A tiny map of Africa, visible only with a microscope, represents a global paradox. Credit: COURTESY OF PHYSICS DEPT, TURIN POLYTECHNIC UNIV.

Satellite pictures of Earth have become too familiar to inspire awe. But two Turin-based artists have been prompted by the large-scale view of our planet — and by that other world, at the molecular level, that nanotechnologists can now reveal and manipulate.

Alessandro Scali from Turin, and Robin Goode, a South African, conceived Actual Size, the smallest ever map of Africa. The artwork is a tiny sliver of silicon just a thousand or so atoms wide, made with atomic force microscopy, and visible only with the same technique. It is one of the 'nanoartworks' to be shown in the duo's first exhibition next month, as part of the Bergamo science festival in Italy.

“We know from books that Africa is the cradle of humanity, and we can see from maps and the beautiful satellite images that Africa is vast and is at the centre of the world,” says Scali. “But we also know that Africa is poor, exploited, neglected.” The artists wanted to represent the paradox of Africa being geographically and anthropologically central to our world, yet unrecognized, unexplored, even 'invisible'.

Scali and Goode brought their concept to Fabrizio Pirri, a physicist at Turin Polytechnic University. Pirri's group turned its atomic force microscope — usually used for biomedical engineering — to a modern form of lithography. Through electrical interaction, the microscope's 10-nanometre-wide tip oxidized individual atoms of the silicon to trace the shape of Africa. They made dozens of copies before obtaining the unique piece that satisfied the artists. For the exhibition, Scali and Goode have made poster-size copies of their work, which could otherwise only be seen in the lab.

A second, larger version of Actual Size, as big as the point of a needle, will also be on show at Bergamo, and visible to visitors through a microscope. In this case, the scientists used a laser — which removes atoms through sublimation — to etch the map onto silicon.