Just to think, all of these wasted planet re-defining hours could have been spent helping NASA find the Apollo 11 tapes.

Actually if a large KBO is discovered, it could be designated a planet if it is large enough to meet the equilibrium critieria and if it is massive enough to have cleared it orbit of debris.

The Dundee quote is funny. <br><br>Seriously though - since we are now discovering extra-solar planets and planets not in any star system - soon we'll have to have different classifications of planets (like ESGG - extra-solar gas giant or whatever) and Pluto may make the cut into one of the potential new subclasses.<br><br>Always looking on the bright side of life: now we can see all of the planets with 10 x 50 binoculars!

Right On. In their haste, the final proceedings were moderated with a ballon, an umbrella, a cereal box and a stuffed toy. "IAU GONE WILD" DVD's anyone? <img class='' src='http://new.astromart.com/astromart/javascripts/sceditor/emoticons/wink.png' alt='wink' title='wink'/>

http://www-csm.stecf.org/mirror/www.iau.org/iau0603/index.html<br><br>It seems that the resolution technically refers only to our own solar system AND presupposes that that Neptune is a planet.<br>--<br>Mike

What a great point!<br><br>Last week they I heard a proposed definition of planet that made lot's of sense, it was something like:<br>1) Orbits the Sun and not some other body (works for extra Solar planets if you substitute the central star(s) for the Sun) - moons eliminated<br>2) Is round due to the effect of it's gravity - most asteroids, probably all comets eliminated<br>3) Has an arbitrary minimum size, I think I heard 1000KM diameter - most asteroids and comets eliminated<br><br>So Pluto is a planet, Ceres is a planet, a couple of the recently discovered KBOs also qualify as new planets. Sounds good to me! And we have a very objective easy to verify definition that applies everywhere. What's wrong with that? <br><br>The whole "clearing it's orbit" criteria of the newly accepted definition seems very subjective and hard to verify to me, and as pointed out here, Neptune clearly doesn't qualify.<br><br>How much more exciting would it be to be discovering and exploring new planets rather than eliminating existing ones based on fuzzy, subjective criteria? I think this is a very poor, politically motivated decision that will reduce rather than encourage the public's interest in Astromony.<br><br>

In fact, the clearing of an orbit isn't silly - its one of the most important criteria (aside from orbiting the Sun of course). It is a backdoor reference to how the body formed.<br><br>What you're all missing is the science behind the definition. And that's the IAU's fault because they haven't articulated it to the public or media very well.<br><br>If an object is massive enough it can either accumulate or eject asteroids, debris, etc. as it forms, while "smaller non-planets" do not. If you plot and compare an object's mass and orbital period, the planets and non-planets sort themselves out. And there is a clear gap between planets and non-planets. Unfortuantely Pluto, Ceres, UB313 and the others fall on the wrong side of the tracks.<br><br>Neptune qualifies because is clearly dominating its orbit as well as the inner edge of the Kuiper Belt. IE Pluto is locked in 2:3 with Neptune's orbit. Neptune is controlling Pluto et al, not the other way around.<br><br>