Proposed Rules for Calcing Planet Sizes (CGM Only)

[KLOL506]

I have no horse in this race.

@DontTalkDT @Executor_N0 @Mr. Bambu Your thoughts on this topic would be appreciated.

 

[Armorchompy]

Consistent cartography is really hard, and tweaking numbers so that they fit a story is ultimately going to be most authors' choice over consistency. It's also worth mentioning that most maps aren't actually to scale. The Mercator projection shows Greenland (2650 km) as nearly taller than Africa (8000 km) and that's something we as a modern civilization still use. When it comes to more old timey maps it's much worse, they just didn't have the tools or ability to make it 100% consistent. Of course even if it's meant to be consistent it could be drawn in such a way to emphasize certain locations or just without perfect accuracy, it takes a tiny inaccuracy to make a planet's size balloon up (or down).

I'm all for forbidding large planet calcs unless they have clear canonical backing (or are just clearly shown to be big in comparison to other planets/celestial bodies). It doesn't need to be a size statement, but something equally viable like an impossibly high population count is necessary. If there's clear evidence it's bigger... maybe you can try to figure something out, though I do like the "largest" rocky planet thing.

 

[DontTalkDT]

Not sure if I see the issue with the idea of planets being scaled large or with subsequent calcs that use the characteristics of the magical planet as if it were a plausible physical construct.

 

[M3X_2.0]

Not sure if I see the issue with the idea of planets being scaled large or with subsequent calcs that use the characteristics of the magical planet as if it were a plausible physical construct.

It’s not “planets”, it’s Earth. I actually wrote a huge OP about that and I hope people read it.

 

[DarkDragonMedeus]

This is a practice that is definitely easier said than done. And I really do not think there are any one size fits all protocols that could be done about this. Fiction can get really whacky; especially ones intended to be a homage to ancient mythologies that basically consist of infinite sized flat earths that otherwise still appear to have normal atmosphere and normal gravity. And I feel as if planet's with super massive diameter/surface areas to an extent have some things in common with them, but there are other details here and there that really leaves a lot more room for interpretation.

I know a long time ago, someone made a thread trying to make rules against Naruto, Bleach, and One Piece (Especially this one) taking place in planets many times larger than planet earth, but not sure what happened to that or if that got overturned. And while I have read the OP and emphasize on a lot of points brought up, but just because I emphasize with them doesn't mean I fully agree. For one, planets super massive in terms of volume could also just have abysmally low density. I think that's what we ultimately decided with planet Namek. We see on panels that it is super gigantic from the human eye, it is located in the center of three stars "Which also kind of requires being considerably durable for a planet" not to mention the destruction has shown signs of covering interstellar distances. That's another thing, fiction can often full of planets made of materials such as Mythril/Mithril, Vibranium, Adamantium, or Beskar. There are fictional alloys that appear lighter than feathers but still a solid state that appears to be more durable than some of the strongest composite metals known to man.

Likewise, abysmally low density isn't quite the only way to explain massive surface area but not so crazy gravity. Other explanations could be the idea Hollow Earths that were common in a lot of 19th century era Sci Fi novels. Which plenty of verses with giant versions of Earth could very well be structured like them. It was the foundation of underworlds existing in various stories like the Under Dark from DnD or how Donkey Kong Bananza revealed that the "Earth" Mario/DK universe takes place in is a multilayered hollow planet with multiple subterranean worlds withing subterranean worlds. Which would still mean the surface area is massive but probably not the actual volume or by extension the average density. That being said, while it could be pointed out that just like RL, some countries, Islands, or Continents in our world map aren't drawn to scale and aren't accurate reflections of how big each of them are compared to the earth's surface area, which is a concern for One Piece's scale. But as pointed out the 50km wide river is extremely miniscule compared to its length, which is miniscule compared to the Alabasta Island, which is miniscule compared to other Islands, which is miniscule compared to the width of the Grand Line, and in turn is miniscule compared to the rest of the world. Our world map may not be accurate, but it's not like "the entire continent of Asia is smaller than Cyprus Island levels of off," which is kind of the interpretation being used to reject the scope and scale of the 50km wide river. Not to mention, One Piece is still located in a world where sky islands and floating continents exist, has 6 moons; has a lot more ocean to land ratio compared to our earth (And much like a flooded earth), and the grand line (Which is pretty much just their version of an equator) is still wide enough to contain some pretty large land masses.

