Why so few planets?

[kojikun]

The Empire supposedly has 1 million member worlds and some 50 million inhabited systems (SWTC - Astrophysics).

Now, according to Islands in the Sky page 162, simulations show that about 1 in 226 stars have a planet that is about habitable to humans and 1 in 18 stars have a planet thats "easily terraformed" (meaning a few hundred years for modern human technology to terraform it with things like chlorofluorocarbon factories and asteroid impact).

For a 150 billion star galaxy, thats about 600 million habitable planets and 9 billion easily terraformed planets (habitable planets being a subset of easily terraformed planets). Now you figure, such similar planets would make good places to live for humans, and very good places for the evolution of vaguely earthlike species (biochemically speaking).

So one must ask, why so few systems in SW with inhabited planets? there should be billions!

[Enforcer Talen]

the writers had trouble thinking that big?

[pecker]

Not enough people to go around? I mean, what good are planets in you don't have enough peopel to live on them?

[Kuja]

the writers had trouble thinking that big?

That's a better explanation than you might think. Just try wrapping your brain around that one!

[Ghost Rider]

Do I get a slice of Lemon and gold brink too ?

But yeah most authors have no concept of the size persay of a galaxy...so they make things smaller so it's more palatable.

[kojikun]

Not enough people? Estimates run at over 500,000,000,000,000 people on coruscant alone! at present earth populations thats over 80,000 planets that coruscant could be redistrubuted into. You figure that there an average of maybe 500 billion to 1 trillion per world and 1 million worlds that gives you about 1e18 people (not accurate by far). That could be redistributed into 160 million planets with modern earth density.

It could be a logistics thing, but even native populations would be huge. Estimates go about 20 million species and 50 million systems, for about 1 species every 2.5 systems. If thats the case, the Empire should be home to well over 3 billion species.

[Sea Skimmer]

Not enough people? Estimates run at over 500,000,000,000,000 people on coruscant alone! at present earth populations thats over 80,000 planets that coruscant could be redistrubuted into. You figure that there an average of maybe 500 billion to 1 trillion per world and 1 million worlds that gives you about 1e18 people (not accurate by far). That could be redistributed into 160 million planets with modern earth density.

It could be a logistics thing, but even native populations would be huge. Estimates go about 20 million species and 50 million systems, for about 1 species every 2.5 systems. If thats the case, the Empire should be home to well over 3 billion species.

However the bulk of the core populations likely don't want to and can't afford to leave. Easier to ship resources in over time and build up then to move the people out.

[pecker]

Not enough people? Estimates run at over 500,000,000,000,000 people on coruscant alone! at present earth populations thats over 80,000 planets that coruscant could be redistrubuted into. You figure that there an average of maybe 500 billion to 1 trillion per world and 1 million worlds that gives you about 1e18 people (not accurate by far). That could be redistributed into 160 million planets with modern earth density.

It could be a logistics thing, but even native populations would be huge. Estimates go about 20 million species and 50 million systems, for about 1 species every 2.5 systems. If thats the case, the Empire should be home to well over 3 billion species.

Peole don't wanna leave?

Anyway, an intelligent species would include cavemen-aged races, such as Ewoks. I doubt they count as 'citizens' unless they're part of the Galactic community.

[The Dark]

Cost. It's more cost-efficient to have industries focused on 30 worlds instead of 300 (as an example). There's less need to transport goods from one world to the next, and easier to keep track of. Needless expansion is counter-productive, as it consumes resources better used in other areas. If they wanted to, there's no doubt all those worlds could be colonized by the Empire. However, there is no benefit to outweight the cost.

[Darth Wong]

In my country, the vast majority of the population is clustered in a few major centres. There are vast open spaces where one could easily set up communities, but we don't.

[Joe]

Not to mention that many of these worlds may be considered government property (sanctuaries, or whatever). The federal domain of the U.S. is the size of France.

[kojikun]

well i never said they would migrate en mass

But they wouldnt have to start out clumped together to hugely.

That still doesnt change the fact that the Empire should have far more planets then it does.

[SPOOFE]

Population is not homogenous. I imagine that the 51 million number refers primarily to the core and inner rim, while the outer rim is still almost barren (essentially useless real estate). Remember, while the Empire may have technically had almost the entire galaxy under its thrall, that doesn't necessarily mean that they had an actual presence and/or population in every planet or system inside their borders.

