The widow of the astronomer who discovered Pluto 76 years ago said Thursday she was frustrated by the decision to strip it of its planetary status, but she added that Clyde Tombaugh would have understood.
"I'm not heartbroken. I'm just shook up," Patricia Tombaugh, 93, said in a telephone interview from her home in Las Cruces.
Clyde Tombaugh was 24 when he discovered Pluto while working at Lowell Observatory in Flagstaff, Ariz., in 1930. He spent months meticulously examining images of the sky, looking for a planet observatory founder Percival Lowell theorized was affecting the orbit of Uranus. Lowell was wrong — Pluto is too small to affect giant Neptune's orbit — but Tombaugh found it anyway.
Tombaugh, who died in 1997, was the only person in the Western Hemisphere to have discovered a planet in our solar system until Thursday, when the International Astronomical Union separated it from the eight "classical planets" and lumped it in with two similarly sized "dwarf planets."
Tombaugh had fought off other attempts to relegate Pluto, but his widow said this time he probably would have endorsed the change, now that other planetary objects have been discovered in the Kuiper Belt, the belt of comets on the edge of the solar system where Pluto resides.
"He was a scientist. He would understand they had a real problem when they start finding several of these things flying around the place," Patricia Tombaugh said.
She added that her husband had been resigned to the change.
"He knew it was on the way," she said. "Before he died, they were going around and around. Of course, he was disappointed. After 75 years of seeing it one way, who wouldn't be?"
Planetary astronomers at Lowell Observatory expressed disappointment. Director Bob Millis said he preferred a rejected proposal that would have added three planets to the solar system instead of dropping Pluto.
Closing the door to additional planetary discoveries is "not exactly motivational to young planetary scientists and astronomers," Millis said.
At New Mexico State University, where Clyde Tombaugh worked from 1955-73 and founded the research astronomy department, the news about Pluto was received somewhat glumly.
"To come up with a new classification shows science is not static. It's good to show that to the world," said Jim Murphy, an associate professor and department head. "I suppose our reaction is more emotional. I don't want anyone to think anything less of the discovery by Clyde Tombaugh in 1930."
Tombaugh's legacy is visible across Las Cruces, where an observatory, a campus street and an elementary school bear his name.
Murphy said Tombaugh's discovery was ahead of its time because it took 60 years for stronger telescopes to locate another object with an unusual orbit like Pluto's, and 73 years before scientists discovered a bigger object in the area.
He said the declaration won't change Pluto's importance to science.
"Pluto didn't cease to exist," Murphy said. "It didn't lose or gain any atoms. Its physical characteristics haven't changed a bit because of this. It already was perceived to be a member of a larger group of objects."