Seasons on Pandora

[Kaltxì Palulukan!]

Happy Spring! (er . . . tomorrow: Mar 20 2009 @ 7:44 AM EDT, according to the U.S. Naval Observatory). The sun just set here, and of course I watched it set for the last time this year (astrologically--Pisces dissolves the energies of the year for Aries to start the new year clean and violently ). And naturally I thanked it for everything this year was, and made promises to complete fore the new year, as this is the last sunset of the old year (the end of the year astrologically), and the sunrise will be the first of the new year, as the sun will be in Aries a few hours before sunrise locally.

This got me thinking:

On Earth, our religions and our core philosophies derive from "the motion of the sun moon and stars" and thus the seasons (and all that entails scientifically). On Pandora they have not one sun, but three, and a HUGE PLANET that is crowding their view and often eclipsing the sun mid-day. Additionally, they can easily see their fellow moon,s sometimes much, much closer than we can see ours. Their "seasons" would be less important to daily life and philosophy and religion than they would here on Earth. Their "world" (experiential existence) is so much more complex, due to the close proximity of extra-pandorial objects ("E.P.'s") of various sizes, colors, motions, and of course three suns. Add to this the visible and kinetic proof of Eywa at every turn, and things like seasons become more of a background concern than we have here. But it does make me wonder about things like axial tilt, rotational wobble, and ecliptic orbits--all things that could effectively create "seasons" and enhance or lessons the magnetic/gravitational storms. Could there be "storm seasons" on Pandora, or are these "seemingly random" (to the Na'vi who have no interest in creating measuring devices for such phenomena).

This lack of seasonal change leads to the question of what track of time the Na'vi do keep. Without regular seasons (not to say that they do not have them, but as noted, they would not be nearly as dramatic as her on Earth, and would be eclipsed by more regular stellar-interplay), do they calculate a "year"? As an oral tradition, they have no calendars, no time keeping devices (that we have seen), and seem to be fairly content measuring "generations" and event-based eras ("time of sorrows").

The general sense of timelessness (other than generational, if that even exists really) on Pandora could create a more stable sense of being, a closer connection with nature, as the life-experience is more interwoven with the daily and frequent events (violent storms, migrations of sturmbeasts, etc.) and less with days and nights "getting measurably longer or shorter." This directly forms the basis of their philosophy, religion, and as a result, their culture, rituals, and stories, dances, toys, and games they pass on generationally.

No conclusions here (yet). Just opening the idea up for some intelligent discussion.

[El Jacko]

This lack of seasonal change leads to the question of what track of time the Na'vi do keep. Without regular seasons (not to say that they do not have them, but as noted, they would not be nearly as dramatic as her on Earth, and would be eclipsed by more regular stellar-interplay), do they calculate a "year"? As an oral tradition, they have no calendars, no time keeping devices (that we have seen), and seem to be fairly content measuring "generations" and event-based eras ("time of sorrows").

I'll side with the generation idea. From the looks of things, a generation in terms of Na'Vi is more definite than that of a human (Neytiri is ~20 yrs, Mo'At/Eytukan look ~20yrs older, etc), so would give a better long term keeping of time.

Aside from that, the length of a day/group of days (bearing in mind the orbit of the moon) should be regular, as would be the movement of Polyphemus's other moons. Providing that these cycles are relatively general knowledge, short term timekeeping would also be quite accurate.

[Kaltxì Palulukan!]

See? Now that brings up an interesting point (still waking up0. Pandora would be an astronomer's paradise. With 14 immediate celestial objects (13 moons and a gas giant in close proximity), two of which revolve contra-orbitally to the others, the sky is a playground of large bright objects dancing here and there. To the romantic mind (e.g. poet, artist . . .) it is alive with endless drama and intrigue that invite polytheistic stories. It is this kind of intensity (everything is close up, highly visible, and LARGE--not to mention always buzzing around) that sparks the imagination. Add to that the crazy terrain (wandering vines that travel horizontally to link the hallelujah mountains), intense magnetic storms, and vibrant colors of everything that would "seem" to create a vibrant world--one that lends itself to all kinds of religious beliefs and superstitions . . .

If not for Eywa bing "right there, all the time." The complexity of the light show and lunar/planetary dance above could create calendars of complexity that would make Earth scientists dance with glee. 11 moons orbiting in competition with Pandora, another two distant ones recklessly and rebelliously crossing the sky in the opposite direction, and of course the big purple planet with it's giant eye always looming overhead--watching.