I am ultimately unsure how to handle One Piece's conclusion, and we should come up with something for sure. As saying "We know it's definitely larger than Earth but we don't know how much" wouldn't help much. Some people have reasonable approaches as calculating diameter/surface area is fine, but would avoid assuming anything else like low surface density, GBE, and stick to assuming surface gravity is earth level. It is common knowledge that in IRL, the surface of planets tends to be much less dense than the cores; and this is true even for gas giants, brown dwarfs, and stars (Even red giant stars). To which hollow earths tend to be the opposite where the cores are technically not as dense as the surface due to being mostly empty space. And that can be the explanation for why it's not portrayed as having super masive gravity. Which is a vastly different story compared to planets with small diameters but high mass, density, gravity. Which is precisely why I am 100% in the mentality that planets where both given mass and given diameter/surface area/volume are given to us should make it fair to calculate surface gravity, possibly atmospheric pressure, and gravitational binding energy. But planets like One Piece where it's much larger than Earth based on rough pixel scales, no author statements, and surface atmosphere is relatively earth like are a different story.

But as for the outcome of this thread, I am ultimately kind of neutral.

 

[DontTalkDT]

It’s not “planets”, it’s Earth. I actually wrote a huge OP about that and I hope people read it.

OP doesn't really specify Earth specifically; it's talking about habitable or rocky planets. My point is exactly as I said in my first comment.

To add to it: In my view, the assumption in Rule 2 that an author would acknowledge a not widely known limit for the size of natural rocky planets, rather than shown size, is at odds with the idea of respecting the author's intent. We can't know the author's intent (which is why we often respect it quite little), but if I were to list things by the likelihood of reflecting or even factoring into the author's intention for planet size, then I would put the depicted size above the upper size limit for rocky planets.

From what I read in the comments, I also think Rule 3 is not functional. Reading it in the OP I initially thought it was about author statements on planet size specifically. But from the comments, it sounds like scaling is allowed if it seems like some measure of author intent is involved, which is subjective. A more objective framework would be needed for what are supposed to be the exceptions.

As for technicalities:

1. The rules obviously would need definitions of Earth-like and rocky planet. Like, an inhabited rocky planet with regular humans on it should probably not count for either option, if it turns out that it is held together by a black hole in its center and a layer of magic in between. Any idea of realistic composition is out the window at that point.
2. You would need some additional ruling framework to clarify how to deal with scaling that isn't about planet size, but has planet-size implications.

Overall, I feel like I somewhat lean more to letting giant planets be giant planets and just not using the planet parameters for calcs as if they weren't of magic composition. Seems easier to build an objective ruleset around.

 

[Saqphire]

Overall, I feel like I somewhat lean more to letting giant planets be giant planets and just not using the planet parameters for calcs as if they weren't of magic composition. Seems easier to build an objective ruleset around.

Wouldn't this just invalidate the calcs anyway? As the current planet calcs that are accepted are assuming the parametres for those planets are similar/identical to Earth´s

 

[M3X_2.0]

This is a practice that is definitely easier said than done. And I really do not think there are any one size fits all protocols that could be done about this. Fiction can get really whacky; especially ones intended to be a homage to ancient mythologies that basically consist of infinite sized flat earths that otherwise still appear to have normal atmosphere and normal gravity. And I feel as if planet's with super massive diameter/surface areas to an extent have some things in common with them, but there are other details here and there that really leaves a lot more room for interpretation.

I know a long time ago, someone made a thread trying to make rules against Naruto, Bleach, and One Piece (Especially this one) taking place in planets many times larger than planet earth, but not sure what happened to that or if that got overturned. And while I have read the OP and emphasize on a lot of points brought up, but just because I emphasize with them doesn't mean I fully agree. For one, planets super massive in terms of volume could also just have abysmally low density. I think that's what we ultimately decided with planet Namek. We see on panels that it is super gigantic from the human eye, it is located in the center of three stars "Which also kind of requires being considerably durable for a planet" not to mention the destruction has shown signs of covering interstellar distances. That's another thing, fiction can often full of planets made of materials such as Mythril/Mithril, Vibranium, Adamantium, or Beskar. There are fictional alloys that appear lighter than feathers but still a solid state that appears to be more durable than some of the strongest composite metals known to man.

