Space Wonders: Better than Traveling There

Just a quick gallery today of some of my newer pictures from Space Engine. I’m looking forward to addition of accretion disks around black holes and blue stragglers in globular clusters in upcoming updates. As in the earlier post, all images are exactly as captured in Space Engine, without any post processing, cropping, etc.

Warp Speed: How Fast do you have to go to get the Stars to Sail by?

In a star cluster orbiting the  milky way (Space Engine)
In a star cluster orbiting the milky way (Space Engine)

John Pyle’s post on Light Speed, Not so Much, reminded me about something I wanted to look into based on my Space Engine experience. In this wonderful simulator you can go anywhere in the universe with the engine kindly accelerating you to fantastic speeds, as necessary. As part of the experience, you get to experience the Star Trek warp effect: stars go sailing by all around you as a readout at the bottom of the screen shows your current speed. It might be km/s over a planet or AU/s in a planetary system. Between stars, you typically get to go parsecs per second (a parsec is 3.26 light years). Hop over to the next galaxy and you’ll be travelling at hundreds of kilo-parsecs per second. This is a good thing, because otherwise travel would be tediously slow.

One of the neat things about Space Engine is that it doesn’t just pop you over to your destination, you travel to it, accelerating and decelerating. You fly through dusty arms of galaxies, through nebula, globular clusters. As I mentioned stars zip by a la Star Trek. This got me to wondering: I think Space Engine has a pretty solid model of spatial relationships and velocity. Therefore, I can use it to gauge what Star Trek warp factor I’d need to be traveling to get the same visual effect of star motion that we’ve seen since the original series. Of course, I had a feeling the TV show was way off but it is fun to do the numbers.

First, I’ll use the newer series’ definition of warp. You can find a great definition of what warp factors mean at’s engineering department: Warp Factors Defined. At warp 5, you’re going 215 times the speed of light and at warp 9 you’re going 1516 times the speed of light. That’s pretty fast, right? Indeed it is but as the old cliché goes, space is really big. At warp 5, it’s 40 hours per light year. Not bad for the local neighborhood but not too zippy. At warp 9, it’s only 5.9 hours per light year, so several light years per day.

So what would the star motion look like? Fire up Space Engine, play around with your speed and… you’ve got to be going around a light year per second to start to notice much star motion. Pick a densely populated region like the heart of a star cluster and maybe you can get away with 0.1 light years per second. But at those speeds, you are just starting to notice star motion. If you really want to be seeing stars zip by, like in the opening credits,  you might be looking at 1 to 5 or more light years per second.

Even at warp 9.99, at 7912 times the speed of light, you’re crawling by at one light year per hour+, or ~4000 times slower than the speed you need to get the stars to zoom by. I’m not sure how to turn that back into a warp factor but since warp 10 is the max, it is something like warp 9.9999, perhaps?

This means that if you intend to use that cool “star gliding” effect in your own stories, you better be having your star ships travel much, much faster than they do in Star Trek, so fast that your ship could get to the Andromeda galaxy in a few days. That’s probably too fast for most science fiction stories, unfortunately. Put another way, the Star Trek apparent star motion isn’t really practical, although it sure does look cool.

Just goes to show that space is really, really big.

SpaceEngine: Go Anywhere in the Universe

Sunset on a Brown Dwarf
Comets around a Brown Dwarf

Along with the Universe Sandbox, here’s another great tool for the science fiction author: SpaceEngine. This fascinating program is still in beta, and a bit buggy, but to get an idea of what it can do, take a look at these pictures, all of which are unmodified screenshots. Most are from my son’s exploration over a few hours. The first two are my own effort after about 30 minutes of playing around.

Aurora on a Distant Planet
Aurora on a Distant Planet

Whereas Universe Sandbox is an orbital dynamics simulator, great for playing around with solar systems and disrupting them by blowing up a planet or shooting black holes through them, SpaceEngine takes a different route. It models a huge number of known astronomical objects, from every moonlet in our solar system, to nearby stars, globular clusters, nebula, galaxies, etc.

Gas Giant
Gas Giant and Galaxy

Where it really gets interesting is the vast number of astronomical objects for which there is no known data because where current observational data runs out, it creates the rest procedurally.

Ringed Waterworld
Ringed Waterworld

Pick a galaxy and fly into it. Find a star in that galaxy and zoom to it, visit its planets and moons, search for life, exotic planet rises, there’s really no limit. I’d consider some of these for cover art for certain classes of novels.

Over a Desert World
Over a Desert World

When poking around the universe can keep you busy for days, who knows what story ideas you might find?

