Scientists have come upon a brand-new scent, and they're calling it white noise for the nostrils. Just as white light is a combination of wavelengths and white noise blends frequencies, "olfactory white" is the result of multiple compounds. Researchers arrived at their finding via a handful of experiments. In one, subjects sniffed substances in pairs; each substance contained between one and 43 different compounds, LiveScience reports. "The more components there were in each of two mixtures, the more similar the smell of those two mixtures became, even though the mixtures had no components in common," the scientists wrote. So two 40-component mixtures smelled a lot more similar than two 10-compenent mixtures did.
Next, researchers gave subjects one of four different 40-component mixtures to smell. The subjects were later asked to identify this scent from among four new smells—and most of the time, they selected mixtures with more than 40 components. The research suggests that olfactory white isn't the result of particular compounds; instead, it's the mix that matters: The blend must feature components of equal intensity that span the whole range of human smelling ability. As for what it smells like, "Unfortunately, the scent is so bland as to defy description," notes LiveScience.