A planet in a tri-star system

Hi everybody.

I need some help. I am in the early stages of slow writing a sci fi novel. I have created an antagonist race called the Tripidions. They are a three sexed race but if you think of it in terms of male, female and "other", you are making a mistake. Their biology is not anything like human biology, nor is their reproductive process.

Tripidions have three arms and three legs. Three fingers on each hand and three LONG toes on each foot. They have three eyes, three eyes, three orifices (one to communicate, one to eat/drink, one to breath). Their three eyes are independent of each other and each has three eyelids that work as a filter of some kind. Their eyes have a biological telephoto optic. Their eyes can literally protrude about 6" outward.

Tripidions are about 9-12' tall with shorter Tripidions being down to 8' and taller Tripidions hitting 15'.

The Tripidion homeworld is many times larger then Earth One (our planet).

Their world does a triple looped figure eight around the three stars in their solar system. Each star creates a slightly different gravity on their planet so the Tripidions are a hardened race of beings.

My question is, how plausible is this in reality? I am not beyond taking some creative license to make the story "fit" but I do want it to be at least somewhat believable.

Skeptical criticism is welcome. Thanks for your help!

originally posted by: Genfinity


Tripidions have three arms and three legs. Three fingers on each hand and three LONG toes on each foot. They have three eyes, three eyes, three orifices (one to communicate, one to eat/drink, one to breath). Their three eyes are independent of each other and each has three eyelids that work as a filter of some kind.


My question is, how plausible is this in reality? I am not beyond taking some creative license to make the story "fit" but I do want it to be at least somewhat believable.

If you are Dr Seuss I say go for it.

It's a super sounding story! After watching one of the old Carl Sagan universe shows, and how galaxies swirl around and do a lot of unexpected and a lot of totally not understood things, I would say your tri-star system is completely possible, even with planets doing some star jumping. Maybe you thought of it because it is actually happening somewhere.

Start by reading The Three Body Problem by Cixin Liu.

That will give you a much better background to come up with a new idea.

originally posted by: NoCorruptionAllowed
Maybe you thought of it because it is actually happening somewhere.

Alpha Centauri comes to mind. Proxima Centauri B specifically. The kind of place you might find exotic life forms.

a reply to: Genfinity

I'm no expert by any means, but I'm failing to see how their planet would do a "triple looped figure eight around the three stars in their solar system". Yes, that's the main part that stuck out to me as being unrealistic lol.

originally posted by: Genfinity
Hi everybody.

I need some help. I am in the early stages of slow writing a sci fi novel. I have created an antagonist race called the Tripidions. They are a three sexed race but if you think of it in terms of

My question is, how plausible is this in reality?

In an infinite universe, everything happens.

So...?

I saw a video on youtube last night about a trisun system. Two of the suns were orbiting each other at high velocity and the trio orbited a gravitational center. The planet was orbiting the 3.

Instead of the infinite loop, change it for different alignments cause different effects. You can either make it a very precise mechanism that impacts the life and culture of your Tripidions, or one where there are a multitude of alignments that cause a lot of never seen before effects, or both. The latter would be preferable for obvious reasons.

That'll be whatever is the rate as co-creator, thank you.

Lol, no, just kidding, take what you want.

originally posted by: Tempter

originally posted by: Genfinity
Hi everybody.

I need some help. I am in the early stages of slow writing a sci fi novel. I have created an antagonist race called the Tripidions. They are a three sexed race but if you think of it in terms of

My question is, how plausible is this in reality?

In an infinite universe, everything happens.

So...?

In this universe we observe certain symmetries, constraints on what can happen.

a reply to: Genfinity

Drop the "triple looped figure eight ". Your planet would orbit one of the stars.

A few real tripple star systems for inspiration:
en.wikipedia.org...
en.wikipedia.org...
en.wikipedia.org...

a reply to: Genfinity
It sounds interesting, but I have a few qualms about the orbital dynamics. The more complicated the orbit the greater the chance that some kind of stellar resonance might at some point actually eject the planet from the solar system. And gravity on that planet wouldn't depend on which star it orbits. The planetary mass stays the same, whichever sun it's going around, so gravity would remain a constant.
Keep going though, it sounds promising.

a reply to: Genfinity

It's an interesting idea.

Some thoughts that sprung to my mind: Lower mass red dwarves could possibly exist in a system like yours. An upside is they last for an awfully long time and therefore could have conditions suited to Life. There are systems with more than three stars too.

Orbiting three stars could mean there's an unusual day/night pattern. Long days for one 'year' and short days for the next one. This could introduce character points about sleep cycles and how their society could be something like 24/7. Seasons would be interesting as the planet moves between stars. In your fidget spinner-shaped orbit, there'd be perpetual sunlight for most of the time with night only occurring on the three transits round the 'back' of the three suns.

