Thinking optimistically, this long string of gray, rainy days will end. Meanwhile, the permeating and powerful scent of rain is hard to miss. This time of year it is a promise of things to come. Spring is here, even if it's coursing mostly underground and our bodies are still desperately craving a boost of vitamin D.
So what about the scent of rain? A little background - in the 1960's, Dr. Isabel Joy Bear and Dr. Richard Thomas of Australia's national science agency named the unique smell that accompanies rain after discovering what forms it. Their paper, The Nature of Argillaceous Odour, was the first to define petrichor as the earthy scent that occurs when rain falls on dry earth. It comes from the Greek "petra," meaning stone, and “ichor,” meaning the ethereal blood of the gods.
So how is petrichor created? To greatly simplify, during extended dry periods, plants and soil bacteria release various compounds. When rain drops collide with the earth, the compounds combine and aerosolize to become the unique scent we now call petrichor. Petrichor is most pungent after a dry spell, in the moments when rain first begins to fall.
Human noses are highly sensitive to the scent of rain. Researchers believe recognizing petrichor on the breeze is important to animal survival because it allows us to anticipate and locate coming precipitation. Some people find the scent disagreeable. I like it. How about you?
Artist and naturalist Michelle Louis has a vigorous curiosity about the natural world. She walks with intention in nature at least 1,200 miles yearly, much of it on the Ice Age National Scenic Trail. She makes art along the way and in her studio.