WI: Discovery of Pluto was delayed until 1990?

Delta Force

Banned
Not when they thought it was the size of the Earth, it sure wasn't.

And under the IAU's definition of "planet", Earth, Mars, Jupiter, and Neptune aren't planets either.

Except for their footnote stating they are.

So it's truly nothing more than a racket to force a double standard on the entire world.

Seems like a poor definition if half the planets are only planets because of exceptions to the definition. Also if Pluto is excluded for having failed to clear it's orbit that should have disqualified Neptune because their orbits intersect.
 
I might have said that nothing is a planet that is smaller than the system's largest moon, But that would exclude Mercury, since it's smaller than Ganymede and Titan.
 
Not when they thought it was the size of the Earth, it sure wasn't.

And under the IAU's definition of "planet", Earth, Mars, Jupiter, and Neptune aren't planets either.

Seriously? I'd be grateful to hear your reasoning for this as it doesn't map across to anything I've heard, cheers.
 
Not when they thought it was the size of the Earth, it sure wasn't.

And under the IAU's definition of "planet", Earth, Mars, Jupiter, and Neptune aren't planets either.

Except for their footnote stating they are.

So it's truly nothing more than a racket to force a double standard on the entire world.

According to what I could find the definition of the AIU for a planet is this:

(1) A planet [1] 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, and (c) has cleared the neighbourhood around its orbit.

Please explain your reasoning.
 
Earth and Jupiter have (a) trojan(s) in their orbital neighborhood.

Neptune has Pluto crossing into and out of its orbital neighborhood.

I don't know what Mars' excuse is.

The use of the term "neighborhood" in a scientific definition was the greatest flaw. I personally think Pluto should be a planet, but if they really wanted to reject it as a planet they should have used some sort of minimum mass criteria alone. Anything else smacks of seeking an answer to "How Do We Get Rid of Pluto?" rather than an answer to "What is a Planet?"
 
Please explain your reasoning.

None of those planets have cleared their neighborhood, under the IAU definition.

Then you get the IAU coming back and saying "well, that's not what we mean, (despite explicitly stating it in the definition itself) we mean 'is the dominant body in the region'.", which even then immediately makes Pluto a planet since it's the largest object anywhere near the Kuiper Belt. And it makes Eris a planet because it's all out there on its lonesome, and is bigger than anything else out there.

My children will learn of the ten planets and the racket to short them to eight, I'll tell you.

And what happens if we DO find that gas giant out at the fringes? It magically becomes a planet without question? Total crock.
 
None of those planets have cleared their neighborhood, under the IAU definition.

Then you get the IAU coming back and saying "well, that's not what we mean, (despite explicitly stating it in the definition itself) we mean 'is the dominant body in the region'.", which even then immediately makes Pluto a planet since it's the largest object anywhere near the Kuiper Belt. And it makes Eris a planet because it's all out there on its lonesome, and is bigger than anything else out there.

My children will learn of the ten planets and the racket to short them to eight, I'll tell you.

And what happens if we DO find that gas giant out at the fringes? It magically becomes a planet without question? Total crock.

You seem overly bitter about Pluto's demotion.
 
None of those planets have cleared their neighborhood, under the IAU definition.

Yes they have. "clearing the neighbourhood" means that everything in the same orbit has either accreted to the main body or is gravitationally tied to it, which latter criterion includes satellites, trojans and stuff in resonant orbits. The definition you're insisting on would mean that the only planets in the solar system were Mercury and Venus, which is pretty damn ridiculous.

Then you get the IAU coming back and saying "well, that's not what we mean, (despite explicitly stating it in the definition itself) we mean 'is the dominant body in the region'.", which even then immediately makes Pluto a planet since it's the largest object anywhere near the Kuiper Belt.

No, it's not. Pluto is locked in a resonant orbit with Neptune (as near as matters, Pluto goes round the sun twice for every three times Neptune does), which makes Neptune the dominant object in that neighbourhood, not Pluto.

And it makes Eris a planet because it's all out there on its lonesome, and is bigger than anything else out there.

So far.

My children will learn of the ten planets and the racket to short them to eight, I'll tell you.

Then you're doing them a disservice. Your outrage does not overrule reality.

And what happens if we DO find that gas giant out at the fringes? It magically becomes a planet without question? Total crock.

First of all, it's extremely unlikely we will, but if so, not at first. It will depend on what else is out there.
 
The definition you're insisting on would mean that the only planets in the solar system were Mercury and Venus, which is pretty damn ridiculous.

It's almost as though they should have used different words if they wanted to use a definition that didn't apply to the words they used, isn't it?

No, it's not. Pluto is locked in a resonant orbit with Neptune (as near as matters, Pluto goes round the sun twice for every three times Neptune does), which makes Neptune the dominant object in that neighborhood, not Pluto.

And Neptune Uranus. Guess Neptune's still not a planet.


Foresight is 0/20. Hindsight often isn't even 10/20.

Then you're doing them a disservice. Your outrage does not overrule reality.

It overrules pathetic and arbitrary definitions for the purpose of keeping one faction's belief in the "status quo".

First of all, it's extremely unlikely we will

People got laughed at when they suggested extrasolar planets… 20 years ago.

Imagine what we'll laugh at 20 years from now.

…if so, not at first.

Gas giant? You bet your britches the IAU will instantaneously declare it a planet. "Legally."
 
It's almost as though they should have used different words if they wanted to use a definition that didn't apply to the words they used, isn't it?

They should definitely have used less colloquial phraseology, but that's what happens when you attempt to draft resolutions that can be issued as a press release. It's not as if they haven't gone out of their way to explain what they meant since.

And Neptune Uranus. Guess Neptune's still not a planet.

If you like. Neptune and Uranus are sufficiently close in size that they either both count as planets or neither does. The IAU went for both - if you think they were wrong, I suggest you take it up with them.

It overrules pathetic and arbitrary definitions for the purpose of keeping one faction's belief in the "status quo".

:rolleyes: It's got nothing to do with factions, and everything to do with the fact that so many planet like objects were being discovered (both in our solar system and others) that a formal definition of planet was increasingly needed.

People got laughed at when they suggested extrasolar planets… 20 years ago.

This I want to see a cite for, because it's garbage. I was doing my astronomy degree 25 years ago (not that it matters much, but what are your qualifications for discussing the topic?) and nobody was laughing then. Oh, and 20 years ago is 1993, five years *after* the first extrasolar planet was discovered.

Imagine what we'll laugh at 20 years from now.

I'm guessing the idea that an impartial definition of what a planet is was ever considered to be controversial.

Gas giant? You bet your britches the IAU will instantaneously declare it a planet. "Legally."

Again, colour me sceptical. Not that it matters, the chance of their being an undiscovered gas giant that far out is pretty damn low.
 
Do Trojans really count as 'not having cleared the neighbourhood', since by definition those objects are tied to the planets? I can think of a couple of ways of getting Pluto removed as a proper planet (size and/or orbital eccentricity, but unfortunately both of them of them would see Mercury removed as well.
 
This I want to see a cite for, because it's garbage.

So the documentaries where astronomers say it was exactly like that (and the old magazines I'll have to find that corroborate) are garbage?

Oh, and 20 years ago is 1993, five years *after* the first extrasolar planet was discovered.[/QUOTE]

1. Two years.
2. Time flies, dunnit. Just change dates accordingly.

I also think it's funny that the IAU has a separate definition of 'planet' for when it's extrasolar. That pretty much throws anything they have to say out the window.
 
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