So I want to "build my own solar system" (for things like astrology, solstaces, etc.)

[Kraven Kor]

I want to, if at all possible, set up a actual working calendar, some vague astrology, etc. for my world.

 

Difficulty: There are 2 Suns, and 2 Moons.

 

The planet orbits the primary star of a binary system, with the secondary star 'trailing' the primary star such that it is really just a very, very bright star itself. But it is bright enough that, when it is in the night sky for about half the year, it would be brighter than either of the two moons and offer near twilight conditions.

 

I've tried to wrap my head around "Universe Sandbox" or whatever, but I lack the math skillz to do that properly, and every system I set up turns into a game of galactic billiard balls with my lovely planets flung off to the far reaches of space.

 

Anyone know of any easy way to set this up (short of building a science fair style mobile)? I want to kind of know when during the year the second sun would be in the night or daytime sky, when it would be dawning early or setting later, etc.

 

I've already got a calendar, with the moons phases done, but would also like to maybe know on a particular day if the moon is maybe full but not in the night sky, etc.

 

The calendar itself is a 482 day year, with one moon on a 24 day cycle and the other on a 37 day cycle, roughly, with the first day of each year always coinciding with a double full moon. I haven't quite figured out whether my fantasy setting has figured out leap years or not, but am thinking they will as they have fairly advanced optics and math and such (it is a steampunk / fantasy setting with airships, guns, etc.)

 

Any help or advice would be appreciated.

[Pizza Man]

Re: So I want to "build my own solar system" (for things like astrology, solstaces, e

 

Make is so complicated that the players will never figure it out that you never took the time to do the math.

Anytime they need to consult an astrologer they should enter a bizzare room like Ogra's in the Dark Crystal where everything seems to orbit everything else, and only massive moving models can predict anything...

 

Further, you could move the second star closer, and into a quicker orbit than you world.

thats lets you change you'r world's orbit to a decades long ordeal, and its the close passes of the 2nd sun that give your earth like seasons.

When the 2nd sun is away your world is at winter in both hemispheres. When the sun is close its summer everywhere.

 

as for the twilight bit,,,think of the poor vampires...they'll just be a seasonal menace...

[Lucius]

Re: So I want to "build my own solar system" (for things like astrology, solstaces, e

 

I'm not sure the moon can BE full and not in the sky, unless you mean it's cloudy.

 

Full means that the side facing the planet is fully illuminated by the sun. I think that implies that it would have to be on the opposite side of the planet from the sun.

That means it's on the side of the planet that's experiencing night.

 

Except you've got two suns, which may just blow your neat little moon phase system out of the sky, unless you want to say the smaller star is dim enough that it simply doesn't "illuminate" the surfaces of the moons from the point of view of the planet.

 

 

Lucius Alexander

 

Illuminating a palindromedary

[Steve]

Re: So I want to "build my own solar system" (for things like astrology, solstaces, e

 

How far apart can binary stars be and still be a binary system? Can they be a light-month apart? A light-week? A light-day?

[Kraven Kor]

Re: So I want to "build my own solar system" (for things like astrology, solstaces, e

 

I would think that the secondary sun would usually be shining on the "dark side of the moons" or would be mostly eclipsed by the planet from the point of view of the moons. Depending on the exact inclination of the orbits or whatever. And this is exactly what I want to have at least a basic understanding of - where would the secondary sun be in the sky during any given time of year.

 

And a binary system can be fairly distant - I think Alpha Centauri and Proxima Centauri are about .4 LY apart.

 

My thinking is that the primary sun, a yellow/orange dwarf like our own, is probably half a lightyear or more from the blue giant secondary star. Far enough away that it has little influence on the orbit or seasons of the world - it is just a neat special effect of two suns. The secondary star is going to kind of be tied to a lot of the magic of the campaign - the intense radiation and such from the blue star causes the planet to have an intense and fluctuating magnetic field, which the 'Aether' airships rely on for their ability to fly, and which influences some other aspects of magic and such.

 

And while I don't need that much accuracy for the sake of the campaign, I am trying to transition this into a writing project, and I do want a fair amount of accuracy in things for that.

 

As to the big mechanical astrology labs, that is almost exactly what I pictured. As such, I'm thinking the solar system has lots and lots of planets and lots of moons around other planets. I don't think I'll ever fully flesh out the astrology, but I'd like to have at least the basics thought out.

