Strong cages of carbon, known as buckyballs, have been found not only in the exploded remains of stars, but also in interstellar space, raising the prospect that they may be the packaging to transport other molecules and atoms through the galaxy.
It was just three months ago that scientists first announced they'd found the 60-packs of carbon molecules, known as buckminsterfullerens, in a planetary nebula, the death shroud of an exploded star.
This week, astronomers report four more sightings of buckyballs in planetary nebula, including one located beyond the Milky Way in the Small Magellanic Cloud, a neighboring galaxy about 210,000 light-years away.
Scientists are at a loss to explain how buckyballs can exist in such hydrogen-rich environments. In laboratory studies, hydrogen nudges carbon molecules into chains and other shapes, preventing them from forming tiny hollow spheres that resemble geodesic domes, like the structure at Disney World's Epcot theme park.
Buckyballs, named after American architect and dome-lover Buckminster Fuller, are the third form of solid carbon, after diamond and graphite.
The most widely known buckyball consists of 60 carbon atoms arranged by pentagons and hexagons into a hollow molecular cage one-billionth of a meter wide. They can grow quite complex, with cages holding cages, holding cages, like layers of an onion.
"In nature, you need a lot of carbon atoms to see fullerenes. The importance of finding them in space is that it shows they occur in nature, but it's not super common," Letizia Stanghellini, with the National Optical Astronomy Observatory in Tucson, Ariz., told Discovery News.
Stanghellini's team looked at 250 targets with NASA's Spitzer infrared space telescope and found buckyballs in four of them, though the planetary nebula in the Small Magellanic Cloud had quite a lot of them -- about the mass of 15 Earth moons.
The strength and resilience of buckyballs -- and the fact that they're hollow -- make them a suitable container for holding single atoms or small molecules. Astronomers point to meteorites where buckyballs have been found holding gases that don't match what's found in our solar system, as an example.
"It really was surprising to find them in interstellar medium. That was not expected," astronomer Kristen Sellgren, with Ohio State University, told Discovery News.
From interstellar space, buckyballs apparently somehow migrated to star-forming regions, with some ending up in meteorites that fell to Earth.
"If I was FedEx of space, I'd want buckyballs for packaging. With a buckyball you can put something all the way inside, but it has to be small," Sellgren said.
Stanghellini's research appears in this week's Astrophysical Journal Letters. Sellgren's study was published in the journal's Oct. 10 edition.