[a习作temp] 3/6 argument 50 很没感觉,觉得问题找的不正,麻烦大家指教 [复制链接]

iceforeverkid
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发表于 2010-3-6 20:05:13 |只看该作者 |倒序浏览

本帖最后由 iceforeverkid 于 2010-3-7 11:43 编辑

TOPIC: ARGUMENT50 - From a draft textbook manuscript submitted to a publisher.

"As Earth was being formed out of the collision of space rocks, the heat from those collisions and from the increasing gravitational energy of the planet made the entire planet molten, even the surface. Any water present would have evaporated and gone off into space. As the planet approached its current size, however, its gravitation became strong enough to hold gases and water vapor around it as an atmosphere. Because comets are largely ice made up of frozen water and gases, a comet striking Earth then would have vaporized. The resulting water vapor would have been retained in the atmosphere, eventually falling as rain on the cooled and solidified surface of Earth. Therefore, the water in Earth's oceans must have originated from comets."

In this argument, the author claims that comets are the origin that water in Earth's ocean from. To defend this argument the author explains that the Earth is formed by the collision of space rocks which caused the heat to melt the planet and evaporate the water. Retaining water in the atmosphere then fell to the ground as rain. It seems to be true, at the first glance, but a close scrutiny may prove it a mistake.
First, the author imprudently concludes that water vapor in the atmosphere has a definite relation with the water vapor evaporated by the heat due to collisions. However, it offers no evidence that they are directly linked. Thus, the conclusion is unconvincing. There is certainly possibility that the proportion of water formed by collision occupies little in the whole amount of atmosphere water. Similarly, the author provides no proofs, as well, to demonstrate that it is the gravitation of the planet making effective the holding of water vapor. Perhaps it is other planet or other factors of the planet which probably accounts more to affect the water vapor. Without ruling our all these possibilities, it cannot be easily accepted that the falling as rain is the origin of the oceans.
Moreover, even I concede that the water vapor in the atmosphere resulting from the water vapor evaporated by the collision, and that the water vapor remaining in the atmosphere is held because of the gravitation, I query the casual relation between the rain and ocean. Ocean is derived from many kinds of waters, such as rivers, lakes, and pools. Simply stating that they are closely related without certain evidence cannot be recognized as truth, as far as the entire reasons given by the author. It might be wise for the author to enclose more results of the relation between them in a scientific way.
Still, the author strangely raised an opinion that the comets are mostly made up of ice without any further scientific proof, while there is no doubt that it could be rocks or other ingredients that compose the comets. Once it is proved trustless, the hypnosis that the rain caused the oceans is false.
Finally, the notion that any water present eventually vapors into the atmosphere can hardly be regarded as persuasive in that it is commonly known that waters underground amounts to a certain percentage of the total water on the earth, which not vapors a lot running into the oceans, let alone some other blocked waters on the earth. Hence, without ruling out these possibilities, the argument is controversial.
In sum, the author weakly present the relation between the water vapor brought by collision and that in the atmosphere, between rain and the ocean. Lacking of evidence that the comets are mainly constructed by the water and that the gravitation contributes to the holding of the water in the atmosphere makes the notion even more questionable. Unless the possibilities and other factors are carefully figured out, I won’t accept the argument.