INDUCED TRANSPARENCY IN A SOLID OBJECT . An atom generally moves between two energy states by absorbing or emitting a photon---a red-light photon to take one example. If one of those states is itself a doublet of closely spaced states (the energy difference corresponding to a microwave photon, say), then an interesting interference effect can occur. By shining microwaves at the atom, resonance between the twin states becomes paramount, and the atom forgets about absorbing or emitting red light. In effect the atoms become transparent to red light. This electromagnetically induced transparency has previously been demonstrated in gases and figured in the Nobel Prize-winning effort to produce dark-state atoms---see Update 343. Now the effect has been achieved in a solid by scientists at Wayne State University, who reported a 20% drop in the absorption of light in ruby when they also shone microwaves at the resonance frequency into their sample (Zhao et al., Physical Review Letters, 28 July 1997). It is unlikely that this method will allow one to see through thick objects since the microwave power would have to be prohibitively high. The process might, however, create useful modifications in the material's refractive index. (Physics World, October 1997; Science, 15 August)