Likewise, abysmally low density isn't quite the only way to explain massive surface area but not so crazy gravity. Other explanations could be the idea Hollow Earths that were common in a lot of 19th century era Sci Fi novels. Which plenty of verses with giant versions of Earth could very well be structured like them. It was the foundation of underworlds existing in various stories like the Under Dark from DnD or how Donkey Kong Bananza revealed that the "Earth" Mario/DK universe takes place in is a multilayered hollow planet with multiple subterranean worlds withing subterranean worlds. Which would still mean the surface area is massive but probably not the actual volume or by extension the average density. That being said, while it could be pointed out that just like RL, some countries, Islands, or Continents in our world map aren't drawn to scale and aren't accurate reflections of how big each of them are compared to the earth's surface area, which is a concern for One Piece's scale. But as pointed out the 50km wide river is extremely miniscule compared to its length, which is miniscule compared to the Alabasta Island, which is miniscule compared to other Islands, which is miniscule compared to the width of the Grand Line, and in turn is miniscule compared to the rest of the world. Our world map may not be accurate, but it's not like "the entire continent of Asia is smaller than Cyprus Island levels of off," which is kind of the interpretation being used to reject the scope and scale of the 50km wide river. Not to mention, One Piece is still located in a world where sky islands and floating continents exist, has 6 moons; has a lot more ocean to land ratio compared to our earth (And much like a flooded earth), and the grand line (Which is pretty much just their version of an equator) is still wide enough to contain some pretty large land masses.

I am ultimately unsure how to handle One Piece's conclusion, and we should come up with something for sure. As saying "We know it's definitely larger than Earth but we don't know how much" wouldn't help much. Some people have reasonable approaches as calculating diameter/surface area is fine, but would avoid assuming anything else like low surface density, GBE, and stick to assuming surface gravity is earth level. It is common knowledge that in IRL, the surface of planets tends to be much less dense than the cores; and this is true even for gas giants, brown dwarfs, and stars (Even red giant stars). To which hollow earths tend to be the opposite where the cores are technically not as dense as the surface due to being mostly empty space. And that can be the explanation for why it's not portrayed as having super masive gravity. Which is a vastly different story compared to planets with small diameters but high mass, density, gravity. Which is precisely why I am 100% in the mentality that planets where both given mass and given diameter/surface area/volume are given to us should make it fair to calculate surface gravity, possibly atmospheric pressure, and gravitational binding energy. But planets like One Piece where it's much larger than Earth based on rough pixel scales, no author statements, and surface atmosphere is relatively earth like are a different story.

But as for the outcome of this thread, I am ultimately kind of neutral.

This is probably the most thorough response in the thread and I'll try to address everything properly.

On low density and hollow earth explanations: these are legitimate alternatives and I'll concede they weaken the gravity argument as a standalone point. A sufficiently low density or hollow planet could theoretically maintain Earth-like surface gravity at a much larger size. The issue is that these are explanations we're inventing to patch a problem the calc introduced, not something the series establishes. One Piece never depicts or implies a hollow planet or anomalously low density, so we'd be stacking one unsupported assumption on top of another to salvage a calc result Oda never validated.

On the map accuracy point and the 50km river: agreed that maps in fiction are rarely accurate and that's a fair concern for any pixel scaling calc. But the argument cuts both ways. If we acknowledge that Oda's maps aren't drawn to cartographic accuracy, that's actually a reason to be more skeptical of pixel scaling results, not less. The 50km river being minuscule compared to Alabasta being minuscule compared to the Grand Line being minuscule compared to the world is a compelling chain of reasoning for the planet being large, but it's still an inferential chain built on a single stated measurement and proportional assumptions about a map Oda drew for narrative purposes. The further you extrapolate from the original measurement the more uncertainty compounds, which is precisely why the result ranges from 1.5 to 7 million kilometers depending on methodology.

On the six moons, sky islands and ocean to land ratio: these are all valid worldbuilding details that support the planet being larger than Earth, and I've conceded that point repeatedly throughout this thread. None of them specifically validate a sun-sized result though. A planet twice or three times Earth's size would accommodate all of those details just fine.

On planets with explicit mass and size versus pixel scaled ones: this is exactly the distinction the thread is trying to formalize and I'm glad we agree on it. Planets where both are given explicitly allow for consistent physics-based calculations. Planets like One Piece where the size comes entirely from pixel scaling with no authorial confirmation and surface conditions are portrayed as Earth-like are a fundamentally different category and shouldn't be treated the same way.

The middle ground you proposed, using the size for distance-based calculations while defaulting to Earth-level surface gravity, is probably the most defensible position until Oda says something concrete or a more reliable calc methodology is established. That's essentially what the thread is trying to codify.

OP doesn't really specify Earth specifically; it's talking about habitable or rocky planets. My point is exactly as I said in my first comment.

To add to it: In my view, the assumption in Rule 2 that an author would acknowledge a not widely known limit for the size of natural rocky planets, rather than shown size, is at odds with the idea of respecting the author's intent. We can't know the author's intent (which is why we often respect it quite little), but if I were to list things by the likelihood of reflecting or even factoring into the author's intention for planet size, then I would put the depicted size above the upper size limit for rocky planets.