Ice Moon orbiting gas giant in a binary star system
Ice Moon orbiting gas giant in a binary star system

SpaceEngine not only creates lovely visuals, it backs it up with  physical data: object mass, gravity, atmosphere, orbital period, mean temperature, even modeling presence of life. It’s fun if you just want to poke around alien worlds and its a dream come true for Science Fiction worldbuilders. Plus it has more lens-flares than the last Star Trek reboot!

An Alien Shore
An Alien Shore

Has anyone else given it a try yet? What do you think of the pictures from it?

Souls and Virtual Reality

poster for The Matrix
poster for The Matrix (Photo credit: Wikipedia)

You go to sleep and wake… as an elf in a tree-city much like Tolkien’s Caras Galadhon. Pretty cool, eh? You likely would experience angst over left-behind loved-ones. But how else might you react?

What fantasy reader hasn’t given this at least some thought? Myself, since as long as I can remember, I’ve spun daydreams, sometimes weeks long, of just such adventures. But what would I really think if suddenly transported to another world, maybe even in a different body? Sadly, I would be forced to alter my assessment of the chances that I’m living in a virtual world.

There has been a lot of discussion lately about whether all of us are presently living in a Matrix-like world. Some even go so far as to say it is likely that this is the case, probably because if there were virtual worlds, there would be a lot of them, therefore you’d more likely be in a virtual one than a real one. I’d like to see the analysis for those who posit this because while I think it is entirely possible, I don’t think it is all that likely.

My assessment would change, though, if fundamental elements of my current reality suddenly changed. And nothing is more fundamental than my body and the world I perceive. This is because while I think you can construct ways for people to move from one world to another or body swap (or both), and it’s an accepted fictional trope, in reality making such a move seems nearly impossible. How does one change universes? There may in fact be multiple universes but in no cosmology proposed by scientists is it very easy to travel between them. Under some theories, the other universes would not even have our laws of physics.

But even supposing you could make the leap, how do you pick out the cosmically insignificant speck of habitable space (not just a planet but the surface of that planet) and arrive at an appropriate velocity (an extension of my discussion under Teleportation and Momentum Matching.) I suppose you could posit universes that fork off our own and remain connected in some way but, even so, it still seems unlikely you could simply pop from one to the other without some sort of high-tech cocoon to protect you in transit.

Then, once arrived in the new universe, there’s all the issues of communicating there: do you already know the language? How is that shoved into your brain? And do the denizens appear human: our basic body plan may be likely, perhaps, but it isn’t likely that the other folks would be so human-like that we would find it desirable to be one of them. And what about atmospheric and microbiological compatibility? Not an issue if you get a new body but a big deal if your current one pops over to the new world. And a really big deal if the portal is bi-directional. I would be a lot less concerned about dragons ravaging our Earth and a lot more concerned about alien diseases doing the same.

On the body-swapping, how exactly do you move a consciousness from one body to another? It seems possible you could move memories, especially imperfect ones to a new body, but the actual consciousness? If you believe in souls you could imagine the soul moving along but there is no scientific evidence or justification for souls that I’ve ever come across. I suppose if the cranial cavity is the same in both skulls, you could move the brain and re-connect everything. That seems do-able. But a consciousness swap such as we’ve seen in Star Trek episodes? Cool to write, hard to imagine how that really works.

None of this is strictly speaking impossible but it seems extraordinarily unlikely to me. If I ever found myself in such a situation, I’d be forced to conclude that I am more likely a virtual entity and I was simply moved from one simulation to another. As discussed earlier, any virtual simulation is likely to have well-defined abstraction layers for speech, body perception/interface and so on. Re-targeting these to a new language, body, world, even physics system, is a small extension for any entities capable of executing a virtual world simulation that can fool us. Therefore, there is no practical barrier to moving a simulated consciousness to a new simulation. Now, that simulated entity might be very sad at the loss of his old friends and family or freaked out to the point of insanity if it suddenly found itself in a Cthulhu-esque squid body. But you can certainly imagine the transfer taking place without any messy issues of wormholes and hostile microbes.

In the end, I might not object to such a transfer, especially if it occurred at the end of a (simulated) life. But it would certainly raise fundamental questions about the meaning of life, my family and friends, and so on. These are not the sort of realizations those who run the VR show may want their VR entities aware of, as it would affect the simulation. But maybe they move people without full or any memories intact. Perhaps those who remember past-lives are simply remembering incompletely purged past-memories. If a simulated world is not complete, that is, if not all the entities are fully realized, than the fact that past-life recallers seem to remember a disproportionate number of historically “cool” lives (me, I was King Henry V in a past life), might actually make sense because in that case, any given VR entity was pulled from a limited pool of past people, which could, if the VR executor so chooses, be disproportionately higher stature folks.

