The size of Spore's Planets.

[Whirligig Girl]

(taken from my post on /r/Spore)

"The planets are an average of 500 somethings, with a range in size between 400 and 700 somethings." This is from the Siggraph 2007 Planet Lecture.

But just how big is a Something?

The creators of Spore have seemingly done all they can to hide any reference to real world size units, aside from the Parsec. The Parsec is on a totally different scale from planets, and given the following information I heavily doubt it has any bearing on the real world parsec distance.

DISCLAIMER: All of these are based upon close estimations and may be off by quite a bit. We're not being too precise here.

Obviously the planets in spore are small. The buildings and trees and things are visible from orbit. But just how small is it? Because of the fact that the trees appear to be far, far bigger than cities, we can't use them for scale. They're too different from any real world trees that we have to throw them out.

What about Creatures? Well at first this appears to be a dead end, but there is one thing which saves us. The Maxis-Made creation Al Packa. Because of the apparently similar build, appearance, and name, I am going to make the assumption that an Al Packa is the same size as a real world Alpaca. This may be wrong, but it's the only creature we have in Spore canon that could possibly correspond directly to an Earth creature.

An Alpaca is 1 meter from the top of the shoulder to the ground. The head of an Al Packa and an Alpaca is somewhat different, so we will have to use a proportion to find the height of the Al Packa based only on the body of the Alpaca. I chose a height of 1.85 meters from ear tips to ground.

I put an Alpaca in a Civ Stage game, and measured his size compared to one of the small circle textures in the city's ground. One of those circles is 7 Al Packas across. A city is 8 circlethings across. (Pictures) A large city is 103.6 meters across. That's really small for a city.

So then I had to find out how big a City was compared to a planet. So I loaded up my space stage game, and opened the planet Sporepedia, and found my homeworld, covered in cities.

Using this, I found that a planet is about 8 cities in diameter. So that's 103.6 times 8. 829 meters across. A planet is 829 meters in diameter. That's not even a single kilometer, and just over half a mile.

Assuming my homeworld planet had a size of about 650 Somethings, a single Something is 1.27 meters (4.17 feet), For the purposes of being nice and round, and giving Spore a fighting chance at being large, let's make it 1.5 meters per something.

I initially hypothesized that the rescale factor from real scale to spore scale was about 4/500, or 0.008. I was wrong by almost two orders of magnitude.

And all of this gives a rescale factor in actuality of 0.00014. For every 1 Real Earth Diameter, you could fit nearly 7143 Spore Earths in the same length. If you had a hollowed out Earth, you would be able to fit over 364.4 Billion Spore Earths inside. Let's have some fun and calculate the density of a world needed in order to have 1 gee of surface gravity and a radius of a Spore planet. We'll use the PlanetMaker equation. All of these units are in Earth units equal to 1.

Surface Gravity = Mass / Radius³ = Density(Radius)

Plugging in for the Spore Planet we get:

1 gee = Density(0.00014)

Density = 7142.857 Earth Densities. Earth Density 5.51 g/cm^3. Density for Spore planets is 39,357,158.6 kg / m^3. White dwarf stellar remnants in the real world have a density of 1,000,000,000. That's only two orders of magnitude of difference, like the difference between styrofoam and osmium.

One more thing. We now know the size of a Spore planet, so let's figure out the size of gas giants, stars, and planetary orbits. According to this image, SporeEarth's semiMajorAxis is seven SporeEarthDiameters from the Sun's center. So one Spore AU is about 5.81 kilometers. That is also exceedingly tiny. The rescale factor for Spore Orbits appears to be 1/25,000,000, or 0.00000004. That's 3500 times smaller than the planet size rescale. That would be like if the Earth orbited the Sun at a distance of 42,000 kilometers.

As for the size of the Gas Giants and Yellow Stars:

• Yellow Stars are 4 SporeEarthDiameter across, or 3.3 km across.
• Gas Giants are about 2.25 SporeEarthDiameter across, or 1.9 km across.
• Comets appear to be the size of a building.
• Moons are about 1/2 the diameter of a SporeEarthDiameter.

TL;DR

• Spore homeworld planets are about 830 meters (2723 feet) in Diameter.
• Spore's Earth orbits about 6 kilometers (3.72 miles) from the Sun.
• Spore's gas giants are about 1.9 km (1.2 miles) across.
• Spore's small Moon-sized objects are about 415 meters (1361.55 feet) in Diameter.
• Spore planets are around 7000 times smaller than real planets (Rescale factor of 0.00014)
• Spore orbits are around 25 million times smaller than real planet's orbits. (Rescale factor of 0.00000004)
• Conclusion: Spore planets are really small.

