SciFi Question of the Day: How careful do I have to be in my descriptions if I say the planet where my story is set has 3 moons? Can I say things like “All three moons were visible at dusk…” frequently, or would that be a rare phenomenon?
Elizabeth Sykas-Ringgenberg a rare phenomenon – that might be considered predictive of some good/bad event…
Heather Leigh Cameron maybe if the moons were at different stages in the cycle it might be realistic?
Eden Mabee It would depend on a lot of factors, but in general, I agree with Elizabeth. It could happen, but to get them all appearing in the sky in similar degrees of fullness would be one of those “prophecy” moments
Gwendolyn Wilkins Being the little pagan that I am, I can tell you that a full moon rises at sunset, is at zenith at midnight and sets at sunrise. A new moon rises at sunrise, is at zenith at noon and sets at sunset. A waning moon rises after sunset and a waxing moon before sunset.
To have all three moons at the exact same phase at the same time would indeed be rare, but they could certainly be within a fairly decent range of phases and still be visible at dusk.
Daniel Beard Actually Heather, they would have to be within a half cycle to be in the sky at the same time. otherwise they would be on the wrong side of the planet. Example (assuming standard Keplerian orbits, and not being massively out of the Ecliptic) you could see on a flat plane a full moon directly above you, and each of the quarter moons on the horizons, one to the east, and it’s opposite to the west. But you could not see a full moon and two opposite crecents at the same time for one of them would be under the horizon.
Daniel Beard and what phase they are in depends on how long their day is. one could have a day of 20 days, one of 28 days, and one of 50 days. They will line up, every 700 days (planet days, not moon days). Actually, I should change that. It would not be how long their day is, it would be how long their Year is. Was just thinking about our moon whose day and year are the same duration. (called being Tidally Locked)
AmyBeth Fredricksen Would they all orbit in the same plane?
Daniel Beard no
Daniel Beard just look at our solar system, every planet (except ours, thank you very much) is slightly out of the Ecliptic (I can never spell that right, thank you Wikipedia). but they could, especially if you wanted to go with an engineered system, or just go with the “I said it was so” excuse. Hell, they don’t even have to be stable orbits, just look at Phobos, gonna crash into Mars. Not soon, but within a couple million years.
James Lucius Not to mention (at least potentially), massive tidal effects if they were all full and in the sky at the same time.
AmyBeth Fredricksen Ooh… I could have a scene in one of the stories where they were experiencing some odd tidal stuff, and vaguely say it’s because of the moons, but not go into detail (which would lead people to dispute my science… but just saying “Yeah. Weird tides. It’s a moon thing.” isn’t very disputable 🙂
Daniel Beard or at 90 or 180 to each other, as well as the system primary (this is a single star system?)
AmyBeth Fredricksen Yes, it’s a single star system.
Daniel Beard these are called the Neap and Spring tides here
Daniel Beard Could be all sorts of interesting, I see the building of tidal walls and dikes as being a high art form for civilizations near water. which is most major cities.
James Lucius Or a Venice type of affair, with canals to guide and control the water flow.
James Lucius Not to mention class divisions involving how far away from the beach, (and therefore how high up) you live.
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Nes Anderson considering our own solar system, id say 3 moons is lowballing it :p
Of course, it seems moons are less common toward the inner system than the outer system..
Both Saturn and Jupiter have over 60 moons… Uranus has 27 according to wikipedia..
Mars has 2, we have one…
Their orbital velocities and periods of visibility are all random, so it would be fairly easy to have a planet with 3 visible moons.
Jocelyn Kelly How rare would it be that the 3 moons are visible on any given night? How might you compare seeing the 3 moons to how we see our 1 moon?
Nykki B At some point in the past I had found an online calculator that would take your world calendar and all satellites and, given the periods of each, calculated a calendar including full/ half/ new phases, eclipses, etc. I will have to see if I can find it again.
AmyBeth Inverness Nykki… that would be cool!
Thomas Sanjurjo Not only should you be concerned with which moons are visible, but what phase they are in also. You could paint faces in the sky with them. They could also eclipse one another, depending on their color they could give tint to each other, one could be pocked like our moon, while another could be gaseous.
Then there’s Iapetus. http://www.enterprisemission.com/moon1.htm
Eden Mabee Nes makes a good point about the number of moons decreasing as we get out of the solar system. However, it’s been discovered that we actually have several natural satellites here on Earth as well. They just aren’t normally visible due to size.
Another thing to consider …and I’m not going to spend too much energy dealing with any of Veilokovsky’s theories (you all can read what little literature is out there and decide what you think on your own), but IF there is any chance that those theories are correct, then all those moons of Jupiter are actually “young worlds” that were ejected from the gas giant and had not managed to escape its orbit. So now we have the possibility of those moon potentially being worlds as developed as the one you might be living on.
Perhaps your society is actually living on a MOON and not on a planet, but they don’t know that yet. It matters little for the actual story. However, it certainly would set a very different pattern to the orbits of the celestial bodies.