One reason those who run a VR show may not want their entities aware of this is it raises the basic question of why? Is my entire life and all the pain and suffering simply for the entertainment of others? One plausible and morally acceptable reason might be for self-entertainment: we’re all astronauts on a million year journey to another galaxy and the simulations are a way to pass the time. But even then, during the simulation, you might not want to know you are in one. There are many other possibilities for the ‘why’ behind a virtual world.

For instance, imagine a future where synthetic entities have replaced organic ones. Some might argue the fate of humanity is to go extinct, the only question is whether we leave behind self-aware synthetic progeny. In such a world, the synthetics might wish to keep alive, for historical purposes or as a hedge against unknown threats, a simulation of their fore-bearers. Or perhaps, in order to “seed” synthetic consciousness with a good range of capabilities, they actually grow their consciousness in a simulation of organic civilizations. Maybe the childhood of a self-aware android is a life or two in a simulation of 21st century Earth. If I were creating synthetic entities, I might do exactly that. It’s not be a bad way to train a virtual entity’s neural network (or however it is technologically realized).

Back to the topic of souls mentioned in the title, if a soul is the “something” that makes a self-aware being unique, extracting that from an organic brain seems rather close to impossible to me. But extracting that from a simulated VR entity seems quite possible. Put another away, it may be that the only beings with souls are simulated beings. Therefore, the only way for life to develop to the point of having souls is for organic humans to create a virtual world with virtual entities, or create synthetic entities in real robot bodies whose consciousness could be moved from machine to machine. Or both: if you can have a synthetic entity running around a simulation, you could put the same being into a physical body to allow it to interact with the real world.

This leads to perhaps a disquieting thought: what if only synthetic entities are able to have a soul and an afterlife? Or what if we are all androids-in-training in the year 120,000 CE?

How to Make Time Travel Work

Cover of "Back to the Future"
Cover of Back to the Future

I’m talking about how to make it work in your stories, not how to build a time machine. Apologies if you are looking for engineering schematics.

Time travel has got to be one of the oldest tropes in fantasy and science fiction. Who wouldn’t want to go back and fix a mistake or just observe the past? Trouble is, basic time travel has, as we all know, fundamental paradoxes. What happens if you kill your grandfather or commit one of the endless variations? Yet, there doesn’t seem to be an end to time travel stories in sight, and, why not? They can be fun. Plus for TV shows, there’s the added bonus of getting to use all those cool historical outfits the studios have lying around.

While I usually groan at time travel, I have to confess one of my favorite Star Trek: Next Generation episodes is Yesterday’s Enterprise. And I still get a chuckle out of Back to the Future.

As with Teleporters or Lasers or the like, an author can simply ignore any issues with time travel. However, in this case, if you are too blatant with the impossibilities it is likely to kill your story with editors and agents, not to mention readers. This is one trope where some amount of hand-waving is required. Let’s look through the methods.

First off, I’m just talking about going back in time. Going forward is easy.

Don’t Pollute the Timeline

This is a favorite of Star Trek but shows up in many other places. It’s basically a way to say you are dealing with time travel paradoxes without actually dealing with them, which makes it fine for certain stories but, for me, anyway, not very satisfying.

Why doesn’t it solve the problem? Because there is truly no way to avoid polluting the timeline. Even if you avoided making contact with any sentient beings, what about that fly that changed course, causing the frog to be elsewhere when the snake wanted to eat, causing the snake to search farther afield for food, biting the naturalist causing her to spend a week in the hospital and miss meeting the man with whom she would have mothered the next Einstein? Or leave out organisms, what about changes in gravitational or electromagnetic fields? You might not think that speck of dust floating in space is all that important but maybe it’s trace as a meteor inspires a poet who writes a poem that changes the life of a person who… You get the point. History is a very chaotic system and tiny perturbations can have dramatic effect. Oh, and don’t forget the microbes time travelers will leave behind.

Echo Park Time Travel Mart
Echo Park Time Travel Mart (Photo credit: Scott Beale)


One way to deal with this is to take the approach that the time travel event was always part of how things were meant to be. There was never an earlier timeline where the time traveler did not appear. This sounds weird but Hawkings has noted that, so far, anyway, we don’t have a good physics reason for why time runs forward. And maybe the universe is cyclical: it runs forward to a certain point then runs backward undoing everything in exactly the same way. If we were living on the backward progressing arc, supposedly we wouldn’t even realize it (we would still think as if we were going forward). Or something like that.

