WHY PLUTO SHOULD STILL BE A PLANET

 

In August of 2006, the International Astronomical Union came up with a definition of the word “Planet”.  According to this new definition, Pluto is no longer a planet.  It is a “Dwarf Planet”. However, this has created controversy around the world among Astronomers.

The IAU members gathered at the 2006 General Assembly agreed that a "planet" is defined as 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, and (c) has cleared the neighbourhood around its orbit.

A "dwarf 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 not cleared the neighbourhood around its orbit, and (d) is not a satellite.

The definition is flawed, relating to  “cleared the neighborhood”.  Every 228 years Pluto crosses inside of the orbit of Neptune, so technically speaking, it does not clear its neighborhood.  But that also means that Neptune does not clear its own neighborhood.  Mars and Jupiter don’t clear their neighborhoods as they “interfere” with the Asteroids, and the Earth actually orbits the Sun with thousands of Asteroids.  So the Earth doesn’t clear its own neighborhood either.

So if we use the definition set forth by the IAU, Pluto, Neptune, Jupiter, Mars, and the Earth, are NOT planets!  Also, why aren’t “Dwarf Planets” known as planets?  Dwarf Stars are still stars, and Dwarf Galaxies are still galaxies.

These new definitions ONLY apply to objects in OUR Solar System, making the definition even more un-scientific.

Along with the definition being both linguistically and scientifically flawed, so was the voting process.  Although there are over 10,000 Astronomers in the IAU, only 237 of them voted and approved this definition.  Therefore, there was NOT a majority consensus of what a planet is.  Hundreds of Astronomers around the world (and this planetarium) have signed petitions to ignore the new definition and still refer to Pluto as the ninth planet in our Solar System.

Discovered in 1930, Pluto orbits the Sun, has three moons, has an atmosphere, has weather, and even polar caps.  It is not that much different than any of the other planets.  It has been known as a planet for more than 75 years, and to change its status with a poor definition and process, is bad science.

The East Kentucky Science Center and Planetarium recognizes the fact that Astronomy changes as our knowledge grows, but we do not go along with the IAU’s flawed voting process and flawed definition.

Therefore, our official policy is that Pluto is STILL the ninth planet in the Solar System!

This sheet prepared by the staff of the East Kentucky Science Center and Planetarium.

 

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