If the Na'vi had developed a written system of recording their knowledge, surely they would have stacks and piles of mathematical formula, astronomical recordings of conjunctions and oppositions, and lunar line-ups, eclipses of everything; there is so much in their sky they could hardly not notice it and be awed. Or maybe it is just too much activity. Too much jumble to waste time on, when there are things to be woven, pots to be made, and children to be fed. It would be a wonder to see inside Grace's head on this.

[kintìomum]

Light sources
There are not really three suns.
ACA is the sun for Pandora since Polyphemus is orbiting it. The sun, not Pandora!
ACB is a bright spot in the sky (yeah, hundreds of times brighter than our moon but still not that bright) and is generally too far away to give much light to the pandoran surface. It's stated that ACB is only on very few occasions the one orbital object lighting the pandoran nights with an orange glow.
The third sun of the Alpha Centauri system, ACC, is only a brown dwarf that is "close" in astrophysical terms. Brown dwarfs are notoriously dim and with ACC being far away it's more like an oversized Mars viewed from Earth.
And there's another lightsource that's quite surely making nights interesting.

Some definition: A night is the time of the planetary rotation (called day) when the sun is not seen on the heaven.
OK, when you're on Pandora this tends to happen quite often. But what about that gas giant looming in the sky? It's a giant reflector! Even when "your" Pandora is facing away from the sun and you're seeing Polyphemus filling a good part of the heavens, Pandora is not big enough to cast a mentionable shadow on Polyphemus surface. And Polyphemus -having the size of Saturn- is receiving a lot of sunlight from ACA which is then reflected back into space and onto Pandora.
The only times when it's really dark in a pandoran night is when ACA and ACB are on the close part of their 80-year-dance and Polyphemus is blocking both of them.
I could go draw a diagram (perhaps) but believe me: this are seldom, really rare occasions.


Day/night-cycle changes
These changes in the length of the day are a result of axial tilt. If I remember correctly Pandora is said to have some 16° of tilt. This would mean that the changes in the day-night-cylce are a good deal smaller than here on Earth.
Questionable sources place Hell's Gate somewhere near the equator of Pandora. Sure bet that it really is there since the rotational velocity of a planet is highest at the equator and this velocity is "lift for free" for starting shuttles. Remember: Pandora is all corporate business and as such bound to be designed for maximum profit!
OK, so when Hell's Gate is near the equator so are the other locations seen in the movie.
On the equator of a planet the changes in the day-night-cycle have the least effect and given the constant lighting from Polyphemus and ACA you're not really noticing this little effect. Add the bioluminosity and our average Na'vi will stand there and wonder: "What? Days shorter? You not funny!"

The one thing that will be easily noticeable are the positions of the various moons on the night sky. They will have a "slow" repeating pattern that could be used for measuring time.
But since that's something I can hardly imagine anyone doing without written record on where which moon was the last howmanyyouwant nights I take bets on the Na'vi only paying attention to special events like several moons lining up like pearls on a string or all moons hiding behind each other.

[Kaltxì Palulukan!]

And this, ladies and gentlemen, is why I created this thread. Just got back form the late late showing of Avatar. Almost 3 am. Too tired to say more now. I defer to your brilliance (for the moment) Peter.

[kintìomum]

Almost 3 am.

And? I'm awake at 3am, too!

Too tired to say more now. I defer to your brilliance (for the moment) Peter.

Now let's hope he never wakes up

[magne]

Very interesting discussion, you would actually have a outside and inside of Pandora, inside is towards Polyphemus outside is away. The inside in seldom very dark because of Polyphemus and ACB, outside might be as a dark as a moonless night if you don't have ACB, you might get some light from the outer moons then in position, but doubt you get more than moonshine.

The nights last a long time, more than a week. Does anybody know the day length on Pandora?
This would probably give different plants and animals on the outside as you have more darkness, Na'vi have huge eyes the might have evolved on the outside. They would get a surprise moving inside and see the edge of Polyphemus at the horizon

And the Na'vi might know much astronomy compared with ancient humans because they get it pretty much in the face. The rotation of Polyphemus would be very useful as a clock as new features rotate in and out. On the outside the movement of the moons might be critical as if will give more light then they are up in the week long night.

One correction, the RDA would have little reason to place hells gate at the equator. The ground to orbit craft is so effective the delta-v gain from equator location can be ignored,
Yes hells gate is located in a tropical location but it does not have to be at the equator.