This method has neither aesthetic nor intellectual appeal to me. I have to confess it doesn’t even make a lot of sense to me but I’m willing to concede that smarter people than me think it does so there you go. While your story need not posit the backward replay of the universe to make use of this method, it has similar problems: that of freewill. If things can run backwards as well as forwards, then there is nothing unpredictable in the universe. Using destiny to make your time travel work isn’t any different: something must occur, therefore the characters have no choice in what they do.

There are some physicists who think freewill may be an illusion. But do you really want your story to be about characters who can’t actually make any choices? Seems to remove the entire point of a story. If you use this one, you may want to be very sparing with it and be careful of nudging the reader into the conclusion that your characters’ desires are irrelevant to what occurs because if that’s the case, why care about what happens to them?

Observability Horizon

Time travel involves a violation of known laws of physics. This is not a problem because your time travel story is speculative fiction. But that doesn’t mean we can’t take advantage of other laws of physics: if the time travel is to a place beyond the temporal event horizon from earth, there is no possibility of a paradox, at least for a single time travel event.

As any astronomy buff knows, looking into space is looking back into time. If you look at the sun, you see the sun as it was about 500 seconds ago. Look at a star and you are looking back at least a few years, maybe thousands. Galaxies are millions of years away. So, for something that is X light seconds away, if you travel back in time less than X seconds, anything you do can’t change anything that has happened on Earth. It’s harmless.

For instance, lets say you had a 10-year-old child. Let’s also say you travel back in time 11 years. If you do that on earth, who is to say something you did might not change whether your child was even born, let alone the course of his life? But instead, let’s say you travel 10 years back in time to Gliese 832, which is 16 light years away. Now, even if the first thing you did was construct a planet-destroying death beam and fired it at earth, it would not arrive until after your ‘present.’ There is no way for your time travel to affect your child or anything else on earth, at least in the present. When that death beam pulse finally gets here, it’s another matter.

Of course, you might be wondering, what good is time travel if it can’t actually affect the past? Well, obviously, this method doesn’t allow you to change events in your local space. But it could still make an interesting story. Imagine if humans are losing a war to an alien race in 2113 but they have the ability to do this sort of time travel. They send humans back in time 10,000 years to several habitable planets 10,000 light years away with the hope that some of them proceed to the point where they can arrive at the home-world in 2113 with the technology necessary to save the world. Kind of a deus ex machina ending but there’s a story there. Or maybe there is no intent for the time traveling humans to save the present, instead, this is an ark-in-time: humanity dies on Earth but lives on, propagating through time and space.

This falls apart if your time travelers turn around and go back in time to the originating world. However, just like it takes infinite energy to go the speed of light, maybe it takes infinite energy to violate the laws of temporal observability: you can try but it won’t work. It’s hard for me to imagine a mechanism that would actually cause that to be but (a) I’m not a cosmologist and (b) this might be obscure enough that this method might satisfy most readers.

Forked Universes

Another way to deal with time travel is to say that each time travel event “clones” a universe: when you travel back in time, you create a duplicate of the universe at the time you arrive. Anything you do occurs in a separate universe. You can still kill your grandfather but only the grandfather in this duplicate universe, not the one who sired your father who then made you. No paradox.

Of course, universes do tend to contain a fair amount of energy, as in mind-bogglingly vast amounts. But according to current theory, the universe sprang from perturbations in a vacuum so I am not sure this is a really a problem. The energy would come from outside the universe, maybe it doesn’t really matter in the grand scheme of things. Or maybe it’s the old “how many angels can dance on the head of a pin” conundrum. The answer in the middle ages was an infinite number because god could put an angel down on half of the pin, make a half-sized angel, put it down in a quarter of the remaining space, make a quarter size angel, put it down in an eighth of the remaining space, and so on without end. Maybe when you duplicate a universe through time travel you actually make two halves, like a fertilized egg dividing: same mass but now two half-sized cells. To someone in the smaller universe, things might still look the same.

The main issues with this approach for your readers is how to make the universe cloning seem plausible. Some may also wonder just what can cause a cloning event. For instance, does it have to be a sentient being, because if physical processes can cause it there would be a near infinite and ever-increasing number of universes. Even if it has to be a sentient being, you might soon have a vast number of clones out there. Of course, any person in any given clone would only be aware of his or her universe. And maybe the plethora of many universes provides a setting in itself: your characters might hop between possibilities. While they could not return to their own universe in the past, nothing says they couldn’t go from universe A to B and back to A, as long as they arrived in A later than their departure.

As a side note, you could use this for the issue of freewill instead of time travel: maybe every decision results in a universe fork. While it is true that all possible decisions exist in the set of all universes, any given individual is experiencing the results of his decisions. Not sure it really solves the freewill problem but it’s an interesting thought.


