Pandora has the same rotation period as Earth

[ISV Venture Star]

How do I know this? Check out the details in the video log. One of them is LST: local solar time. Here's an example of the use of LST on Mars:

Mars' Calendar - Explore the Cosmos | The Planetary Society


Ten seconds of film time during a video log results in ten seconds of change in the LST clock. So Pandora has the same rotation period as the Earth. Being tidally locked it must also have the same revolution period.

[Human No More]

Interesting, although there's no real reason why it shouldn't

[txen]

Pandora would sure have to be close in. Jupiter's closest large moon Io has a orbital period of a bit under 41 hours.

One thing to consider. We are built for 24 hour cycles of waking and sleeping. I bet you could extend or reduce that a bit and still work effectively. However, stretch it too much and we start having problems. The humans and the "sun" light may be on different schedules.

[Human No More]

Well, Pandora being in orbit around Polyphemus means that it would have periods of both extended day and extended night. Humans can adapt to longer or shorter sleep cycles without a problem, in most cases then when denied any clues to time (no clocks or daylight), most humans will drift to a sleep cycle of around 26 hours.

[Thorinair]

Finally this information!
It will be of great value for my project...
Thanks

[Grifff]

hmmm, i find that unlikely that it has the same rotation time

[ISV Venture Star]

It may not be exactly the same. I only measured a baseline of 10 seconds.

[Sothis]

So, does that mean that every 24-ish hours, pandora makes a complete revolution around polyphemus? Also, does "tidally locked" mean simply that the same side of pandora is facing polyphemus at all times, or does it also mean that pandora is always over the same point on polyphemus and it therefore revolves at the same rate that polyphemus rotates?

Anyway, thanks for this information! I've been pondering this exact question for the purposes of fanfic. I must say, it would make my life easier if pandora's diurnal cycles were approximately the same as earth's in the canon, even if that's actually scientifically unlikely.

[ISV Venture Star]

Originally Posted by Sothis

So, does that mean that every 24-ish hours, pandora makes a complete revolution around polyphemus? Also, does "tidally locked" mean simply that the same side of pandora is facing polyphemus at all times, or does it also mean that pandora is always over the same point on polyphemus and it therefore revolves at the same rate that polyphemus rotates?

The former. The latter is generally only found in systems where the physical separation and difference in mass between the two bodies is much smaller (Pluto-Charon).

Originally Posted by Sothis

Anyway, thanks for this information! I've been pondering this exact question for the purposes of fanfic. I must say, it would make my life easier if pandora's diurnal cycles were approximately the same as earth's in the canon, even if that's actually scientifically unlikely.

Maybe not too unlikely. Mars has a rotation period that's very similar to the Earth. The only issue might be having Pandora close enough to Polyphemus to give it a 24 hour orbital period. I might try playing with the numbers to see if I can make things work out without having to disregard what the ASG says about Polyphemus.

[Human No More]

Yes, it does
As for tidal locking, yes, that is correct about facing, remaining over the same area is a geosynchronous orbit.

[Boba Fett]

The first time I noticed the times of the video logs it bugged me a little. It's not only the clock but also the dates. Even if it didn't take 10 seconds of the film for 10 seconds of local time to pass, it would still still break the date as a different numbers of days would pass on Pandora than on Earth.

However, it's possible that they add or remove days in the calendar to fix any deviation from the current date on Earth, or use another calendar with the same year length but different day length.

As for the equivalence between film time and log time - it could be just an inaccuracy. And you don't have any evidence that they use 24 hour cycle for the local time. It could as well be 25 or 26 hour. All we know is that 06:00, 08:00 and 09:00 are in the morning, and that 17:00 etc. are in the evening. One thing is certain - the day length is similar.

And it makes sense, because I think that Polyphemus plays a significant role in making the floating mountains float, and a close orbit would certainly help. But I'm not sure if closer orbit wouldn't mean more quakes and volcanoes like on Io? Polyphemus is smaller, more comparable to Saturn, maybe we ought to look at Mimas? Mimas has an orbital period of 22 hours and 37 minutes. Sounds about right. And unlike Io there's no significant geological activity.

By the way, why are they using 1/24 of a second as the last part of the time in the logs? Is that a common time format?

[Human No More]

The floating mountains float because of the effect of Pandora's strong magnetic field on unobtainium, this effect can be observed with superconductors available today. I can't remember seeing any numbers on Pandora's distance from Polyphemus, but gas giants put out a lot of radiation and Pandora would need to be reasonably distant to be inhabitable (although it is stated that radiation on Pandora is higher than Earth's natural radiation and that life found on Pandora has a higher tolerance to exposure). In addition, being too close would result in a loss of atmosphere, although the atmosphere is helped by being more dense than Earth's.

[Boba Fett]

The radiation shouldn't be a problem with the magnetic fields and the thick atmosphere. And since the magnetic field on Pandora is more powerful than that ours I don't think you'd have any issues with the radiation. The quakes and volcanoes would still be a major concern, though.

About the mountains, I personally find electromagnetism too complicated so I'm not expecting to ever understand why exactly the mountains float, but my understanding was that the magnetic field of the planet and the moon interact creating spots where you'd see with weird stuff happening. At least that's what my gut feeling and Avatar's wiki told me. Now my gut feeling lied me that this should happen at the equator, so it is not trustworthy, but I still trust the wiki. The Wikipedia article on Io seems to suggest the existence of flux tubes which sound somewhat similar, and their location seems to match the position of Polyphemus in the sky.

This guy also seems to suggest a similar thing, though I disagree with him on everything else, so YMMV.
A Look At The Science Of 'Avatar' : Discovery News

But the thing is, with the existence of something as awesome as a gas giant in the sky, it should play some role. You don't put something as magnificent as a gas giant in the sky just because it looks cool. And the poor Na'vi could never set their foot on their planet like we did on the moon, so at least give them something from the planet that lifts their mountains.

[Human No More]

Superconductors float on magnetic fields. That's the reason, because Pandora's is strong enough to have the effect.

[ISV Venture Star]

Originally Posted by Boba Fett

As for the equivalence between film time and log time - it could be just an inaccuracy. And you don't have any evidence that they use 24 hour cycle for the local time. It could as well be 25 or 26 hour.

Possible, but bizarre. The Mars rovers use 24 hour local solar time clocks with seconds, minutes and hours that are in proportion with the length of the longer Martian day.

Originally Posted by Boba Fett

And it makes sense, because I think that Polyphemus plays a significant role in making the floating mountains float, and a close orbit would certainly help. But I'm not sure if closer orbit wouldn't mean more quakes and volcanoes like on Io? Polyphemus is smaller, more comparable to Saturn, maybe we ought to look at Mimas? Mimas has an orbital period of 22 hours and 37 minutes. Sounds about right. And unlike Io there's no significant geological activity.

Correct. It's a common misconception that Io's activity is solely due to its proximity to Jupiter. Europa and Ganymede play the most significant role.