现在，当彗星撞地球，会发生什么？

Now, when the comet hit the earth, what would happen?

youdao

有一种前沿理论认为：这些水是地球形成约5亿年之后，一连串呼啸撞向太阳的彗星所带来的。

One leading theory: it came from a fusillade of comets that came screaming back in toward the sun a half-billion years or so after our planet formed.

youdao

有一种前沿理论认为：这些水是地球形成约5亿年之后，一连串呼啸撞向太阳的彗星所带来的。

One leading theory: it came from a fusillade of comets that came screaming back in toward the sun a half-billion years or so after our planet formed.

youdao