From what I read in the comments, I also think Rule 3 is not functional. Reading it in the OP I initially thought it was about author statements on planet size specifically. But from the comments, it sounds like scaling is allowed if it seems like some measure of author intent is involved, which is subjective. A more objective framework would be needed for what are supposed to be the exceptions.

As for technicalities:

1. The rules obviously would need definitions of Earth-like and rocky planet. Like, an inhabited rocky planet with regular humans on it should probably not count for either option, if it turns out that it is held together by a black hole in its center and a layer of magic in between. Any idea of realistic composition is out the window at that point.
2. You would need some additional ruling framework to clarify how to deal with scaling that isn't about planet size, but has planet-size implications.

Overall, I feel like I somewhat lean more to letting giant planets be giant planets and just not using the planet parameters for calcs as if they weren't of magic composition. Seems easier to build an objective ruleset around.

These are fair critiques and Rule 3 definitely needs tighter wording to be more objective, that's a valid point. Rule 2 assuming authors know the rocky planet size limit is also a reasonable concern, though I'd argue the threshold existing regardless of whether the author knows it is what matters for our purposes, not whether they consciously intended it.

The conclusion you landed on is interesting though. "Let giant planets be giant but don't use planet parameters for calcs as if they weren't magic composition" is functionally pretty close to what this thread is already proposing, just worded differently. Almost like the framework here isn't as far off as the last 30 posts suggested.

 

[Qurbonboev]

Likewise, abysmally low density isn't quite the only way to explain massive surface area but not so crazy gravity. Other explanations could be the idea Hollow Earths that were common in a lot of 19th century era Sci Fine novels

To have same surface gravity as Earth, Blue would need to be either:
1. Have very low density. Around 50 kg/m^3, in same realm as styrofoam.
2. Be a Hollow Earth. Assuming interior is air, hard surface shell should be around 2-4 km wide(depends of exact density). Seemingly contradicted by Sea Floor being 10 km deep, and Reverse Mountain being taller than 10 km(from here).
But even if one of these options above were correct, we still would face problem of high escale velocity. Assuming same surface density as Earth, Blue would have escape velocity 121 km/s(OP is slightly wrong on this: if Blue had same density as Earth, it's escape velocity would be not 121 km/s, but 1350 km/s).
Atmosphere would be dominated by light airs, like Hydrogen and Helium(could be explained as Blue not having such materials in abundance from the start, from some astrophysical reason). It would be much bigger and extends much higher into space(which seems to be true for Blue). And yeah, pressure.
OP says that liquid water at surface would be impossible under 11,920 kPa pressure. Maybe I missing something important, but phase diagram of water tells me that it's possible to have liquid water under such pressure with room temperatures.
It's small nitpick thought. Raindrops can exists as high as 114,000 km in One Piece(based on same map that is currently used for measuring size). So Armstrong limit for Blue is massively higher than for Earth: at least 114000 km(One piece sups prolly can provide example of liquid water existing at much higher altitudes) vs 19 km. Armstrong limit is defined by amount of pressure. To make example, at 114000 km altitude Blue atmosphere has x10 higher pressure than Mars. I didn't find a method to exactly quantity pressure at surface for Blue yet, but intuition tells me it wouldn't be low number.

I can prolly add more(including about normal limit for rocky planets), but I think we should tackle this problem first:
Oda didn't thought allat. It seems undeniable that he envisioned for Blue to much bigger than Earth, but I don't think he has some concrete number in mind. And he certainly didn't through implications of such a big size, and broadly envisioned for Blue to be Earth like(as in have similar surface density, having liquid water at surface).

Best course of action in my opinion, is to search through work for relevant for size facts(like stated number of islands), and create several different methods to calculate size. One calc that gives us 1,576,000 km for diameter through comparison of several maps is not very strong support. Several of such calcs, plus fact that horizon being 50 km supports big sizes, is good enough support(in absence of several other methods that give totally different results).

