Accepting the Unacceptable?

[Skyrender]

So I've been doing a lot of research about lunar cycles, orbits etc. in trying to figure out if one of my simple details is actually going to work.

Basically, I just want to have 2 moons for my planet, one that is, for all intents and purposes, the same as ours, and then one that is much larger in appearance and generally gives off beautiful white light.

In my findings, if a moon is larger/closer it ruins the tides, changes day length, curves your spine, etc. I was thinking with it being basically a visual, does it really matter if it is scientifically impossible? I mean, it is fantasy after all.

I think most people would just say "oh yeah, cool, a large moon. I know what that is," and move along with the story. But I am afraid others may be more prone to "that's impossible!". I know that I never really gave much thought to the double suns on Tattooine.

I'm thinking that if people are into the story, they will accept it if everything else is sound and believable. Kind of like the ending to Jaws.

Thoughts?

 

[Penpilot]

Don't worry about it. Just do it. Dragon flight is impossible too but not too many people doubt and complain about that.

If a person is distracted by the fact that the two moons is impossible the way you set it up then it's a possibility that what you've written isn't interesting enough to pull them into the world and accept that fact, so write it well and it'll work.

Also there's always those who look to pick things apart, saying this ain't possible that ain't real, and no matter how well something is written, won't accept it. They're just too grounded in reality and just can't leave even for fun.

 

[Guru Coyote]

As a reader of SciFi, I might object to an 'impossible moon', but that's not the kind of story you are writing, is it? And besides, even in a lot of SciFi you have less than scientific things.

But maybe it's not so much the reader who is distracted by the 'impossible moon' than you? (I know I want my world to be plausible as a writer...)

Here's an idea that could give you this very large 'moon': what if your world is not actually the planet around which both moons orbit, but actually a moon of a largge gas-giant? That would give you a very large celestial object in the night sky...

 

[ThinkerX]

Ok...

long term problem with two or more moons is that sooner or later, they're going to collide or one will be ejected from the system unless there is something unusual about their orbits (such as having one moon in the other Lagrange point or something).

But...if all you want is for the moon to be more reflective, then have it an 'iceball' type worldlet instead of dead stone like our moon. Ice is vastly more reflective than rock, hence said moon would be far brighter than ours, even if not very big.

Now...if you want to set up a long term situation for your worlds populace, go with two moons, with one in an unstable orbit. Even if it doesn't collide with your planet, the gravitational effects of a near miss would be devastating. (A near miss like that, though would probably result in the moon being ejected from its orbit.) Or just have the two moons collide. The larger would not be destroyed, but there would be a lot of stuff falling out of the sky for a while, some of it big enough to inflict serious damage.

 

[Saigonnus]

It would be entirely plausible... after all Mars has two and though they may eventually collide, they have a fairly standard orbit at the moment. I believe they are fairly similar in size though.

I think perhaps one of two possible scenarios for having more than one moon:

1. One moon IS bigger and it is far enough away that the effects of gravity aren't that pronounced on the smaller moon, but they would probably look close to the same size in the sky from the added difference in distance.

2. Both moons are of similar size and one is; as suggested above ice or has large amounts of ice to make it reflect more sunlight.

I don't think it would throw too many people off in the scheme of things considering it is fantasy. My world has 3 moons and generally I don't really think about it. You will always have those people that question every little thing people write so the best thing is to write it how you want and just not worry about it.

 

[Ravana]

long term problem with two or more moons is that sooner or later, they're going to collide or one will be ejected from the system unless there is something unusual about their orbits (such as having one moon in the other Lagrange point or something).

Uhm… you do realize that the outer planets each have dozens of moons, right? "Long-term" has to be understood in the sense of hundreds of millions, even billions, of years in this context. If ever, when it comes to "colliding"; most will probably follow their own individual death spirals into their primaries eventually, a few will go the opposite direction. (Luna is one of these: it's getting farther away over time. But don't panic: the Earth/Luna system will be engulfed by the Sun's expansion before it escapes.)

-

As far as the science goes: a larger moon might be far less dense–Luna is the second densest moon in the Solar System, but is only the fifth largest; Ganymede, Callisto and Titan are all larger but less dense. (Io is both larger and marginally more dense.) One thing that could cause a lower density is a high composition of ices… which would also make it reflect more light, thus making it brighter as well (Luna is actually pretty dim compared to some of the others). As others have mentioned.

I'm not sure it even makes sense to speak of "ruining" tides–since our sole example of tidal forces acting upon liquid water is probably a bit biased, since comes from the influence of our single moon. Oh, and the Sun. Which is not an inconsiderable influence. Having two large, nearby moons will certainly make the tides different–and require a lot more math if you want to know their precise effects; on the other hand, when have you ever seen someone go to the trouble of doing the math even for the Earth system? The tides would be less significant most of the time, as usually the two will be pulling in different directions; they would be rather higher whenever the two moons were in line with the planet, but this will be a small percentage of the time compared to when they are not so aligned.

