When someone says you're in their personal bubble, they aren't exactly speaking metaphorically. In a new study, University of Oregon researchers say they've found people really are surrounded by a sort of cloud that's unique to them. The gross part: It's made up of millions of "skin and fart bacteria," per Wired. Scientists placed 11 people in a sanitized chamber and tested the microbes in the air around them using air filters and petri dishes. Though researchers chose to focus on whole microbial communities rather than specific pathogens, they identified thousands of different types of bacteria across 312 samples. "If I scratch my head, thousands of skin cells, cell fragments, bacteria, and fungi get airborne," says lead author James Meadow, who notes bacteria also escapes in our breath and, yes, our farts. "The world is covered in a fine patina of feces," he generously adds.
While scientists found mouth bacteria Streptococcus and skin microbes Propionibacterium and Corynebacterium were present in the clouds of all 11 participants, the different combinations provided a signature so distinctive that scientists could identify the person in the chamber just by looking at the bacteria in the air. The results "demonstrate for the first time that individuals release their own personalized microbial cloud," the authors say in a release. "If you are close enough to shake hands with someone, you are in their microbial cloud," adds Meadow. "When someone walks by and you feel breeze, that’s taking your bacteria with them." The research could help us better understand the spread of diseases. It might even be possible to determine where a person has been if an expert can test a location, like a crime scene, for this "invisible fingerprint," per Smithsonian. (The dust in your house says a lot about you.)