Equestria, Ponya, and Worldbuilding stuff

[Isoraqathedh]

This is it.

I finished my article on Ponya, the semi-realistic planet for Equestria to sit on. It looks glorious.

A bit of background: after reading Planetocopia, I am rather interested in making everything make a little bit of sense. Now I have recognise one fault in Equestria: where's the rest of the planet? That's when I started filling in the form, doing the maths, and working on a lot of factors, until it finally worked more or less.

I actually made a national map of Equestria at one point, which I may or may not post, due to incompatibility.

Anyway, enough blabbering.

TREATISE ON PONYA, THE HOMELAND OF THE PONIES

Perhaps it may just be me, but I can't stand any country sitting on its own without a supporting planet! That's why I set out of my way to create a planet for Equestria to sit upon, and this is the result.

ASTRONOMICAL PROPERTIES

Ponya is a medium-sized terrestrial planet. It has a remarkably circular orbit, with an eccentricity of 0.007 – comparable to Venus'. Orbiting at 0.94 AU away from its parent star, it's the innermost planet in its system, with the other planets orbiting significantly further away.

Ponya is constantly being pulled on by its massive moon, a close 200000 km away and almost one-third the size of Ponya itself (for reference, the Moon is about 300000 km away and one quarter the size of Earth). It creates massive tidal stress on the planet, cause it to go haywire and create one of the strangest terrains, especially when compared to Earth. It also makes tidal drag a much more serious thing, which meant that the planet has to be manually/magically pulled by the natives to ensure a roughly stable day length of 23 hours and 36 minutes. If this does not occur, the day will lengthen by as much as 3 seconds an Earth decade.

It takes about 340 local days to orbit the sun once, and that means about 333 Earth days. It spins with a very large axial tilt of 28° 44' 30', which is a full five degrees more than Earth's. As this goes, its seasons are very, very pronounced.

PHYSICAL PROPERTIES

Ponya is almost 1.4 times the mass of the Earth. Its size, however, turns out to be about 7127 km, which is just big enough to cancel the added mass and return the gravity of Ponya to be just shy of 1.0 G. That means, just like Earth, things fall at 9.8 ms-2.

It has an iron-nickel core, again similar to Earth, which gives it an Earthlike density of 5.4 g•cm-3. It again is split into five layers: two cores, a mantle, a crust and an atmosphere.

GEOLOGICAL PROPERTIES

Ponya retrieves pretty much the same amount of sun as Earth, but takes in somewhat less of it; the worldwide extensive shallow seas make reflection all too easy and make sunbeams bounce back to space. In fact, Ponya is dry: if you swap Ponya's water with Earth's, Earth will have both continuous continents as well as seas, and Ponya will have a situation much similar to Abyssia. The seas are shallow, 1 km deep pools that just so happen to fill the whole globe into a pretty much contiguous sea. This is because that there are no large gas giants to hurl comets at Ponya and give it the water it may need. Ponya only has 30% of Earth's water! The amount of planet surface area flooded, however, is much more Earthlike: about 60% of the surface is water, compared to Earth's 71%.

Ponya has an extremely rugged terrain however! The String, a large continent that bisects the Midyon Ocean, is a giant mid-sea spreading ridge, like the Mid-Atlantic for us, except the String passes the water-line almost contiguously, like a snake across the ocean. This is because of the moon's extreme tidal drag; the tectonic activity is intense and continuous, and inward coronae (also known as sunspots) are common features of Ponya, like they are in the Sun or Venus.

This of course means that the volcanoes belch out a lot of gas. This is where most of the water comes from: the volcanoes give out, in addition to lava, lots of steam, which then become clouds as they enter the atmosphere. They also give out CO2, which means that the CO2 of Ponya is much akin to what environmentalists of Earth may fear: 600 parts per million. This relatively high CO2 level raises the global temperature to a 25°C average, with ice-free poles and the Equator averaging somewhere in the high 30s, lashed with lots of storms. However, there are fewer storms than what pure science will dictate, because of a little thing we call magic. We'll get to that later.