[El Jacko]

Very interesting discussion, you would actually have a outside and inside of Pandora, inside is towards Polyphemus outside is away. The inside in seldom very dark because of Polyphemus and ACB, outside might be as a dark as a moonless night if you don't have ACB, you might get some light from the outer moons then in position, but doubt you get more than moonshine.

Is Pandora tidally locked? I think I remember reading something about it once, but I can't remember.

[Tsa'räni]

Is Pandora tidally locked? I think I remember reading something about it once, but I can't remember.

Yes, it's tidally locked.

The whole system would be pretty complex.  While ACA would provide the main "daytime" light, the shine from Polyphemus, other moons, and even ACB would be significant.  The problem with ACB is that we're not sure where in its relative orbit around ACA it is, so we don't know about how far it would be away from Pandora at the time of the movie.  While the amount of light would never come close to ACA, it would still be notable.

In short, most nights would probably be more like dusk or late dusk (depending on a lot of things) for the Omatikaya.  Truly dark nights would be very rare and, who knows, might even hold some kind of special significance for them.

Edit - Oh yeah, if someone wanted to, you could figure out ACB's relative position projected out to 2154.  We have the motions of the AC stars mapped out pretty well.

[El Jacko]

Is Pandora tidally locked? I think I remember reading something about it once, but I can't remember.

Yes, it's tidally locked.

Cheers

The whole system would be pretty complex.  While ACA would provide the main "daytime" light, the shine from Polyphemus, other moons, and even ACB would be significant.  The problem with ACB is that we're not sure where in its relative orbit around ACA it is, so we don't know about how far it would be away from Pandora at the time of the movie.  While the amount of light would never come close to ACA, it would still be notable.

Well, we know that Cen A and B orbit a common centre with the distance between them varying between 11.5 AU and 35.6 AU. Cen A has a luminosity roughly 1.5x that of the sun, and Cen B has a luminosity of roughly half the sun. So, at some points during the 80 year cycle of the two stars, Cen B may appear brighter than Cen A.

What we don't know is the potential orbit of planets. Having a planet orbit around the stars' common centre would be interesting at best (the stars have high orbital eccentricities, so would stray into any 'standard' orbits), and would be too cold to sustain life if it were outside the orbits of both stars. More likely would be that 'inner' planets orbit around either of the stars, up to a few AU away (any more and the gravity of the other star would hijack it). So by that reckoning, Polyphemus could be orbiting around either of the stars, and therefore the brighter Cen A might only appear as a very bright star rather than a full blown 'sun'.

[Tsa'räni]

Polyphemus orbits around ACA, so ACB should never appear brighter than ACA from Polyphemus.  ACA is the main light source for the system Polyphemus is a part of and ACB would just play a minor role.  During the day, if both were in the sky, ACB would probably make no real difference at all (to humans, at least).  But at "night" it would definitely add to the apparent ambient light if it was visible, even to humans.

[El Jacko]

Ahh...so it does orbit round ACA (I don't have much to go on about the general story other than the film and other snippets)

Well, the habitable zone for a star of that power will be wider than that of Sol, extending roughly 1.5-2.5 AU (depending on the emitted spectra), which would put the length of a year for Polyphemus quite close to a Terran year (300-400 standard days). However, the seasons wouldn't be affected as severely as on Earth. More likely, the Pandoran seasonal cycle would be more dependent upon its orbit around Polyphemus than anything else, so a Na'Vi 'year' could be anything from a few weeks to several months.

[Roiki]

The ideal distance to ACA of a habitable planet is about 1.25 AU(year being 1.3 earth years), an eath-like planet would get mostly similiar sunlight than earth and at night ACB appearing around 180-2500 times brighter than the moon(depending where it is), when ACB would move to a stellar opposition(planet between the stars) the nights would be like dusk, similiar to midnight sun for about half a year, the other half of it would see similiar day-night sycle as earth.

Depending on the moons orbit around the gas giant(their orbits might be some way synchronized with the sun) the planet might have a quite peculiar cycle, when stellar opposition takes place the planet would see periods where everyone would have the same day-night cycle at the same time on both sides of the planet, when passing between polyphemus and ACA, ACA would illuminate the outer surface and the reflecting light from polyphemus would light the inner side, when at the opposite side the light from ACB(which is dimmer yes but still a notable light source) would illuminate the outer face and the inner face would get the reflection.
of course this doesn't take into account any other moons polyphemus might have and their possible effects on the cycle.

