Pluto is No Longer One of the Nine Planets

Scientists in Prague have demoted Pluto from its previous position as one of the nine planets of our solar system. Since being named a planet in 1930 when it was discovered by the American Clyde Tombaugh, Pluto has suffered from those who labeled it a poser and claimed that it should not be considered a true planet. In a historic, textbook revising vote from the International Astronomical Union, Pluto was downgraded from planet to “dwarf planet”.

The new guidelines that determine whether or not a celestial body is truly a planet have been stated as: “a celestial body that is in orbit around the sun, has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a ... nearly round shape, and has cleared the neighborhood around its orbit.” Unfortunately for Pluto, it does not meet these requirements. Pluto has an oblong orbit that overlaps that of Neptune and therefore is disqualified from being a true, classical planet.

Joining Pluto in the ranks as dwarf planets are the asteroid Ceres, which was actually considered a planet in the 1800s, and 2003UB 313 which is an icy body that is a bit larger than Pluto. In addition to adding the dwarf planet classification to the grouping of objects in the solar system, there will be another class of celestial objects called “small solar system bodies”.

The some scientific community is not shocked by the demotion of Pluto from planet to dwarf planet. The wife of Pluto’s discoverer, Patricia Tombaugh, 94, is quoted as saying that her husband would not have been upset by this historic scientific change because “he was a good scientist. (Reuters) Science is ever changing as new discoveries are made and though Tombaugh might have been disappointed he would have understood.

A montage of the solar system before Pluto was banished as one of the nine.

Credit: NASA

Copyright: NASA