In 2005, a team of Yale scientists partnered with other astronomers to discover a celestial body that could have been the 10th planet in the solar system.

The planet, discovered using the world’s largest area detector camera, a device created at Yale, was larger than Pluto and more than 100 times as far away from the Sun. One Yale scientist, Charles Baltay, seemed to foreshadow the future of both this planet and Pluto in a 2005 interview with the News.

“If this one isn’t a planet, then neither is Pluto, which means it may be demoted,” he said.

A little over a year later, on Wednesday, Sept. 13, 2006 — five years ago Tuesday — a new definition for the term “planet” by the International Astronomical Union forever changed the solar system. In a decision that rocked grade school science class curricula across the world, the IAU reclassified Pluto as a “dwarf planet,” reducing the number of planets in the solar system from nine to eight.

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It was a team of Yale-based scientists, partnered with people from CalTech and including Baltay, that developed the camera which illuminated the issue of Pluto’s planetary qualifications.

They created and used the QUEST camera — a device described by Yale physics research scientist David Rabinowitz as one of the “largest and most ambitious” cameras in the world — to see, for the first time, hundreds of celestial bodies the same size and composition as Pluto.

According to Rabinowitz, it would be simply inconvenient to introduce all of these newly discovered bodies into the accepted group of planets. So, five years ago this week, Pluto’s planetary status became collateral damage.


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Although Yale researchers played an important role in the reclassification of Pluto, they said the actual event did not much change the world of astronomy — or the scientific signifiance of Pluto.

The researchers and 10 other astronomy students and professors interviewed all said they agreed with the IAU’s decision, but added that it is not as significant as some sentimental Pluto fans believe.

“I think the re-classification, from the scientist’s perspective, is not especially significant,” astronomy major Charlie Sharzer ’12 said. “All the researchers studying Pluto did the same thing the day before it was reclassified and the same thing the day after.”

The reclassification, director of undergraduate studies for astronomy Debra Fischer said, does not make Pluto less interesting.

“It just makes more sense given our current understanding of the solar system,” she said.

Former astronomy DUS Charles Bailyn added that technically the original nine-planet solar system is divided into three subsections: inner planets, including Mercury, Venus, Earth and Mars, outer planets, including Jupiter, Saturn, Uranus, and Neptune, and finally dwarf planets like Pluto.

“If you are going to put the inner and outer planets together, you’re already in a classification scheme that doesn’t make sense,” he said. “If you’re doing a cultural thing, you might as well keep Pluto around too!”


But while Pluto’s profile has been on the decline in the past five years, faculty members in the astronomy department said that Yale’s research and undergraduate study efforts aimed at the heavens are on the rise.

“This is a great time to be in the astronomy department at Yale,” Fischer said. Fischer’s own research is in the field of “astrobiology,” where she studies the possibilities for life on other planets.

Over the past 10 years, the Astronomy department at Yale has become increasingly more interdisciplinary, Bailyn said. The field of astrophysics has become more prevalent, with astrophysicists working in the physics department and collaborating with the astronomy department.

“The growth of astrophysics in the physics department has been a huge step forward, I’d say,” he said.

Bailyn said the pairing of physics and astronomy is a fairly common practice, but is only beginning to become mainstreamed at Yale.

Indeed, Fischer said the department is exploring different ways for astronomy to collaborate with other areas of study at Yale, ranging from biology to literature.


Just a few years after Yale scientists developed the QUEST camera, the University increased funding to the department to continue their research on celestial bodies.

The most major gain, members of the faculty said, has been the purchase of dedicated Yale research time on the world’s largest telescopes — the Keck telescopes — located on top of Mauna Kea in Hawaii. Since 2008, Yale researchers have had 15 nights per year to observe the skies from these devices and this rare opportunity has not only increased research opportunities for Yale faculty, but has increased the department’s profile in the astronomy community, Fischer said.

“When I attend meetings now, other astronomers often start the conversation with ‘So … Yale has Keck time now! Do you think there will be any faculty openings?’” she said.

While the research with the Keck telescope has been the most significant change, Bailyn said the department has also made strides recently in computational abilities, making interdisciplinary work with the physics department easier. He said the University also has gained access to a number of ground-based observatories, many of which are privately owned.

In the five years since Yale research helped change Pluto’s planetary status, Yale astronomy has continued to produce cutting edge work. But Rabinowitz and his team’s work with the former ninth planet of the solar system remains one of the department’s most culturally significant discoveries.