Everything You Wanted to Know: Physics of Nuclear Explosions

Barack Obama may have instructed the Pentagon to prepare for massive cuts to the US nuclear arsenal, but a book published in Brazil has sparked fresh worries about nuclear proliferation.

Unbelievably, the book, by physicist Dalton Barroso, is called The Physics of Nuclear Explosions (translation from the Portuguese "A Física dos Explosivos Nucleares") and explains some of the physics required to engineer both fission and fusion bombs, from the dynamics of detonation to the plasma physics of the core.

The publication of is said by Brazilian media to have alarmed the International Atomic Energy Agency and the Pentagon because it may mean Brazil has a fresh interest in developing such nuclear weapons - despite being a signatory to the nuclear nonproliferation treaty.

Barroso has responded to his critics.

He told the Federation of American Scientists - whose excellent Secrecy News blog has the full story - that the book's information is deducible from public domain information in any case and represents no novel threat. It's actually a subset of his PhD thesis from the Military Institute of Engineering in Rio de Janiero.

Perspective is indeed called for here. A similar furore blew up in March 2008 over the release by the whistleblowing website Wikileaks of a Manhattan Project fission bomb design from 1947. Much of the information had been in the public domain since 2002 if anyone had cared to seek it out.

And as Wikileaks points out (scroll down its page), the British government cared so little about the "leak" it wouldn't field an official to deal with its own proposed take-down of the info. The reason? It was an Easter bank holiday weekend.