[Steve]

Re: So I want to "build my own solar system" (for things like astrology, solstaces, e

 

Well, if you set the second sun half a light-year distant, that should keep it as the brightest star in the heavens.

 

The next question I have is regarding the relative orbit of the planet from the second sun. Does the planet pass between the two stars as it orbits the yellow sun, or is its orbit perpendicular to the second star? If the latter, it makes for some interesting stellar visuals, and the second sun could be something like Polaris is to Earth.

[Kraven Kor]

Re: So I want to "build my own solar system" (for things like astrology, solstaces, e

 

I am thinking the orbit passes between the two stars, with maybe some slight inclination / tilt or whatever. And this seems 'plausible' as the larger secondary star would have an influence on the orbits of the planets around the primary star. I'm not looking for exact scientific accuracy, just something that is at first glance believable.

[gojira]

Re: So I want to "build my own solar system" (for things like astrology, solstaces, e

 

From what I understand, it would work just like our solar system.

 

Just replace one of the planets with a really bright star, and you've got your orbits. If the home planet passes between the primary and the secondary, then the home planet will see the secondary with an orbit similar to Jupiter or Saturn.

 

I don't think there's any way to have a secondary behind a planetary moon all the time, any more than there's a section of the sky now that's always behind our moon. Two stars that are orbiting each other... there can't be any planets in between. You'd get sucked into the gravity well. You can have planets orbiting both, around their common center of gravity. Secondary and primary work if the secondary is orbiting far enough that the secondary works like a planet.

[Steve]

Re: So I want to "build my own solar system" (for things like astrology, solstaces, e

 

Gojira makes a good point. If you substitute another star for a planetary body like Jupiter, it would probably work like Jupiter does in our solar system. That being said, I think you'd have to have it much further out distance-wise than Jupiter is, to avoid perturbing orbits. Half a light-year apart might be too far, but someone more knowledgeable about celestial mechanics than I am would have to comment.

[Kraven Kor]

Re: So I want to "build my own solar system" (for things like astrology, solstaces, e

 

I seem to recall from the research I did for a Star HERO campaign that the Alpha Centauri / Proxima Centauri binary pair has at least one planet in orbit around one of the stars, and those stars don't 'orbit' each other; one is just kind of following the other through space, for the most part. Could be misremembering.

 

That's it, I'm building a mobile XD

[tkdguy]

Re: So I want to "build my own solar system" (for things like astrology, solstaces, e

 

Try this.

 

And this (has a bit of math).

[Kraven Kor]

Re: So I want to "build my own solar system" (for things like astrology, solstaces, e

 

Yeah, I almost had a working solar system in the NatGeo thing... almost. Somewhere about 6,000 years after creation, things go horribly awry

 

And that NatGeo thing is a very light version of Universe Sandbox. I've also got AstroSynthesis, which I got for my Star HERO game, and it too is just way too complicated lol.

[Kraven Kor]

Re: So I want to "build my own solar system" (for things like astrology, solstaces, e

 

And World-Builders.org seems to be all broken links

[tkdguy]

Re: So I want to "build my own solar system" (for things like astrology, solstaces, e

 

And World-Builders.org seems to be all broken links

 

Sorry about that. I haven't visited that site in a while. I guess that course isn't being taught anymore.

[Kraven Kor]

Re: So I want to "build my own solar system" (for things like astrology, solstaces, e

 

Sorry about that. I haven't visited that site in a while. I guess that course isn't being taught anymore.

 

No need to apologize - it would have been a very useful response to this had it not gone dark

[tkdguy]

Re: So I want to "build my own solar system" (for things like astrology, solstaces, e

 

I just checked the site, and there are a lot of working links. I haven't checked a lot of them, however.

[KawangaKid]

Re: So I want to "build my own solar system" (for things like astrology, solstaces, e

 

I don't think that this matches the need for the extra suns and moons... but it's sorta related for a different view from 'earth'.

 

 

Hope that works!