 

[DarkDragonMedeus]

To have same surface gravity as Earth, Blue would need to be either:
1. Have very low density. Around 50 kg/m^3, in same realm as styrofoam.
2. Be a Hollow Earth. Assuming interior is air, hard surface shell should be around 2-4 km wide(depends of exact density). Seemingly contradicted by Sea Floor being 10 km deep, and Reverse Mountain being taller than 10 km(from here).
But even if one of these options above were correct, we still would face problem of high escale velocity. Assuming same surface density as Earth, Blue would have escape velocity 121 km/s(OP is slightly wrong on this: if Blue had same density as Earth, it's escape velocity would be not 121 km/s, but 1350 km/s).
Atmosphere would be dominated by light airs, like Hydrogen and Helium(could be explained as Blue not having such materials in abundance from the start, from some astrophysical reason). It would be much bigger and extends much higher into space(which seems to be true for Blue). And yeah, pressure.
OP says that liquid water at surface would be impossible under 11,920 kPa pressure. Maybe I missing something important, but phase diagram of water tells me that it's possible to have liquid water under such pressure with room temperatures.
It's small nitpick thought. Raindrops can exists as high as 114,000 km in One Piece(based on same map that is currently used for measuring size). So Armstrong limit for Blue is massively higher than for Earth: at least 114000 km(One piece sups prolly can provide example of liquid water existing at much higher altitudes) vs 19 km. Armstrong limit is defined by amount of pressure. To make example, at 114000 km altitude Blue atmosphere has x10 higher pressure than Mars. I didn't find a method to exactly quantity pressure at surface for Blue yet, but intuition tells me it wouldn't be low number.

I can prolly add more(including about normal limit for rocky planets), but I think we should tackle this problem first:
Oda didn't thought allat. It seems undeniable that he envisioned for Blue to much bigger than Earth, but I don't think he has some concrete number in mind. And he certainly didn't through implications of such a big size, and broadly envisioned for Blue to be Earth like(as in have similar surface density, having liquid water at surface).

Best course of action in my opinion, is to search through work for relevant for size facts(like stated number of islands), and create several different methods to calculate size. One calc that gives us 1,576,000 km for diameter through comparison of several maps is not very strong support. Several of such calcs, plus fact that horizon being 50 km supports big sizes, is good enough support(in absence of several other methods that give totally different results).

While lots of these are indeed valid concerns, there could still be other things we do not know about. Because as mentioned, when it comes to pretty much any RL planet, the surface that walk on including the ocean is the least dense part of the planet where as the closer we get to the inner core, the denser it gets. And for all we know, One Piece fictional planets such as Blue could be following the opposite logic. With likely missing and/or replaced with much lighter substances for all of its mantles or the core. That, and the crust layer holding up the seas and land is made of a substance similar to Mithril (The element from fantasy works like LotR and DnD that's lighter than feathers but harder than diamonds and many times more tougher than even some of the strongest composite alloys known to man).

Of course, we do not know all that either and is up to speculation. And iirc, there actually is probably evidence that gravity and atmospheric pressure is greater than our own to extent, but we just do not know how much greater. But the way Skypiea is positioned does basically showcase how immense and variable the atmospheric pressure of Blue can be. The Strawhat Pirates not being used to how atmosphere works in the high skies was an important known plot point during the Skypiea arc. That being said, we also do know that One Piece follows a common comic/cartoon/manga/anime logic where even civilian characters in the One Piece universe are considerably superhuman. And that various common animals that resemble various real world animals are considerably larger and stronger than RL counterparts. Like there exist lions, tigers and bears that dwarf the size of various RL dinosaurs. And speaking of dinosaurs, they also are still around in Blue; while also being considerably massive compared to RL counterparts and even Jurassic Park's versions. And of course, Sea Kings are literally Kaiju Godzilla/Gamera sized creatures; which the oceans would have to be much larger in order to have so many of them for sure.

But anyway, I suppose I also agree with what a lot of things DontTalkDT has laid out.

 

[Qurbonboev]

With likely missing and/or replaced with much lighter substances for all of its mantles or the core. That, and the crust layer holding up the seas and land is made of a substance similar to Mithril

Supporters of verse obviously want to be able to calc things like earthquakes. And for our earthquake formulas to work, Blue crust would need to have material with broadly similar physical and mechanical properties to Earth Cryst. Which includes density for obvious reason. And crust layer that is big enough to conduct earthquakes, and has similar enough composition for our formulas to apply, would invariably result in much higher values of surface gravity than Earth ones(and Blue doesn't seems to have abnormally strong gravity).

 

[DarkDragonMedeus]

I agree Earthquake policies would be complicated by those formula; and also the fact that Volcanoes and natural hot springs exist in one Piece gives the impress that it does have a mantle underneath the lithosphere I forgot to mention yeah.

 

[HammerStrikes219]

This is a practice that is definitely easier said than done. And I really do not think there are any one size fits all protocols that could be done about this. Fiction can get really whacky; especially ones intended to be a homage to ancient mythologies that basically consist of infinite sized flat earths that otherwise still appear to have normal atmosphere and normal gravity. And I feel as if planet's with super massive diameter/surface areas to an extent have some things in common with them, but there are other details here and there that really leaves a lot more room for interpretation.

