引用:
原帖由 wannabe 於 2009-7-9 02:25 PM 發表
i always thought moon's surface was like that since existed
obviously given your hints above, it's not the case
=.=
Lucky that you are not a science student nor Cherry will inch you to explode XDD
Just kidding, Cherry is a nice girl
Moon, together with most of planets/stars/moons whatever which name you like ( they are different in astronomy though ).
Was made from a group of gas/dust and originally, a sphere ( or very closed to a sphere even consider the conversation of angular momentum, and sphere has the best energy/volumne ratio, imagine water bubble, water droplet, etc, all are sphere if gravity is absent.)
As you all know, moon's mass is 1/4 of earth and gravity is only 1/6 of earth one ( not sure the data now....haven't recited that data for 10 years LOL )
The gravity is not good enough to hold moon's atmosphere that , there is no atmosphere protection from meteor. The meteor just hit on the surface on moon and you have those craters , i.e my left face
In the Earth, next to our moon, lucky that we have our holy atmosphere. It shelters us from high energetic ray/particles stream from the Sun and the Universe. It also shelters us fro meteor bombardment by burning them during their trip onto the Earth surface
So, Earth has less craters, relatively
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本帖最後由 chefung 於 2009-7-9 02:36 PM 編輯 ]