How long before they open up planets for people to name, much the same way they do the Star Registry? Some names I’d like to see for some planets, down the road:

Tweenis 12
Limbaugh (preferrably a hot gas giant)
Bob
Peanut (after my dog, when I was a kid)
Slurpee
Honda
Death (but it has to be creepy-looking)
Dryer Lint (and, if it’s inhabited, we’d have to make contact with the Dryer Lintians)

And, of course, a whole gaggle of worlds named after Japanese kaiju.

Air?

Actually it depends on how you define elements!

The philosophical type have four – the chemical periodic table type has well over 100.

I agre too with The Ridger who noted :
“Do we stop calling them “elements” just because we’re getting to many for middle schoolers to comfortably memorize? I like the way ScottG and gopher65 want categories of planets.”

& I’ll third that!

Its probably best if we say there are X types of planet – rocky ones like Earth and Mercury, Gas giants like Jupiter and Neptune, Ice dwrafs like Pluto and Eris, asteroidal dwrafs like Ceres and Vesta, Hot Jupietrs like
“Bellopheron” or 51 pegasi b & “Osiris” or HD 209458 b!

& quote :

“The solar system has too many planets to memorize all their names: that’s actually cool.”

Unquote.

Definitely!

“We don’t have strict definitions that separate stones from rocks from pebbles from boulders. We don’t have strict definitions that separate villages from towns from cities from hamlets from metropolises. But we remember the important ones: Plymouth Rock, rocks from the Moon, New York, London, Tokyo.

Why can’t it be the same with plan… err, all the things orbiting the sun? Remember the important ones. Be familiar with them. Jakarta, where’s that? Indonesia, let me tell you about it… Pluto, what’s the deal with that one? Well it’s icy and part of a triple system with Charon and Nyx. … ”

Actually its a quadruple system – you forgot Hydra!

Pluto has three moons – Charon, Nix and Hydra.

Mercury has no moons and neither has Venus.

Pluto has an atmosphere -and Mercury lacks one.

True Pluto has a distant and weird orbit near other icy planets like Eris, Quaoar and Sedna but then if Mercury – or Erath or even Jupiter – was orbiting out where pluto is then they’d be in exactly the same situation
– so NOT calling Pluto a planet just makes no scientific or logical sense at all.

It is a decison that simply must be changed if the IAU is to have any real credibility -& if the IAU doesn’t come to its senses & restore Pluto to “proper planethood” then the IAU should be abolished and replaced with a reasonable astronomical authority that does.

Its current anti-Plutonian definition does astronomy & astronomers no favours & brings us into disrepute among the wider community.

Surprised you haven’t corrected that yet! Itokawa is an asteroid.

Plus I thought there were some really small astereoids up to the point where they merged into meteoroids?

Pluto is indeed a planet. I don’t see that a dwarf planet is any less a planet than a dwarf star is less of a star – 90 % ofd stars incl. our sun as dwraf stars -are they somehow not to be counted “proper” stars – I think not!

Additionally, just as there are more smaller stars than larger ones it makes sense that there are more smaller planets than large ones.

The current IAU definition of planet is as Alern Stern said at the time “idiotic.” Orbital clearing? Come on, NO planet’s orbit is entirely clear and the implications of this as I’ve noted elsewhere are just ridiculous. That criterion fails on many counts and was only added to eliminate Pluto – which was a politically motivated and NOT a scientific or logical decision. The IAU mob who voted against Pluto being classed as a planet should quite simply hang their heads in shame – and correct their error ASAP!

Do we stop calling them “elements” just because we’re getting to many for middle schoolers to comfortably memorize?

I like the way ScottG and gopher65 want categories of planets.

The solar system has too many planets to memorize all their names: that’s actually cool.

I think any argument that bases itself on getting a required number as a result is doomed to failure. That includes both the idea that we don’t want less because it makes us seem less enlightened as well as we don’t want more because they’ll be hard to memorize. If there’s 4, 8, 9, 12 or 50, that’s fine, just so long as we know how they are defined so that we can count them up ourselves and revise the count as new things are discovered.

Whatever the cutoff point, I just want to know the reason. If “clearing the area” (the definition of which obviously needs to be better explained, too) is important to planet formation, I’d like to know why. Why is spherical shape important? Heck, why is orbit important (although that should be obvious)? What do these constraints tell us about the objects that we a studying that make it important that are or aren’t included in a given group.