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Old 11-26-2017, 10:19 PM   #1
AlexanderHowl
 
Join Date: Feb 2016
Default Changing Planet Creation Rules to Reflect Realism

I was wondering what everyone would think about changing the planet creation rules to reflect realism, at least for the purpose of moons. In the Sol System, Jupiter possesses 69 moons and Saturn possesses 62 moons, neither of which can be replicated by the current system (Uranus is also problematic because of its outer moonlets). In addition, Pluto possesses 5 moons, which cannot occur with Tiny terrestrial planets in the current system.

In order to create Saturn, we would have to allow for three major moons (Tethys, Dione, and Rhea are technically major moons because they are large enough to be tiny terrestrial planets with ice cores) and eighteen moonlets in the first group of moons and one major moon (Iapetus is technically a major moon because it is large enough to be a tiny terrestrial planet with an ice core) and thirty-nine moonlets in the third group of moons. Jupiter could be created with the current rules except that it possesses 41 moonlets in the third group of moons.

I would suggest the following changes to the rules for gas giant moons. Within the first group of moons, gas giants possess 1d-2 major moons and 6d-12 moonlets (+1 major moons and +6 moonlets for medium gas giants and +2 major moons and +12 moonlets for large gas giants). Within the second group of moons, gas giants possess 2d-4 major moons (+2 major moons for medium gas giants and +4 major moons for large gas giants). Within the third group of moons, gas giants possess 12d-24 moonlets (+12 moonlets for medium gas giants and +24 moonlets for large gas giants). The other modifiers for gas giant moons would be unchanged.

I would suggest the following changes to the rules for terrestrial moons. First, terrestrial planets are capable of having major moons and moonlets, just like Pluto (Charon is technically a major moon because it is large enough to be a tiny terrestrial planet). Second, terrestrial planets possess 1d-2 moonlets and 1d-4 major moons (+2 moonlets and +1 major moons if beyond the Snow Line). The other modifiers for terrestrial moons would be unchanged.
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Old 11-27-2017, 07:22 AM   #2
Fred Brackin
 
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Default Re: Changing Planet Creation Rules to Reflect Realism

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Originally Posted by AlexanderHowl View Post
I would suggest the following changes to the rules for terrestrial moons. First, terrestrial planets are capable of having major moons and moonlets, just like Pluto .
Pluto is not categorized as a "terrestrial planet" in reality and shouldn't be in game

.https://en.wikipedia.org/wiki/Pluto

They're serious about that "dwarf planet" thing and for good reason.

Pluto's density is only 1.8 and that's less than half that of Mars and about a third of the Earth, Mercury and Venus. Pluto absolutely should not be put in to the same category as the 4 terrestrial worlds.
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Old 11-27-2017, 01:49 PM   #3
Say, it isn't that bad!
 
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Default Re: Changing Planet Creation Rules to Reflect Realism

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Originally Posted by Fred Brackin View Post
Pluto is not categorized as a "terrestrial planet" in reality and shouldn't be in game

.https://en.wikipedia.org/wiki/Pluto

They're serious about that "dwarf planet" thing and for good reason.

Pluto's density is only 1.8 and that's less than half that of Mars and about a third of the Earth, Mercury and Venus. Pluto absolutely should not be put in to the same category as the 4 terrestrial worlds.
A surprise meeting of a small fraction of the Astronomical Union is not "serious", and "dwarf planet" is not an internally-consistent category.
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Old 11-27-2017, 01:54 PM   #4
David Johnston2
 
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Default Re: Changing Planet Creation Rules to Reflect Realism

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Originally Posted by AlexanderHowl View Post
I was wondering what everyone would think about changing the planet creation rules to reflect realism, at least for the purpose of moons. In the Sol System, Jupiter possesses 69 moons and Saturn possesses 62 moons, neither of which can be replicated by the current system (Uranus is also problematic because of its outer moonlets). In addition, Pluto possesses 5 moons, which cannot occur with Tiny terrestrial planets in the current system.

In order to create Saturn, we would have to allow for three major moons (Tethys, Dione, and Rhea are technically major moons because they are large enough to be tiny terrestrial planets with ice cores) and eighteen moonlets in the first group of moons and one major moon (Iapetus is technically a major moon because it is large enough to be a tiny terrestrial planet with an ice core) and thirty-nine moonlets in the third group of moons. Jupiter could be created with the current rules except that it possesses 41 moonlets in the third group of moons.