Quantum mechanics tells us that an electron in a hydrogen atom isn’t orbiting the proton like a planet around a sun. It’s actually in a probability cloud, sort of smeared out in time and space. I think QM would say even Jupiter is in a probably cloud in its orbit around the sun, just that given the mass of the sun and Jupiter, and the distances involved, the probability envelope is really tiny: i.e., for all practical purposes it inhabits a point in a space.

What if time travel works this way? Any given time travel event adds to a cloud of timelines. What happens in the now is the sum of timelines in the past. You can go back and kill your grandfather but that will either not really happen in the present because that event is improbable or you will change the now so that you aren’t present.

Maybe to change the past, you have to go back multiple times and nudges events so that the probability sum results in your desired outcome, or at least a different outcome: this sort of time travel seems rife with unintended consequences. This is actually at the core of my next short story (see, I take my own advice to heart. While I find most time travel stories paradoxical, how would I make this impossibility possible? I’m going with superposition.)

Where in the Past Art Thou?

That’s it for ways I can think of to make time travel work but before I wrap, let’s touch on the where of time travel. Let’s say you do find a way to travel back in time. Where do you go? Not only is everything moving in space, it is moving relative to other things. There isn’t a universal coordinate system. If you want to travel back to Earth one hundred years ago, how do you specify where the earth was then, both in its relationship to the sun (and remember our orbit is not perfect, it does vary due to interactions with the other planets, even with passing asteroids) and the sun’s position in the galaxy and the galaxy’s position in the local cluster, etc., etc. Not only would it be very difficult to compute where the earth was with respect to where it is now, how does your time machine spit you out in the intended spot, and at a velocity that allows you to interact with the Earth (rather than, say, impact it at relativistic speeds?)

Let’s say you can do all that: you can put your time traveler in the exact spot and with the precise velocity vector to avoid smacking into something. Do you know where the surface of the Earth was 100 years ago? Things move, not just down but up. Continents drift: 100 years ago America was about 8 feet closer to Europe. Trees grow. It would suck to appear in the middle of an oak tree, wouldn’t it? For all those reasons, time travel might be best executed in a spaceship with enough delta-v to match the destination.

It’s all handwaving

While the Observability Horizon and the Universe Forking methods avoid time travel paradoxes, they have their own problems. In the end, all of these methods simply constitute more obscure ways to explain time travel. Even so, they may satisfy many readers’ suspension of disbelief better than “avoid polluting the timeline”. And for those it doesn’t satisfy, you might get points for trying or at least amuse them as they think through the puzzle you posed.

Putting the Impossible into your Fantasy Settings

Cover of "Lucifer's Hammer"
Cover of Lucifer’s Hammer

Speculative fiction really shines when it makes the impossible possible. Not the variety of implausibility that was accidental: that can be overlooked for a good story but is never a plus (oh- there’s no such thing as a 1000 Megaton bomb in the Russian arsenal? Oops). What really grabs me is when an author builds a story around something that seems outlandish and makes it work. Larry Niven is good with that, especially when writing with Jerry Pournelle to give him some engineering ballast: what would it be like to survive a comet strike or how would a modern person take to a trip through Dante’s Inferno?

In posts like Map-Making Pitfalls, I tend to call out what shouldn’t be. But shouldn’t be isn’t the same as can’t be. As I mentioned in that post, casually putting a fork in a river that results in egress to two different seas is lazy map-making. It makes you look careless and who wants a prospective buyer thinking that when they are flipping through your book? But a powerful technique is to take these ‘impossibilities’ and turn them around: okay, this does exit. How do I make it work?

In this exercise lies the seeds of gripping, unique stories that aren’t a knock-off or variant of a hundred fantasy epics that have come before. Take Lord of the Rings. Tolkien started from mythical underpinnings, which gave him the idea of a cursed ring. Next, one can imagine him wondering, how do I make this ring so important, so cursed that it can sustain a long story arc? Because normally, a little bit of gold fashioned into a circle isn’t going cause that much sturm und drang. What if the ring is tied to an evil overlord, one so powerful he could cast the world into endless darkness? But how can the heroes fight such a foe? Maybe the ring contains part of his power, making him weaker than he would be, and so on…

Let’s take the implausibilities of Map-Making Pitfalls as an example. That post already covers ways to dial with a down-stream facing river fork: put something there to maintain the fork and make the distribution of water at the fork relevant. E.g., without the fork, an entire valley will dry up and die. That gives you some seeds for conflict right there.