I know a long time ago, someone made a thread trying to make rules against Naruto, Bleach, and One Piece (Especially this one) taking place in planets many times larger than planet earth, but not sure what happened to that or if that got overturned. And while I have read the OP and emphasize on a lot of points brought up, but just because I emphasize with them doesn't mean I fully agree. For one, planets super massive in terms of volume could also just have abysmally low density. I think that's what we ultimately decided with planet Namek. We see on panels that it is super gigantic from the human eye, it is located in the center of three stars "Which also kind of requires being considerably durable for a planet" not to mention the destruction has shown signs of covering interstellar distances. That's another thing, fiction can often full of planets made of materials such as Mythril/Mithril, Vibranium, Adamantium, or Beskar. There are fictional alloys that appear lighter than feathers but still a solid state that appears to be more durable than some of the strongest composite metals known to man.

Likewise, abysmally low density isn't quite the only way to explain massive surface area but not so crazy gravity. Other explanations could be the idea Hollow Earths that were common in a lot of 19th century era Sci Fi novels. Which plenty of verses with giant versions of Earth could very well be structured like them. It was the foundation of underworlds existing in various stories like the Under Dark from DnD or how Donkey Kong Bananza revealed that the "Earth" Mario/DK universe takes place in is a multilayered hollow planet with multiple subterranean worlds withing subterranean worlds. Which would still mean the surface area is massive but probably not the actual volume or by extension the average density. That being said, while it could be pointed out that just like RL, some countries, Islands, or Continents in our world map aren't drawn to scale and aren't accurate reflections of how big each of them are compared to the earth's surface area, which is a concern for One Piece's scale. But as pointed out the 50km wide river is extremely miniscule compared to its length, which is miniscule compared to the Alabasta Island, which is miniscule compared to other Islands, which is miniscule compared to the width of the Grand Line, and in turn is miniscule compared to the rest of the world. Our world map may not be accurate, but it's not like "the entire continent of Asia is smaller than Cyprus Island levels of off," which is kind of the interpretation being used to reject the scope and scale of the 50km wide river. Not to mention, One Piece is still located in a world where sky islands and floating continents exist, has 6 moons; has a lot more ocean to land ratio compared to our earth (And much like a flooded earth), and the grand line (Which is pretty much just their version of an equator) is still wide enough to contain some pretty large land masses.

I am ultimately unsure how to handle One Piece's conclusion, and we should come up with something for sure. As saying "We know it's definitely larger than Earth but we don't know how much" wouldn't help much. Some people have reasonable approaches as calculating diameter/surface area is fine, but would avoid assuming anything else like low surface density, GBE, and stick to assuming surface gravity is earth level. It is common knowledge that in IRL, the surface of planets tends to be much less dense than the cores; and this is true even for gas giants, brown dwarfs, and stars (Even red giant stars). To which hollow earths tend to be the opposite where the cores are technically not as dense as the surface due to being mostly empty space. And that can be the explanation for why it's not portrayed as having super masive gravity. Which is a vastly different story compared to planets with small diameters but high mass, density, gravity. Which is precisely why I am 100% in the mentality that planets where both given mass and given diameter/surface area/volume are given to us should make it fair to calculate surface gravity, possibly atmospheric pressure, and gravitational binding energy. But planets like One Piece where it's much larger than Earth based on rough pixel scales, no author statements, and surface atmosphere is relatively earth like are a different story.

But as for the outcome of this thread, I am ultimately kind of neutral.

I like to point out we can have and do have rock solid planets irl that is considered as Super Earth.

Like quite literally the case here.

What Is a Super-Earth? - NASA Science

Super-Earths – a class of planets unlike any in our solar system – are more massive than Earth yet lighter than ice giants like Neptune and Uranus, and can be made of gas, rock or a combination of both.

science.nasa.gov

“Super-Earths – a class of planets unlike any in our solar system – are more massive than Earth yet lighter than ice giants like Neptune and Uranus, and can be made of gas, rock or a combination of both. They are between twice the size of Earth and up to 10 times its mass.

Super-Earth is a reference only to an exoplanet’s size – larger than Earth and smaller than Neptune – but not suggesting they are necessarily similar to our home planet. The true nature of these planets remains shrouded in uncertainty because we have nothing like them in our own solar system – and yet, they are common among planets found so far in our galaxy.