[Kraven Kor]

Re: So I want to "build my own solar system" (for things like astrology, solstaces, e

 

And another thing I kind of want is for the planet to have an odd alignment to the sun. I want the south pole to almost always have sunlight, and the north pole to almost never have sunlight. The planet would spin on an axis that is nearly parallel to the plane it orbits. And again I just want to be able to visualize that somehow; have a good idea of how that would affect the length of days and nights in various seasons, etc.

[Old Man]

Re: So I want to "build my own solar system" (for things like astrology, solstaces, e

 

And another thing I kind of want is for the planet to have an odd alignment to the sun. I want the south pole to almost always have sunlight' date=' and the north pole to almost never have sunlight. The planet would spin on an axis that is nearly parallel to the plane it orbits. And again I just want to be able to visualize that somehow; have a good idea of how that would affect the length of days and nights in various seasons, etc.[/quote']

 

If I understand what you're saying, that's going to be hard to do without playing some serious games with axial precession. If the south pole almost always has sunlight during one part of the year, it will almost never have sunlight when on the other side of its orbit. This being SF, I wouldn't have a problem with it conceptually, but I think few existing orbital models will take this into account.

[Cancer]

Re: So I want to "build my own solar system" (for things like astrology, solstaces, e

 

Decades back (the last time I spent serious time looking at dynamical astronomy) ... the rule of thumb was that if you have stars the same mass (about 1 solar mass) and have planets with masses the way we think of them (no more than 1/300 of a solar mass), and you want to have any hope of stable planetary orbits around one of those stars, then the two stars must be separated by at least 25 times the largest planet orbit that you want to be stable. That was for a single planet trying to survive in a binary system.

 

That said, it's hard enough making a system with multiple planets orbiting a single star and having that system be stable in the long term!

[Cancer]

Re: So I want to "build my own solar system" (for things like astrology, solstaces, e

 

And another thing I kind of want is for the planet to have an odd alignment to the sun. I want the south pole to almost always have sunlight' date=' and the north pole to almost never have sunlight. The planet would spin on an axis that is nearly parallel to the plane it orbits. And again I just want to be able to visualize that somehow; have a good idea of how that would affect the length of days and nights in various seasons, etc.[/quote']

 

There isn't a way to do that; the rotation axis of an object is approximately fixed in space (it changes, but on times like many hundreds of orbital periods). The Earth precesses and its obliquity oscillates, but the period of that obliquity change is on the order of 100,000 years, and the amplitude is tiny (like a degree). Mars is much more extreme in its obliquity changes, btu the timescale is about the same.

 

Instead, it sounds like you are describing something like Uranus now, whose rotation axis is within 15 degrees of its orbital plane.

[Steve]

Re: So I want to "build my own solar system" (for things like astrology, solstaces, e

 

With that sort of rotation, with the north pole leading in the orbit around the sun, how would that affect heat transfers by the ocean currents? Would the equator be hotter or colder than Earth's?

[Kraven Kor]

Re: So I want to "build my own solar system" (for things like astrology, solstaces, e

 

I was just thinking that the south pole kind of always points toward the sun. There is (in the current plan) a huge magnetic storm there that no ship can sail through, which drives a strong current; ships sailing from one continent to another have to follow this current around the storm at the center, making travel between continents a bit complex. Ships from Telos can make it to Shaolos quickly, but then have to follow the current all the way back around, past Orohos, then back to Telos. And that magnetic storm has a lot to do with the magic and cosmology of the world.

 

This is all just ideas I am kicking around and trying to solidify, as eventually I would like to convert this from just a campaign setting I use for my Fantasy HERO games, into some short stories or even novels or even a published setting. But I lack the know-how to work out a lot of the specifics on what my imagination is presenting.

[Steve]

Re: So I want to "build my own solar system" (for things like astrology, solstaces, e

 

For the magic, you could borrow an idea from the old Shadow World by ICE. The planet and star system was in the science fiction universe of Space Master but the planet was exposed to flows of Essence from a different dimension that allowed magic to function there as well. The impression I had was that the planet was partly in-phase with a different reality where magic worked.

[Starcloud]

Re: So I want to "build my own solar system" (for things like astrology, solstaces, e

 

If the south pole is always facing towards the sun, you basically have a tidelocked planet. There won't BE a day/night cycle; One side is going to be massively hotter than the other, the planet's atmosphere and hydrosphere is just going to be more turbulent than in the more traditional way.