Many people expected Pluto to be a dead ball of ice, but it's geologically active, and scientists have no idea why.
许多人认为冥王星是一个死冰球，但它在地质学上很活跃， 科学家们也不知道为什么。
中文百科
死球
棒球中，死球也可能是指坏球。
英语百科
Dead ball 死球
Dead ball is a term in many ball sports in which the ball is deemed temporarily not playable, and no movement may be made with it or the players from their respective positions of significance. Depending on the sport, this event may be quite routine, and often occurs between individual plays of the game.