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Pandora - the parameters of the orbit and other astronomy
If the internal parameters of the Pandora (radius - 5724 km and mass - 0.72 from the earth, the data from wiki)
Radius of the orbit of Pandora can not be large for two reasons:
1) The planet should not depart from the area of life;
2) The planet must not fall into the long shadow of Polyphemus - otherwise pomerznet...
2) The planet must not fall into the long shadow of Polyphemus - otherwise pomerznet...
Distance to Polyphemus can be very rough estimate only apparent disk ofPolyphemus (in the beginning of the film is footage when the "Venture Star" is hanging in the orbit of Pandora, and in the background - Polyphemus). about 10 degrees. About knowing the radius of Polyphemus, one can estimate the radius of the orbit of Pandora - it's about 600000-1500000 km ...
Accordingly, the period - 6-20 days the earth ..
1) Main light - Aca. Since Pandora is seen almost as the Sun from the Earth(apparent magnitudes and -26.74 -26.7, respectively). By the way, all mycalculations have indicated that Cameron went to very good choice of places ...
2) The second star - AAB. Due to the motion of the stars Alpha Centauri relative to each other, the apparent magnitude varies AAB great - from -20.87 (at 215 timesdimmer than the Sun at closest approach) to -18.03 (in 2935, at the greatest distance). In any case, it shines the moon is stronger (-12.7, 400 000 times dimmer than in the Sun) ...
3) the starry sky. Practically does not differ from ours (because we are the closestneighbors), but the two stars. Our nearest star - Proxima Centauri, is the nearest and Pandora (obviously, without regard to Alpha Centauri). True, it will help a little -from the category of invisible to the naked eye (11.1), it goes into the category ofbarely visible (4.69). The second star, our Sun will enter the top ten of the brightest stars of the sky pandorskogo (0.46) ...
Pandorianskienatural cycles.
ButPandorahas twocycles,which do not dependon the inclination ofthe axis of rotationandthat you can tryto shortchange...
1)RotationaroundPolyphemusAca(annual cycle) leadsto a change inlightof PandorabyAAB.Apparent magnitudevaries fromAAB-20.87-19.23to.However,even at the maximumshare ofthe approximation of theAABinlightof Pandorais very small-only 0.4% ofthe total,at a minimum(we areon the year)- 0.1%.That is,there arevariations, but verylittle...
2)The rotation ofthe starsof Alpha Centauri(the age-oldcycle) is similar.Andwith the same effect-infact,veryfar awayAABprovides only0.03%of the totallight...
Pandoraisthe anglebetween the rotation axisand the normal tothe orbital planeis 29degrees (the Earthis -23.4),respectively,the change of seasonsthereis.Butthis isunimportantforOmaticaya-theytusyatin the tropics...
Day and night on Pandora.
Actually, if the day, even in Africa Day - Aca rose, and came a typical day. The presence or absence in the sky AAB has little effect on day light - much stronger than it is affected by clouds ...
But the night of Pandora is very interesting. They are there for a few.
1) Regular Night - Aca and AAB on the horizon. Depending on the position relative to the stars Pandora's active site varies from almost zero to half pandorianskih days. 0 - this is where Pandora is on the line between Aca and AAB, half - when the Aca and DVR in one sector of the sky. "Darkness" of the night depends on the phase Polyphemus - as it should have a significant albedo (reflectivity), then polnopolifemii
Pandora is enough light ...
2) the darkness - the sky AAB. Again, the duration depends on the position relative to the stars Pandora's actually normal amount of night and darkness - it's exactly half pandorianskih days. AAB lighting gives a different - from the darkness itself to the possibility of hard to read. Again, your contribution is Polyphemus ...
3) Eclipse - Pandora falls in the shadow of Polyphemus. It is longer than the analogues in the world - a few hours. Net eclipse - this is where Pandora, Polyphemus, Aca and AAB are arranged in a line in that order. Then the whole Pandora's very dark ... Eclipse also from other celestial bodies on Pandora unrealistic ...
When you watch a movie certainly very curious pointed out that the bands are not directed at Polyphemus under the same angle to the horizon of Pandora. When moving across the sky slowly turns Polyphemus. The angle of rotation depends, inter alia, on latitude observations on Pandora.
By the way, it follows that the action takes place in the tropics, because Polyphemus can only get up to 29 degrees latitude.
That's actually what is known and what is the problem ...
1) There are basic parameters of the planet - diameter (11447km), weight (0.72 Earth masses) and the gravitational acceleration (0,8 g). The problem is that they do not dock, the error of about 10% ...
