Beginning about 4.5 billion years ago, the theory goes, a galactic cloud of interstellar gas and dust collapsed and ignited in a blaze of thermonuclear fusion to create our Sun. Swirling around that fireball were particles that gathered into spherical clumps, whose gravitational fields attracted smaller clumps, and so on, eventually creating the four terrestrial planets (Mercury, Venus, Earth and Mars) and the four gas giants (Jupiter, Saturn, Uranus and Neptune), with Pluto, that icy enigma, playing at the outskirts. All told, cosmologists say, it took 100 million years for the solar system to take shape.

Of course, you can do the job much faster if you use fiberglass—provided, as Kevin McCartney is discovering, you have lots of help. McCartney, 48, a professor of geology at the University of Maine at Presque Isle and director of the Northern Maine Museum of Science, is the man behind one of the world’s largest scale models of the solar system. When completed this spring, it will stretch along the northernmost reaches of U.S. Route 1, from the 50-foot Sun inside Presque Isle’s museum to the one-inch Pluto and its half-inch moon, Charon, mounted on the wall of the tourist information center 40 miles away in Houlton. In between, at precisely calibrated intervals, the other eight planets will rest atop ten-foot steel posts—heavenly roadside attractions in parking lots and farm plots in northern Maine’s remote Aroostook County, which juts so deeply into Canada that many residents grow up speaking French as a second language.

Maybe four years is a long time to set up nine painted spheres, but McCartney has used only volunteer labor and donated materials. Total funding for his project: zero. He planned it that way, he says: "We’ve had a dozen phone calls in the last year, saying, ‘This is great. We were going to do the same thing. Where did you get the money?’ The answer is, we never had any thought of money. We knew we couldn’t get it."

I first spot the Maine Solar System Model through the car windshield. I’m on the road to catch the raising of Saturn. It’s late October, and McCartney is racing the calendar to install the planet before the snow flies. In this awkward, in-between time of year in the Pine Tree State’s northernmost county (which is larger than Connecticut and Rhode Island combined), the hills appear rather bleak; the potato harvest has been in for a few weeks, leaving brown, barren fields. Forget any picturesque notions of rocky coasts, quaint cottages and $10 lobster rolls. This is hard country, where folks endure cruel winters with a can-do attitude. I drive past poor but tidy homes; past potato barns built into the earth like dugouts; past Littleton, Monticello, Bridgewater and Mars Hill (pure coincidence—the celestial Mars rests about eight miles north of Mars Hill); past farm fields and over a long hill. And suddenly Saturn hovers there.

Suspended from a crane and being lowered gingerly onto its post, the planet is a four and a half foot orange orb, painted with curling stripes, tilted on an axis 26 degrees from the vertical and sporting a set of steel mesh rings. It weighs 1,200 pounds.

Several dozen people are on hand to see the ringed giant rise. Men in suits and ties mingle with laborers in baseball caps and students from Caribou Tech Center, who built the planet’s frame. Distinctive in a long mustache-less beard, white trousers, white work shirt and white Greek fisherman’s cap, McCartney buzzes through the crowd, issuing commands. "Early on I used to say this project’s going to have a thousand and one problems. But I think it’s going to have a thousand and one solutions," McCartney says. "Well, we’ve had a thousand and one problems. We really have." Saturn, for instance. Only after the school group that painted the planet put down their brushes did the students learn that the image provided them by NASA was a bit too purple. So they repainted it in proper saturnine oranges.

McCartney, whose academic career brought him to Maine 15 years ago from Florida, is a master of the unlikely project. He assembled the Northern Maine Museum of Science from scratch, with volunteer help and, as usual, no funding. A few of the display cases are fashioned from wood fished out of a trash bin. A diorama depicting sea life more than 400 million years ago is on loan from the American Museum of Natural History in New York City. Trained as a paleontologist, McCartney collects model airplanes and images of Abraham Lincoln. At their 1913 Arts and Crafts house in Caribou, he and his wife, Kate, have more than 250 antique laundry irons.

But the solar system possesses him now. "My neck is stuck way out on this project," McCartney says of his model. "I’m sort of the instigator. People have worked very, very hard."

Just now, newspaper ad sales manager Jim Berry is drilling a hole in Saturn’s post and remembering his first encounter with McCartney at a Kiwanis Club meeting. "I went home that night and said to my wife, ‘I met this guy today. He’s a wacko. You can’t believe what he’s going to try to do.’ " When he got up the next morning he said, "Wait a minute. This is a great idea. I’ve got to get involved in this. This is just too good to pass up."

McCartney has that effect on people; one day they think he’s crazy, the next day they’re painting Jupiter’s spot. His list of prominent "squirrels," as he inexplicably calls his volunteers, runs eight pages long. Add the anonymous students who worked on a planet here or a stanchion there, and McCartney estimates that more than 500 squirrels have pitched in so far. Perley Dean, a retired Presque Isle High School guidance counselor who wears a "Maine Potato Board" baseball cap, got the job of persuading several landowners that what was missing on their property was a planet. "Many of them don’t stay up late at night reading about the galaxy," Dean deadpans.

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.