Nearly 100 years ago, a graduate student named Mary Lea Heger observed contaminated starlight. As the light traveled to her telescope, it was interacting with great clouds of—something—in the spaces between stars. No one could figure out what that something was, until now.
When you pass sunlight through a prism, it separates into different colors, which correspond to different wavelengths. Astronomers like Heger often analyze incoming light by looking at something called a spectrum, which is a bit like looking at the colorful end of a prism. A spectrum shows you the relative strengths of the different wavelengths of the light comprising your sample. If the light interacts with something before it gets to you—say, a cloud of gas, the spectrum will change, because the gas absorbs some wavelengths more than others.
Heger’s spectra had an unusual pattern that didn’t match any known substances, so no one could figure out what those interstellar clouds were made of. The spectra, referred to as “diffuse interstellar bands” (DIB), remained mysterious for many decades.
In 1983, scientists accidentally discovered a strange molecule called buckminsterfullerene. Commonly known as a “buckyball,” this substance consists of 60 carbon atoms in a soccer-ball shaped arrangement. John Maier, a chemist at the University of Basel in Switzerland, and his collaborators suspected that buckyballs might be part of the strange signal coming from Heger’s interstellar medium, but they needed to know how buckyballs behave in space—a challenging thing to measure here on Earth.
Here’s Elizabeth Gibney, reporting for Nature News:
Maier’s team analysed that behaviour by measuring the light-absorption of buckyballs at a temperature of near-absolute zero and in an extremely high vacuum, achieved by trapping the ions using electric fields, in a buffer of neutral helium gas. “It was so technically challenging to create conditions such as in interstellar space that it took 20 years of experimental development,” says Maier.
Maier’s team published the work in the journal Nature this week, helping to shed light on what the Nature commentary calls “one of the longest-standing mysteries of modern astronomy.” Not only do the results show that Buckminsterfullerine comprises some of the mysterious interstellar medium, but they also suggest these “spaceballs” are stable enough to last millions of years as they wander far and wide through space.