YAY! Scientists have discovered a FAIR AND BALANCED way to kill people more effectively. We don't need no stinking nukes...

An exotic kind of nuclear explosive being developed by the US Department of Defense could blur the critical distinction between conventional and nuclear weapons. The work has also raised fears that weapons based on this technology could trigger the next arms race.

The explosive works by stimulating the release of energy from the nuclei of certain elements but does not involve nuclear fission or fusion. The energy, emitted as gamma radiation, is thousands of times greater than that from conventional chemical explosives.

The technology has already been included in the Department of Defense's Militarily Critical Technologies List, which says: "Such extraordinary energy density has the potential to revolutionise all aspects of warfare."

Scientists have known for many years that the nuclei of some elements, such as hafnium, can exist in a high-energy state, or nuclear isomer, that slowly decays to a low-energy state by emitting gamma rays. For example, hafnium-178m2, the excited, isomeric form of hafnium-178, has a half-life of 31 years.

The possibility that this process could be explosive was discovered when Carl Collins and colleagues at the University of Texas at Dallas demonstrated that they could artificially trigger the decay of the hafnium isomer by bombarding it with low-energy X-rays (New Scientist print edition, 3 July 1999). The experiment released 60 times as much energy as was put in, and in theory a much greater energy release could be achieved.