Parameters for new definition of a Planet?

Question

Looking for a link giving the new parameters that exclude poor Pluto.

Answer 1

http://www.iau2006.org/mirror/www.iau.org/iau0602/index.html

This is a link to International Astronomical Union(IAU), the leading authority on planetary rulings and classifications. It gives a detailed report of the resolutions made regarding the now 8 "Classical Planets" and the new celestial objects known as "Plutonian Objects", formerly "Plutons".

Answer 2

I've just read the new definitions for what a planet is supposed to be and I disagree with their decision. It's not only ambiguous but I believe it was put together in rather a hurry, so as to "top" off the conference. Only 424 astronomers voted on the issue, which is only a tiny percentage of the astronomical community. But that aside, just on technical grounds, the definition is faulty. The fact that they say that a planet should have cleared it's orbit of other objects is erroneous to begin with. What do we call the Earth then, considering there are several thousand NEA's and a few hundred asteroids in trojan orbits with the Earth. What about Jupiter. There's even more asteroids associated with it than with Earth. Neptune has a system of asteroids with it. Saturn has some. By their new definition none of those planets are planets. Then they use the definition of self-gravitation forming a sphere. Geez, call Ceres, Charon, the Moon, the four Galillean Satellites, many of Saturn's Uranus' moons and Triton, and all the other large Kuiper Belt objects planets as well if you use that.

No, the definition is too ambiguous. A planet should be defined because of its size.......say a given arbitrary size that's agreed upon by ALL astronomers, not just a few. Something like this....

"A planet is any body that through self gravitation is spherical in shape, that orbits the Sun (or star) as the central mass of the Solar System, and whose physical diameter is equal to or greater than 2000kms."

There's a more precise definition. It basically says that to be a planet you have to be spherical through self gravitation, orbiting the central star of the solar system you're in, and 2000kms in diameter or greater.

On that basis:

Even if you're Earth sized, if you orbit another planet as the centre of mass, you're a satellite.

It doesn't require you to have an atmosphere at all. Or anything else on the surface for that matter.

It doesn't matter what the characteristics of the planet's orbital geometry is.

Even in a multiple star system, if the planet orbits the centre of mass of the system, it's still a planet by definition. So long as the centre of mass is between two or more stars.

I believe the above definition is a far more sensible one, and far more workable so far as a definition goes.

Answer 3

I am astounded at the massive ignorance of anything to do with space, shown on this board. So, why is it that people who have no concept of the makeup of the Solar System are so upset about a simple re-classification. It happens all the time in the classification of animals and plants.

So, why is everybody so upset. It's really a joke.

It is not a planet. If it remained a planet, we would have to start calling hundreds, perhaps thousands of other objects planets, as they are discovered in the outer regions of the planetary system.

The fact is that many astronomers have had doubts about Pluto's status right from its discovery in 1930.

It is just the silly public that can't stand change. Science changes all the time, as new discoveries are made. That is what is good about science - it always seeks to add to knowledge in stark contrast to religious fanatics who can't get past texts written millennia ago by people who had no idea what the Earth looked like, let alone the rest of the universe.

Pluto exists. It is the same physical body it always has been. It has simply been re-classified in the light of new discoveries. That is what science is all about.

Answer 4

Planets: The eight worlds starting with Mercury and moving out to Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.

Dwarf planets: Pluto and any other round object that "has not cleared the neighborhood around its orbit, and is not a satellite."

Small solar system bodies: All other objects orbiting the sun.

Answer 5

Dinky Pluto loses its status as planet
WILLIAM J. KOLE
Associated Press

Astronomers boot Pluto from planetary club

PRAGUE, Czech Republic - Pluto, beloved by some as a cosmic underdog but scorned by astronomers who considered it too dinky and distant, was unceremoniously stripped of its status as a planet Thursday.

http://www.duluthsuperior.com/mld/duluthsuperior/15344070.htm

Answer 6

Below is a rather good article that looks at it from a more scientific angle.

Answer 7

size