Looks look at others:

Not enough forests: what could suppress forests in a climate where they would naturally flourish? Disease, blight? Sure, although that might be somewhat impersonal or smack so much of ecological activism as to offend some readers. The sauropods were such voracious herbivores that they probably shaped their landscape. What about some sort creature whose very presence destroys (or at least culls) woodlands? You could have dinosaur-like grazers but that could be a little dull (unless you made use of them as war-beasts like Ollyphants). Since this is fantasy worldbuilding, let’s go with something more exotic: the dominant intelligent lifeform are giants, really, really big giants. They knock down trees much as humans might mat grass. Where they go, humans and trees do not. Now you have the beginning of conflict: human-giant, and a reason why forests are patchy. Similarly, you could have some fire-breathing critters that tend to cull the woodland: maybe dragons prefer open grasslands with grazing herds they can swoop down and eat at will (I think I might prefer that if I were a dragon). Dragons would need vast feeding grounds and could easily keep large areas mostly clear of woods. What other reasons can you come up with for fewer forests?

Mount St. Helens erupted on May 18, 1980, at 0...
Mount St. Helens erupted on May 18, 1980, at 08:32 a.m. Pacific Daylight Time. (Photo credit: Wikipedia)

Gap between forest and mountains: this one is a little tougher. What would keep trees from growing all the way into the mountains? You could go with variations of the “not enough forest” ideas above but have the creatures that keep the land free of trees prefer mountains, so they just clear the mountains and the adjacent areas, something like crazed mountain goats that graze a little beyond the mountains proper. Going a different direction, what if there is something about the mountains that does not lend themselves well to trees? Maybe they are highly volcanic? In Earthly volcanic mountain chains, like the Cascades, volcanoes aren’t erupting enough to do anything more than clear local blast zones, as with Mount St. Helens, or lava fields, although Hawaii does have some relatively barren stretches. But maybe your volcanoes are more active. Makes a good place for fire giants and other such creatures. Maybe the fire giants actually perpetuate this, or even make volcanoes more common by their mining, magic, or some other methods. Now mountains aren’t just a physical obstruction that makes travel difficult:  they are home to an alien and dangerous race who, at least near their volcanoes, can harness tremendous power. There would be no wonder now why forests don’t run into the mountains: they run into lava (and harsh lava lands) first.

Compass Point Rivers: I mentioned in my last post that one reason for rivers running along a grid might be that the world overlies a computer or other structure arranged on a grid. For a more fantastic setting, what if your world has ley lines. Maybe the magic on these lines is so strong that it weakens the underlying rock, providing a preferential path for erosion leading to rivers. The same effect happens on earth when erosion is faster along a fault line leading to rivers delineating fault lines (see the San Lorenzo River in the Santa Cruz mountains of California for an example). Such a world might look as if compass roses and nav-lines had been inscribed on it with rivers, seas and bays. One glance at the map and a perspective reader would know something was unique about your world.

Moving beyond map-making pitfalls, how about flying castles? There’s no practical way on Earth that I know of to make a castle float in the sky, Castle in the Sky‘s Laputa not withstanding. But who doesn’t love the imagery of massive piles of stone floating high above? I do and have made use of it in multiple D&D campaigns as well as my current project. So, let’ s turn it around from castles can’t float in the sky to how do I have floating castles in my world? The first option is to have them and not explain them. This is, in fact, a perfectly sensible response assuming you are writing in the fantasy genre where floating castles are an accepted trope. But as always with tropes, scratching below the surface will improve the richness of your setting and will likely generate some great character and plot ideas to use in your story.

Maybe your world, like Avatar’s Pandora, has some rock strata that floats. This would mean that flying castles could only be made from certain places where this strata exists. It would also mean that the continued buoyancy of the castle depends on the strata remaining intact. Perhaps this would not be a real issue in your world, perhaps the bottom of the castle-rock tends to break away over timing, causing castles to age and fall. Or maybe there’s some way to attack this rock layer to neutralize the buoyancy or mine it away (earth elementals?).

Alternately, maybe there’s magic that imparts buoyancy. Life on a flying castle would be very different if the buoyancy was just on the lower part of the block of rock it was built on or whether it was more of a bubble that encapsulated the rock and some or all of the castle. In the latter case, those on the flying castle might be living in low or zero G. Rather than the magic just ensorcelling the bedrock, maybe it depends on enchanting objects or structures embedded into the castle or its supporting rock. Such structures could provide points where enemies might attack as well as an interesting flourish to describe in your story (maybe the structures are gigantic stone rings?)

carbon cartography
carbon cartography (Photo credit: neil cummings) These look like ley lines and nodes to me!

