When people think of space, they often picture a cold, empty void. But the space between stars is actually full of invisible activity.
More than 300 different molecules have already been discovered drifting through the cosmos.
Chemist Kim Steenbakkers has been studying some of these rare molecules for her Ph.D. at Radboud University, and her work has helped confirm the existence of at least one of them in space. She defended her research on June 3.
“Molecules behave very differently in space than they do on Earth,” Steenbakkers explains. “It’s extremely cold—about minus 240 degrees Celsius—and the pressure is incredibly low.
On Earth, molecules crash into each other constantly, about a billion times every second. In space, a collision might happen only once every 10 days.”
That’s why certain molecules that exist in space don’t last on Earth. Here, they would quickly react with other molecules in the air, making them impossible to study under normal conditions. So how do you study something that can’t survive here?
At a special laser and magnet lab called HFML-FELIX, researchers can recreate space-like conditions by cooling equipment down to nearly minus 270 degrees and removing most of the air.
Steenbakkers used this setup to work with special charged molecules called C2H+ and HC2H+, which scientists believe exist in space. These molecules can’t survive naturally on Earth, but they’re related to welding gas (C2H2), which is highly flammable and used in industry.
By zapping welding gas with a stream of electrons, Steenbakkers was able to break it apart and isolate the rare charged molecules she was interested in. Then, using a powerful infrared laser, she measured how they responded to light. This gave her a unique “fingerprint” for each molecule—a way to recognize them.
These molecular fingerprints can now be matched with data from space telescopes. One such fingerprint has already helped identify CH3+ (a slightly modified version of methane) in the Orion Nebula, a region where stars are born, using the James Webb Space Telescope.
Understanding these molecules gives scientists clues about how stars and planets form, how far along a nebula is in its life cycle, and even how life might begin. “The more we understand space chemistry,” says Steenbakkers, “the closer we get to answering big questions about the origins of life—here and elsewhere.”
