For New Mexico, the fight for Pluto is not over.
Seven months after a conclave of scientists downgraded the distant heavenly body to a "dwarf planet," a state representative in New Mexico aims to give the snubbed world back some of its respect. State lawmakers will vote Tuesday on a bill that proposes "as Pluto passes overhead through New Mexico's excellent night skies, it be declared a planet."
The resolution, House Joint Memorial 54, was introduced by Rep. Joni Marie Gutierrez (D-Dona Ana County). It reiterates the importance of astronomy to the state of New Mexico and calls for March 13 to be "Pluto Planet Day."
The date is the birthday of Percival Lowell, the astronomer that posited the existence of a "Planet X" beyond the orbit of Neptune. The resolution also highlights that Pluto's discoverer, Clyde Tombaugh, comes from the county Gutierrez represents. Tombaugh found Pluto in 1930.
"We always took a lot of pride in the fact that he discovered Pluto," Gutierrez said in a phone interview with Wired News. "When they declared it a dwarf planet, we took it as a personal affront, so I envisioned that when then legislative session started, I would propose that at least in New Mexico, Pluto still be considered a planet."
Gutierrez believes the resolution will pass easily.
The resolution is the latest pro-Pluto move following a vote last August by the International Astronomical Union, or IAU, to reduce Pluto's stature among the solar system's objects from a planet to a dwarf planet.
The astronomical group decided at its 2006 General Assembly to define a planet as a celestial body that orbits the sun, has enough mass so that gravitational forces create a round or nearly round shape, and has cleared the nearby space of other objects. Objects that have not met all the criteria are considered to be candidates for dwarf planets. Three objects have so far been thus labeled: Pluto and Eris (formerly known as 2003 UB313) from the Kuiper Belt and Ceres from the main asteroid belt..
The decision was not a sudden change of heart: Pluto's pedigree as a planet has been questioned for years. Pluto was the first object discovered in the Kuiper Belt, an area of space on the outskirts of the solar system that contains a large number of irregular objects, such as asteroids, comets and larger bodies, now designated dwarf planets.
The IAU withheld its opinion of the New Mexico representative's legislative maneuver, but welcomed any discussion of
the status of Pluto.
"The main point for the IAU is the interest this brings to astronomy," said Lars Lindberg Christensen, spokesman for the organization. "The fact that the solar system consists of bodies in many different sizes and different compositions is a very good debate to have in school. And the debate over Pluto opens this up to the outside world."
The resolution has also been welcomed by other astronomers that do not agree with the demotion of Pluto or with the IAU's definition. David Weintraub, a professor of astronomy at Nashville, Tennessee's Vanderbilt University, pointed out that neither Neptune nor Jupiter would technically be considered a planet under the definition: Neptune has not cleared its orbit, because Pluto crosses its path, and Jupiter has objects in its orbit -- the so-called Trojan asteroids that sit in stable gravitational pockets, known as Lagrange points.
"It is very hard to come up with a definition of a planet that excludes Pluto and doesn't exclude other planets in the solar system," said Weintraub, who wrote Is Pluto a Planet?: A Historical Journey Through the Solar System.
Weintraub agrees, however, that anything that gets U.S. citizens thinking about science is a good thing.
"I think it's great that New Mexico might consider Pluto a planet," Weintraub said. "But I would like it better if Tennessee, and wherever (else), considered it a planet as well."
Last year, NASA launched the New Horizons probe, which is expected to reach Pluto by 2015.