[Superfluous J]

Yikes that means that if you're Spore civilization develops Kerbal Space Program, their Kevin would be 83 meters wide!

[Whirligig Girl]

9 hours ago, 5thHorseman said:

Yikes that means that if your Spore civilization develops Kerbal Space Program, their Kevin would be 83 meters wide!

That's a really fat Kevin.

 

I shudder to think of what their Spore would look like...

Edited May 29, 2016 by GregroxMun

[Superfluous J]

12 hours ago, 5thHorseman said:

Yikes that means that if you're Spore civilization develops Kerbal Space Program, their Kevin would be 83 meters wide!

*shakes fist*

AUTOCORRECT!

[kerbiloid]

When I measured them myself, they were: Earth-like about 800 m, the bigger ones - 1.4..5 km.

P.S.
And I'm still sure, that not the density is high, but the gravitational constant differs.

P.P.S.
Kerbal Spore Program would mean "Single Rover To Jool" trips instead of "single stage".

Edited May 30, 2016 by kerbiloid

[Findthepin1]

On May 29, 2016 at 11:49 PM, 5thHorseman said:

Yikes that means that if you're Spore civilization develops Kerbal Space Program, their Kevin would be 83 meters wide!

The Gary is relevant

[kerbiloid]

Found my old table with spore measurements.

Name		Type	Diameter, m	Orbit radius, km	Orbital period, min.	Rotation period, sec.	Circ. velocity, m/s	Parabol. velocity, m/s
N.		star	3900	-	-	-
D.		gas/ice giant	2100	5.0	4	76
E.		earth	750	7.6	6	260	60	84
	B.	moon	430	2.4	13.5	67	47	66
M.		earth		13.5	15	92
Q.		earth		18.4	23	108

Eurinome planet ("Earth"):

Trees height: 20 m
Atmosphere thickness: 100 m.

[ChrisSpace]

Someone needs to make a rescale mod for KSP using these measurements. Also someone needs to calculate the Dv the orbit or escape one of Spore's homeworld planets.

[kerbiloid]

1 hour ago, ChrisSpace said:

Someone needs to make a rescale mod for KSP using these measurements.

Kopernicus mod rescales planets and orbits. Someone would create configs for it.

[Whirligig Girl]

6 hours ago, ChrisSpace said:

Someone needs to make a rescale mod for KSP using these measurements. Also someone needs to calculate the Dv the orbit or escape one of Spore's homeworld planets.

I'm actually working on this (it's the reason why I made these measurements in the first place). I found that if you make it exactly the rescale of Spore Planets (0.0014 for KSP, because it's already 1/10 scale), then the game just breaks too much. It's a fairly fundamental limit of how low KSP can go. So my KSP: Spore Mode is 10 times larger than real Spore. And I don't know about calculating the escape velocity assuming the smaller SOI of these planets, but orbital velocity would be sqrt(0.00014) times Real Solar System Orbital Velocity. For KSP planets, that's sqrt(0.0014) times KSP Orbital Velocity. Note that you have to take account of the much higher atmospheres of these planets.

5 hours ago, kerbiloid said:

Kopernicus mod rescales planets and orbits. Someone would create configs for it.

I think you have "mod" and "plugin" mixed up. Kopernicus plugin is itself a mod, but the configs made for it are also mods. 

[kerbiloid]

27 minutes ago, GregroxMun said:

And I don't know about calculating the escape velocity assuming the smaller SOI of these planets

Earth-like Spore planets have about the same ~9.81 gravity. So, v = sqrt(g*R)

[Whirligig Girl]

1 hour ago, kerbiloid said:

Earth-like Spore planets have about the same ~9.81 gravity. So, v = sqrt(g*R)

I know you could do that*, you could even do sqrt 0.0014 times the stock KSP escape velocity, and you'd get the velocity required to go on a parabolic/hyperbolic orbit around a Spore planet. The problem is that the spheres of influences for these Spore Planets are so much smaller that you actually escape the body much much sooner.

 

*or at least I could have looked it up. I didn't actually have that equation memorized  My point is that knowing the velocity required for a parabolic or hyperbolic orbit isn't actually that useful.

