In “The Big Bang Theory”, Sheldon Cooper has said more than once that Neil deGrasse Tyson singlehandedly kicked Pluto out of the system. True or false?
It’s an exaggeration but Neil deGrasse Tyson did play a controversial role in the demotion of Pluto. The story goes like this.
In the early 20th century, some investigators became interested in the possibility that there was a planet in the solar system that was farther than Neptune. One of these people was Dr. Percival Lowell who created a research program in 1906 that lasted until his death in 1916. Using equipment that are too hard to write about but you may want to read about, Dr. Lowell searched for the elusive “Planet X” which became the subject of a paper he published in 1915.
The following year, Dr. Lowell died and the research took a hiatus for 13 years. The research resumed in 1929 and, in 1930, astronomer Clyde Tombaugh finally discovered what would later be designated as Pluto, Dr. Lowell’s “Planet X”, the ninth planet of the solar system.
However, from 1992, indubitable findings that Pluto may not a planet at all started gaining attention. According to some scientists, Pluto was just one of many celestial bodies in the Kuiper belt — “a region of the solar system beyond the orbit of Neptune, believed to contain many comets, asteroids, and other small bodies made largely of ice.” The scientific community was polarized by these findings.
Meanwhile, in 1996, astrophysicist Neil deGrasse Tyson became Director of the Hayden Planetarium at the American Museum of Natural History in New York City.
Later that year, the Museum announced that with a $20 million donation from Mr. and Mrs. Frederick P. Rose, there was a plan “to transform the north side of the Museum and the Hayden Planetarium. In honor of their generosity, the facility will be named the Frederick Phineas and Sandra Priest Rose Center for Earth and Space.” In 1997, Hayden Planetarium closed and the work began on the Rose Center.
In 2000, Hayden Planetarium opened its doors again to the public. A year later, the New York Times published a story that someone noticed there were only eight planets in the solar system exhibit at the Planetarium. A huge controversy followed.
Neil deGrasse Tyson wrote a letter in response to the story where he explained the absence of Pluto and chided the New York Times for implying that Hayden Planetarium was alone in taking the position that Pluto was not the ninth planet of our solar system.
In 2005, NASA announced that Eris, a body larger than Pluto, was discovered in the Kuiper belt. At the time of the announcement, NASA classified Eris as a planet.
In 2006, the International Astronomical Union (IAU) finally came up with a definition of a planet of the solar system:
A planet is a celestial body that:
(a) is in orbit around the Sun,
(b) has sufficient mass for its self-gravity to overcome rigid body forces
so that it assumes a hydrostatic equilibrium (nearly round) shape,
(c) has cleared the neighbourhood around its orbit.
“Cleared the neighbourhood” means:
What a planet should do to clear the neighborhood around its orbit? Make a Neighborhood watch? Well no. It means that it has to be a big bully, and get rid any other orbiting objects apart from its satellites around it. In more scientific words, it has to become gravitationally dominant, and there are no other bodies of comparable size other than its own satellites or those otherwise under its gravitational influence.
Members of the IAU took a vote and resolved that Pluto did not satisfy the third criterion and was, therefore, not a planet but a “dwarf planet”.
The definition and the resolution were met with a fierce backlash from other members of the scientific community with some starting a petition for the reinstatement of Pluto’s classification as a planet.
I don’t know who’s correct — the ones that say Pluto is not a plant or those that claim the opposite. This post is just about getting to the bottom of Sheldon Cooper’s repeated reference to Neil deGrasse Tyson as the person who singlehandedly kicked Pluto out of the solar system. He did not do it singlehandedly although it is clear which side of the debate he supports.