The prolific volcanoes are also a factor of the atmospheric pressure being much higher than ours. The atmosphere here is on average 2540 bar, or about 2.5 times the pressure on Earth. This extreme pressure makes the air much more like liquid, and that allows for a lot of heavier creatures to take flight. More importantly, sentient creatures can rule the skies without the need of tools. You should know who they are.

ATMOSPHERIC PROPERTIES

Speaking of atmospheres, the atmosphere of Ponya is again similar to Earth's. It has about 60% nitrogen, 30% oxygen and 2% water vapor. (The massive volcanoes and strong evaporation contribute to this proportion.) With the dense atmosphere, the sky appears as a bright blue throughout the day, with the thick atmosphere making twilight last a full hour on each side. During the night, the bright moon makes darkness near-impossible: a deep blue even in the darkest of nights. Occasionally, strange colors can be seen, such as lavender, purple and pink.

There are lots of clouds on the planet, helped no less by the humid air and the volcanoes (again!) Clouds occur far more often in Ponya than on Earth, except in places where magic is present. Due to this and certain other characteristics such as shallow seas and the anomalous snowfield at 75° N 83° E, Ponya reflects lots of sunlight back into space, a vital fact that prevents it from overheating.

BIOLOGICAL PROPERTIES

The first thing you'd realize when you enter the seas of Ponya is: my god, it's full of fish! That's because of the simple fact that sea life are suited to the 0 m – 200 m range, the range where sunlight can penetrate. This zone is extant on Earth, but even more so on Ponya, because of the shallow seas and rare deeps. Lots of strange creatures are down there, and it's most likely an untapped resource.

The land, however, is much more Earthlike, with your average insects (that are twice as large as any insect on Earth), birds (can be up to fifty kilos!) and mammals (that can fly as well as swim). There are also a couple oddities, like dragons and griffins that occasionally have to share the same place.

This creates a large patchwork of biodiversity unparalleled in basically anywhere on Earth except Australia. The tall mountains force everyone to follow several strict paths and create natural walls for parallel evolution, but then the fliers appeared and cleared that. The oceans still pose some obstacle, but they're now being cleared due to the discovery of small islands for resting.

This all boils down to six or seven civilizations all over Ponya. Sometimes, especially under crisis, they'd learn to live with each other, but usually, they still have certain grudges against each other.

[Ginger Mint]

hi hi

I was under the impression that they had a significantly denser atmosphere, especially given what we know about the sonic rainboom and how everypony seems to fall from great distances with little more than a scratch. A denser atmosphere would mean a slower speed of sound than earth and a slower terminal velocity.

[Isoraqathedh]

hi hi

I was under the impression that they had a significantly denser atmosphere, especially given what we know about the sonic rainboom and how everypony seems to fall from great distances with little more than a scratch. A denser atmosphere would mean a slower speed of sound than earth and a slower terminal velocity.

I set the atmospheric pressure to 2.5 atm. Here's how I did it:

The great bustard, the heaviest bird on Earth, weighs 21 kg.

I guessed each pony to be about 30 ~ 40 kg.

21/40 = 2.025, so I played it safe and multiplied air pressure by 2.5.

I think the max cap of how much air a planet can hold is close to Titan, an airmoon with 1.45 atm. Because Titan is 0.404 times the mass of the Earth, I guess that a planet with as much gravity as Earth/Ponya is 1.45÷0.404 ≈ 3.58 atm, which is the absolute maximum. Deep time will bleed the planet of its air.

[Dio]

Now this is something to work with. Hard numbers, rich description, potential geopolitical flashpoints, possible evolutionary trees. Brilliant. I love it.

[Hippo]

this thread is 20% over my head.

[Ginger Mint]

hi hi

((The following comments are intended to be constructive, as presented by a peer who is also very interested in world building. I've worked on a few myself, but climate is probably my biggest weak point.))