Edited June 1, 2016 by GregroxMun

[ChrisSpace]

16 hours ago, GregroxMun said:

I'm actually working on this (it's the reason why I made these measurements in the first place). I found that if you make it exactly the rescale of Spore Planets (0.0014 for KSP, because it's already 1/10 scale), then the game just breaks too much. It's a fairly fundamental limit of how low KSP can go. So my KSP: Spore Mode is 10 times larger than real Spore. And I don't know about calculating the escape velocity assuming the smaller SOI of these planets, but orbital velocity would be sqrt(0.00014) times Real Solar System Orbital Velocity. For KSP planets, that's sqrt(0.0014) times KSP Orbital Velocity. Note that you have to take account of the much higher atmospheres of these planets.

I figured it wouldn't be possible on this scale, since KSP is more focused around almost-planet-sized things.

Also in case anyone was wondering, I did some calculations and it turns out a planet with a 830m diameter/415m radius and earthlike (9.81m/s^2) gravity would have a mass of 2.532E+16 kilograms, and an escape velocity of 90.25m/s. If we assume that each planet has the same land coverage as Earth (29.2%), that would give each planet 0.632km^2 of solid land. For comparison, the Vatican has an area of 0.44km^2, and if we use the average population density of the US we'd be able to fit nearly 21 people on said landmass. If we use Macau's population density we can bring that up to 13,414 people. But with the planet's insanely low escape velocity, perhaps that may be enough people to begin a space program?

[kerbiloid]

4 hours ago, ChrisSpace said:

But with the planet's insanely low escape velocity, perhaps that may be enough people to begin a space program?

Escape speed = 90 m/s, so circular speed = 60 m/s.
Probably they would have a swarm of easy riders orbiting the planet on their bicycles — and road police with nets and lassos.

Also this means that due to the centrifugal force any car moving >10-20 m/s feels like a dancer on ice.

[ChrisSpace]

18 hours ago, kerbiloid said:

Escape speed = 90 m/s, so circular speed = 60 m/s.
Probably they would have a swarm of easy riders orbiting the planet on their bicycles — and road police with nets and lassos.

Also this means that due to the centrifugal force any car moving >10-20 m/s feels like a dancer on ice.

Huh. I wonder if model rockets (the child-friendly kind) would be able to reach orbit/escape velocity? And how far exactly are the "moons" from their planets?

 

Also, I did some calculations and on the scaled-down scale of the orbits (1AU = 6km), one light year equals 379,446 kilometers, or about the distance from Earth to the moon IRL. This means the entire Spore galaxy is likely less than 38 billion kilometers wide. Actually, since the galaxy only contains about 100,000 stars (and I'll assume the star density is the same as the Milky Way IRL), that means the Spore galaxy likely has one four millionth to one two millionth of the volume, or a width of only 630 to 794 Spore light years, or 239.1 to 301.3 million kilometers. Well, at least that provides a solid explanation to the game's "FTL" travel.

[kerbiloid]

1 hour ago, ChrisSpace said:

Huh. I wonder if model rockets (the child-friendly kind) would be able to reach orbit/escape velocity? And how far exactly are the "moons" from their planets?

2-10 kilometers.

[Whirligig Girl]

On 6/3/2016 at 2:16 AM, ChrisSpace said:

Huh. I wonder if model rockets (the child-friendly kind) would be able to reach orbit/escape velocity? And how far exactly are the "moons" from their planets?

 

Also, I did some calculations and on the scaled-down scale of the orbits (1AU = 6km), one light year equals 379,446 kilometers, or about the distance from Earth to the moon IRL. This means the entire Spore galaxy is likely less than 38 billion kilometers wide. Actually, since the galaxy only contains about 100,000 stars (and I'll assume the star density is the same as the Milky Way IRL), that means the Spore galaxy likely has one four millionth to one two millionth of the volume, or a width of only 630 to 794 Spore light years, or 239.1 to 301.3 million kilometers. Well, at least that provides a solid explanation to the game's "FTL" travel.

I suspect that the interplanetary drive is just an extremely basic chemical rocket with high thrust. The Interplanetary Drive is a Nuclear Salt Water Rocket engine.

 

Delta-v to orbit around a Spore Planet would probably be (just like every other rescale) R^0.5 δv = Δv.