By orbiting a gas giant and being tidally locked, this would mean that the inner face of the planet would never receive direct sunlight, but it would always come at an angle, which might have some effects on the flora and climate of the inner face.

[Kaltxì Palulukan!]

Edit - Oh yeah, if someone wanted to, you could figure out ACB's relative position projected out to 2154.  We have the motions of the AC stars mapped out pretty well.

Hey Peter! This sounds like your specialty

[Kaltxì Palulukan!]

I gave everyone a cookie here for being so smart.

Okay, so this is above my paygrade, but let's see if I can ask this intelligently:

Taking all of the above into account, we know that Pandora has .72 mass, .8 surface gravity, 1.1 surface pressure, and (my personal favorite) 1.2 atmospheric density--comparable to Earth. So . . .

Given that gravity has the ability to bend light (if you have enough of it concentrated in the right area, etc.) Pandora's gravity may not displace much light over the horizon ("wraparound effect") BUT with the "higher air density," coupled with the ongoing magnetic resonance, and endless storms--could there be a higher amount of particulate matter (dust, or debris) in the atmosphere that works with the afore-mentioned higher density to effectively "scatter and disperse" light from various sources, creating a "brighter effect" (sorry for my lack of proper terminology) or "more apparent light"?

In short: Could the thickness of the air on Pandora, possible floaties (given the constant agitation of molecules in the atmosphere from Polyphemus--source ASG), and several light sources work together to "trap light" to an extent (even though the lower gravity works against this) and create a "glowy halo" effect around Pandora that is noticeably brighter (at some points--depending on all other extra-pandoral objects)?

Point summary:

1: Pandora is smaller (28% smaller) so it "grabs less direct light" (per object).
2: Pandora has not one, but three starts, two of which provide enough light for the sake of this equation.
3: ACA being "1.5x brighter than Sol," puts out a LOT of candlepower. Given the additional air density, can that "wrap around" the (moon) at all?
4: Planetshine (Polyphemus reflection)
5: ACB; a lesser force, but still reckonable, especially since moonshine (on Earth) in clear, non-polluted, non-cloudy areas can be "REALLY BRIGHT!" at a full moon--or--similar to the light provided on a heavily overcast day.
6: Eclipses caused by Polyphemus would create planetary dark-zones, which may be mitigated by extremely violent lightning storms.

Okay, did any of that make sense?

[kintìomum]

Arr, one day not looking and so much to do.

(snip) outside and inside on Pandora...
(snip) day length on Pandora...
(snip) Hell's Gate at the equator

The thing about outside and inside seems a bit moot since I'm pretty sure that Pandora is rotating and not tidally locked. Later more on that one.
Until now we don't know the day length of Pandora but I remember seeing some good maths on possibilities in the german part of the forums. I don't have the numbers in head but I'll go and dig them out.
Yeah, the Valkyries are very effective but as I said: Pandora is corporate business and even with a whole planets ressources ready to fuel refineries and power production plants why shouldn't they place Hell's Gate at a location that gives inbound crafts some free velocity?
This velocity is TOTALLY free just because you placed your spearhead at the right spot. And every bit of free velocity is something that you don't need to burn fuel on that had to be created/refined/produced in your complex. Thus: more time slots in the plant free for the production of other stuff. Or: profit-induced environmental preservation...

Yes, it's tidally locked.

I dare to object.
Tidally locked moons always show one side towards the planet they are orbiting, thus they  rotate their surface only very slow in direction to the sun. This means that the surface is either baked nice and crispy while it faces the sun or getting very cold due to missing sunlight. Pretty bad conditions for live to evolve and/or survive without good shelter.
It might be that Pandora is orbiting Polyphemus very fast - faster orbit means less exposition of one side to the sun or the open space but that's quite unlikely. Why?
We see different shots of Polyphemus from the surface of Pandora and the view doesn't change that much. So, this either means that Pandora isn't orbiting fast (atmospheric phenomena like the different coloured bands tend to "stay" at one spot for a rather long time) or that the whole atmosphere of this gas giant is rotating fast (which would tend to disrupt phenomena like the coloured bands because gas just doesn't stay in place when it's whirled around).
The one thing that's always visible is the storm eye on Polyphemus' surface which is created by the strong magnetic fields from Unobtanium and could be "dragged along" if Pandora was on a race-track-orbit.
But given the little change in the overall views of Polyphemus and the fact that we have day-and-night-cycles should be proof that Pandora is not tidally locked.