Changing day lengths is a function of the age of the system as a whole… and thus will have no effect on your story. You just set it in whatever point of the system's history provides a day of the desired length. For those who are wondering, Earth's days are slowing down–at a rate of fifteen millionths of a second per year.

Having two moons should straighten spines, courtesy of that minuscule extra pull of gravity from space.

Note that your planet need not have formed with two moons: the second could be a late capture… though an Earth-sized planet capturing a moon that large is fairly unlikely, I'd have to say. It would have had to be moving really slow. Still, this is not impossible.

And note finally something I often remind people of in the context of creating their own mythologies: "With gods, all things are possible."

 

[Devor]

I think most people would just say "oh yeah, cool, a large moon. I know what that is," and move along with the story. But I am afraid others may be more prone to "that's impossible!".

I wouldn't do it without considering the implications. There's two reasons for that. First, a little complexity adds depth. If you casually mention that the tides were skewed and funny because of the two moons, that's cool, if you do it right. Second, people know that a second moon will affect at least the tides. I would notice it right away, and it would bug me if you didn't play off the implications. Star Wars didn't have to consider it. Maybe because it's an old movie from the seventies. More likely because, y'know. Tatooine.

 

[Steerpike]

Unless something to do with the tides impacts the story, it might appear odd to have a character mention it. After all, to them the two moons and the corresponding effect on the tides will be normal. They wouldn't perceive anything odd about it without another frame of reference.

 

[BWFoster78]

The great thing about writing fantasy is that you can do whatever you want because you're making up the rules. You can change the laws of physics if you want to make it plausible to have the setup you want. You can also use your magic system to break the laws of physics so that the moon setup is plausible.

Bottom line, IMO, it's okay to have implausible setups, but you have to justify them somehow.

Note: you do not need to go into great detail in your book about your justification unless it is warranted for your storyline. As long as it's plausible to you, that's all you need.

 

[The Dark One]

Why not call the story "Impossible Moon"?

Your dilemma reminds me of watching a fantasy/adventure movie at the cinema, years ago, and at this particular dramatic point where someone scaling a battlement is waiting for some guards (with dogs) to pass, this kid behind me suddenly says: That's ridiculous! As if the dogs wouldn't have sniffed him!

This kid has just watched 90 minutes of magic and dragon flight and all sorts of outrageous plot-inducing coincidences, and it all just washed over him. But there was no way he'd accept a guard dog with a weak sniffer...

 

[Guru Coyote]

This kid has just watched 90 minutes of magic and dragon flight and all sorts of outrageous plot-inducing coincidences, and it all just washed over him. But there was no way he'd accept a guard dog with a weak sniffer...

Good point
It all comes down to "suspense of disbelief" ... and that movie may have achieved it with the dragons and the magic, but failed at the guard dogs - at least for that kid. Maybe that's because the situation was just too 'real' ... while all the dragon-flight and magic was just 'wow'. How can we know if dragons can't fly? We don't have dragons... but we do have dogs, and we know what they can or can not do - at least we think we know.

As to the impossible moon... I think it's important that it makes sense to the writer, and that the world is plausible to the writer. That feeling will translate to the story. If the writer thinks it's not plausible... the reader will catch on.

 

[srcroft]

So I've been doing a lot of research about lunar cycles, orbits etc. in trying to figure out if one of my simple details is actually going to work.

Basically, I just want to have 2 moons for my planet, one that is, for all intents and purposes, the same as ours, and then one that is much larger in appearance and generally gives off beautiful white light.

In my findings, if a moon is larger/closer it ruins the tides, changes day length, curves your spine, etc. I was thinking with it being basically a visual, does it really matter if it is scientifically impossible? I mean, it is fantasy after all.

I think most people would just say "oh yeah, cool, a large moon. I know what that is," and move along with the story. But I am afraid others may be more prone to "that's impossible!". I know that I never really gave much thought to the double suns on Tattooine.

I'm thinking that if people are into the story, they will accept it if everything else is sound and believable. Kind of like the ending to Jaws.

Thoughts?

It's not impossible. It depends on distance and balance-- location of other planets that can pull on that moon and the sun. It isn't for you to explain, its enough for the possibility. If you can have a planet that's bigger than a moon and stay in orbit yu can have a moon that's bigger then the planet. You may (like Dragon's Bloods' 2 Suns) want to have extra effects. Like maybe nights are longer and twice as cold, deadly in fact. Just and idea.

 

[srcroft]

Good point
It all comes down to "suspense of disbelief" ... and that movie may have achieved it with the dragons and the magic, but failed at the guard dogs - at least for that kid. Maybe that's because the situation was just too 'real' ... while all the dragon-flight and magic was just 'wow'. How can we know if dragons can't fly? We don't have dragons... but we do have dogs, and we know what they can or can not do - at least we think we know.

As to the impossible moon... I think it's important that it makes sense to the writer, and that the world is plausible to the writer. That feeling will translate to the story. If the writer thinks it's not plausible... the reader will catch on.

