MARQUETTE - A new program at the Shiras Planetarium in Marquette spotlights the controversial 2006 decision to downgrade Pluto from planet to dwarf planet.
The program "Nine (?) Planets and Counting" was presented at the planetarium Monday and will be shown every Monday through the rest of the month.
In 2006, the International Astronomical Union issued a resolution that said planets must orbit the sun and they have to be massive enough to be a sphere by its own gravitational force.
Visitors to the Shiras Planetarium in Marquette are seen enjoying a recent program. (Journal photo by Christopher Diem)
In addition the IAU said planets must be gravitationally dominant, with no other bodies of comparable size nearby other than its own satellites, such as moons. Since Pluto shares its orbital neighborhood with objects in the Kuiper belt, scientists at the IAU said it was not a planet, but a dwarf planet.
The IAU's decision touched off a debate that is still going on today. Chris Standerford, the planetarium's director, sides with the IAU.
"I think Pluto was a sort of prototype world. it was the first such prototype world we discovered but now we've discovered many more very similar to it. It's a new class of smaller, minor planets," he said.
The program takes its title from the fact that many people were taught there are nine planets in our solar system - Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto.
"It's a great tour of the solar system. It starts with the sun and goes all the way out," Standerford said. "Along the way it does address the Pluto debate. It gives you some background - like a hundred years ago how many planets did we think there were and how that number has kind of fluctuated with time. There's the big question mark on the nine because technically, these days we say there's eight planets."
The program, which had its debut in Marquette in August. The planetarium presents a different program each month, and in September the program is "Icy Worlds," which focuses on smaller, icy planets within and outside our solar system.
During the school year the majority of attendees at the planetarium are school groups.
"We keep very busy with not only the classrooms from Marquette Area Public Schools but classrooms from all over the Upper Peninsula. They drive from as far away as Houghton, Newberry and Escanaba," Standerford said.
The planetarium's shows also attract a large number of community members, both local and those from out of the area.
The entrance fees, $3 for adults and $2 for students, help pay for new programs and light maintenance around the theater, Standerford said.
The planetarium has two different star projectors - the Minolta MS-8, an optical, mechanical class star projector that uses lightbulbs, lenses and pinholes to recreate a realistic starry sky and the Konica Minolta MediaGlobe-Lite, a digital star projector capable of playing movies.
For more information go to www.mapsnet.org/pages/planetarium/planetariumindex.htm.
Christopher Diem can be reached at 906-228-2500, ext. 242.