Seasons on Pandora

[Tsa'räni]

It's possible, give me a few moments to hunt down the specifics on the focal lengths used by Apollo 8..  Hopefully I can find the specific lens used for the picture I'm thinking of.  It would only be approximate, but if I know the lens and film format, I can tell if it's a telephoto, wide angle, normal, etc.

Without that info you could just do an angular diameter calculation of Polyphemus from Pandora and it should tell you how big Polyphemus would look in a picture from Pandora using the same camera and focal length as this picture from Apollo 8.



Edit - Better image used from Wiki.

They apparently had an 80mm and a 250mm for the camera, the first being a normal for the film they were using, the second being a telephoto.  I don't know which was used for the above image, but probably the normal (meaning it would appear about that way to our eyes).  That's just a guess, though.

So the Earth, as seen from the Moon, has an angular diameter of about 2 degrees.  The Moon, as seen from the Earth, is about 0.5 degrees.  We don't know the orbit of Pandora about Polyphemus, but we can make some comparisons using various distances.  We have to make an assumption for the size of Polyphemus, which the ASG states as similar to Saturn but smaller.  I'm going to go with 90% of Saturn's radius.

These figures would be the approximate angular diameter for Polyphemus as seen from Pandora:

If Pandora orbits around Polyphemus at the distance our Moon orbits the Earth - 9 degrees (4.5x larger than the Earth from the moon, or 18x larger than the Moon from the Earth)

There are a lot of assumptions there, but without more specific info on the orbits and all that, we can't do more.

Oh yes, and don't forget, that doesn't take into account the illusion of things appearing larger near the horizon.  As big as our moon appears to get at times on the horizon, no doubt Polyphemus would also appear to grow substantially.

[kintìomum]

And with something as big as a close gas giant it's bound to be "near the horizon" on a good deal of the time it's visible at all!
We should go and harass JC (or the folks at FOX) for orbital information!

[Kaltxì Palulukan!]

Thanks for the info and the image. Here is my basic idea:

We can tell from the image, the exact center of the Earth.
We know the diameter of the Earth.
We know the diameter of Saturn and Jupiter, and Polyphemus is supposedly between them.
We know how far away the Earth is from the moon.
So...
Replace earth with Saturn, Jupiter, or (if diameter is known) Polyphemus.
Size accordingly*

Here is the problem. How would you know what 'size accordingly is? Can you look at a 4" diameter of Saturn and say "This is 1:10(12) scale," or a 1" diameter image of earth and say "This is 1:10(4) scale"? I think so. That is what math (geometry, trig, calculus, other big-sounding mathy words) is for, right? That should give us an easy size ratio:

Earth at 1:10(4) next to Jupiter at 1:10(4) gives us the image sizes.

Note: these example equations mean nothing. They are just to illustrate my unintelligble point. Confused srak?

[El Jacko]

Earth at 1:10(4) next to Jupiter at 1:10(4) gives us the image sizes.

Note: these example equations mean nothing. They are just to illustrate my unintelligble point. Confused srak?

Well, if you superimposed Jupiter onto your moon pic, it'd be roughly 10-12 times wider than Earth. Then compare that to a still of Polyphemus from Pandora, using landmarks to judge zoom, and you should be able to get a rough ratio between the two sizes. Using that ratio you can work out the relative distance with some basic trigonometry.

I ain't confused yet, try harder.

[Tsa'räni]

Just a quick note on Polyphemus' size.  The ASG says it has more mass than Saturn, but is smaller in terms of size.  I used 90% of Saturn's radius for my numbers, but it is a pure guess.

[Ni-Alu]

This is actually something I've been thinking about. I think we can safely assume that for the Omatikaya and nearby areas, the seasons may be similar to the seasons of the Terran Equator. A sort of Wet and Dry season. As for other locations on the planet, I can't say.

My question is, I wonder what the Na'vi would call the seasons. Maybe something along the lines of

"the time of Eywa's tears" OR "the time of Eywa's grace"

What do you guys think?

[kintìomum]

I think that would hardly depend on how much "negative ballast" is on the word tears.
The idea to have simple names for seasons is good and easy to grasp but for us "tears" is something sad (which is sad since there is tears of joy, no?).
OK in a jungle the density/frequency of rainfall might well be the only indicator for changing seasons you get. I doubt that the jungle we see the Omatikaya in knows seasons as we in the northern hemisphere with leaves changing color and falling and finally regrowing after a period of cold...

[Kaltxì Palulukan!]

Okay, Another hour of research time completely wasted and I feel like a stooge:

The ASG was written by Maria Wilhelm, who has known JC for a time. She brought on Dirk Matheson (who had no prev. sci-fi exp.). The man we ant to get to is James Tanenbaum--sound editor/mixer/designer, and amateur astophycist. he and JC debated heatedly on the make-up of the AC system. This is the man to ask questions of, BUT, of course there is no known contact for him. maria and Dirk are also hidden as if they are unobtanium.

