argument50 G-89-互助社-8.10日同主题写作

wsdegUID: 199069

Argument50
From a draft textbook manuscript submitted to a publisher.
'As Earth, 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 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 must have originated from comets.'

Merely based on a series of unwarranted assumption and dubious evidence, the author of the manuscipt concludes that the water in Earth’s oceans must have originated from comets. To support this conclution, the author cites the fact that the heat from collisions of space rocks which generated Earth and from the increasing gravitational energy of the planet render the whole planet molten, including the surface; any water present would have evaporated into space; when the planet approached its current size, its gravitation became strong enough to hold gases and water vapor around it as an atmosphere. On the basis of this evidence, the author infers that for comets are mostly made up of frozen water and gases, a comet striking Earth then would have vaporized. The argument also claims that the resulting water vapor would have been retained in the atmosphere and falling as rain on the cooled and solified surface of Earth. Close scrutiny of each of these facts, however, reveals that none of them lend credible support to the conclusion.

To begin with, the author fails to inform us the correlation between the gravitation and temperature of Earth. One one hand, as the Earth was being formed out of the collision of space rocks, if the effetc of the gravitation of Earth is much larger than those of the heat from the collisions, then the conclusion which depend on the basic assumption turn out be unreliable. On the other hand, as the Earth approached its current size, whether the temperature is low enough to hold gases and water vapor around it as an atmosphere. Perhaps the temperature of Earth is high enough to counteract the effect of gravitational energy. For that matter, the formation of the water in Earth's oceans may be due to other reseaons. Lacking such evidence, the speaker simply cannot draw any firm conclusion about the sourse of the water in Earth’s oceans.

In addtion, even if the relationship between the temperature of Earth and its gravitation has been solved, the argument unfairly assumes that. It is common knowledge that there should be enough quantity of gases forming into cumulas and then the cumulas precipitates rain. Since the author has not clearly infer the quantity of gases, I cannot be convinced that the water in Earth’s oceans must have originated from comets.

Finally, a careful reading of the argument reveals another additional flaw. Even assuming that a comet striking Earth would have vaporized, the author ignores other possiblities, other than the gases of vaporized comets, that may also lead to the rainfall on Earth. It is entirely possible as some scientists assert that the original water was derived from rocky material formed in the Earth’s region of the solar nebula, or arrived from outer-space, as part of meteorites. Thus, without more evidence to clear out such a problem, it is unconvincing to claim that the origin of water is the vapor from commets.

In sum, the author’s draft, is logically indefensible as it stands. Not only does it leave out such key issue, but also cites in the argument the evidence, which does not lent strong support to what the arguer alleges. To bolster the allegations, the author must provide enough evidence to illustrate the relationship between between the gravitation and temperature of Earth during different eras. The author must also show that the quantity of the water vapor resulting from a comet’s vaporization after it strikes the Earth are large enough to cummulate into falling as rain on the cooled and soliefied surface of Earth is fairly enough to form into rain. To better assess the argument, I would also need to know other possibilities about the origin of water on Earth.