We’ve all heard the words of wisdom using rain as a metaphor: “Into every life some rain must fall,” according to Longfellow; or, “The rain falls on the just and the unjust,” as written in the Bible, Matthew 5:45.
But whatever figurative meaning rain holds, consider this fact: all the rain that ever was, still is. The rains that fell at the Earth’s beginning are still falling from the clouds—soaking into the soil, running into rivers and oceans and evaporating back into clouds. All the rain that ever was, still is—it’s called the hydrologic cycle.
Water spends different amounts of time along its stops through the cycle. If you’re a drop of rain that evaporates back into the clouds, you don’t have much time to rest. Water stays in the atmosphere for about nine days.
That droplet can rest a bit if it soaks into the ground. Water hangs out in the ground for about one month. Add a few more months if the water drop is taken up into a plant, a bush or a tree. The water will need to move through the plant and drop off nutrients before transpiration sends it back out again.
Time looks a bit different for a raindrop that stays in the ground as shallow groundwater. It could stay in the ground for 200 years.
If it soaks deep into the aquifer, the raindrop can really settle in. It could stay underground for 10,000 years.
A raindrop on the move spends much less time in one place, flowing over or through the ground and into a stream, a river and eventually into the ocean. It could wash around with all of the other drops in the ocean for roughly 3,000 years.
You might not look at a rain shower the same way again.
Frank Graff is a producer/reporter with UNC-TV, focusing on North Carolina Science Now, a weekly science series that airs Wednesdays, beginning in August 2013, as part of North Carolina Now on UNC-TV. In addition to producing these special segments, Frank will provide additional information related to his stories through this North Carolina Science Now Reporter's Blog!