Benzonitrile: Organic Molecule Discovered in Space Smells Like Almonds

1_9_Space Molecules Almonds
The Taurus Molecular Cloud and surrounding sky, taken from Charlottesville, VA, on January 2, 2018. The top left of the image shows a dark region, where gas and dust from the molecular cloud obscure the stars. Brett A McGuire

Scientists have identified organic aromatic molecules in space—and they smell like almonds.

Called benzonitrile, the chemical compound emits a sweet almond scent and is apparently abundant throughout the universe. The discovery marks the first time scientists have pinpointed a particular aromatic molecule in space. Researchers found the compound while probing a molecular cloud in the Taurus constellation with the powerful Green Bank Telescope. Their results were published in Science.

"One way of observing molecules in space is by looking at the light they absorb or emit when the atoms in the molecule vibrate," first author Brett McGuire from the National Radio Astronomy Observatory explained to Newsweek. "The way the carbon and hydrogen atoms vibrate in aromatic molecules gives us a distinct signature to look for at the wavelengths of infrared light we can observe with telescopes."

This light pattern grabs astronomers' attentions—but it also obscures the individual molecules. As McGuire explained, each aromatic molecule has a unique pattern, but that pattern is often very similar to many others. "Think of it as trying to pick out a single person in a choir of a hundred tenors, all singing the same note, with your eyes closed," he said.

Each voice is unique, but altogether it's almost impossible to pick out an individual. Instead of watching these vibrations, the team studied the shape of the molecules. Their shapes can be "wildly different."

"Just like with vibrations, each molecule has a unique pattern of light it absorbs or emits as it tumbles and spins in space," McGuire said. "These are very often easier to distinguish, because they are very sensitive to the three-dimensional shape of the molecules."

Almonds, raspberries and vodka

As well as almonds, you might catch the scent of raspberries in space. Jeffrey Keeton/Flickr

Light patterns suggest about 10 percent of all the carbon in the universe might be made up of aromatic molecules such as benzonitrile. Does this mean space smell of almonds? Well—sort of. "If you condensed down a cloud containing enough benzonitrile, you could smell some almonds," McGuire said.

You might also catch a whiff of vinegar (from acetic acid), Windex (from ammonia), raspberries (from ethyl formate) and vodka (from ethanol), he says. It is probably not worth taking your space helmet off to smell just yet, however. "In most regions of space, the molecular soup is so dilute that there wouldn't be enough molecules for you to just step outside and sniff," McGuire said. "You'd really have to scoop up a big area and bottle it all up for a good whiff."