One of the world’s most powerful supercomputers has built a computer model of the satellite tobacco mosaic virus.

The researchers say the simulation is the first to capture a whole biological organism in such intricate molecular detail.

Running on a machine at the National Center for Supercomputing Applications, Urbana, the program calculated how each of the million or so atoms in the virus and a surrounding drop of salt water was interacting with almost every other atom every femtosecond, or millionth of a billionth of a second.