Constructing planets built to last 20 years without maintenance and 50 years overall is no mean feat. Giants Jupiter and Saturn in particular needed surveyors, heavy equipment, gravel and steel-reinforced concrete pads.
But the greater challenge is scale. If you want to be able to see tiny Charon, then the Sun has to be the size of a building and has to be many miles away. Most astronomy books and most museums fudge the problem with two separate representations: one comparing the objects’ relative sizes, the other the distances between them. That wouldn’t do for McCartney. To be sure, there are precedents. The Lakeview Museum Community Solar System in Peoria, Illinois—the largest, according to Guinness World Records—spans 40 miles, as the Maine model does, but boasts somewhat smaller astronomical objects, like a 36-foot Sun. Then there’s the Sweden Solar System, which has a Sun in Stockholm and covers four times more ground than McCartney’s. But it lacks a Saturn. "If you don’t have ten objects," he says, "you don’t have a model."
Given that the Earth is 93 million miles from the Sun, the Maine model’s scale is 93 million to 1. That puts the grapefruit-size Earth (built around a Styrofoam core) a mile from the Sun, or squarely on the lawn of Percy’s Auto Sales in Presque Isle.
Percy’s salesman Phil Mills says customers don’t seem to notice the Earth and Moon hovering at the car lot’s edge. The heavenly bodies, he hypothesizes, are just too small. Alas, a suitably conspicuous, beach-ball-size Earth would call for a 300-foot-diameter Sun, not to mention a Pluto about 240 miles away.
Travelers wishing to explore the solar system start at the Northern Maine Museum of Science in Folsom Hall on the university campus. Putting a 50-foot-diameter Sun inside a three-story building wasn’t feasible, so the Sun, the model’s only non-spherical item, consists of a wooden yellow arch curving through stairwells and hallways on all three floors.
Heading south by car, drivers may miss the smaller planets. As the odometer hits 0.4, a two-inch Mercury appears in the garden of Burrelle’s Information Services. At 0.7 miles, you can find five-inch Venus in the parking lot of, aptly, the Budget Traveler Motor Inn. At one mile comes Earth, tilted at its 23-degree angle, and, 16 feet away from it, the Moon. Mars is at 1.5 miles, near the "Welcome to Presque Isle" sign.
The outer planets are worth the voyage. At 5.3 miles giant Jupiter hovers, more than five feet in diameter and spectacularly painted with multicolored stripes and its Great Red Spot, the vast hurricane-like storm raging in the planet’s southern hemisphere. Jupiter’s four largest moons—Io, Europa, Ganymede and Callisto, which were discovered by Galileo and are made out of two golf balls coated with fiberglass and two billiard balls, respectively—sit atop separate posts nearby. (In the interest of expediency, McCartney and crew have chosen to ignore the 36 small moons discovered since Galileo.)
After passing Saturn, it’s almost a billion "miles" farther to the future site of Uranus, at 19.5 miles on the odometer, in Bridgewater, and another billion to Littleton, where rests 21-inch Neptune, which McCartney and coworkers managed to hoist in mid-November just before the snow came. Odometer reading: 30.6.
As for the debate among astronomers about whether Pluto is a planet or an asteroid, McCartney is of the old school. "Pluto was certainly part of the solar system for all my life up to the present," he says. "We’ll keep it here," at the 40-mile mark, on the wall in the Houlton information center. The real Pluto is so far away and so small—with a diameter of some 1,400 miles— that astronomers didn’t observe it until 1930. I couldn’t find it either until an attendant showed me where it was hanging between the center’s rest rooms and the pamphlets for other local attractions.
Soon there will be another brochure on the rack—a much-needed guide to the hard-to-spot roadside planets. McCartney says he didn’t want to clutter the highways with signs pointing out the celestial objects. Then, too, there’s something fitting that those model celestial objects await discovery, betraying no obvious evidence of the quirky force of nature that made them.