δv = Non-rescaled Delta-V. Δv = Rescaled Delta-V. R = Rescale Factor.

So Δv to orbit would be 118 meters per second. I believe it's reasonable to assume that a multistage Estes model rocket would be able to provide that thrust, but you'd have to have some interesting engineering to get it all the way to orbit without any computerized guidance.

Still though, given the ludicrous size of Spore Planets, it seems likely to me that your Civilization-stage societies are secretly exploring the whole solar system with WW1-era Spaceplanes.

[ChrisSpace]

15 hours ago, GregroxMun said:

I suspect that the interplanetary drive is just an extremely basic chemical rocket with high thrust. The Interplanetary Drive is a Nuclear Salt Water Rocket engine.

I'm guessing the "planet buster" or whatever it's called is just a really big nuke. Would that be possible? Can someone calculate the gravitational binding energy of a mini-planet?

[kerbiloid]

6 hours ago, ChrisSpace said:

Can someone calculate the gravitational binding energy of a mini-planet?

E= 2/5 * GM²/R,
as I can remember.

[Whirligig Girl]

30 minutes ago, kerbiloid said:

E= 2/5 * GM²/R,
as I can remember.

U = (3GM²)/(5R)

U = Gravitational Binding Energy.

GM = Gravitational Constant Times Mass

R = Radius

Edited June 7, 2016 by GregroxMun

[ChrisSpace]

16 hours ago, kerbiloid said:

E= 2/5 * GM²/R,
as I can remember.

So for an 830m planet with 1g of surface gravity, that's a gravitational binding energy of 6.180E+19 Joules, or 1.477×10^10 tons of TNT, or about 295.4 times the explosive energy of the Tsar Bomba, or equivalent to 688 kilograms of matter turned into energy. That's more than I expected.

[kerbiloid]

59 minutes ago, ChrisSpace said:

So for an 830m planet with 1g of surface gravity, that's a gravitational binding energy of 6.180E+19 Joules, or 1.477×10^10 tons of TNT, or about 295.4 times the explosive energy of the Tsar Bomba, or equivalent to 688 kilograms of matter turned into energy. That's more than I expected.

We can watch the situation from another side.

(As GregroxMun calculated, probably their should be 3/5 in the fornula, not 2/5, as I've wrote this by memory).

We can measure only orbit radius and period in Spore. They both depend on GM value.

We can't know exactly if the Sporeworld has extra-dense planets (so, large M) or extra-great G constant (so, large G).
All what we know: a planet of ~10000 times less than Earth radius has nearly the same gravity acceleration.
As g ~ G * ρ * R , either a density is x10000, or G is x10000.

So, as E ~ GM²:
If take G is usual, the density is high, then the result is 15000 Mt
If take density is usual, but G is x10000 (i.e. 6.67*10^-7), then the result would be 10000 times less (because G¹ while M²), ~= 1.5 Mt.

At the human scale different G values should not make any visual difference, as the gravitational interaction is too weak on such scale.

Edited June 8, 2016 by kerbiloid

[ChrisSpace]

On 8 June 2016 at 4:59 PM, kerbiloid said:

We can watch the situation from another side.

(As GregroxMun calculated, probably their should be 3/5 in the fornula, not 2/5, as I've wrote this by memory).

We can measure only orbit radius and period in Spore. They both depend on GM value.

We can't know exactly if the Sporeworld has extra-dense planets (so, large M) or extra-great G constant (so, large G).
All what we know: a planet of ~10000 times less than Earth radius has nearly the same gravity acceleration.
As g ~ G * ρ * R , either a density is x10000, or G is x10000.

So, as E ~ GM²:
If take G is usual, the density is high, then the result is 15000 Mt
If take density is usual, but G is x10000 (i.e. 6.67*10^-7), then the result would be 10000 times less (because G¹ while M²), ~= 1.5 Mt.

At the human scale different G values should not make any visual difference, as the gravitational interaction is too weak on such scale.

Well, I just got my calculations from http://www.stardestroyer.net/Empire/Tech/Beam/Calculator.html

Also, I did some calculations on what the maximum population of a miniplanet could be, since the previously mentioned Macau isn't completely self-sustaining as a miniplanet would have to be. So if we use the numbers provided by http://worldbuilding.stackexchange.com/questions/9582/how-many-people-can-you-feed-per-square-kilometer-of-farmland and assume 90% of the planet's land (0.5688km^2) can be used for agriculture that gives us a maximum population of:

1336 people if we use conventional farming

7565 people if we use hydroponics

27990 people if we use aeroponics

That's actually more than I expected.