(Off to work, later more)

[Kaltxì Palulukan!]

. . . And every bit of free velocity is something that you don't need to burn fuel on that had to be created/refined/produced in your complex. Thus: more time slots in the plant free for the production of other stuff. Or: profit-induced environmental preservation...
(snip snip snip)

Okay, so, at the risk of getting off toping in my own topic this thought (above) makes me think.

There is an table somewhere in RDA accounting (on Earth) that goes something like this:

Cost comparison (rounded down)
-----------------------------------------------------------

	Earth	Moon	Mars	Other*	Pandora
Labor	1	3.7	7.6	?	197.4
Local Manufacture	1	4.3	6.8	?	21.6
Transport	1	15.3	94.2	?	3985.1
Maintenance	1	2.3	4.4	?	77.5

-----------------------------------------------------------
* These locations are unknown to me and may include Io or various asteroids in the asteroid belt of the Sol ystem.


The purpose of this chart would be to reflect the costs of operation "off planet." The further from Terra (Earth) one gets, the more fuel required, the more stress on personnel, the more expensive the cost of labor or parts replacement, especially since "other than Pandora," all colonies ARE heavily Earth reliant, thus making the cost of a Snickers bar in the local commissary well beyond the average labor-grunt's weekly salary. Pandora brings with it all manner of expense headaches. While resources abound, anything manufactured there must include the cost of everything that took place to make its manufacture possible and take into consideration the cost (in time, energy, finance, and psychological toll invested) in its creation. Every attack on Hell's Gate by Eywa; every wasp sting; every trip to the HG head-shrink (psychologist) and anti-depression meds eats away at the profitability of this enterprise, even given the staggering amount unobtanium goes for.

So, I dunno if the big P is tidally locked or not, or if it wobbles in rotation, does back flips, or gets cooked by the incessant radiation from three suns (of which two are pounding out the ergs or whatnot), but I do guess that the environment is taking its toll on every piece of RDA equipment on Pandora:

First there is the U.V. from hell--and the density of the atmosphere combined with low gravity means every particle of dust kicked up by the constantly patrolling Scorpions stays in the air to wiggle its way into seams and cracks and joints in AMP suits, helicopters, air circulation units (etc.). Then there is all of that soot being pumped out 24/7 (scene: early part of the movie, and I believe later, we can see the factory belching filth into the sky**). All of that "crap" floating around, not to mention the immeasurable dust and debris kicked up by those 2 giant sawz-all mining things in the pit, and the wonderful slash and burn fires on "the edges of town," has to find its way into everything human-made.

That is one expensive place to be--and if you are NOT absolutely necessary to creating massive profits, I doubt you will be there long. But anyway, I want to hear more about this rotational thing, and the possibilities of how much sunlight Pandora gets.




**cookie if you got it.

[kintìomum]

Edit - Oh yeah, if someone wanted to, you could figure out ACB's relative position projected out to 2154.  We have the motions of the AC stars mapped out pretty well.

Hey Peter! This sounds like your specialty

Hmm, interesting! I'll see to that later, if I get some time between work and the next Avatar-screening.

(snip) Given that gravity has the ability to bend light (if you have enough of it concentrated in the right area, etc.) Pandora's gravity may not displace much light over the horizon ("wraparound effect") BUT with the "higher air density," coupled with the ongoing magnetic resonance, and endless storms--could there be a higher amount of particulate matter (dust, or debris) in the atmosphere that works with the afore-mentioned higher density to effectively "scatter and disperse" light from various sources, creating a "brighter effect" (sorry for my lack of proper terminology) or "more apparent light"? (snip)

Now, gravity lenses are a nice tool but sadly even for the effect known as microlensing you need at least -as far as known today- the mass of a single star. Neither Pandora nor Polyphemus have that mass. So this is a no.
Now, atmospheres tend to absorb much more light than bending or deflecting it so this is also questionable. Remember sunsets on Earth: they appear reddish because light comes in at a lower angle, has to pass more atmosphere, starting from the "blue side" of the spectrum light gets absorbed and red colors are the ones finally reaching you.
Since magnetic fields are not able to affect light the magnetic storms and Unobtanium can't create a brighter effect, too.
Particles in the air are very well able to scatter light in all directions (our sunsets are mainly so long and beautifully coloured because of the dust and microdirt where blowing up since the start of the industrialization) so these might give a bit more light.
But think of one thing here:
As El Jacko and Roiki pointed out Polyphemus receives about as much light as Earth does. OK, slightly different spectral composition (more blue if I remember correctly) but the same amount per area.
Well, this is Polyphemus which receives the same light/area. A planet as big as Saturn. Or: roughly ten times as big as Earth. With the reflection from that surface you'll pretty much get a "brighter halo" around Pandora.

