A world caught between two suns

[Ban]

With this post i have to be honest that i am not planning to put it to use in any of my current stories. I open this post simply out of curiosity and considering the magnificent results i received from my "space people" thread, i thought why not post another idea to think on.

How would an earthlike planet caught between two suns function? I am thinking that the planet is situated at the point where the gravitational pull of both suns are equally powerful. The planet hovers in the same space at the same spot. The equator would be a ring of ice and the poles are tropical zones. Warmth distribution by sea would be cut in half so to speak due to the icering. Biological exchange would also be made difficult by this ring. The two sides of the planet could therefore be extremely different, with different species populating them. This is all i can think of, so what ideas can your creative minds come up with?

 

[NerdyCavegirl]

I'd like to give a better answer, but I ain't a math person and gravity requires math. So here's Wikipedia: https://en.wikipedia.org/wiki/Habitability_of_binary_star_systems

 

[qWirtzy]

The Earth's revolution around the sun is what gives us seasons, so if your planet doesn't move, I don't think the season would ever change. Depending on which sun was closest, one side of planet would be warmer/colder than the other. Also, assuming it rotates on its axis, it would never quite be night, considering that as the world turned there would always be a sun in the sky. Ooh, there could be periods of extended twilight and dawn, that could be fun to play with.

 

[Ban]

Good points. I thought about seasons and i don't see why they can't work. They would certainly be different but seasons exist because our earth wobbles a little on the north-south axis. Meaning that warmth from the sun either hits the earth on a steeper or more moderate degree depending on which side of the earth you're on. The movement of the arth around the sun has almost nothing to do with it.

I really like your idea of night and day though. With the introduction of a moon or multiple moons there could be some shade from time to time but you're right that it would never be night. I suppose the closer you'd come to the ice ring the darker it becomes.

Also the tropical regions would be rather small while the coldest regions (i'll just call them this because polar regions seems a little weird in this context) are the largest.

 

[Heliotrope]

Do mean the planet has two closely spaced suns, like Tatooine? Or it is literally caught between two suns?

If a planet were caught between two suns there would be no rotation, I wouldn't think, because the gravitational pull on the planet would be equal on both sides, so there would be no rotation…

Also there would be no day or night, as the planet would be receiving light from both sides, unless one sun was really far away and emitted less light. Perhaps a dying sun.

 

[Ban]

As i stated in the intro i meant that it is literally between two planets. There is equal pull on both sides causing it to stay in the same place. And i agree with what you and qwirtzy stated about the planet having no night and day. I am thinking that if the palnet had at least one large, slow moving moon than it could block out the sun temporarily. This would however cause night time to be a relatively rare occurence. Maybe only 1 in 3 days has a night. I don't know what effect a giant, slow moon would have on a planet however.

 

[Heliotrope]

hmmmm, that got me thinking… I wonder if it might make more sense to have the inhabitable planet be the moon of a large planet caught between two suns? If you have large planet like Jupiter or Neptune, where it takes the moon considerable time to rotate around it then it would block out the sun long enough to have a 'night' time on the moon…. Plus the gravity of the planet would allow it to still have a rotation.

 

[Ban]

That could be interesting but wouldn't that moon mostly function like a relatively normal planet? I think the fun with this is how radically different this planet is. The climate zones are different, half the world is isolated from the other, there is no night and day.


If you have stumbled upon an idea that you like however feel absolutely free to use it.



New idea! Calendars would be very different without sun rotation. Maybe based on the moon like the islamic calendar?

 

[Penpilot]

Scientifically, I don't think this is possible, because I'm not sure if the gravitational forces wouldn't have ripped the planet apart. BUTTTT... I'm not here to pee on your parade, because as far as I'm concerned, cool trumps scientifically accurate as long as there's not too much of it going on. As a rule of thumb, in stories, you're allowed one or two do-not-look-behind-the-curtain things before you start to lose credibility.

With that said, if you had a very large moon or a moon incredibly close, the magnitude of the tides would be affected greatly, lower low-tides and higher high-tides. As for night and day caused by the moon and the rarity of it, that just depends on the speed of the moon's orbit and how often it circles the planet. Also the areas affected by this faux night will be limited by where on the planet you are.

The equator will get a full eclipse, but the further north and south you go, the angle changes so the sun(s) are no longer 100% blocked and will only get a partial eclipse.

FYI the moon is 1/4 the size of the Earth and is the 5th largest moon in the solar system, just to give you an idea of how big a moon you might need.

Thinking about this further. The planet wouldn't be necessarily trapped between the two suns. The only way this would work is if the planet was situated perfectly at the center of mass between the two suns. Two suns would be orbiting the planet. So this would be a planet centric system like what people though in ye olden times.

FYI technically we don't orbit the sun. The Sun and the planets orbit the center of mass of the whole solar system. It just so happens the sun contains most of the mass of the solar system, so the center of mass is actually located inside the sun.