Suspension of Disbelief is a contract that is broken by modern movie watchers and readers all too often. There does need to be a responsibility to a bit of authenticity. What I mean is this--If its a book about a magic motorcycle, you should probably know about motorcycles. In this case its not a story about moons, the moons are adornment to make an interesting planet. However, I will say if you don't have a purpose or scene that is going to be effected by it, pointing it out may not be important. This is why I mentioned earlier you may want to assign a reason for it, like adding danger.

 

[srcroft]

Why not call the story "Impossible Moon"?

Your dilemma reminds me of watching a fantasy/adventure movie at the cinema, years ago, and at this particular dramatic point where someone scaling a battlement is waiting for some guards (with dogs) to pass, this kid behind me suddenly says: That's ridiculous! As if the dogs wouldn't have sniffed him!

This kid has just watched 90 minutes of magic and dragon flight and all sorts of outrageous plot-inducing coincidences, and it all just washed over him. But there was no way he'd accept a guard dog with a weak sniffer...

But, sometimes we have to be leery as writers of this effect. Instinct can ruin one novel but let another work. Someone like Rowling can make up hubbly bubbly words and its brilliant, and others its corny. Magic and Dragons kids wanna see--but all little kids with dogs know too much about them. I've seen it in lots of movies too, tons of crazy stuff, and then you get a weird feeling like "why would the character do that?"--Thats a sign that a 3D character is known a bit better by the reader--which should never happen. As far as the moon, ya no big deal. The Dogs Sniffer "LMAO" probably an oversight that could've been field tested on some kids prior to publishing.

 

[Benjamin Clayborne]

If the moon is just a visual background detail in the sky, then whether or not it's possible is irrelevant. Just say it's there and that it's pretty.

Also keep in mind that if it provides substantial illumination at night, that can have an effect on the plot of the story, since e.g. characters could see better at night.

 

[Zero Angel]

Don't worry about it. Just do it. Dragon flight is impossible too but not too many people doubt and complain about that.

Why do people keep saying that dragon flight is impossible? What is impossible about it?

For the moon, what causes all of those things? Not the presence of the moon itself, but its gravity. And what causes the gravity? Its mass. Just have it be less massive, and as someone else mentioned, more reflective, and you're good to go. In fact, if you lower the mass of both moons, then you can probably approach a "standard" Earth-moon system.

 

[srcroft]

Why do people keep saying that dragon flight is impossible? What is impossible about it?

For the moon, what causes all of those things? Not the presence of the moon itself, but its gravity. And what causes the gravity? Its mass. Just have it be less massive, and as someone else mentioned, more reflective, and you're good to go. In fact, if you lower the mass of both moons, then you can probably approach a "standard" Earth-moon system.

Dragon flight is impossible because animals that fly have hollow bones or it wouldn't be possible to have enough energy, so the dragons wings couldn't support its weight. The dragon would have to be light and frail or if it had bigger wings it would have other issues.

Most animal experts agree they would be able to glide.

 

[Sheilawisz]

I love the idea of a huge moon in the sky or even more than one moon, it's a fascinating concept and this is something that I have included in my own Fantasy worlds: One of them has a violet moon that takes about a quarter of the night sky, and another has two smaller blue moons that give off a sinister light.

I have another moon composed entirely by ice where visiting Mages can have fun ice skating =)

I would say that if you like this idea, and it makes you feel good and like your world even more, then go for it and do not worry if it's cosmically plausible or not.

 

[Feo Takahari]

For the moon, what causes all of those things? Not the presence of the moon itself, but its gravity. And what causes the gravity? Its mass. Just have it be less massive, and as someone else mentioned, more reflective, and you're good to go. In fact, if you lower the mass of both moons, then you can probably approach a "standard" Earth-moon system.

As a Freefall fan, I'd like to point out that this can be complicated. You can set up a dual-moon system that mimics Earth's moon, but you'll need to do a lot of research (and some basic geometry.)

Unlike most of the posters in this thread, I'd say it's actually worth the effort to get things right. You'll probably be having gravity work the same way as in our world in every other circumstance, so why have it differ in this case, even if most people won't notice? If you're uncertain of the details, you can always hide them--you'll probably never need to specify the exact mass and diameter of each moon--but accuracy on a general level makes a world feel more lived-in.

 

[srcroft]

As a Freefall fan, I'd like to point out that this can be complicated. You can set up a dual-moon system that mimics Earth's moon, but you'll need to do a lot of research (and some basic geometry.)

Unlike most of the posters in this thread, I'd say it's actually worth the effort to get things right. You'll probably be having gravity work the same way as in our world in every other circumstance, so why have it differ in this case, even if most people won't notice? If you're uncertain of the details, you can always hide them--you'll probably never need to specify the exact mass and diameter of each moon--but accuracy on a general level makes a world feel more lived-in.

I'm not disagreeing just to disagree, but I would rather read: John could see the two moons in the sky. Rather then a 4 page dissertation on the science that makes it possible. If its important to the plot and theme, or its a symbol or allegory--I agree do the research--if not, its just embellishment and I wouldn't do more than find out that its possible.