It’s raining outside right now. It’s pouring, actually, but this old man isn’t snoring. I’m sitting at my computer with a snifter of brandy, musing on the rain as it taps fitfully at the window beside me. What do we know about the rain? Are there any facts untapped, mysteries that could unfold before us? Here are some of the most surprising rain facts I could dig up.
1. Sometimes Rain Never Reaches The Ground
Not every rain drop that falls from a cloud actually reaches the ground. In a phenomenon known as “phantom rain,” rain drops fall out of a cloud, but evaporate or sublimate before they reach the Earth’s surface. Phantom rain (rain that evaporates mid-air) creates what are known as Virga Clouds, which appear to be a tail or wisp emanating from the bulk of a rain cloud. Phantom rain is most common where it’s hot and dry.
2. Rain’s Unmistakable Smell
That strange, particular scent you smell after it rains? That’s called “petrichor,” and it comes any time rain falls on wet soil or clay. Why? When rain drops on a porous surface, like soil, escaping air from the pores forms small bubbles, which float to the surface, pop and release a vapor. That’s how the smell is transmitted into the air, but where does it come from in the first place? It turns out that there are two sources responsible for the particular compounds that give petrachor such a pleasant scent. During dry periods, certain periods exude a special oil, which is absorbed by the ground. Along with compounds produced by certain strains of actinobacteria, this plant oil gets trapped in the little bubbles, thus producing the scent of petrichor.
3. Some Raindrops Are Fast
How long do raindrops fall through the air before they hit the ground? According to Weather.com, the average speed of a raindrop is around 14 mph, while the average cloud height is 2,500. After a short calculation, that means the average raindrop would take 2 minutes to reach Earth.
But the speed of a raindrops depends on its size – some very small raindrops can take up to seven minutes to reach the ground, while very large drops may fall at speeds of up to 20 mph.
4. There’s A LOT Of Rain
Every minute, a total of one billion tons of rain falls on the earth.
5. The World’s Wettest Place
Mawsynram, a village in the Meghalaya state of northeast India, takes the cake for wettest place in the world, receiving an average of 471 mm of rainfall every year. By comparison, most regions of North America only collect about 256 inches of rain on an annual basis.
6. The World’s Dryest Place
It’s not where you’d expect. Most people would probably guess the desert, but the world’s driest place is also the iciest – Antarctica. The continent only receives an average of 6.5 inches of rain or snow every year. By definition, and seemingly against all common sense, Antarctica is in fact a desert.
7. Rain Isn’t Always Made Of Water
On Venus, what we refer to as rain is made of sulfuric acid or methane, not good old H2O. Weirder yet, on a planet 5,000 light years away, scientists discovered raindrops made of iron. Imagine metal rain.
8. Rain Makes Grass Greener
Rain contains dissolved nitrogen that is absorbed from the surrounding air. When this natural fertilizer reaches the ground, it actually makes grass greener and more lush.
9. Where It Never Stops Raining
On Mount Waialeale in Kauai, Hawaii, it never stops raining. The mountain has up to 350 rainy days every year.
10. The Shape Of Raindrops
While we instinctively picture raindrops as teardrops falling from the sky, this isn’t exactly an accurate depiction of what rain looks like when it’s coming down.
High up in the clouds, when raindrops are created, they are initially spherical. This is due to the polar, almost magnetic forces between water molecules that “pulls” them towards one another.
However, as the water bundles are affected by the pull of gravity and they begin to fall, the shape changes into more of a jellybean configuration. This is caused by air resistance which flattens out the bottom side of the droplet while the aforementioned polar forces continue to hold it together resulting in a cylindrical shape as the droplet comes barreling down towards the earth.
11. Rain Doesn’t Always Equal Water
On our home planet, rain almost always refers to water. However, on other planets, even ones in our own Solar System, it can rain methane (normally encountered as a gas on Earth) or even sulfuric acid.
How can it rain methane? Well, it’s important to remember that methane is generally encountered as a gas on Earth due to temperature. However, there under extreme temperature and pressure, methane does become gas and rain down on some faraway planets such as Venus.
12. “It’s Been Raining Forever”
Thanks to fossils and other scientific methods, humans have been able to gauge how long it has been raining on planet Earth. The answer – as long as 2.7 billion years.
How can we tell? Rain leaves significant footprints behind. such as raindrop indentations in rocks. If we can figure out how old the rock is, such as by carbon-dating, then we’re able to get a relatively accurate measurement of how long condensed water gas particles have been falling from the skies.