 

[Seraphim]

In order to have an ice ring the planet must rotate along the axis which points at the two suns. This is to say the north pole would point at one of the suns and the south pole points toward the other. Rotation is still possible, because the sum of forces from the suns is equal, so no change in rotation that could be induced by gravity which mean any predetermined rotation would be preserved whether by design or event. My concern would be the overall surface temperature. Earth needs night time to cool off. If there was thicker cloudier atmosphere it could be possible for tolerable surface temperatures for less light would be absorbed and there would be significant shade to keep surface creatures from being baked alive. Also, undersea worlds would be very possible. I don't know how this fits into your world though.

 

[Ban]

Great ideas Seraphim. This world is purely hypothetical and i don't know what i'm going to do with it. Basically this is just some exercise in creative thinking

 

[arboriad]

Hi Banten,

This could be really cool. The only 'consideration' that comes to my mind is interfacing such obviously scientific thinking with a fantasy world. I don't know about y'all, but in my mind, fantasy worlds exist in some nebulous imaginary somewhere that's not an actual galaxy, but a reality. I never thought about developing fantasy along galactical lines.

That being said, another aspect to this discussion is the pull of the suns. If the suns are equally large, then they are probably a binary duo, and orbiting 'each other' or a common center of mass. For a planet to be swinging around them - perhaps in a figure 8 - and get caught right in the center, might cause some incredible pressure on the planet. I'm not an astronomer, so I defer to the experts.

But thinking 'cool factor', this might be a regular thing throughout history, where it's an extinction level event that shatters the planet and forces it to reboot. Perhaps the magicians are committed each era to building up defenses to protect the world.

Another thought might be that the planet was normally rotating around one of the suns, but has now been caught for aeons between the two suns. There was a time in memory when it was different. But if there are moons spinning through this center area, I would imagine it would destablise the planet as a single point between two equal pulls, causing the world to wobble between the two suns, and ultimately go with one or the other.

I could see some serious dualism coming into play as the world waits with bated breath to see which god wins the wrestling match, or divine ballgame over possession of the world realm. Separate elements like meteors could be not only 'divine weapons in the battle', but dice-rolls to sway the world one way or the other.

From your initial description, I imagined that the icering would be a polar ring, not equatorial - unless the planet has changed it's position. Ice would form the furthest from the suns, so where the world bellies out toward the suns is where vast deserts would blister and bake. If the world rolled over at some point, then these deserts would once be mighty kingdoms, etc. Folk could have drilled into the ground for cover, like the caves of Dendera. It seems to me that the world would spin not like ours, along our equatorial line, but along the polar line, so that the deserts were always pointed toward the sun. I think that pretty much everywhere habitable in the world there would be a midnight sun.

Anyway, this seems to open up lots of possibilities for history, and I think some instant upcoming conflict. 'Winter is Coming. Finally.'

 

[TWErvin2]

In binary star systems, often one star revolves around the other...the more massive being central, but there are some where the two spin in a sort of dance. A planet in between, already discussed, would lack night. I am not sure a moon would orbit the planet, with such greater forces of suns pulling two directions. Probably not impossible, but over time it would seem to be an unstable solution.

Also, the weather patterns would not be the same as they are on Earth. The earth's rotation influences this. It might be possible to have different seasons, or even weekly shifts depending on the speed of the suns' rotation around the planet. if the suns going around had different intensities, such as one being a yellow star like our sun and the other a red giant.

Just a few thoughts.

 

[ThinkerX]

The planet would be orbiting either one or both stars, depending on the separation between the stars. Likewise, one star would almost certainly be orbiting the other. More, that orbit (star and star) would probably be eccentric - meaning the one star would swoop in close to the other and then head way off into space. Orbital period would probably be on the order of a couple centuries.

So, as for the planet, what you'd have would be a fairly normal world most of the time: one primary sun, plus a second fainter sun. But when the second star drew close...hmm...major tidal effects. Seasonal changes. All probably worked into the local mythology.

(I considered something like this with one of my worlds ages ago.)

 

[K.S. Crooks]

Some things to consider:
Does the planet orbit both suns at the same time, do a figure-eight around and between them, or orbit only one as does the second sun.
At what speed does the planet orbit, what is the rotation speed for day and night cycles
How many moons does the planet have to stabilize the orbit, create tides and block light and heat from the suns
The size of the planet and surface composition

 

[Ban]

The planet does not orbit. The suns circle the central point where the planet is and the planet turns at the exact same speed as both suns. This is of course highly improbable, but i think it makes for a fun world. Moons, size of the planet, surface composition etcetera has not been determined yet. But in my head all are the same as on earth unless someone comes up with something more fitting.

 

[bgmyhan]

There would be two days a year (Im calling one cycle around both suns a year) where the waves would be epic on one side of the planet and the best surfers would compete with one or two dying every year the surfs so epic. include that if someone does make this idea. So pitted!