Rain comes and goes all over the Earth. It never disappears, because the water cycle on Earth is a “closed system.”
Water is very, very rarely lost to outer space. This means that the same water falls as rain over and over again. Water that fell as rain when the dinosaurs existed could be falling on you today, and rain that just fell on you may fall on someone in Spain someday or vice versa. How is it possible that the same water keeps moving around in one big cycle? If we could follow a raindrop, we would see how this endless cycle works.