I'm not sure about the gravity points you mentioned. It seems to me that different gravities would cause crazy tidal systems and thereby chaotic weather systems. Obviously these elements wouldn't be great for evolving intelligent life. Then again, it could be a dramatic backdrop to the story knowing that certain seasons are going to be extremely hostile. Might even inject an element of suspense as characters hasten to avoid the stormy seasons or even have their stories taking place in one.

ETA - Arthur C Clarke's Rama books had some theme about triplets and threes too.

a reply to: Genfinity
Apart from the orbital concerns, the creature design is very interesting, and I'll have a go at creating something like what you described in the game SPORE. I'll probably post some screenshots here, too.

We know of at least one triple system with a planet, so here's how it works: www.space.com...

The planet is orbiting star A — the lonely star in this scenario. The planet and star A are then orbited by a pair of stars that the scientists call "star B" and "star C.

www.youtube.com...

Or, to be more precise, the three stars orbit around the common centre of mass (the barycentre)



The sizes and distances represented here and in the animations are not to scale; the planet orbits the star at a distance of about 82 astronomical units, which is about twice the average distance from the Sun to Pluto. From the planet's surface, the main star will appear much fainter than our Sun appears from Earth, but still much brighter than the full moon. The other two stars will be even fainter.

In a system like this, large distances are necessary, otherwise the planet would be gravitationally perturbed out of its orbit and flung out of the system entirely. Thus, there would be practically no gravitational effect from those stars on the planet's inhabitants.

a reply to: wildespace

Great animation - but 82 AU! No chance of life as we know it starting on that planet. Too cold!

The more I think about it the more worried I'd be at the OP's planetary orbit. The orbital dynamics would be very complicated indeed.

Here's one attempt at such a Tripidion, lol.



As for the fictional planet's distance from its star, it could be within the habitable zone. It's just that the other two stars need to keep at a big distance so as not to perturb the planet out of its orbit.

As others have pointed out, the orbit you specified won’t work for the simple reason that the stars are moving. This detail has tripped-up some very famous science fiction writers. In decades past, several novels (“The Flying Sorcerers” by Larry Niven & David Gerrold to name one) described planets in figure-8 orbits around double-stars:


(All of these illustrations are greatly simplified and not-to-scale)
In reality, double-stars orbit each other around a common center-of-gravity called a barycenter:


(For elliptical orbits, the two ellipses would share a focus, and the long-axis of the ellipses would be in line with each other. Have I mentioned that these illustrations are greatly simplified?)

A third object moving past these whirling stars would experience something called momentum transfer (more popularly known as a gravity slingshot). Imagine throwing a rubber ball against a wall. Ideally, the ball will bounce back at the same speed that you threw it. Now imagine that the wall is moving towards you. The ball will come screaming back to you at the speed you threw it plus the speed of the wall! That’s momentum transfer (Note that if the wall is moving away from you, the ball bounces back with less speed).

An object making a close pass past one of these stars and moving in the same direction picks up a lot of speed, and will get launched into an elliptical orbit that takes it far from the two stars:


Eventually this orbit will bring it around for another close pass, where it will pick up even more momentum – enough to eject it from the stellar system forever:




(Note that if the object passes going in the opposite direction that the stars orbit, then (like the wall moving away from you) the object will lose momentum and probably fall into one of the suns)

Momentum transfer is what allows us to send space probes to the outer planets of our solar system without using exorbitant amounts of fuel. Using a minimum-fuel transfer orbit, it would take 30+ years to reach Neptune from Earth. However, the Voyager 2 spacecraft flew by Jupiter, zipped by Saturn, and zoomed past Uranus to reach Neptune only 12 years after it launched. The Cassini probe is the grand-master of momentum transfer… but I digress.

Wait a minute – Why do any planets have moons? If momentum transfer is a thing, why haven’t they all gotten ejected to the Oort cloud? The short answer is, proximity matters. If an object orbits a star or planet so closely that the perturbation from the gravity of any other body is minor by comparison, it will be stable. How close is close? When it comes to planets in double-star systems, there are two stable configurations:

1. If the average orbital distance between the planet and its parent star is less than 1/3 the minimum distance between the two stars, the orbit can be stable.


2. If the average orbital distance between the two stars is less than 1/3 the minimum distance between the planet and the stars’ barycenter, the orbit can be stable.


