The stars form when gas in the cloud condenses under its own gravity and becomes packed enough to ignite nuclear fusion.
星云中的气体在它的重力下凝聚形成新星，新星变得足够满以避免核聚变。
2
To make his recycled paradise, Sowa packed bottles into plastic mesh bags and fishing nets. He lashed those to the bottom sides of wooden pallets, which form the island's foundation.
His conclusion is that the main difference is in the structure of the small columns of nerve cells that are packed together to form the cerebral cortex.