It turns out tiny bubbles may be to thank for that earthy smell we get after it rains, according to a from researchers at the Massachusetts Institute of .

Youngsoo Joung and Cullen R. Buie used high-speed cameras to capture raindrops on 28 different types of surfaces and studied what happened to the rain on .

Joung and Buie found that when rain hits a porous surface, like soil, tiny champagne-like bubbles of air are trapped and shoot upward, according to a statement from MIT. The researchers contend those bubbles, or aerosols, may release aromatics (i.e. that earthy smell) and other things stored in soil, such as viruses and types of bacteria.

“It’s a very phenomenon, and it was intriguing to us that no one had observed this mechanism before,” Buie, an assistant professor of mechanical engineering at MIT, said in the statement.
The study may serve as a jumping off for other research about chemicals in soil and how they “can be delivered in the , and possibly to humans,” Joung noted in the release.
Joung and Buie conducted approximately 600 experiments for the study that was recently in Nature Communications.