The quick and easy rule of thumb is that a planet can hold onto a gas for the age of the solar system if the velocity of the gas is less than one-sixth the escape velocity of the planet. Since Ponya has an escape velocity of 12,515 m/s it can hold onto gasses slightly better than Earth. (2086 m/s molecular velocity)

(Although I don't have any equations for it, the presence or absence of lighter molecules can effect this as well. I'm going to assume that the planet was created deliberately through some sort of magic -or terraforming superscience if you like-, so they could have excluded lighter elements that would kick the heavier elements out.)

The velocity of a molecule can be determined by its temperature and its mass. Velocity in m/s is roughly = 157 √ temperature in ºK over molecule mass. Thus titan is able to hold more atmosphere because it is cooler, but the composition of the atmosphere plays an important role as well. So if we can assume that Ponya has an Earthlike temperature at its present atmospheric density, I don't think there is any worry of significant near term atmospheric loss. (atmospheres usually cool as they thin out as well)

If we assume a safe high end of 400ºK, then there are plenty of gasses that will stay for the long term.

• H2 = 2220 m/s (this one will vent away for sure)

• H2O = 740 m/s

•Ã‚ N2 = 593 m/s

•Ã‚ O2 = 555 m/s

It is important to note that Venus has a mean surface gravity of 8.87 m/s but has a surface pressure of 9300 kilopascals. Earth has 9.81 m/s and only 101.3 kilopascals at the surface.

((edit: although while going over the terminal velocity calculations, it looks like you'd need quite a lot thicker an atmosphere than I was thinking to make falls less dangerous.))

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I dig the tidal drag phenomenon, though I think you could cut out the large axial tilt and allow the changing of the seasons to be due to greenhouse engineering. The pegasi did fill the sky with gloomy clouds during the winter to reflect extra sunlight back into space, and when they removed the clouds the temperature quickly rose again. I'm guessing that they monitor and alter the atmospheric composition to achieve the desired temperatures.

Also, without the large axial tilt, you could say that the moon would regularly eclipse the sun, allowing Nightmare Moon to block out the sun using it's natural orbital path even though the planet remains spinning.

---

I'm not sure how Ponya would maintain a rugged terrain and shallow seas at the same time, however, one could make the claim that the shallow seas are in part due to a massive coral reef system that is continuously broken up by frequent (though mild) tectonic shifts. This might help create an almost karst like undersea topography. (but that last bit is probably wishful thinking) Still, even more habitat for fish.

[Isoraqathedh]

hi hi

((The following comments are intended to be constructive, as presented by a peer who is also very interested in world building. I've worked on a few myself, but climate is probably my biggest weak point.))

[a] [atmosphere, air loss discussion]

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[Orbit and Inclination discussion]

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[c] [Topology discussion]

Letters added for quick and easy reference.

[a] Our given fauna here obviously won't support any atmosphere over about 15 atm, as it would squash most creatures into a pancake (or at least very squat and wide). I think I can fudge it all the way up to 6, maybe 6.5?

As for air loss over time, you pretty much got this right. You handle atmospheres very well, I say.

I'm always worried about the pegasi and their cloud-manipulating. Truly, it's kind of hard to drag clouds -- ever tried to bring a piece of fog with you? -- which means that a lot of the effects are going to be laid up on our poor little magnon, a subatomic particle that replaces the electron for magical purposes. More on that when I actually finished a part of it.

However, axial tilt seems irrelevant to eclipses. Please refer to this diagram:

Wot, no spoiler tags?

If the orbits of the Earth and Moon (or in this case, Ponya and Yuet) are to be perfectly aligned (or to within perhaps 50', as the moon is 30' wide) then eclipses will happen more often. Although, that may mean that they lose a lot of the mystique among the locals, which may be a bad thing.