Or perhaps it’s a matter of lines of magic. I don’t go into this much in my current project, Shadows of the Archons, because it isn’t germane to the story but my thought is that there are ley lines in the world. These used to pass within the bedrock of the world but one of the Archons found a way to pop the ley out of ground. The lines are still anchored in the mountains (where they re-enter) but between the mountains they arc free of the world. As a first step, this allowed the Archon to tap the ley better for use in various arcane arts but he later figured out that he could pull land from the ground and float it into the sky by fixing the slab of rock on the ley lines before popping it up. (I imagine something like a sheet of metal that was flexed downward but popped to flex upward by a sudden force.) What does this mean for the world? In this case, the isles don’t move, they are fixed on the ley (I supposed you could also have them slide along the lines but I like them stuck there like a bead on a knotted string for my story.) My dragons are also able to fly because their wings can catch the ley– which means they can only fly where the ley is accessible.

There are other ways to float rocks in the sky. While they aren’t likely to work with Earth physics, they can provide enough of a rationale to improve reader-suspension-of-disbelief and, more importantly, these details can give you many hooks to hang your story and plot twists on.

In summary, it is best to avoid the unintended ‘impossible’ because that can make you look sloppy, at best, or clue-less, at worst. But figuring out how to make something that seems impossible plausible can be at the heart of memorable speculative fiction.

Map-Making Pitfalls

Kelvin Kay, user:kkmd Category:Columbia River ...
Kelvin Kay, user:kkmd Category:Columbia River Gorge (Photo credit: Wikipedia)

One of the joys of creating a fantasy world is making your own maps. As discussed in Worldbuilding is not Mapmaking, even though maps aren’t the most important part of fantasy worldbuilding, they are iconic and our reaction, both as creators and readers, is visceral: maps are a portal into a wonderful place. They make foreign places seem real. A well-drawn map, like a well-executed cover, grabs us.

However, as with writing where one needs to watch for too many ‘shows’, flat dialogue, uninteresting characters, etc., there are pitfalls to map-making that can scream amateur and other aspects, while accepted in the genre, might be places where you could make your maps more distinctive. Here’s a list of a few I’ve come across.

Compass Point Rivers:

This is a surprisingly common feature for those making their first maps: they have their main rivers run north-south and their tributaries run east-west. While it is certainly possible and in some story might go to the core of the setting (e.g. rivers run this way because the world is built on top of a giant computer laid out in a grid), this is a rather rigid arrangement. Aesthetically, it looks forced or careless. Geographically, while many rivers in the United States tend to run north to south (Hudson, Colorado, Mississippi), many others do not (Willamette, Columbia). And if you look farther than North America, you see plenty of other examples.


Between the Nile and a North American bias for many readers, it is easy to see where this comes from. Geologically, this happens because both the Americas and Africa are moving part from each other on a east-west axis (the mid-Atlantic ridge) and mountains tend to form perpendicular to the expansion. Since rivers generally go around mountain chains, you generally get the rivers parallel to the mountains. Exceptions exist, though, such as the Columbia River, which cuts right through the Cascade mountains in the spectacular Columbia River Gorge.

In general, rivers run downhill. Or put another way, they move away from your mountains. Whether you start with the mountains and add the rivers or vice versa, is a matter of style and what your story demands. For instance, if you want your story to occur in a land where the kingdoms abut each other in a line, you might want to create two mountain chains and put the kingdoms in between. Naturally, there would be rivers draining the resulting valleys, with tributaries in the mountains and probably one or possibly two major rivers between the mountains. The mountains could be mostly straight but nothing says you can’t put some kinks into their general run, which would give you more interesting rivers to match. Or you could start with the rivers and add the necessary hills and mountains as head-waters.

Downstream Forks

This one puzzles me because I can’t think of any real-world examples of this yet it shows up in maps fairly often. It’s not braiding in a meandering river or delta that I’m referring to but a fork in a river that causes it to discharge into two different bodies of water. For example, imagine if the Mississippi split in St. Louis, with part continuing on to the Gulf and the other part heading east to the Atlantic. Absent magic, this can’t happen, at least not for very long. To me, it tells me the mapmaker really doesn’t have much of a sense for geography, which rightly or wrongly, makes me question the writer’s ability to deliver a good story.

There could be a short-lived condition where a body of water drains two different ways but it wouldn’t take very long for one of the egress points to cut deeper than the other. It’s inherently unstable. Even in the exceptions noted above where it does occur (deltas and braided rivers) it is unstable. The water channels are constantly shifting about over the course of just decades. As an example, if you are wondering why Vicksburg was so important during the Civil War, don’t look at modern maps to figure it out: the river has moved quite a bit since then.

