Science
The smell of rain is half a billion years old.
Falling over and over again on this Earth, rain has cycled through countless clouds, skies, rivers, and living organisms — stretching the boundaries of time and place.
The Poetics of Evolution
The smell of rain is also known as “petrichor.” It derives its name from the Greek words for “rock” and “the blood of the gods.” Petrichor is subtly unique to different locations due to the weather, flora, runoff, streets, and soils. People often have a special connection to the rain smells from particular places… especially the place they grew up, or places of personal significance in their memory.
While we might take the smell of rain for granted, what makes it truly remarkable is that it is ancient. And, in a way, it is alive.
The biological beginnings of rain point to a tiny soil bacteria called Streptomyces. The bacteria created a chemical signal - geosmin - to attract small arthropods, which in turn helped the bacteria spread their spores (see below).
Despite evolving half a billion years ago, this evolutionary leap was so successful that it spread across the entire planet. Thus, the ancient smell of rain has filled the lungs of dinosaurs, drenched the soils and canopies of ancient forests, and drifted through landscapes occupied by the first humans.
Today, science is discovering more animals and insects that are attuned to the ancient chemical signal, with humans detecting it in smaller amounts than sharks detect blood in the water.
Mosses, Plants, and Memory
During an artist residency in 2024, Rosburg was researching small Arctic plants and mosses. One day, while using a microscope, she saw movement and began recording video. There, in her field of view, moving up and down the fungi and mosses, were Springtail arthropods.
The relationships between the soil, bacteria, small arthropods, and mosses share an important, remarkable evolutionary history — an ongoing miracle that is largely unappreciated by most of us.
Rain is a poetic part of our personal and planetary memory.
It continues to be the reliable carrier for seed nourishment and life-giving hydration, the gentle watery kisses that hushed parched soils, and the torrential downpours that sculpted the ever-changing landscapes. Rain is the memory of resilience, hope, change, respect, balance, and promise.
To smell rain is to be reminded of a much greater story, one that spans place and time.