[c] I too was a tad worried about the shallow seas and how they may be broken at times to create a world-continent that is significantly different from a supercontinent, but then, that may be the charm! By opening and closing land roads, we can allow crossings and biodiversity redistribution (mixing will reduce earthly biodiversity; separation will increase aquatic biodiversity). It may (must?) be a hot period now, which means it's now time for land animals to diversify themselves.

In the end though, I'm pretty sure we'd have a relatively flat (compared to Earth) abyssal plains with enormously tall platforms coming up from it. It also supports the age of Ponya: old planets have more land due to aboveḡround weathering.

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[d] Now: a global map! I originally proposed Equestria to sit somewhere down that dotted line there in "Haysia" (still novice pun master...) but with the current data I cannot be sure.

You would notice that already, I'm filling in what the terrain might look like from space.

[Hippo]

About the moon...

If we are to assume that the moon is always opposite the sun, than the moon would always be at a full state. We've seen cresents, though.

Could there be a scientific explanation of the temporary darkness during the thousandth year of the summer sun celebration (summer solstice)? Maybe once every a thousand years, Ponya's moon, which is slightly bigger in appearance from Ponya as the sun, eclipses the Sun at this time. Maybe Ponya's sun is one of the stars that aided Nightmare Moon's escape.

[brianblackberry]

Speaking of atmospheres, the atmosphere of Ponya is again similar to Earth's. It has about 60% nitrogen, 30% oxygen and 2% water vapor.

Lightening strikes on this planet are a far greater potential natural disaster thanks to that oxygen rich atmosphere, same with any artificially started fire. I can imagine how much more difficult it would be to control a raging wildfire.

[Ginger Mint]

hi hi

That could be why everypony was so relieved to hear the smoke wasn't from a fire in Dragonshy, because a forest fire is a super dangerous occurrence.

I'm not sure if even flying creatures would be able to cross "The String," depending on how tall it is, unless they were specialized in high altitudes and strong winds. I'm pretty sure the winds traveling along that ridge, especially at sunrise, would be phenomenally strong.

The hight of peaks is usually derived from the ratio between uplifting and weathering. In Ponya, it seems that weathering might even be less of a factor that it is on Earth, due to the dryness; while on the other hand it seems to be more geologically active. That leads me to believe that mountain peaks would be even higher than they are here on Earth.

[Dio]

Perhaps Nightmare Moon's plan could have been to secure the moon at Lagrangian point L1, resulting in a permanent eclipsing of the sun, at least for most of central Equestria (the area eclipsed will change based on inclination of the moon's orbital plane). This could also be a hook for the Heart of Equestria campaign, as having Central Equestria blacked out would put the ponies at a disadvantage while leaving most of the outlands untouched. Because L1 is unstable, Luna would have to put her magic into stationkeeping rather than actually setting the orbital trajectory correctly, causing the moon to become "stuck."

[Ginger Mint]

hi hi

If Celestia can move both the Moon and the Planet (if not also the sun) then Nightmare Moon might have had enough power to move the planet far enough away from its star that the solar eclipse would cover the entire world.

Another option would be to tide lock the planet facing away from the sun and place the moon at L2. If the far side was entirely covered by ocean, deep sea currents might make life on the dark side at least habitable.

[Isoraqathedh]

hi hi

That could be why everypony was so relieved to hear the smoke wasn't from a fire in Dragonshy, because a forest fire is a super dangerous occurrence.

I'm not sure if even flying creatures would be able to cross "The String," depending on how tall it is, unless they were specialized in high altitudes and strong winds. I'm pretty sure the winds traveling along that ridge, especially at sunrise, would be phenomenally strong.

The hight of peaks is usually derived from the ratio between uplifting and weathering. In Ponya, it seems that weathering might even be less of a factor that it is on Earth, due to the dryness; while on the other hand it seems to be more geologically active. That leads me to believe that mountain peaks would be even higher than they are here on Earth.

I can only give how tall they are in atmospheres, because I know what things to let through and what things not to let through. The String has mountains 0.8 ~ 2.1 atm tall, with the south end slightly more active than the north end (though they're pretty much the same).