Over the last three decades, we have discovered all kinds of strange planets we never knew existed and that have no analog in our solar system. Super-Earths can be up to 10 times more massive than Earth. We don’t yet know enough about these planets to tell at what point they might lose a rocky surface. But in the range of 3-10 times the mass of Earth, there might be a wide variety of planetary compositions, including water worlds, snowball planets, or planets that, like Neptune, are composed largely of dense gas. Exoplanets at the upper limits of the super-Earth size limit can also be referred to as sub-Neptunes, or mini-Neptunes.”



It is very safe to assume and consider the OP’s planet size to being a Super Earth/Exoplanet without necessarily being Sun sized from a fan made calculation that manages to assume a massive diameter for a planet like that.

 

[HammerStrikes219]

Exoplanets - NASA Science

Most of the exoplanets discovered so far are in a relatively small region of our galaxy, the Milky Way. (“Small” meaning within thousands of light-years of

science.nasa.gov

Edit: It is also worth mentioning we literally just scratching the surface in the Milky Way Galaxy alone when it comes to numerous planets irl.

Other Galaxies will have a lot of planets that has and will varied a lot considerably.

 

[Saqphire]

It is very safe to assume and consider the OP’s planet size to being a Super Earth/Exoplanet without necessarily being Sun sized from a fan made calculation that manages to assume a massive diameter for a planet like that.

That was what I was trying to get at here, but saying the OP planet can be calced to be a superplanet without being sun-sized, as those aren't the same claims

 

[HammerStrikes219]

That was what I was trying to get at here, but saying the OP planet can be calced to be a superplanet without being sun-sized, as those aren't the same claims

Yeah, although I can confirm there is the formerly theorized Mega Earths that is like 10 times the size of the Earth or higher too.

Mega-Earth - Wikipedia

en.wikipedia.org

 

[HammerStrikes219]

That was what I was trying to get at here, but saying the OP planet can be calced to be a superplanet without being sun-sized, as those aren't the same claims

Although there is one more thing I need to also point out as well.

I get the fictional angle and argument, I really do, but it also works both ways as well as rock solid planets portrayed in fiction that are bigger than Earth isn’t actually unrealistic by any means, in fact, I find to being the opposite as in, it is completely possible when it come to planets irl as well.

Anyway, fanmade calculations are directly using mathematical formulas that is used for theoretical physics and astro physics as well for all calculations related to the size of a planet.

I can’t afford to overlook the scientific angle of such calculations as this is a important concern and a valid concern from the OP.

Let me make myself clear, I actually find the concerns of the OP perfectly valid and solid imo from a scientific angle including the mathematical aspects of such calcs when trying to guesstimate a planet size that is bigger than our own Earth and all.

The opposition points imo doesn’t really invalidate the concerns the OP has presented when it comes to large planet size calculations that involve mathematical formulas for a astro physics calculation as well

 

[Saqphire]

Although there is one more thing I need to also point out as well.

I get the fictional angle and argument, I really do, but it also works both ways as well as rock solid planets portrayed in fiction that are bigger than Earth isn’t actually unrealistic by any means, in fact, I find to being the opposite as in, it is completely possible when it come to planets irl as well.

Anyway, fanmade calculations are directly using mathematical formulas that is used for theoretical physics and astro physics as well for all calculations related to the size of a planet.

I can’t afford to overlook the scientific angle of such calculations as this is a important concern and a valid concern from the OP.

Let me make myself clear, I actually find the concerns of the OP perfectly valid and solid imo from a scientific angle including the mathematical aspects of such calcs when trying to guesstimate a planet size that is bigger than our own Earth and all.

The opposition points imo doesn’t really invalidate the concerns the OP has presented when it comes to large planet size calculations that involve mathematical formulas for a astro physics calculation as well

Yeah what you're saying makes sense. Fictional planets have their rules, but their rules can also apply in our world and since we're using real life mathematics and physic for both real life and fictional planets, we should also take note of the limitations of said formulas when it comes to each subject here. If these Earth-like giant ass planets wouldn't work in an IRL setting, why should we use a formula that relies on real life settings and limits to find the parametres of that planet. For these gigantic ass planets from these xianxia medias or One Piece, we'd actually have to invent a whole new formula at that point

 

[HammerStrikes219]

Yeah what you're saying makes sense. Fictional planets have their rules, but their rules can also apply in our world and since we're using real life mathematics and physic for both real life and fictional planets, we should also take note of the limitations of said formulas when it comes to each subject here. If these Earth-like giant ass planets wouldn't work in an IRL setting, why should we use a formula that relies on real life settings and limits to find the parametres of that planet. For these gigantic ass planets from these xianxia medias or One Piece, we'd actually have to invent a whole new formula at that point

Tbf, astrophysicists have actually managed to calculate the size of planets outside of our solar system as they have used their own mathematical means to measure such planets and we already have measurements of all the planets in our solar system.