I would suggest the following changes to the rules for gas giant moons. Within the first group of moons, gas giants possess 1d-2 major moons and 6d-12 moonlets (+1 major moons and +6 moonlets for medium gas giants and +2 major moons and +12 moonlets for large gas giants). Within the second group of moons, gas giants possess 2d-4 major moons (+2 major moons for medium gas giants and +4 major moons for large gas giants). Within the third group of moons, gas giants possess 12d-24 moonlets (+12 moonlets for medium gas giants and +24 moonlets for large gas giants). The other modifiers for gas giant moons would be unchanged.

I would suggest the following changes to the rules for terrestrial moons. First, terrestrial planets are capable of having major moons and moonlets, just like Pluto (Charon is technically a major moon because it is large enough to be a tiny terrestrial planet). Second, terrestrial planets possess 1d-2 moonlets and 1d-4 major moons (+2 moonlets and +1 major moons if beyond the Snow Line). The other modifiers for terrestrial moons would be unchanged.
I would suggest just not calculating the number of moonlets for gas giants because they aren't good for much. Just take it as read that any gas giant has a swarm of moonlets sufficient for any purpose that you might want to use one for.

Last edited by David Johnston2; 11-27-2017 at 03:29 PM.
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Old 11-29-2017, 05:53 PM   #5
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Default Re: Changing Planet Creation Rules to Reflect Realism

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Originally Posted by Say, it isn't that bad! View Post
A surprise meeting of a small fraction of the Astronomical Union is not "serious", and "dwarf planet" is not an internally-consistent category.
I don't find the meeting to be much of a surprise; Pluto's inclusion as a classical planet was debated back in the 90's. And the IAU's definition of "dwarf planet" is very straight forward: hydro-static equilibrium but not having cleared it's orbit of other bodies.

The 2nd point is well defined; there is a gap of about 5 orders of magnitude of Λ (a body's measured ability to clear it's orbit, based on mass and size of the orbit) between the planets and dwarf planets, as well as Π (a similar value that's more theory based).

It's the 1st part that causes the problems. Not that's poorly defined or inconsistent, but that's it can be hard to say a Kuiper belt object is in hydro-static equilibrium.
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Old 11-29-2017, 06:13 PM   #6
Flyndaran
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Default Re: Changing Planet Creation Rules to Reflect Realism

I didn't like Pluto being a planet back in 1st grade 1981. It's pretty obviously "wrong".
And I don't think the rules were meant to include all the insanely tiny moonlets that the gas giants collected.
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Old 11-29-2017, 06:32 PM   #7
Fred Brackin
 
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Default Re: Changing Planet Creation Rules to Reflect Realism

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I didn't like Pluto being a planet back in 1st grade 1981. It's pretty obviously "wrong".
.
You can even call it a "full" planet rather than a "dwarf planet" if you want to but it's very obviously a different sort of thing than either of the two groups the first eight planets fit into.

As to the new category that was pretty much unavoidable and it was for pretty much the same reason Ceres became the first of a new category (i.e. asteroid or planetoid) rather than being the "new planet" it was originally hailed as being.
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Old 11-29-2017, 07:04 PM   #8
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Default Re: Changing Planet Creation Rules to Reflect Realism

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I didn't like Pluto being a planet back in 1st grade 1981. It's pretty obviously "wrong".
Nobody could ever really explain well enough why Pluto was a planet and nothing else that big was.

But I was also completely fooled by the Mercator projection into thinking Greenland was bigger than all of America, so...
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Old 11-29-2017, 08:49 PM   #9
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Default Re: Changing Planet Creation Rules to Reflect Realism

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Originally Posted by AlexanderHowl View Post
I was wondering what everyone would think about changing the planet creation rules to reflect realism, at least for the purpose of moons. In the Sol System, Jupiter possesses 69 moons and Saturn possesses 62 moons, neither of which can be replicated by the current system (Uranus is also problematic because of its outer moonlets).
For GURPS purposes, I feel like breakdowns by mass are the best criterion; they make it obvious that Jupiter has four moons, Saturn has one and a bit, Uranus has four and Neptune has one (albeit an aberrant one - the gravitational capture of Triton from the Kuiper belt all but destroyed Neptune's autochthonous satellites).
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Old 11-29-2017, 09:44 PM   #10
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Default Re: Changing Planet Creation Rules to Reflect Realism

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Originally Posted by David Johnston2 View Post
I would suggest just not calculating the number of moonlets for gas giants because they aren't good for much. Just take it as read that any gas giant has a swarm of moonlets sufficient for any purpose that you might want to use one for.
Not only that, but the number will vary with the time taken to look for them and the quality of the instruments, and also over time as some are lost and others gained.
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