For perennial space watcher Jesse Silverberg, the announcement that Pluto is no longer a planet caused him unease.

“Eight planets, and Pluto would’ve made nine, is enough thank you,” the middler physics and mathematics major said. “I do think that for the last 70 or 80 years having Pluto commonly considered a planet has made me …a little bothered by its excommunication.”

Though it may seem strange, astronomers, students and anyone with a second grade education will have to adjust to the new reality: Pluto is no longer a planet. It is now a dwarf planet.

The so-called demotion came as a result of changes to the rules governing what constitutes a planet by the approved International Astronomical Union (IAU) August 24.

“The word ‘planet’ originally described ‘wanderers’ that were known only as moving lights in the sky,” said a statement issued by the International Astronomical Union. “Recent discoveries lead us to create a new definition, which we can make using currently available scientific information,” an IAU statement said.

The new definition for planet is a body that meets three criteria: it is in orbit around the sun, it maintains enough gravity to keep other bodies from blocking its path, and it has “cleared the path around its orbit,” according to the release.

Pluto did not fit the third criterion because of its colliding path with Neptune.

The IAU, which is recognized as the governing body for astronomical issues by scientists worldwide, is made up of delegates from all countries with a recognized astronomy program and individual members who are experts in their individual branches of astronomy.

“We knew in advance that no matter how this decision would come out, a part of the astronomical community would be disagreeing,” said IAU spokesperson Lars Christensen.

And criticism has come in spades after a decision reversing years of commonly held belief and elementary school training by sentence scheme (My Very Earthly Mother Just Sold Us Nine Pies) that Pluto, like its eight counterparts, is a planet.

About 50 family, friends and supporters of Clyde Tombaugh, the astronomer who discovered Pluto in 1930, protested Friday at the University of New Mexico, as have many astronomers who were not at the IAU’s General Assembly in late August. The Associated Press reported the New Mexico protesters were wearing shirts that said “Size Doesn’t Matter.”

Northeastern’s campus has not reacted in such a visible fashion, but a quiet anger among some students persists.

“For now, many of us can remain hopeful that one day the International Astronomical Union will accept Pluto back and reinstate its planetary status,” said Veronica Dobrovitsky, a recent behavioral neuroscience graduate who works as research assistant for the university.

Dobrovitsky and Carolyn Meda, a senior psychology and sociology double major, created the Facebook group “Pro Pluto” in order to promote their viewpoint.

“It seems to me that people think because we live on a planet, and its this great thing, that every planet has to also be this great thing, similar to it,” Meda said.

“The definition of a planet was always simply, a satellite that revolves around the star. Simple and to the point. People are now trying to change definitions to what they think will result in ‘appropriate’ planets.”

Dobrovitsky said she agreed the scientific logic of the decision was sound, while Meda said it was not.

Pluto was a latecomer to the planetary club, making it an anomaly that astronomers have always struggled to define. Tombuagh discovered the planet in 1930, while the other eight were discovered centuries ago.

But it was actually the discovery of another object, 2003 UB313, that prompted the IAU to rethink Pluto’s title. That object, discovered by California astronomer Michael Brown, is larger in diameter than Pluto and is orbited by at least one moon. He has nicknamed the object “Xena,” though that name has yet to enter the official celestial lexicon.

“Pluto was always a bit of an odd man out, and there are a lot of things in orbit around the Sun besides the traditional nine planets,” said John Swain, a physics professor at Northeastern who teaches the Introduction to Astronomy course. “So when a slightly more rational definition is made its not surprising that Pluto might not make the roster.”

As a result, the eight original planets will be considered classical planets in order to tell them apart from the dwarf planets. So, in short, the simple name 2003 UB313 will no longer be valid.

Though it is now a dwarf, Swain said he didn’t think this would lead to less attention to Pluto from astronomers.

“This might be a good thing to stimulate more thought about Pluto and why it is so different,” he said.