ARGUMENT50 地球上的海来源于行星么 互拍互拍

speaklessUID：2205899

题目：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."
字数：640          用时：0:35:23          日期：2007-7-20

The conclusion of argument is that the water in Earth's oceans must be the only originated from comets which are made up of frozen water and gases. To support the conclusion, the arguer wants to cast off the possibility that water on earth when it was just being formed should not retained on earth due to the high temperature. In the mean time, (another source of water) from comets has been proved by the arguer as the only source of water. Although the logical process seems reasonable, I have to contend that there are some fallacies that weaken the validity.

Although the water on earth cannot exist on the planet because of its molten surface, it is no indication that the water which would have evaporated and gone off into space will never return back to earth. As the arguer explains, when the earth evolved into its current size, the gravitation is strong enough to hold gasses and water vapor around it. In this circumstance, if the water, even if part of them, which was exited on earth before could suspend around the earth in the form of gasses or water vapor. It is more likely that they could be drawn back to earth when its gravitation has been largely strengthened. And then it can form the oceans with waters from other sources together. Therefore, without explaining the outlets of evaporating water and answer the questions whether they have left the neighborhood of the earth or spreaded into the universe, it is still early to cast off the possibility that the water in Earth's oceans may come from the water on it before.

Still more, the arguer also makes some logic errors and overlooks some alternatives when he/she wants to testify that water from comets can form Earth's ocean. Firstly, the arguer fails to give any information about the time when the earth became cooled and solidified. If the time is much later than that of comet rains, although the water contained in comets can reach the earth, it is more likely to follow(receive) the same destiny as the former water: being evaporated and gone off into space. Secondly, even if the earth has been in the state of cooling and solidity, other circumstances about the details of falling process should be examined carefully: for example, as we all know, the rains occur only when there is certain amount of water which is preserved in the air. So at that time, if the atmosphere cannot retain such amount of water because of lacking gravitation, although quite strong, the rains on earth should never happen in that period. In this case, it can be hard to explain how this source of water falls down the earth. Without casting off the alternatives that weaken the validity of the arguer's theory, it is far from making a conclusion.

In addition, other sources of water that may be used to explain the form of oceans have been totally neglected. In this argument, the arguer only lists out two possible reasons to explain the phenomenon which is quite limited and narrow-sighted. Other possibilities should be also taken into account. For example, some water under the Earth’s surface may save from the evaporation. And later they could be pushed out by the movement of crust, such as earthquake and volcanic explosion. In this circumstance, the arguer cannot firmly confirm the origins of oceans without considering other sources of waters.

In sum, the arguer fails to exclude the possibility that the water of Earth before could be possible to remain on it. And to support the water from comets can form the oceans, the arguer should provide more details of the whole process and reconsider other possible alternatives. So, it is unreliable to make the hasty conclusion that the water in Earth's oceans must have originated from comets.

写完小改了下错误~刚开始恢复~还不熟练


[ 本帖最后由 speakless 于 2007-7-20 23:07 编辑 ]

speaklessUID：2205899

别怪我...我现在感觉ARGU开头如果可以从逻辑层次把作者文章的逻辑关系阐述好效果也不错...所以做个尝试,因此第一段变多了....像个初学者套用北美一样

speaklessUID：2205899

顶一下~=. =

speaklessUID：2205899

再顶一下～ARGU恢复期征求各方意见～

yutaroUID：2272435

顶！五体投地。。。

nornsUID：2325187

发指的字数..