PASADENA, Calif. - A tour of the solar system soon may be as easy as a leisurely drive through Pasadena.
Plans are in the works to build a scale model of the sun and planets that stretches nearly five miles across town from Central Park to Jet Propulsion Laboratory, NASA's lead center for interplanetary exploration.
''People don't always have a good feel for how tiny the planets are relative to the vast distances that separate them,'' said Charles Kohlhase, director of the PlanetTrek project and a former mission designer at JPL. ''When you do a scale model of the solar system, it really puts us in perspective.''
The sun and planet sculptures will each be contained in stations that will be spaced out in proportion to distances in the actual solar system. The sites also will include a sculpture of a planet, also scaled down in proportion to the actual size.
Earthlings might feel overwhelmed: Our home planet will be represented by a blue sphere only a half inch in diameter.
The stations also will contain a larger planetary model, educational information and 10 panels featuring unanswered questions in science, art, music and philosophy.
''These are not questions that have easy answers,'' Kohlhase said. ''These would be questions that will inspire people to use their imagination and their intellect to discuss the question.''
The project is being planned by the Planetary Society, an international space advocacy group based in Pasadena. Design plans were announced this week, though the campaign to raise money for the $1 million project is just beginning.
The sun, located at the southern end of Central Park, will be a five-foot diameter stainless steel ball covered with enamel and polished to suggest the shining star. It will be mounted on a 15-foot granite pedestal.
Stations representing inner planets Mercury, Venus, Earth and Mars also will be within the park but placed hundreds of feet apart. Earth will be 845 feet from the sun. In real life, it's about 93 million miles away.
Because of the distance of the outer planets, organizers must place Jupiter, Saturn, Neptune and Pluto in other parks. Jupiter - 6-inches in diameter - is to be set near City Hall while Saturn will be planted in a park near the planned Kidspace Museum.
Tiny Pluto - represented by a sphere only a tenth of an inch in diameter - will be located near JPL's campus about five miles away from the sun sculpture.
Similar planet models can be found in Ithaca, NY, Boston, Peoria, Ill., and the Swiss Alps. Peoria's solar system stretches for about 45 miles.
Organizers hope to unveil the Pasadena display in December 2001, but they have just started seeking funds from individuals and corporations. Each planetary station will cost about $90,000. The larger sun display will cost about $180,000.
The Planetary Society was founded in 1980 by the late astronomer Carl Sagan, planetary scientist Bruce Murray and former JPL engineer Bruce Friedman. It has about 100,000 members in more than 140 countries.
On the Net: PlanetTrek home page: http://planettrek.planetary.org
Planetary Society: http://www.planetary.org.