperature cooling are not presented. To convince me that volcanic eruption is the reason of cooling, the author must provide more records from other regions, what caused the loud boom and the temperatures comparison between before the boom and the after.作者: xiaoyaozi5566 时间: 2009-2-16 21:27:48
楼主的第一个攻击点有点牵强，原文说的是很少有史料留下，不过在亚洲和欧洲发现了一些史料，并不是说没有去其他地方找史料，只是找不到而已（个人理解）
第二点的other factors找的不太好，虽然我也没找到什么比较靠谱的
第三点我认为还有一个可能的原因是就是这部分的史料没被找到或被毁坏了（few historical records survive from that time)
其他的没什么了，不过语言上变化少了点，the author provides no evidence to substantiate the assumption. 这句话用了两遍，楼主需要多多积累啊！