Photo by: Uncredited

The undated diagram that was given to the AP by officials of a country critical of Iran's atomic program allegedly calculates the explosive force of a nuclear weapon — a key step in developing such arms. The diagram shows a bell curve and has variables of time in microseconds and power and energy, both in kilotons, the traditional measurement of the energy output and hence the destructive power of nuclear weapons. The curve peaks at just above 50 kilotons at around 2 microseconds, reflecting the full force of the weapon being modeled. The Farsi writing at the bottom translates as "Changes in output and in energy released as a function of time through power pulse." (AP Photo)