(snip) (nice table with comments)
(snip) Unobtanium prices
(snip) maintenance

Nice chart you got there. You really need to tell me your sources!
Side note: given that an ISV returns with 350t of Unobtanium and a price of 20 million per kg you get 7,000,000 millions for one load... 
There's not only much dust in the pandoran atmosphere around every human activity, there's also traces of hydrogen sulphide in the air. And having an acid in contact with all your equipment 24/7 really adds to maintenance needs.
And the factory: I think it's more the refinery, as seen first when the shuttle comes in over the pit on the horizon, then seconds later during the landing in the background and the third time when the troups start against kelutral.

[Tsa'räni]

I dare to object.
Tidally locked moons always show one side towards the planet they are orbiting, thus they  rotate their surface only very slow in direction to the sun. This means that the surface is either baked nice and crispy while it faces the sun or getting very cold due to missing sunlight. Pretty bad conditions for live to evolve and/or survive without good shelter.
It might be that Pandora is orbiting Polyphemus very fast - faster orbit means less exposition of one side to the sun or the open space but that's quite unlikely. Why?
We see different shots of Polyphemus from the surface of Pandora and the view doesn't change that much. So, this either means that Pandora isn't orbiting fast (atmospheric phenomena like the different coloured bands tend to "stay" at one spot for a rather long time) or that the whole atmosphere of this gas giant is rotating fast (which would tend to disrupt phenomena like the coloured bands because gas just doesn't stay in place when it's whirled around).
The one thing that's always visible is the storm eye on Polyphemus' surface which is created by the strong magnetic fields from Unobtanium and could be "dragged along" if Pandora was on a race-track-orbit.
But given the little change in the overall views of Polyphemus and the fact that we have day-and-night-cycles should be proof that Pandora is not tidally locked.

(Off to work, later more)

I thought the ASG said it was tidal locked, but I can't find it at the moment, so I may be mistaken there.  I got it from somewhere, though.

Anyway, to begin with, tidal locking on moons that we can observe is very common.  I believe all the major moons in our solar system are tidal locked.  That right there is a strong reason to assume Pandora is tidal locked, though of course it's not proof.

Moons orbit pretty fast around the big planets.  Titan around Saturn might be the closest example to Pandora around Polyphemus.  Titan has an orbital period of 16 days.  There are obviously differences, but Pandora seems to be pretty close to Polyphemus in the movie.  And wouldn't it have to be if their magnetic fields were to interact so vehemently as is claimed?  So I see a rather quick orbit as the most likely scenario.

While tidal locking does prevent a day and night scenario as we are used to it, it doesn't prevent days and nights altogether.  The same side of the moon is not always baking in the sun or hiding in the shade.  You can easily see this by setting up a sun, planet, and moon on your desk with 3 random objects.  Rotating the moon around the planet in a tidal locked fashion (the same side always pointing to the planet, as you mentioned), shows that different sides of the moon are exposed to the sun during its orbit of the planet.  Or you can just look at how our own moon waxes and wanes.

And do we ever really get a sense that they have standard days and nights on Pandora?  The movie really jumps around in time without giving us a true indication beyond what we see from video logs.  And those are often weeks apart.  I think it's shaky ground at best to get a normal day and night cycle due to planetary rotation from the movie.

All of this is probably reading far too much into the movie, though, on both sides.

Edit - Just another thought.  I'm not sure there's a way around tidal locking except to manufacture a reason that they would not be tidal locked.  Since the norm seems to be tidal locking, especially for big planets and close moons (which would speed up the process), there would need to be a reason for the deviation.

On that point, the ASG does mention a theory about a planetary body colliding with Pandora in the past, which could be reasoned to impart the necessary rotation for a day and night cycle.  If it was recent enough relative to the time of the movie, you could make a reasonable case that Pandora remains out of tidal lock.

[Toruk Makto]

KP, something you said got me thinking...  Suppose the "Eye of Eywa" is the eye cloud formation on Polyphemus... Could Eywa actually be there and communicating with Pandora via the flux?