Edited November 11, 2017 by ChrisSpace

[Whirligig Girl]

1336 people is about right. Spore cities can hold no more than 180 people (but unless your cities are only houses, it will be closer to 90), and homeworlds have about 10 cities. 1800 people would work if you have conventional farming with some limited hydroponics. (unless of course you decide that you want to look at how long it takes for creatures in Spore to get hungry, or for plants to grow, and you have to recalculate everything)

Now on the nature of the Spore Parsec:

The parsec in real life is based upon the arcsecond, a unit equal to 1/3600th of a degree. Star distances are measured this way because of trigonometry and parallax. Go look it up somewhere else if you're curious. In real life it's a distance equal to about 3.26 light years. Obviously this distance can't be right in Spore, can it?

The thing is, if you change the size of the orbit you're measuring from, the size of the parallax second changes. So one twenty-five-millionth the semimajor axis means that the parsec in spore in just about 3.21 lunar distances which is eerily close to the value in lightyears actually.

It does appear to be true that the size of a star in the galaxy view is the same as the size of a star in the solar system view--it has the same angular size when it pops into space and you can still see its model as more than just a glowy dot. The size of the dot seems to scale accurately with distance, which means that, at least on the scale this picture was taken in, there is no "button-like" resizing that Spore likes to pull off.

All player stars are yellow stars, so I will assume this is the same size as Spore's version of Sol (which is where I got some of the original measurements for orbit and planet sizes)

The red dwarf star in the upper left corner is 1.43 spore parsecs away. 

My ruler says the yellow star is 0.3 cm across. The distance between the center of the yellow star and the center of the red star: 16.7 cm.

The Spore Parsec isn't even close to the parallax second measured from one of its planets. It is not 3 lunar distances. It is 128 kilometers. That's about a 90 minute drive.

 

Now that we know how small the Sporeparsec is, how big is the galaxy?

The dashed circle is 40 pc in diameter.

The distance between two landmark stars about 20 pc away from the edge of the SETI circle is, well, 80 pc. They are both binary stars that can be seen well in the first image and are very faint in the second image. Luckily enough, those stars roughly trace out a big gap in the home spiral arm--I'll be making my measurement assuming it's a 90 pc wide gap.

Gap: 1.9 cm = 90 pc

Galaxy: 24 cm = 1137 pc

So the Galaxy is 145536 kilometers wide.

Finally we have an impressive number: that's just over the size of Jupiter. The distance from my homeworld to the center (which I know is about the same as the distance from Sol to the center) is 39416 km (80% the diameter of Neptune, or just under the circumference of Earth.)

 

 

The knowledge of how long a parsec is can tell us roughly what the acceleration of star ships using an Interstellar Drive is.

It took my ship, using a Tier 3 Interstellar Drive, 14 seconds to travel 1.43 parsecs ten times. Given imperfections in my measuring system, I'm willing to call that 1 second/1 parsec. Let's assume it uses a brachistochrone trajectory, accelerating forwards until halfway, the slowing down the other half.

Using this calculator, where s is how far we've traveled at half way (64 kilometers), u = 0 m/s starting velocity, t = 1 second travel time. Acceleration is 128000 m/s^(2).

That's *Thirteen thousand gees!* That's insane!

However, with the tiny size of spore planets, you don't really need a space drive. With only a few days of travel time, you can get anywhere in the galaxy with a small rocket ship, less than you would really even need for an Apollo-type moon mission. The exploration and colonization of the planets within your own solar system ought to have been started in the early civilization stage, with the first interstellar missions being run in the mid-to-late game. Even inter*galactic* distances are achievable with modern real world technology.

Admittedly, a lack of resources on a planet which can only support around 1300 people would mean that a single rocket would be a much bigger part of the economy of the cities that build them. But I'd argue that it is precisely because of the limited resources--and limited spice--that would cause civilizations to turn to the skies. They didn't need to wait for magic space warp technology, they could have just been even the slightest bit patient.

Edited November 10, 2017 by GregroxMun

[DAL59]

On 6/1/2016 at 4:06 AM, kerbiloid said:

opernicus mod rescales planets and orbits. Someone would create configs for it.

It can't be done, because the KSC is not rescaled.  It would float above the planet.