I not against large size planet calcs myself completely, but I will still emphasize that the calculations come from fans trying to guesstimate a planet’s parameters and could very easily inflate the results to assume a massive diameter that is Sun like planet or so.

IIRC, I doubt we have any standards for mathematics forumulas when it comes to planets outside the default Earth parameters that would involve a planet that is larger with Earth like solid properties and all on the wiki.

 

[HammerStrikes219]

Yeah what you're saying makes sense. Fictional planets have their rules, but their rules can also apply in our world and since we're using real life mathematics and physic for both real life and fictional planets, we should also take note of the limitations of said formulas when it comes to each subject here. If these Earth-like giant ass planets wouldn't work in an IRL setting, why should we use a formula that relies on real life settings and limits to find the parametres of that planet. For these gigantic ass planets from these xianxia medias or One Piece, we'd actually have to invent a whole new formula at that point

Technically fiction is more inspired by reality rather than the other way though because while it is true fiction has its own thing that differ heavily from reality, fiction get their inspirations from irl ideas, concepts, views, beliefs, and so on.

To say otherwise is counterproductive there as fiction is written by authors who ain’t scientific by any means, but as a form of escapism and having a sense of realism in some ways as well.


Still means fiction has its own rules of course, but it is an inspiration from reality in some ways when it comes to things that seemingly defy irl science and all. However, it is important to note that science and math are evolving over time, but I getting off topic here.

I already say my piece and concluded the OP’s concerns regarding large planets parameter calculations to being reasonable and stuff.

We need some measurement of skepticism as without skepticism, we never get any results that seems reasonable and convincing that helps resolve said skepticism in a satisfactory way and all.

 

[DarkDragonMedeus]

Almost every fantasy setting ever created was inspired by "Myths and legends." While most view Tolkien as the one who popularized dwarves, elves, orcs, hobbits/halflings, and many other fantasy races, the lot of them had origins related to Greek, Norse, and may other ancient religions. And even a lot of the oldest Science Fiction verses were based on philosophical studies and theories that basically explore the idea of "What if certain debunked theories were accurate?"

But we should probably stay on topic. I still share some same sentiments of what I have said earlier as well as things DontTalkDT said. While I agree that scale drawings aren't 100% accurate, the actual overall value shouldn't be too different from OP's conclusion of its SA. But other details such as density, gravity, ect are harder to determine without further details. And as for other planets like "Super Earths," I am 100% firm that planets with both a given official mass and given official dimensional length(s) would give us an average density by default. And as a result, would gives us average values for surface gravity, atmospheric pressure, gravitational binding energy ect. Which wouldn't apply to OP Blue of course, but I do think a planetary parameter calculations page explaining details/rules would be alright.

 

[Schattenbach]

About the discussion regarding planet composition or hollow earth, it is important to remember that even for our "earth-like" planet, only less 1% of mass is in the crust (with avg. density of 2,7t per m³) with roughly 30% of the mass being in the core and 70% being the mantle. Assuming atypical core or mantle compositions might - especially with all those anomalies we have going on in examples like One Piece - actually make it easier for explaining bigger planets (or planet-like planes or super large exotic continents) without extreme differences in actual on-the-ground conditions compared to earth. Local differences through special characteristics (superdense or super-magnetic or super heavy meteoroids, mountains or whatever) would skew the results further.

 

[HammerStrikes219]

https://www.open.edu/openlearn/mod/oucontent/view.php?id=87798§ion=_unit6.4.2#:~:text=If%20you%20want%20to%20calculate,it%20if%20you%20are%20unsure!

I have find some other alternative when it comes to exoplanet’s size calculation formulas

Measuring an exoplanet

Let's learn about exoplanets and how to measure their size!

astroedu.iau.org

Including this one.

How Predicted Observables for Exoplanets are Calculated

The formula used for exoplanets by NASA and other important things

 

[Wrath_Of_Itachi]

Bump

 

[KLOL506]

Bump

 

[Wrath_Of_Itachi]

Is there any consensus for this thread or can any verse calc planet size?

 

[Chritin]

Is there any consensus for this thread or can any verse calc planet size?

I feel like this thread got bogged down with discussion as to whether or not specific verse should have planet calcs rather than the core discussion of having rules in place for planet calcs at all. It's kind of a shame, since the former should've been saved for other threads as to not bog down this one, and unless people want to revitalize this it seems kind of dead in the water for the time being :/

 

[Breadbear83]

Bump

Bump again