Pluto dodges a bullet

Committee proposes new definition of "planet" that expands family of planets from 9 to 12 and solidifies Pluto's status.
The New York Times
Images: Three new planets?

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[swokjr]

Very simple

Instead of redefining what a planet is why cant we change what a planetoid is? I am just a simple man...as evidenced by by statement.....but why cant we set a size minimum for a planet and a size maximum for a planetoid? Obviously you could take into account the shape of objects like asteroids and use common sense with this....just my opinion.

[djcaseley]

Common Sense?

Now thats just wishful thinking!

Seriously though, if you want to include common sense, it can't be one man, it'll have to be 9. Or 15. Or more. There will be a meeting. Make that meetings. And debates. They'll be on the international stage. They end up where we are now.

You were right at the beginning. We need more rules and more exclusions. Something like:

- A planet is xyz.
- A planetoid is abc.
- If something meets abc & xyz, its still a planetoid.

Perhaps, like you, I'm thinking too simply...

[zaznet]

Just measure it!

It sounds like they didn't look at our solar system when they made the definition. You can measure many things, but they just say "oh, it's round so it must be a planet." How about it's actual mass? It takes very little mass to turn an object into a sphere if it has enough time and is not acted upon by outside forces.

By using Pluto as a base, you can firmly establish limits on the definition of a planet. We clearly do not need to call all objects in a solar system planets. How much light from our sun reaches the planet? What is the mass of the planet? What are the characteristics of it's orbit? You measure everything you can, then set that as the cut off point for a planet.

This is a classification system. It is like the difference between a rock, pebble or grain of sand. What is the difference between a puddle, a pond or a lake? For the most part this really should be about size and other qualities that can be readily measured.