Should Pluto be demoted? | SteamboatToday.com

Should Pluto be demoted?

Some astronomers suggest the 'planet' may not be a planet

Autumn Phillips

When a group of astronomers met in 1999 and suggested that Pluto may not be a planet, they could never have imagined how upset people would get.

“Pluto is our favorite planet,” CMC astronomy professor Jimmy Westlake said. “And Dr. Clyde Tombaugh is the only American astronomer to discover a planet. Astronomers immediately dropped the subject like a hot potato.”

Pluto’s designation as a planet is not only a scientific issue but also an emotional and political one. It will be the focus of Westlake’s lecture, “Pluto: Planet or Imposter?” sponsored by the Colorado Mountain College SKY Club on Saturday.

Westlake plans to lead an unbiased discussion of the pros and cons of demoting Pluto. At the end of the evening, he will hand out ballots and let the audience members make their own decision.

Part of the debate stems from the fact that “planet” is a poorly defined word.

“The ancient Greeks came up with that word,” Westlake said. “To them, it meant wandering star.”

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By their definition, the planets that can be seen with the naked eye met that definition, as well as the sun and the moon.

The definition shifted once scientists began to find objects that wandered through their telescopes like comets. Today, a planet is simply a large body that orbits the sun.

“It was left ambiguous,” Westlake said. “How big is large?”

Pluto was discovered in 1930. At the time, it was considered to be the same size as Earth. Later, scientists learned that not only was Pluto smaller than our moon, but it was simply the largest rock in an orbiting ring of debris called the Kuiper Belt.

“Since then, astronomers have opened the floodgates,” Westlake said. “There are a thousand KBOs (Kuiper Belt Objects) out there. Do we consider its largest member, which is itself small, to be the ninth planet? If we had known at the time how small it was, it would never have been considered a planet.”

Pluto’s fate is being debated in the astronomical community, but Westlake doubts a decision will be made any time soon.

Because it is 40 times Earth’s distance from the sun, astronomers know very little about Pluto. It takes a very large telescope to see it as a tiny dot, Westlake said. And it remains the only planet that has not been visited by a spacecraft.

“We’ve mapped every planet except Pluto,” he said. “There are plans to send a craft within 10 years and it will take another 10 years to get to Pluto.”

The CMC SKY Club hosts “An Evening with the Astronomer.” Professor Jimmy Westlake will present “Pluto: Planet or Imposter?” at 7:30 p.m. Saturday in Bogue Hall, Room 300. Seating is limited. Telescope observing will follow the indoor program, weather permitting.