This really pisses me off. I am a published author of several books. I make DAMNED SURE people can get a hold of me if they have questions. Since when are authors afraid of their readers? Oh well. No email addresses or phone numbers.

[Kaltxì Palulukan!]

I think that would hardly depend on how much "negative ballast" is on the word tears.
The idea to have simple names for seasons is good and easy to grasp but for us "tears" is something sad (which is sad since there is tears of joy, no?).
OK in a jungle the density/frequency of rainfall might well be the only indicator for changing seasons you get. I doubt that the jungle we see the Omatikaya in knows seasons as we in the northern hemisphere with leaves changing color and falling and finally regrowing after a period of cold...

Yeah, axial tilt is the "reason for the season" and we have no knowledge of that (see my previous post/rant). I am doubting there would be any set reason for a wet vs. dry season, unlessssss . . . it is possible that Polyphemus has a hyper-extended elongated elliptical orbit which may translate into some sort of cold/wet season for Pandora. "might." This is really grasping at straws. Bah! I need to find out if Pandora rotates! grrr! at authors who hide from their readers! As to equatorial seasonal changes, the real difference is closer to the tropics (Cancer/Capricorn). Whether the sun is 15 north or south is slight variation on the equator, but in Australia or Africa the difference is pretty extreme.

[kintìomum]

(snip)BUT, of course there is no known contact for him. maria and Dirk are also hidden as if they are unobtanium.(snip)

I bet they were kidnapped by operatives to be hidden until they can chew out more informaion that'll be marketed through the one big corporation that owns Pandora now. No, stupid. Not the RDA. FOX!

Man, I wish that I had the BluRay here. More material to look at and draw conclusions from and no more "waiting for tuesday" before I can see it again. I'm going to slow-motion-watch the long cut!

[kintìomum]

I made some more thoughts on the original subject. You remember? Seasons on Pandora.
These things that always tend to leave your yard full of leaves once you got the lawn trimmed to a nice level...

Now, on Earth we basically have two sets of climate.
Continental and oceaniac (or coastal).
Continental climates tend to have hot summers, freezing cold winters and rather short periods of spring and autumn between them. Temperatures are changing in a great margin because land can not store heat as well as water does. Examples for this are the greates part of Russia and the middle of the US.

Coastal climates -due to the regulating/buffering effect of a close-by body of water- are rather mild in their average temperature and have nice long springs and autumns with winters where you actually dare to go out for fun and a summer that's not melting you on the sidewalk. Examples are coastal US, countries around the Mediterranean Sea and most of Europe...

OK, this is a pretty general description and things like the geographic makeup, prevailing wind directions, distance to lakes/oceans tend to mess with it but you should get what I mean.

Now, Pandora on the other hand has a larger water-to-surface-ratio than Earth meaning even more great lakes and oceans.
And as we can see in the opening scenes from orbit these water areas are scattered above the surface of Pandora and not forming three or four large oceans like water does on Earth.
Now, Pandora is in the habitable green belt of ACA, so it does receive roughly the same amount of light and energy as Earth does. But with all these great lakes and small seas scattered climate overall should be much more balanced.

[Tsa'räni]

Yeah, the ASG basically mentions that due to the smaller continents and higher water to land ratio, Pandora doesn't get the extremes we often see in the middle of our large continents.

[kintìomum]

Imagine a whole planet with a climate like southern France or hmm, Mississippi (the state)...
No wonder that the whole planet is covered in wood/jungle. There wouldn't be something like our harsh winters to stop the plants from growing.
Mee, I'm a bad person. I just thought about how many successful harvest cycles one could manage on Pandora...

[El Jacko]

Although as we know, Rainforests do tend to need a rainy season and a dry-er season to actually prosper. Ours are caused by the earths tilt (outside the tropics) and various jetstreams, whereas inside the tropics its a very regular cycle (see: monsoons). The tropical monsoon systems are caused by excessive low pressure building up over landmass, which the moist (cooler) ocean air compensates for, thus drenching the land.

This could happen on Pandora as part of its orbit of Polyphemus, since it would cool and heat to higher extremes than Earth in the extended night as it passes through the shadow of Polyphemus. The sudden heating of the land as it re-emerges could cause a very sharp change in pressure, kicking off a smaller, shorter rainy season once every orbit. Something like this occuring on a regular basis would give a very regular climate, not unlike a rainforest or tropic.

[Kaltxì Palulukan!]

