Fullerenes from space?

Buckyballs -- the 60-carbon buckminsterfullerenes known for their soccer ball shape -- may occur naturally in space, according to two research groups.

The recent reports offer data supporting the contention that the spherical carbonaceous shells, known to occur naturally on Earth, can also form in the inky void of space.

In the May 5 [N.sub.ATURE], Filippo Radicati di Brozolo, a apace scientist at Charles Evans and Associates in Redwood City, Calif., and his colleagues describe finding fullerenes among carbon residue in a tiny impact crater on NASA's Long-Duration Exposure Facility after that spacecraft's return to Earth.

The scientists believe that the crater -- roughly 100 micrometers in diameter -- formed when a chondritic micrometeoroid struck the craft at high velocity, leaving a dent in an aluminum panel near its leading edge. Inspecting the carbon residue with laser ionization mass spectrometry and Raman spectroscopy, they saw evidence of fullerenes. Further tests to determine whether fullerenes can survive such high-velocity impacts into aluminum showed that they can. Moreover, the scientists found no indications that the buckyballs formed as a result of handling or contamination.

Even if further study shows that the impact itself produced the fullerenes, the researchers say, "this suggests a viable mechanism for fullerene production in space."

In the May 26 [N.sub.ATURE], B.H. Foing and P.Ehrenfreund of the European Space Agency and the Leiden Observatory, respectively, both in the Netherlands, report observing fullerene spectra in the near-infrared light of seven stars.

Specifically, the scientists found two spectral bands that resemble those from fullerenes made in the lab. On the basis of their measurements, they estimate that 0.3 to 0.9 percent of all interstellar carbon could exist in fullerene form.

For many years, scientists have observed more than 100 well-defined absorption bands in the visible and near-infrared ranges, which arise from diffuse interstellar gas. They have suspected that fullerenes play a role in those spectra, but until recently they had only weak evidence. These new data, though not definitive, buttress the belief that buckyballs do exist naturally in interstellar space.