Earlier this week, Rice University's Smalley Institute quietly unveiled commissioned portraits of the late Richard E. Smalley (for whom the institute is named) and Robert F. Curl, co-recipients of the 1996 Nobel Prize in Chemistry -- along with Harold Kroto (who does not get a portrait at Smalley Institute, perhaps because he's based in England) -- for their discovery of Carbon-60, dubbed a "buckminsterfullerene" because it resembled the signature geodesic domes of famed architect Buckminster Fuller. But is also looked a lot like a soccer ball, so they were nicknamed "buckyballs."
I have a soft spot for buckyballs, since I was a budding young science writer when Science named buckyballs their "Molecule of the Year," and it was among the earliest materials science stories I covered. I even sported a snazzy buckyballs T-shirt at the APS March meeting where Smalley and Curl gave invited talks (sadly, I accidentally left it in the hotel room when I returned home). The most perfectly round molecule yet discovered! Able to withstand collisions with metals traveling at more than 20,000 MPH! It's Super-Carbon-Molecule!
Okay, so I was relatively new to physics, and like all new converts, that made my enthusiasm somewhat annoying to those who'd been following the story for years (Smalley, Curl, and Kroto started working on C-60 in the early 1980s). More jaded, established science writers tended to roll their eyes in exasperation when I expounded enthusiastically like a rambunctious puppy with a shiny new bone. I was all, like, "OMG! There's this AMAZING NEW MOLECULE! HAVE YOU HEARD? THEY'RE CALLED BUCKYBALLS!"
"We know, Jennifer," they would sigh with the pained looks one reserves for when the new puppy inevitably soils the pricey imported Persian rug. And like that errant puppy, I was only temporarily mollified. I mean, photonic crystals, fractal patterns, levitating frogs, and singing Tesla coils are old news too. That doesn't make them ANY LESS AWESOME! Somewhere out there, another freshly minted science enthusiast is burbling over with excitement over something we've known about for years. It's all about the thrill of discovery -- and if it's new to you, it's a discovery.
I'm older and wiser now, but -- I hope -- not yet jaded. I still have an irrational affection for buckyballs, even though their fame in the materials science world has since been overshadowed by the more practical-minded carbon nanotubes, and that audacious upstart, graphene (honored with this year's Nobel Prize in Physics, a rather controversial decision that is still raising a few hackles among physicists).
I'm not the only one, either: Think Geek and Neatorama report that science toy creators are capitalizing big-time on the "OMG Adorbz!" appeal of buckyballs. You can now purchase Buckyballs Magnetic Building Spheres, in which the molecule is scaled up to macro-size, with rare earth magnetic spheres replacing the individual atoms. There are 216 rare earth magnets, intended to be shaped, molded, torn apart and snapped back together -- the flexibility of fullerenes writ large.
Not only do we have carbon nanotubes, but we've made "buckybabies" (asteroid-shaped smaller versions of buckyballs) and "dopeyballs" (wherein one knocks out one or more of the carbon atoms and replaces with a metal atom). The hollow structure of buckyballs means it's easy to fill them other kinds of atoms -- think "molecular cage" or a diamond with a hole in the middle -- and potentially use buckyballs as a deliveray mechanism for, say, therapeutic agents.
Where do buckyballs come from? Well, Curl and Smalley first built a device that used a laser to vaporize any given material in a plasma. Along with Kroto -- who had been using microwave spectroscopy to analyze the composition of carbon-rich stars -- they decided to vaporize carbon (using a graphite surface) and study what was left: in this case, buckyballs. The process only yielded teensy amounts; it wasn't until 1990 that scientists figured out a new method yielding about 1 gram of C-60 per day. I won't go into all the gory technical details (you can find them here, and elsewhere via a Google search), but it involves a water-cooled, pressurized cylinder and a graphite rod and disk. Zap an electrical current through the contraption and you end up wth soot deposted along the walls of the cylinder. Wash the soot with toulene, and you get a reddish-brown solution -- what the Crayola Crayon folks might call "raw umber" -- and that, in turn, leaves a reside that is very C-60 rich. Whew!
The difficulty of mass-producing significant quantities of buckyballs on Earth via synthetic means has led scientists to look for naturally occuring forms of the molecule. Don't go looking at the soot lining your fireplace and chimney flue: scientists already checked there (they probably checked behind the sofa cushions, too). That's because the air we breathe is rich in nitrogen and oxygen, both of which inhibit the growth of buckyballs. Inert gases, like helium, are much more conducive to the formation of buckyballs. Still, C-60 has popped up in some surprising places. A couple of scientists at Arizona State University -- Semeon Tsipursky and Peter Buseck -- happened upon a bit of shiny black rock called shungite in northeastern Russia. When analyzed under electron microscopy, the shungite had a very similar pattern to that found in buckyballs made in the lab.
So shungite is carbon-rich, not just with C-60, but also C-70. And while scientists aren't sure how it might have formed some 600 million to 4 billion years ago, there might be a clue in another type of glassy rock called fulgurite. It's common in the Colorado mountains, and is formed when lightning strikes the ground -- apparently this creates conditions especially friendly for buckyballs to form. Or shungite might be volcanic in origin. C-60 might also be found in meteorites, i.e., Outer Space. I know, I know. Crazy, right? Or is it?
In case you missed the headlines this past summer, a group of astronomers collecting data with NASA's Spitzer Space Telescope announced they had found the first known buckyballs in space -- and the largest molecules yet discovered in places like, say, planetary nebula, the remains of stars that have sloughed off their outer layers of gas and dust as they got older and left that childhood baggage behind them, becoming a white dwarf star in the process. Somewhere in the midst of those clouds, that white dwarf star emits radiation that makes the clouds light up with pretty colors and heats up all leftover gas and dust.
The astronomers found their buckyballs hanging out near just such a planetary nebula, known as TC-1. (Jen-Luc Piquant thinks we could all brainstorm and come up with a much catchier nickname.) How did they know the buckyballs were there? Spectroscopy! There's an infrared spectrometer aboard Spitzer, and those buckyballs give off a unique spectral signature -- their chemical fingerprint, if you will. They compared the Spitzer data with measurements of the same molecules done in the lab. Conclusion? A perfect match!
And the excitement didn't end there. Last month, the same team of astronomers announced their discovery of even more buckyballs in space. The little buggers are scattered everywhere throughout our Milky Way galaxy, lurking in the books and crannies around three dying stars. We just needed to know where to look, apparently. In fact, the number of buckyballs they found lurking around a fourth dying star in a nearby galaxy (the Small Magellanic Cloud) is so large it would be equivalent in mass to 15 of our Moons. One of that study's co-authors, Letiza Stanghellini of the National optical Astronomy Observatory in Tucson, pointed out that this means buckyballs are much more common and abundant in the universe than scientists previously thought, and added this tantalizing tidbit: "This has implications for the chemistry of life. It's possible that buckyballs from outer space provided seeds for life on Earth." (Panspermia, anyone?)
It's kind of like buckyballs have come full circle, since, after all, Kroto got involved with Smalley and Kroto's synthesis of buckyballs because of his work on carbon-rich stars. Kroto, asked to comment on the discovery, took the excitement in stride: "This provides convincing evidence that the buckyball has, as I long suspected, existed since time immemorial in the dark recesses of our galaxy." In fact, as he says in the video clip below, "Apparently there's more C-60 around than there is planet Earth!"