This week's Question: Last week, NASA's 30,000-pound Orion capsule landed in the Pacific Ocean after going further than any spacecraft built for humans had reached in more than 40 years. Without astronauts aboard, Orion circled Earth for two orbits, eventually reaching an altitude of 3,600 miles so it could...

Chemists at the University of California, Riverside have fabricated novel rewritable paper, one that is based on the color-switching property of commercial chemicals called redox dyes. The dye forms the imaging layer of the paper. Printing is achieved by using ultraviolet light to photobleach the dye, except...