[phoenix]argument 50 by 6号

hhfboyUID: 2749089

"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."

The author claims that the comets which contained ice are formed the water in the Earth's oceans. To support his conclusion, he cites an assumption that in the formation of Earth's ocean, there are sufficient comets struck the Earth's surface and the Earth has enough ability to hold the water from ice of comets.
However, the assumption presented by author is unreasonable.

To begin with, the author argues that the Earth was formed by the collision of space rocks and these rocks are not possible to retain water. But it is unconvincing. Because it is entirely possible that the origination of Earth is by the big bang or the chemical reaction by some substance which may are able to produce water.

Moreover, the cited evidence that all water have evaporated for the high temperature after the collision of comets is unwarranted. It is no evidence all water have evaporated. Perhaps, the temperature are not high enough to evaporate all water. Even if the degree of temperature was sufficient and the water in Earth's surface was vaporized, it is possible that the Earth still maintained adequate water under the ground which may form the following Earth's ocean.

Furthermore, the author's assumption is controversial when it comes to the Earth has enough qualification to maintain the water on its surface. It claims that the Earth's gravitational energy can hold gases and water vapor around it as an atmosphere as well as the temperature in Earth's surface have dropped so lowly that the water can be retained on it rather than vaporized into space, is open to doubt. Because as the author's former assertion that the Earth was kept on a high temperature and there is no evidence to prove the latter temperature will be cool enough to maintain the water in the period of the formation of oceans.
Even Perhaps, the atmosphere is so thin that it hardly maintain the vaporized gas.

Last but not least, in the period of oceanic formation, whether have collision of comets or not is open to doubt. Perhaps, it is entirely possible that there is no collision at all, let alone the comets with ice are formed the Earth's ocean. Therefore, the author want to convince us should provide more evidence that the Earth's have collisions on that time.

In sum, the assumption of the water in Earth's oceans originated from comets is not well supported. To convince me, the author should provide the evidence that the condition of Earth's in the process of formation of oceans. To better evaluate the assumption, I would need more information about the collision of comets and the origination of the Earth