Pluto demotion prompts questions about solar model.

Byline: Greg Bolt The Register-Guard

Not so long ago, on a bike path far, far away, a solar explorer erected a monument to a planet.

The monument is still out at the far end of Eugene's West Bank Trail, a waist-high pyramid with a BB-size ball at its tip and a brass plaque on the front that says "Pluto." It's an appropriately lonely place for a marker dedicated to what was, until Thursday, the solar system's loneliest planet.

But Pluto is a planet no more. The International Astronomical Union has decreed that Pluto and all its icy, celestially pint-size ilk be cast from the brotherhood of planets, and henceforth the number of our solar club shall be eight, not nine, as it's been since Pluto's discovery in 1930.

So where does that leave the Eugene Scale Model Solar System? Anchored by the big ball in Alton Baker Park representing the sun, the model is an accurate 1:1 billion-scale representation of our planetary system. Or it was.

The project is the brainchild of local resident Jack Van Dusen, who conceived it in 1990 as a way to help his then-young son grasp the relative smallness of the planets compared to the vast distances of space. It started as painted figures on the bike path and by 1997 evolved into more or less permanent markers along the river trail.

Van Dusen still lives in Eugene and is still the official keeper of the model. He couldn't be reached this week to say whether Pluto's expulsion from the planetary family means a similar exile from the model, and city parks officials said they'll defer to him on the decision.

Hopefully, though, it won't be as tough a choice for Van Dusen as it was for the scientific community.

It took astronomers years of debate to bring the issue before the IAU, and it took that group a full week of often-testy argument at its annual meeting in Prague to finally decide that Pluto just isn't a planet despite how popular it may be in the collective imagination.

As unfortunate as that may be for its many fans, it does make life a lot easier for makers of solar models. Astronomers now know of several dozen other icy, Pluto-like objects in the vast solar fringe known as the Kuiper Belt, and most believe that there are hundreds if not thousands of others waiting to be discovered.

If nothing else, the decision spares generations of schoolchildren a memorization chore that would make multiplication tables seem as easy as recess.

But there's no doubt youngsters will miss Pluto.

"There's a real connection between kids and Pluto," said Sue Peterson, planetarium director for The Science Factory Children's Museum and Planetarium in Alton Baker Park. "Ask a classroom full of kids what their favorite planet is and most of them will say Pluto."

But even Peterson agrees with the astronomers' decision. Not only is Pluto just not planet material, she said, keeping it in the club would mean letting in all those other solar hangers-on too.

"I could end up with really, really, really long solar system shows just to cover everything," she said. "Eight is really a lot more manageable."

UO astrophysicist Greg Bothun sees it much the same way. Bothun, who has taught many a freshman astronomy seminar, said he always tells his students to think of Pluto as a very big comet rather than a planet.

He wasn't at the conference in Prague, but he agreed with those who said Pluto just doesn't have the right stuff for a planet.

"If I were voting, I would vote that Pluto and Pluto-like objects shouldn't be considered as planets," he said. "They formed and evolved in a fundamentally different way."

As for the kids whose favorite planet is now just another bit of cometary debris, don't be sad. You haven't lost a planet so much as you've gained a new frontier, Peterson said.

"These kids, my God, they're going to be the ones that get to go out there," she said. "They're the ones that are really going to get a chance to discover what these places are like. That's not being shortchanged."