Pure carbon comes in many different forms, from the graphite in your pencil to diamonds, the hardest proven material. Another peculiar form of carbon happens when 60 atoms are arranged into a spherical molecule. These molecules have the most excellent name of Buckminsterfullerene, or "Buckyballs", and while they are commonly found in high-combustion soot, astronomers have also spotted them in space.
In a new study, published in The Astrophysical Journal, researchers report the first observation of electrically charged buckyballs within the interstellar medium (ISM), the gas and dust that fills the space between stars.
Molecules in the ISM are the building blocks for the material that will eventually become asteroids, planets, and even life forms. For this reason, understanding the chemical composition of the ISM matters when you want to work out how life might have started.
"The diffuse ISM was historically considered too harsh and tenuous an environment for appreciable abundances of large molecules to occur," lead author Martin Cordiner of the Catholic University of America, said in a statement. "Prior to the detection of C60, the largest known molecules in space were only 12 atoms in size. Our confirmation of C60+ shows just how complex astrochemistry can get, even in the lowest density, most strongly ultraviolet-irradiated environments in the galaxy."
To study the ISM, astronomers use the light of distant stars and look at what specific wavelengths have been absorbed. This creates “chemical fingerprints” and by comparing it to the absorption patterns we see in the lab, it is possible to reconstruct the composition of the ISM.
But some patterns don’t match anything we have seen before, suggesting peculiar molecular structures. These are known as diffuse interstellar bands, or DIB, first discovered by Mary Lea Heger in 1922. The Buckyballs observed by Hubble make up a few of these DIBs, but there are over 400 out there with no confirmation of what they are made of.
The idea that these DIBs are made of carbon-rich molecules is not novel but these observations provide important supporting evidence for the hypothesis. Researchers believe that maybe other DIBs are made of compounds that are related to buckyballs. Studying these molecules in the lab might allow us to find signatures that we recognize from outer space.
While buckminsterfullerene is not very common on Earth, it might be extremely common around the galaxy.