The same rules apply for triple-star systems. Two stars can orbit each other and a lower-mass star can orbit them (Alpha Centauri is like this). Alternately, two low-mass stars can orbit each other and the barycenter of this pair can orbit a higher-mass star. Maybe the third star has about the same mass as the orbiting pair, so the system has two major barycenters:


In triple star systems you can have many possible stable orbits:


(Planetary orbits shown in blue. Not shown is a planetary orbit that swings around 3x further out than the largest stellar orbit shown here)

Hope this helps.

a reply to: wildespace

a reply to: Saint Exupery

Posts like these are a blessing for ATS and a credit to you. Clearly a lot of time and thought has been invested in them

Sometimes a thread gets tanked by people being pernickety or taking things too literally. It's great to see so many posts being constructive and members going right out of their damn way to make fine contributions.

Over the years I've enjoyed Star Trek, Iain M Banks, Clarke, Asimov and even Harry Harrison. Plausibility is a bonus as long as the writers make the whole thing interesting. We happily sacrifice our disbelief on the altar of a good story.

a reply to: Saint Exupery

Thank you for your post, which was brilliant in its clarity. I agree that the orbital dynamics of a triple star system with a migratory planet would not be practical over the long term.
Still a cool idea though.

a reply to: Saint Exupery

Thanks everybody for your input. A more plausible concept may be to have two "married" stars in a bi-star orbit and they would orbit a more massive star. The Tripidion home world would orbit one of the smaller two married stars.

The story won't focus on the Tripidion home world for the vast majority of the story because given the technology advantage the Tripidions have, it's the very last solar system in the entire universe the Feditary would want to visit.

The Tripidions are a hardened reptilian like race of highly sentient beings. With that said, their biology and culture are unlike anything existing on Earth One.

The story begins in the 37th century (Earth One time) after every planet in the Sun solar system has been destroyed. While the tall monsters have no regard for simplistic human life or our antiquated technology, they do make it the highest priority to destroy humanity's hive planet, Earth One.

Leading up to this, relations between the Feditary and Earth One deteriorated into a Cold War in which both embargoed the other. Despite not being able to match the Tripidions in battle, Earth One insisted the Feditary mount attacks to retaliate for repeat attacks against Earth One's outer solar system space force, the Feditary (the Federal Military of Outer Space evolved into the Federal Military which evolved into the Feditary).

The Feditary refused to follow insane orders from a planet thousands of light years away. This created allot of friction between the two. Earth One issued unenforceable sanctions against the Feditary moving the Feditary to declare independence.

The Feditary restocked it's resources via planetary mining and harvesting so there was absolutely nothing they needed from Earth One.

Besides, all the hyper light based communications was vulnerable to Tripidion detection. While the Feditary was always moving, Earth One stayed in the same place from a universal perspective and tracing hyper light proved that.

Ceasing communications made both safer in theory but in reality, the location of Earth One had already been compromised. At least, that is the story the Feditary Lords (leaders) told it's pack (people).

Among rebel minded people, there is doubt about the truthfulness of the demise of Earth One as told by the Feditary. However, such discussion is an act of high treason. Except for rare exceptions, the discussion of Earth One and Earth One culture in general is prohibited. This is difficult for music lovers because music seemed to peak in the 20th and 21st centuries when all human life still existed on Earth One (that's how I get around issues involving music).

While the Tripidions have three defined sexes, it is difficult for a human being to detect which is which by visual inspection. Tripidions do not have external sex organs and it is unclear what advantages one sex has over the other two.

While it takes three Tripidions to reproduce one, Tripidions do not touch each other during the mating process.

There are many unknowns to the Tripidions.

Tripidions have no regard for human life and at times, appear to hunt humans more out of sport then necessity. Sport in the sense that stepping on a cockroach is a sport.

Tripidions weapon of choice are negative matter based guns, both carried by hand and mounted on ships. Massive negative matter cannons are used to destroy planets. Tripidions will destroy every planet in any solar system that has an active or fading human signature so it doesn't do much good to be a rebel. Instead of being hunted by the Tripidions, you are hunted by the Tripidions and the Feditary.

The bottom of the Feditary consist mostly of regular working stiffs like us, struggling to stay alive as long as possible. The top of the Feditary (the Lords) is very dark in nature. Examples would be the Empire in Star Wars or the Nazis in reality. Hence, the conspiracy theories about Earth One.

A growing number of Feditary packman (packman means people; there is no plural for this word) are becoming rebels and hiding on planets.

Rebels don't have the resources to stay in the safety of outer space. If the Feditary finds them, droppack troops will be sent down to kill them. If the Tripidions find them, every planet in the solar system will be destroyed.

The Feditary needs every packman it has and they use violence and fear to keep everyone in line. The Tripidions want humanity annihilated so they promptly destroy every planet they come across they think humanity could benefit from.

In the 37th century, only 15 million humans are still alive in the universe. At the current rate of declination, all of humanity will be extinct within the next 400 years.