[Zoink]

The age of the galaxy is important. A young galaxy will have fewer of the heavy elements needed for planet formation. We know that SW takes place "long ago", maybe that's several billion years ago.

[kojikun]

Regardless, there should still be well over a billion sentient species.

[Spanky The Dolphin]

Well there isn't.

[Illuminatus Primus]

Cost. It's more cost-efficient to have industries focused on 30 worlds instead of 300 (as an example). There's less need to transport goods from one world to the next, and easier to keep track of. Needless expansion is counter-productive, as it consumes resources better used in other areas. If they wanted to, there's no doubt all those worlds could be colonized by the Empire. However, there is no benefit to outweight the cost.

This is actually a very good excuse: with so many habitable and easily terriformed and planets at all period, this would indicate the SW civilization would colonize the best and richest of those worlds automatically. Think about this: with so many to choose from, they've just chosen the planets with the best resources, the systems with most exotic and powerful energy sources, and the systems with the most easily defended and most productive biosphere.

[Illuminatus Primus]

Regardless, there should still be well over a billion sentient species.

So? Science is hardly specific or concrete on estimating the density of sentient species in a given galaxy. The greatest of these species could've wiped each other out or left the galaxy proper in the prehistory of SW. Many species likely followed the path of the dodo here on Earth as more advanced species either exterminated them or carelessly screwed up their system. An Imperial shipbuilding project sends an giant planetoid careening into a Medieval-period Earth...who cares in the Imperial heirarchy?

[Zoink]

Regardless, there should still be well over a billion sentient species.

The model (1 in 18) is for the current state of our galaxy. A newly formed galaxy, billions of years ago would be stocked with population type II stars. These stars are the old star we see today, like those in the globter clusters. They're extremely low in heavy metals (like carbon) because they formed at a time when these materials were not particularly common. You need billions of years of supernova explosions to further enrich the galaxy. Such star systems lack the ability to produce earth-like planets because they are mainly hydrogen and helium (no significant amounts oxygen, carbon, iron, nothing).

If the model is correct: The Star Wars galaxy is somewhere between newly formed and current, so its requires to have somewhere between 0 and 9,000,000,000 planets.

------

Secondly, a habitable planet doesn't automatically mean life. And life doesn't automatically equal human-like intelligence. The number of space-fairing, FTL-capable species might be extremely low. Lets say the a single human-like race started terraforming the galaxy.

If it takes 1000 years to terraform a planet, then over 100,000 years they'd have done 100.

Eventually the new planets will terraform their own, but the fact remains its cheaper to develop your own planet than terraform another. Let's say after 10,000 years each new planet starts terraforming regularly. So after 100,000 years you'd have about a million planets.

[Zoink]

The model (1 in 18)

That should say "(1 in 18 ) ... it turned it into a smiley.

[Illuminatus Primus]

The model (1 in 18)

That should say "(1 in 18 ) ... it turned it into a smiley.

Don't forget, scientists have guessed that many factors other then correct size and distance from the sun and mass govern livability. Jupiter-size planets to sweep asteroids away from rocky worlds, suns located in orbits that don't pass them through overly dense gas clouds which could collapse the helliosphere, and simple bad luck: Mars-sized body lambasts Earth-size planet or it suffers holocaust due to sentient species screwing it up, or suffers geological misbalance and ends up like Venus.

[Zoink]

Don't forget, scientists have guessed that many factors other then correct size and distance from the sun and mass govern livability. Jupiter-size planets to sweep asteroids away from rocky worlds, suns located in orbits that don't pass them through overly dense gas clouds which could collapse the helliosphere, and simple bad luck: Mars-sized body lambasts Earth-size planet or it suffers holocaust due to sentient species screwing it up, or suffers geological misbalance and ends up like Venus.

Yup, there are many such factors. Take these into account and the amount of sentient life in the universe could be very small.

[hvb]

A strong Magnetic field to facilitate long term evolutionary stability (Earth has a far stronger one then the other rock balls in our system).

A large moon, or a double-planet setup, again for stability, this time inclinational (and an asteroid screen). A gas giant orbit would also serve this purpose, so most planets with the stability needed for the developement of sapient species may be the moons of super-Jovians.

Sentient life is likely far less common then bacterial/lichen level life.