Although as we know, Rainforests do tend to need a rainy season and a dry-er season to actually prosper. Ours are caused by the earths tilt (outside the tropics) and various jetstreams, whereas inside the tropics its a very regular cycle (see: monsoons). The tropical monsoon systems are caused by excessive low pressure building up over landmass, which the moist (cooler) ocean air compensates for, thus drenching the land.

This could happen on Pandora as part of its orbit of Polyphemus, since it would cool and heat to higher extremes than Earth in the extended night as it passes through the shadow of Polyphemus. The sudden heating of the land as it re-emerges could cause a very sharp change in pressure, kicking off a smaller, shorter rainy season once every orbit. Something like this occuring on a regular basis would give a very regular climate, not unlike a rainforest or tropic.

Being that Pandora is a satellite of a HUGE gas giant (planetary gravity pull, frequent and violent magnetic storms, extremes of direct sun and sudden, possible long periods of cold and dark), could any of these increase wind activity? With a higher water/land interaction (more coastal areas, presumably more ocean breezes and clouds over land masses), could we see more severe weather patterns? More wind and rain? or--"more appropriate (globally) to a tropical condition/area" because of the massive wetland/coastal interactions of the elements?

Also, rain water is pure h2o, right? Evaporation does not include minerals, right? So the magnetic flux would not directly affect rain, or water, other than anything that has minerals in it (the hot springs, and the waterfalls from the hallelujah mountains for example) . . .

Srak?

[kintìomum]

Although as we know, Rainforests do tend to need a rainy season and a dry-er season to actually prosper. Ours are caused by the earths tilt (outside the tropics) and various jetstreams, whereas inside the tropics its a very regular cycle (see: monsoons). The tropical monsoon systems are caused by excessive low pressure building up over landmass, which the moist (cooler) ocean air compensates for, thus drenching the land.

Well, Pandora got some tilt in it's axis and although I don't remember the exact degree nor have the ASG at hand I think it was somewhere close to Earth's.
With a wider spread of lakes/oceans and smaller landmass this effect should not occur in the same strength as on Earth but...

This could happen on Pandora as part of its orbit of Polyphemus, since it would cool and heat to higher extremes than Earth in the extended night as it passes through the shadow of Polyphemus. The sudden heating of the land as it re-emerges could cause a very sharp change in pressure, kicking off a smaller, shorter rainy season once every orbit. Something like this occuring on a regular basis would give a very regular climate, not unlike a rainforest or tropic.

...this is something that came to mind some time after posting. Pandora doesn't need the same allocation or land/water-ratio as Earth because it has this giant blocking the major part of the suns energy regularly.

Being that Pandora is a satellite of a HUGE gas giant (planetary gravity pull, frequent and violent magnetic storms, extremes of direct sun and sudden, possible long periods of cold and dark), could any of these increase wind activity? With a higher water/land interaction (more coastal areas, presumably more ocean breezes and clouds over land masses), could we see more severe weather patterns? More wind and rain? or--"more appropriate (globally) to a tropical condition/area" because of the massive wetland/coastal interactions of the elements?

If the period in the shadow of Polyphemus is "long" Pandora would get regular ice ages. But yeah: every pass into the shadow causes inland winds (air over sea is warmer than the air over cooling land) and every step back into ACAs light causes seaward winds (land heating air faster than water).
As El Jacko pointed: This should create a very regular pattern of "rain time" and "dry time". The large scattering of the water surfaces on Pandora would counter a major effect (likely very few tornados or such) so that we get a rather calm pattern. Well, calm meaning that there might well be storms everytime Pandora enters/leaves Polyphemus shadow. Storms are natures calm way of dealing with temperature differences in atmospheres...

Also, rain water is pure h2o, right? Evaporation does not include minerals, right? So the magnetic flux would not directly affect rain, or water, other than anything that has minerals in it (the hot springs, and the waterfalls from the hallelujah mountains for example) . . .
Srak?

Srane.
As long as there is no great dustcloud in the air. Then you'd get something that we here on Earth use industry and cars for: dirty rain!

[Greg]

It would seem that we can not sort this out until we know what all of Pandora looks like. It would seem that there is some type of temperate zone between the tropical rain forest and the ice sheets.  Anybody seen a map of the planet or a globe?

[El Jacko]

It would seem that we can not sort this out until we know what all of Pandora looks like. It would seem that there is some type of temperate zone between the tropical rain forest and the ice sheets.  Anybody seen a map of the planet or a globe?

You get a good view of the moon just as the Venture Star arrives, but that's about it. Unless theres something in the ASG about it.

[Kaltxì Palulukan!]

There is so much information about Pandora climate and topography that it should be a sin NOT to own it.

[El Jacko]

There is so much information about Pandora climate and topography that it should be a sin NOT to own it.

I have my reasons. Everything I have written in this thread is based on speculation and what I managed to glean from your posts and the glorious realm of the internet.