2) There are parameters of the atmosphere - the density (1.2 from the earth), pressure (0.9 to earth), the main gas and the concentration of carbon dioxide, xenon, and hydrogen sulfide. The problem is that in the book (and EMNIP in the game) stated that the partial pressure of oxygen (count, percent by volume) is equal to Earth. Again, cannot ...
3) Cheer all around with a circulation of Polyphemus. On the form you can evaluate almost anything you like. Some stating that because of the orbital light changes by 10% - Payment is 0.06 au It basically fits into the radius of the Hill for Polyphemus (the zone where Polyphemus dominates Aca) - 0.065 au But the fact that Pandora - the fifth or sixth satellite, and all remaining should be engraved in the remaining period of ...
About pandorianskom year.
Figuring in the movie of our months, seems to be under a calculated basis, especially if we take the following assumptions. - It is about 475 Earth days (according to the latest refinements - 474.95381). If we take the usual division of the year into seasons - each of the seasons would be 118.75 days, respectively. To convert to earth enough to make a calendar month in which the season is not three, as we have, and four months. Then the season is obtained from three months to 30 days and one to 29. In four seasons - 12 months of 30 days and four - to 29. To remove the excess of the day, enter the local February (or one 30-day month doing 29-day). Total - 12 (11) months of 30 days, 3 (5) months - 29, 1 (0) - 28 ...
So pandoriansky month - a complete turn around Polyphemus Pandora ...
There are three main versions of the duration pandorianskogo months:
A) It is pandorianskim days (1-5 Earth days).
B) about 10 days.
B) about 100 days.
On which we can estimate?
1) The apparent size of Polyphemus.
2) Change in phase Polyphemus (the fact that the rotation axis is perpendicular to its orbit Polyphemus think contested - all kinds of adequate on this point).
3) Changing the light of Pandora.
4) The number of satellites within and outside the orbit of Pandora.
5) The magnetosphere.
We estimate.
A) 1) Must be very healthy. For example: at the back for 2 days (the orbital radius of 334 000 km) Polyphemus will have an angular size of 20 degrees (40 moon diameters). Plus, you should see curves of cloud layers on Polyphemus - and they are straight. 2) Complete the seams. When you rotate the plane of the orbit of Pandora in Polyphemus, he would not turn outside it - would bend cloud layers. 3) It is possible only through the orbit of Polyphemus. 4) It is problematic. 4 satellites have generally hung over the Polyphemus. 5) In fact, any magnetic tracks could not smell and bits - all the deep orbit in a magnetic field Polyphemus.
Conclusion - is unlikely ...
B) 1) Solid - the order of 5-10 degrees (to turn in 10 days - about 7 degrees). In my opinion - the most adequate. 2) All right, PMSM. Very well seen on the night of the meeting - for a few hours have changed considerably and understandable. 3) It is possible only through the orbit of Polyphemus. 4) Normal distribution. 5) The Pandora will be walking on the outer edge of the magnetic field - quite normal.
In favor of this option says that the satellite giant solar system analogs of Polyphemus, have similar orbits - Saturn's Titan and Ganymede, Jupiter's ... The most likely version.
B) 1) is not enough. You can draw an owl on the globe represent a strong vytyannutost, but it will be ugly. 2) There are no problems, but too small. 3) are applied. 4) crooked. It is not very far from the Hill's sphere, so that the outer satellites will kuchkovatsya plotnenko. 5) You can rely only on an exceptional field.
Conclusion - too improbable ...Pandorianskoe time. Actually, the result of torture ...
Units:
1) Second. She does not care - it may not depend on anything ...
2) Min. Pandorianskaya minutes - analogue terrestrial.
3) an hour. Pandoriansky hour - 50 minutes pandorianskih or 3000 seconds.
4) Pandorianskie day - one Pandora turn around its axis. Very specific - 71 921 seconds (rounded to integers). Or 24 hours = 1440 pandorianskih pandorianskih minutes = 72,000 seconds.
5) Pandoriansky month - one Pandora turn around Polyphemus. Again, exactly - 863,550.5 seconds. Or 12 days pandorianskih = 288 h = 17 280 pandorianskih pandorianskih minutes = 864,000 seconds.
6) Pandoriansky season - a quarter of the year pandorianskogo, specifically pandorianskih 143 days. In principle, Omaticaya does not make sense ...
7) Pandoriansky year - 572 days pandorianskih. As on Earth, after three years followed by the usual leap, 573 days. And this, too, have an extra day in the winter ...
What's outpost on Pandora.
Since the only earthlings base is located in the tropics, the commanders decided not to hammer his head at all. The basic unit is pandoriansky month, which corresponds exactly to the earth's decade (or so people and is called). Year 39 continues decades and 8-9 days pandorianskih
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Originally Posted by Ja'k Dawsiin
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