[Space] Adapting to long days and other implications of a generated system

[Indigar]

I've been working on a world to use as a setting for an upcoming campaign, and I decided that I would work out the world's entire system with the Space rules.

I had decided that I wanted a double world, with two standard garden worlds orbiting each other, but all other details of the system I determined randomly.

Random generation came up with the following:
My world-pair consists of two worlds, which I'll call A and B.
A is practically a twin of earth (a result which I predetermined), except that it has only 50% hydrographics and it has a Warm (304K) climate.
B is a less-dense world, but with almost the same diameter; as a result, is has lower gravity (0.76 G), a Very Thin atmosphere and a Chilly climate (267K). It is also 80% ocean.

These worlds orbit each other closely, at a distance of only about 127000 km, and are tidelocked to each other, giving them a 98-hour day.

These worlds orbit a G6 star, with a luminosity of 0.61, and so have quite a short year (270 days, 66 local days).

In addition, the primary star has a relatively close compion, an M0 star (luminosity 0.091), which orbits at a distance of 6 AU (12.4yrs to orbit). Its orbit, however, has an excentricity of .5, so its distance to the primary star varies from 3 AU to 9 AU.

I want to use this as a setting for a fairly standard fantasy setting, but would like to see if the system as it stands offers any opportunities for interesting color or unanticipated difficulties. Specifically:

I intend there to be an established TL3+magic civilisation on planet A, which is the primary campaign world. Would it be feasible for this civilisation to have set up colonies on world B (a powerful empire in the past would have had the resource to teleport and/or set up gates to there)? I figure that their greatest problem would be the low air-pressure, but how well could a TL3 society be able to manage under those conditions?

Also, how hard would it be for normal humans to adapt to the 98-hour (four-DAY) days on such a world? Humans would have arrived on this world from Earth in a Banestormish way about 2000 years ago.
How well would humans arriving from modern Earth be able to adapt?

Since planet B is about 10x the diameter of the full moon as seen from A, I would think that in those parts of the world where B was visible, nights would be much brighter, but I don't know to which extent.

Another source of light would be the companion star. I don't know that much about astronomy, so I don't know how much difference it would make in the level of light during the day or night.

Are there any other interesting implications of this setting that I've missed?

Thanks in advance,

Indigar

[Dagger of Lath]

Originally Posted by Indigar

In addition, the primary star has a relatively close compion, an M0 star (luminosity 0.091), which orbits at a distance of 6 AU (12.4yrs to orbit). Its orbit, however, has an excentricity of .5, so its distance to the primary star varies from 3 AU to 9 AU.

This star is 1 tenth as bright as the sun and 3 to 9 times further away. The brightness decreases by the inverse square law so it will be 90 to 810 times less bright than the sun.

The star will be barely noticeable in my opinion, though I haven't had enough time to figure out the full maths. (If I get the time I'll figure it out exactly for you).

[StevenH]

Since the worlds are orbiting each other, there will be a Long Night (approx 48 hours) and a Short Night (around maybe 10 hours?) caused by the daily eclipses by its companion. Those with better math might be able to come up with the exact number of hours, but it will have an effect on the society's rhythms.

Next question: how would a 49 hour night followed by a 20 hour day followed by a 10 hour night and then another 20 hour day affect circadian rhythms? Would it be synced to the day/night cycle, or would it be something totally separate, and not linked to day and night at all?

If there are good light sources (or good night vision) it may not matter as much.

Another note: Only the half of the world facing its companion will have this cycle. The other side of the primary world will never see the companion, and won't have the Short Nights.

[CattyNebulart]

Originally Posted by StevenH

Since the worlds are orbiting each other, there will be a Long Night (approx 48 hours) and a Short Night (around maybe 10 hours?) caused by the daily eclipses by its companion.

Assuming they are on a plane with the sun yes, but they might not be.
If they are on a plane you will also have the bright night, the dark night followed by bright night as the companion planet is eclipsed by the main planet for 10 hours during the night.