Thomas Sanjurjo I’ve considered that for story telling as well, +Eden Mabee. There are some theories that the magnetic field of Jupiter (a failed star itself, just a few planets short of enough critical mass) might be ‘warm’ enough for the moons to be habitable.
AmyBeth Inverness I think I’m going to keep the moon details vague. Its main importance is making it obvious early in each book that this is NOT Earth.
Eden Mabee Understood, +AmyBeth Inverness, just noting all this stuff because it’s good to think about it. If you’re writing a science fiction story about a society that intends a trip to their moon, only to find that they are actually on the satellite, it’s literally a restructuring of the society. I mean, look at the number of people who still doubt we ever reached our own moon right now…. Look at astrology and many kinds of divination…. A lot of accepted beliefs will have been recently challenged in this world, or are in the middle of being challenged.
There is the potential for a LOT of cool story ideas here.
Christopher Clark But only one sun?
Thomas Sanjurjo I’d say for your particular concern, +AmyBeth Inverness, make sure the moons are named, and that the names hold some deep, cultural significance to the narrator / character. The worst thing you could do would be to just say, “two of the three moons…” it would be much better to say, “Aurora and Denara danced across the summer eve…” and follow that up with a statement about how beautiful the satellites are.
AmyBeth Inverness Good point about naming them… I’d been thinking of “The big one, and the two little ones” but names make much more sense, and I love making up names!
Eden Mabee Your names can even “mean” the big one, the little one, etc… (though in any realistic world, it’s likely there would be some kind of mythology involving them).
Thomas Sanjurjo With issues like this I default to Hemingway’s iceberg theory.
So much more can be said by naming them, giving them a descriptive characteristic, and then ignoring them as common knowledge.
Thomas Sanjurjo LOL, I just had an image of one moon eating another Pacman style. Now there’s some mythos for you!
AmyBeth Inverness This particular planet is a human colony that has only been around for about 300 of their years (almost 400 Earth years) The original colonists were well aware of all the details of the solar system long before they settled on the planet.
Oh and yes… only one sun.
Thomas Sanjurjo Eh, that’s still a few generations of children’s tales, unless they are a really staid society, which would still be telling.
Tiffany Marshall It would be interesting to have a triple lunar eclipse during the story though! I wonder what that would do to the tides?
AmyBeth Inverness This particular planet is the setting for a series of loosely related stories. (SciFi Romance) so I don’t want to say that the moons did something weird in one story, then the exact same weird thing happened in the next story. I need to develop a good idea about what is normal and regularly occurring before I mention more than the barest detail.
Eden Mabee +AmyBeth Inverness I have to wonder if these people will have fully mapped out what is “normal” for this system if, as you note, they have only been here 400 years. As Thomas notes, there could easily be 700 years between all three being seen in the night sky close enough to all be visible at sunset…
Perhaps THAT sort of thing could also be part of the story?
AmyBeth Inverness Yes! There are some anomalies, most notably the historical fact that the colonial starship crashed about a week after arriving in orbit, and 300 years later they still don’t know why. Maybe I’ll blame it on the moons? Maybe I’ll have more than 3 moons… hmmm…
Eden MabeeYesterday 11:10 AM
AmyBeth Inverness Good question +Eden Mabee . In the story (It’s backstory really, and not necessarily extrapolated on) The colony ship left Mars where they’d been doing all their gathering and planning, just like many other colonies did. They knew where they were going. I never say whether they “found” the planet, or whether previous generations terraformed it.
The ship arrives in orbit, and the colonists begin shuttling down with various construction equipment. Many people remain on board or shuttle back and forth because this was all part of the plan… to get there, and begin building a very well-thought-out starter-city. There’s no rush.
Then something goes wrong, and the ship’s orbit rapidly decays. They gain and lose control over and over. So at first, they think they can fix it. As they realize they can’t, colonists take to the escape pods.
After the crash, there is a small pocket of people at the site where they planned their initial city, but it’s an island (Like Hawaii… large enough for many farms) and cut off from the main land. There are many small groups of people across the planet, wherever the escape pods landed, who have to survive. Those who are able congregate at the crash site, trying to save what they can.
Very important to the plot is the fact that there is no Starfleet that comes swooping to the rescue. There is an alliance of sorts, but nothing that is able to help this brand-new colony that is weeks out of the way of any major transport line.
So instead of a well-planned city with all the resources they need, there are scattered colonists desperate to survive, with only a portion of the resources they need. Even though they desperately want to know why the disaster happened, they have to put their energy into survival. They don’t have the ability to do the necessary investigation, and even generations later it remains the planet’s biggest mystery.
Eden Mabee I wrote a big long “brain bubble” about this yesterday. I’ll have to send it to you later. Not right now…
However, it sounds to me like they should have records somewhere about what they have observed…
Afterthought… I think more than three moons is a great idea… names? How about Bester, Bradbury, Riley, Clifton, Blish, Miller…
I would love to hear what you think! Even if you are reading this post a year or more after publishing, I hope you will leave a comment with your own ideas on this topic.
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