Andrew Fraknoi, professor of Astronomy, Foothill College, Los Altos Hills, Calif.
Paul Yeager, writer and meteorologist, author, "Weather Whys. Weather Whys: Facts, Myths, and Oddities," State College, Penn.
David Mizejewski, naturalist, National Wildlife Federation, Reston, Va.
The winter solstice has come and gone, making it officially winter in the U.S., with cooler temperatures, less sunlight, and, in some places, snow, ice, and frost. A panel of experts discusses the different phenomena that combine to make up the season we call winter, and give tips for how best to appreciate the natural world in wintertime.