用现在完成时态写一篇介绍王俊凯的英语作文

Answer 1

To WANG JUN KAI answer this question, we must know the current cosmic expansion speed and its current average density. If the density than a determined by the rate of expansion of a critical value is small, gravity is too weak to insufficient to halt the expansion. If the density greater than the critical value, gravity will at some point in the future the expansion stops and collapse of the universe.