Details of the landscape of the planet Venus as revealed by the Magellan spacecraft are discussed and illustrated. Advances beyond previous space probes are demonstrated. Details of the program are described. Additional work from this project is proposed. (CW)

Reviews seismological studies that provide evidence of the existence of continental roots beneath the continents. Suggests, that through the collisions of plate tectonics, continents stabilized part of the mobile mantle rock beneath them to form deep roots. (ML)

Describes the origin, occurrence, and effects of radon gas. Cites studies which attribute 5,000 to 20,000 deaths per year to radon exposure and the synergistic effect between radon and smoking. Explains ways to reduce risks. (RT)