Ooh, and I didn't know that adding more oxygen has that consequence! Let me add that in the final draft.

Here's a diagram for a star, its planet and its moon.

The sun spins so that AD crosses the equator. Or, the axis of spin of the sun is the line perpendicular to AD passing through A.

The inclination of Ponya is DAB; The inclination of its moon Yuet is ABC.

To get an eclipse angle ABC has to be very small; I don't know what the number is, but it has something to do with 40' 50", the angular diameter of Yuet from Ponya (atan(7127/3 ÷ 200000)).

Because DAB does not stay constant, eclipses happen.

I think Equestria is about 20° S, as I had put here, and DAB is about 2°. Perhaps less than that.

Here's the thing though: you can't have a solar eclipse over the entire earth. The umbra (total darkness) is as large as the body that casts the shadow and only gets smaller from there on in. You'd have to have the moon bigger than Ponya to cast a full shadow over it.

Also do be aware that while both L1 and L2 are unstable, you can keep something there for an appreciable amount of time by missing the mark slightly and making it orbit around the points instead of sitting on them.

[Ginger Mint]

hi hi

L1, L2 and L3 are stable in the distance axis, but not with the side to side movements. However, I imagine it would be relatively easy for a being who can control the rising and setting of the moon to nudge it back into place every day, even if she doesn't have to keep it suspended against the downward force of gravity all the time.

I've been trying to find the calculations to determine how distant the planet/moon pair would have to be from the star in order to achieve a planetwide eclipse, but so far no success. I figure if a distant galaxy can be eclipsed, then a single star might be as well. I dunno, maybe I'm completely wrong and it is totally impossible regardless of distance, but that doesn't seem intuitively correct...

[Dio]

That's why I was saying that only Central Equestria needed to be eclipsed. If it's impossible to get a planet-wide solar eclipse, then eclipsing the plains and their main source of food may be sufficient, along with perhaps Canterlot. As long as the umbra gives sufficient coverage to do so, it should be enough to ruin everypony's day (pun partially intended).

[Isoraqathedh]

Pardon the necroing, but during the period I have other stuff to do.

I have made two things.

One: a very large pony punnet square that deals with alicorns as well as the other three types of pony:

Linked for size.

The next thing is the phylogeny chart. It is extremely extensible, and depending on taste can have nodes added and removed at will.

	 <==O Ponya-Equus
	    |
	    +--O Maxis
	    |  |
	    |  +--O Familiaris		  Horses (Mythologically increased?)
	    |  |
	    |  `--O Dinaris			 Dragon-ponies (Mythologically increased?)
	    |
	    `--O Diminutaris		    Ponies
		   |
		   +--O Tuus-Equus		  No English name
		   |
		   +--X Vester-Equuos	   No English name
		   |
		   `--O Meus-Equus		  THE ponies
			  |
			  +--O Aquatica		 Aquatic ponies
			  |  *
			  |  ***Q Pottamus	  River ponies
			  |  *
			  |   **Q Pelagus	   Sea ponies
			  |
			  `--O Terrata		  Land ponies
				 *
				 ***Q Terrata	   Earth ponies
				 *
				  **Q Munus		 (Gifted ponies)
				    *
				    ***Q Pegasus    (obvious)
				    *
				    ***Q Monocerous Unicorns
				    *
					 **Q Alacerous  Alicorns?

    =============================================


    The pony phylogeny chart.

    Species status:

		    O Extant
		    X Extinct
		    Q Predicted

    Pathways:

		    | Observed via fossil record
		    + Observed via fossil record
		    - Observed via fossil record
		    * Predicted

    Currently the pony reproduction system is strained due to the large amount of morphological
changes that are required in cross-species reproduction. Already, mixed breeds are becoming
rare and Earth ponies together with Earth ponies already only beget Earth ponies. With this in
mind the prediction is obvious.