Also clouds are very reflective so depending on how much cloud formation there is on the ice planet I would list the bright-night as giving only -1 or -2 in vision penalties due to darkness. Doing some back of the envelope math shows the ice planet reflecting so much light that it would be roughly 400 lux equivalent to a brightly lit office. Of course I was assuming the sun for that.

Wheather (and the seasons) on the other planet will affect how much light there is during the night, because clouds are very reflective. The planets could also function as weather satelites for each other and so I assume weather forcasting on the sides of the planets facing each other will be more advanced. Weather forecasting is very valuable to farmers, and for a TL3 society most people are farmers, but taking advantage of the good vantage point to observe clouds from above will require observers to work together. probably some form of guild or government department.

Better telescopes too because you can use the planet to spy down on the other one. you would need a good one to see armies on the march and such, though campfires should be easy to spot at night.

Originally Posted by StevenH

Next question: how would a 49 hour night followed by a 20 hour day followed by a 10 hour night and then another 20 hour day affect circadian rhythms? Would it be synced to the day/night cycle, or would it be something totally separate, and not linked to day and night at all?

it's going to mess up day-night rythms something fierce but for humans at least the system is very dependent on light, which is why electric lightbulbs have messed it up so much for modern man. Try living without electric lights for 2 weeks, it makes an amazing difference.

[CattyNebulart]

Originally Posted by Dagger of Lath

This star is 1 tenth as bright as the sun and 3 to 9 times further away. The brightness decreases by the inverse square law so it will be 90 to 810 times less bright than the sun.

The star will be barely noticeable in my opinion, though I haven't had enough time to figure out the full maths. (If I get the time I'll figure it out exactly for you).

the sun gives on average about 50'000 lux, divide by 1000, 50 lux is around the light in the family living room.

I'd say that's noticable alright.

[Anaraxes]

90 to 810 times less bright than the sun

Astronomical magnitude is a logarithmic scale with a factor of about 2.5x brightness for each step. (The fifth root of 100, if you want to be exact.) 0 magnitude was historically Polaris, then Vega, then just a defined value for flux. High numbers are more dim; very bright objects have negative magnitude.

The sun is magnitude -26.7 (449,000 times brighter than the full moon). The full moon is -12.6.

-4 is barely visible during the day. Planets range from about -2 to -3. Visible stars in the night sky are typically 0 to 6.

1/90th the brightness of the sun is about magnitude -22. 1/1000th the brightness of the sun is about magnitude -20, both still far brighter than the full moon. Or to look at it another way, the companion is about as far away as Jupiter, but a million times brighter.

The companion probably casts its own shadows during the daytime.

[David Johnston2]

Originally Posted by StevenH

Since the worlds are orbiting each other, there will be a Long Night (approx 48 hours) and a Short Night (around maybe 10 hours?) caused by the daily eclipses by its companion. .

Eclipses don't last that long. It wouldn't really be all that difficult over a couple of thousand years for humans to adopt a 32 hour awake/16 hour asleep cycle, maybe with a nap in the middle. Of course most of the time the night will be fairly well lit what with the giant moon and the close stellar companion. In fact the moon will be reflecting so much light that there would probably be noticeably less difference between day and night temperatures.

As for the very thin atmosphere, it would be...difficult to colonise it without actively modifying humans to fit using something like magic biotech. Just about impossible. It doesn't help that 80% hydrosphere means their sea level is comparitively high. On the other hand if somewhere in there they have a super-Grand Canyon, something that goes really really deep at the bottom they might get up to Thin Atmosphere there. But I can't imagine how to keep it from filling up with water.

[Dagger of Lath]

No, surely the sun is no brighter than a firefly...

Uhhh, yeah. What I said before was pretty dumb. Don't know what I was thinking. Been a bit off my game tonight.

[Indigar]

Hey all!
I've been away from my computer for a while so I haven't been able to respond, but I have been continued working on this setting.
I'll respond to posts by several posters in this post.

