Bill Nye the Science Guy unveils the Martian sundial

Jim Bell, Cornell assistant professor of astronomy, and Bill Nye, television writer, engineer and host of the children's TV program "Bill Nye The Science Guy," described the sundial that will be part of the 2002 Athena mission to Mars, at a press conference held Wednesday morning, April 21, in the Spacecraft Planetary Imaging Facility (SPIF) on the Cornell campus.

As Alex Walters looks on, Nye explains the details of a model of the sundial, about three times the size of the real thing, which won't be built for several months. The blue rod above is a homemade heliodyne, holding a light that simulates various positions of the sun. At right, with the lights out, Nye shows how the sun will throw different shadows at different times of the day and different seasons.