For years, "fullertubes" — tube shaped molecules made up of 130 carbon atoms — have existed only in theory. Now, an international team of scientists has successfully shown them in real life. They measures just under 2 nanometers long by 1 nm wide. One possibile future application could be the production of hydrogen. Currently, what's used is a catalyst made of platinum and rubidium, which are rare and expensive. Replacing them with carbon structures such as fullertubes would make it possible to produce hydrogen in a "greener" way.