2009 进军美利坚作文组 wondersmiths2第九次作业 8.26

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高分120 practice 3
In the lecture, the speaker is discussing about the formation of the Moon, and he points out that the arguments stated in the reading passage are not convincing, due to the following reasons.

Firstly, the fact that there is no huge mark on the surface of the Earth is not necessary to prove that the giant-impact theory is wrong, because it happened four billion years ago and perhaps the huge mark has been gone for the cause of the forces of nature such as climate change. So this opinion stated the lecture totally differs from the point shown in the reading passage.

Secondly, It is not surprising that there is no water in the rocks of the Moon because of the high temperature when the giant impact happened. With the high temperature, the water in the rocks already evaporated into outer space. Hence, it is directly contrast to the view in the reading passage.

Finally, the speaker raises the issue that why the density of the Moon is lower than that of the Earth. He thinks that the Moon is from part of the surface of the Earth and in fact the density of the Moon is similar to the density of the surface of the Earth. Therefore, the evidence used in the reading passage still cannot prove the giant-impact theory doubtful.