In the 37th century, the average human who dies of natural causes lives to be about 200 years old (Earth One time). The Feditary has managed to slow down the aging process by about 50-60%. So, given the state of affairs, 400 years is not a long time.

Humanity needs a technology breakthrough or a superior ally to save itself from extinction.

So if you aren't going to finish that synthetic alcoholic beverage, I'd be happy to finish it for you. I'll even throw in a credit or two.

Footnote: Feditary families are allowed coins (residences) of 100 square feet per person, minimum. Promotion of rank will allow for added space. Criminals on death row and Feditary packman on warships have quad bunks in a 25 square foot room.

Prison cells are called pennies and they contain a quad bunk, a chair that doubles as a toilet, a fold out table so you can eat while you sit in your "chair" and a small sink. Most prisoners apply for slave duty. It's hard work, you don't get paid and you still have to sleep in your penny but it sure beats sitting in that penny for the rest of your life!

Word of advice, don't become a rebel and avoid any discussions about Earth One. Follow the rules and you'll promote off the front lines faster.

a reply to: Genfinity

Wow! Great concept – Very well thought-out. Thanks for sharing.

Your use of negative matter is interesting. For those of you who don’t know, negative matter is not antimatter. Antimatter is like normal matter, except that the electrical charge in the particles that make up its atoms is reversed: Instead of negatively-charged electrons orbiting positively-charged protons, you have positive-electrons (a.k.a. positrons) orbiting negative-protons (a.k.a. antiprotons). When matter and antimatter touch, they convert their entire mass to pure energy, annihilating each other in a flash of gamma rays. Antimatter is known to be real. We have observed it in the universe and created it on Earth (very briefly) in particle accelerators.

Negative matter is a hypothetical substance. It has never been observed anywhere. We don’t even know what its atomic structure (if any) would be like. The idea is that it is matter in a negative energy state. Its existence is merely suggested by physics equations. If I were being obnoxiously nerdy, I could say that the number of people sitting at a table is equal to the square-root of 16. Obviously that means 4 people are at the table. However, -4 is also a solution to the equation. Reasonable physicists say that there’s no such thing as negative people, so that solution can be ignored. In a broader sense, though, can it? Most irritatingly (to the same reasonable physicists), there is absolutely nothing in physics that expressly forbids negative matter from existing. Furthermore, there’s an old adage in physics that says, “Anything not expressly forbidden is compulsory.” Sooo… Who knows?

The fun thing is that those same physics equations that do not rule-out the existence of negative matter can also be used to predict in great detail the behavior of the stuff from the quantum to the macro scale, and offer suggestions for practical uses.

All of negative matters interactions with fundamental forces such as electromagnetism and gravity are reversed. Instead of gravity, it has negative gravity. If you use magnets to attract it, it will move away. If you push it, it will come towards you. Don’t touch it though! If normal matter comes into contact with negative matter, their energy cancels-out and they simply stop existing. No explosion, just… gone.

Its use as a weapon is obvious, with the caveat that you need some way of storing, carrying and accurately firing something that cannot be touched (you’d have the same problem with antimatter, but at least negative matter does not have explosive consequences). Note that a -1oz negative bullet will only destroy 1oz of the target it hits. Thus the Tripidion planet-killer (I love the way that sounds) would most likely not obliterate the planet, but maybe drop mountain-sized chunks of negative matter through the crust to induce massive eruptions of magma that poisons the air and covers the surface.

Negative matter can also be used to make a reactionless space drive. Also, negative matter can be used to open an Einstein-Rosen bridge (more popularly known as a wormhole). Irritatingly for most science-fiction writers, genuine wormholes have two drawbacks: It takes the entire energy output of a medium-sized galaxy to open one end, and you have to open both ends at the same time. The thing is, if the Universe is holding wormholes clenched shut, and negative matter pushes back in the same proportion, then it shouldn’t be very hard to tickle the negative matter to open a Planck-length wormhole up to whatever macro-size you want. You still have the problem of opening both ends simultaneously. The practical (if that word as any meaning in this discussion) solution is to make the portal from here to here. In other words, you just have a negative matter Hula-hoop that you can just step through. The trick is, if you split this laterally so that you now have two rings, you can carry one of the rings to anywhere and have a portal to back-home. You could, for example, load one aboard your reactionless space-drive ship and fly it a planet around another star, then just have your colonists and all of their equipment step right through. Yeah, it’s basically a “Stargate” but you can’t change the destination.

Negative matter has been featured in science fiction novels, most notably in Stephen Baxter’s “Ring” series, where it is called “exotic matter”. Dr. Robert Forward was the imaginative physicist who figured out most of what I’ve written above. He published his own novel, called “Timemaster” which featured these ideas and more.