Originally Posted by StevenH

Since the worlds are orbiting each other, there will be a Long Night (approx 48 hours) and a Short Night (around maybe 10 hours?) caused by the daily eclipses by its companion.

Originally Posted by CattyNebulart

Assuming they are on a plane with the sun yes, but they might not be.
If they are on a plane you will also have the bright night, the dark night followed by bright night as the companion planet is eclipsed by the main planet for 10 hours during the night.

Also clouds are very reflective so depending on how much cloud formation there is on the ice planet I would list the bright-night as giving only -1 or -2 in vision penalties due to darkness. Doing some back of the envelope math shows the ice planet reflecting so much light that it would be roughly 400 lux equivalent to a brightly lit office. Of course I was assuming the sun for that.

Thanks. I've checked, and the axial tilt of these planets is only 9 degrees.
(I've assumed that the strong tidal forces that have tidelocked these worlds have also locked their axial tilts to be equal to their orbital inclination, so that they rotate and revolve in the same plane. Is this right?)
This means that the planets are very close to being in line with the sun, so I assume there will be frequent, probable even daily, eclipses.

Since the apparent diameter of these planets from their companions' surface is about 10x the diameter of the moon, they're about 5 arcseconds wide. I believe that makes such an eclipse 5"/360 deg* 98hrs (day length) = about 15 minutes. This doesn't fit with your figure of 10 hours; have I miscalculated?
If I'm correct, these daily eclipses are not going to have a significant effect on day/night rythms, so we're back to a difficult-to-adapt-to 48 hrs each of day and (quite bright) night.

Originally Posted by David Johnston2

Eclipses don't last that long. It wouldn't really be all that difficult over a couple of thousand years for humans to adopt a 32 hour awake/16 hour asleep cycle, maybe with a nap in the middle. Of course most of the time the night will be fairly well lit what with the giant moon and the close stellar companion. In fact the moon will be reflecting so much light that there would probably be noticeably less difference between day and night temperatures.

Ah, thanks. So you think there would not be much of a difference in activity between day and night? Just 32hrs awake/16 asleep twice per day/night cycle?
this is indeed doable if nights would indeed be as bright as normal office lighting...
I'm wondering what kind of effect this would have... I envision different cities' wake/sleep cycles drifting out of phase is they weren't in constant contact; in fact a different time zone for each somewhat-isolated area! That could be a fun detail.

Originally Posted by David Johnston2

As for the very thin atmosphere, it would be...difficult to colonise it without actively modifying humans to fit using something like magic biotech. Just about impossible. It doesn't help that 80% hydrosphere means their sea level is comparitively high. On the other hand if somewhere in there they have a super-Grand Canyon, something that goes really really deep at the bottom they might get up to Thin Atmosphere there. But I can't imagine how to keep it from filling up with water.

Would it be more doable if I declared there to be a much higher percentage of oxygen? Since the atmospheric pressure is about 0.46 atm, could I simply double the oxygen percentage to 40%, or would that cause other effects.
I'm wondering why a high sea level would matter. Wouldn't the pressure that Space gave me simply be the sea-level pressure?

Anyway, thanks for the help so far everyone.
I'll think about this some more and post more later about what I come up with.

[Bruno]

Originally Posted by Indigar

Would it be more doable if I declared there to be a much higher percentage of oxygen? Since the atmospheric pressure is about 0.46 atm, could I simply double the oxygen percentage to 40%, or would that cause other effects.

I'm not sure what other effects there might be, but that would bring the partial pressure of oxygen up to a level that humans can work with, yes. I'd be concerned about the eyes in the cold, thin, and dry air however; aviator goggles or something like a ski-mask or inuit snow-blindess goggles might be in order.

How this would affect combustion, I have NO idea. A magical society may be using Create Air and Heat spells inside buildings, however, just to make them more comfortable. Weather Dome and Atmosphere Dome will still likely be VERY popular, even if humans can live unaided outside. I imagine their mages would rapidly develop a permanent, enchantment form of Atmosphere Dome which would likely be popular with rich people for their sleeping chambers.