Of course, one of the ‘foundation’ techniques of world building is to imagine how something that shouldn’t happen could actually be. Magic solves many problems: you could have a god or water spirit or college of mages who ensure the fork remains stable. Maybe this ‘unnatural’ splitting of waters is the core of your story: long ago the waters were split to flow to three different lands, maintained by a water spirit. But that spirit has disappeared and the heroes must intervene to assure that their lands do not run dry. If you do this, though, best to make sure that something on the map calls out this fork as special so that the casual reader flipping through the book knows you put the fork there on purpose. For instance, put a star there and label it “Temple of the Water Spirit”.

Note that this critique applies to lakes as much as a simple downstream fork in the river. The lake example might actually be more common on maps: it’s just as hard to have a lake with multiple egresses: sooner or later one outlet will erode lower than the other and become the only outlet.

On the other hand, at least some of the US Great Lakes once drained through the Mississippi River. For some period of time, they must have drained through both the St. Lawrence and the Mississippi. Though it probably wasn’t very long, it might have been for a few generations. But unless you have a really good story reason for multiple outlets from a body of water, best to avoid it because it looks amateurish.

Forest-Mountain Gaps

This one you see even with our beloved Middle Earth: it is common to draw the forest distinct from the mountains, with a gap between them. This is not usually the case on earth because between forest and mountains, there isn’t generally a good reason for the trees to peter out. Trees actually tend to do pretty well in mountains because as the air rises over the mountains, it cools, dropping the dew point, resulting in rain. Even in deserts, you find some trees in the mountains. As an example: the Tularosa Basin in New Mexico is one of the harshest deserts in the US yet it is bordered by the fairly lush Sacramento mountains. Even the Organ mountains on the other side manage some trees, although you wouldn’t call it forested.

Mountains don’t generally form a barrier to an existing forest. The forest runs right up into the mountains. The trees may change to suit a colder or wetter climate higher up but there isn’t usually a gap. A really good example of this is the hike to Rockpile Lake from the east side of the Cascades in Oregon, where over the course only six miles, you go from dry Ponderosa pine to firs, to lichen-draped spruce and finally hemlock at the tree-line.

Mountains do form rain shadows, of course. There are almost always prevailing wind directions in a region with the mountains catching the rain on non-lee side. The lee side of the mountain chain is often dry, sometimes desert dry. How many of you realize that Oregon is mostly near-desert: it’s only the rainy west side of the cascades that are wet? So it is perfectly reasonable to have non-forested lands on one side of a mountain chain but these dry-lands tend to extend for hundreds of miles beyond the mountains, as in Oregon (until the next rain catcher: the Rocky Mountains) or the Great Plains of the US Midwest (once called the “Great American Desert” believe it or not.)

What you don’t tend to find, over short distances, are mountains then a bit of grassland, then forest, then a bit more grassland, then mountains. It’s forest -> wooded mountain slopes -> drier mountain slopes -> drier lowlands, which might be too dry for more forest.

Why do mapmakers put gaps between forest and mountain? Convenience: it’s harder to draw the forests running into the mountains. This is true if you are doing your map freehand and it is just as true if you are using something like Campaign cartographer where you might have a limited number of symbols that mix mountains and trees (if you have any at all to work with).

Missing Forests

Forests may be a pain to draw but there is usually too little forest on most fantasy maps. This is because most fantasy settings are in a place with European-like climate and populations levels akin to early Middle Ages (or less in a world overrun with goblins and dragons). Granted, Iron Age civilizations did cut down a lot of forest land but it was nothing as severe as what you see in modern Europe or much of the Eastern US. Without human intervention, the natural state of reasonably well-watered land is forest. Below a certain rainfall you’ll get grasslands as in the Russian steppes or the African Savannah but add a bit more rain and you get vast forests. Almost all of England used to be forested. Same for most of mainland Europe or the east side of the Mississippi, places where today you find farmland with just a few forest islands.

Such scarcity of forests isn’t natural. It takes a lot of humans with reasonably advanced technology to keep the forest at bay. If we suddenly disappeared, it would all return to forest in less than a century. In most fantasy settings, there aren’t a lot of ‘civilized’ people in the world. Middle Earth is particularly sparsely inhabited, as far as I can tell: it would probably be more appropriate for the Shire to be an island in a vast forest than a green gem in a wasteland.

Worlds where humans aren’t dominate, where there are the perils of barbarian races or too many monsters for them to spread out like we did on earth, those worlds would probably have much more forest. Fields and farmlands would be little islands in a vast expanse of trees. And those dark woods would seem alien and creepy: you can get a sense of how people used to view forests from faerie tales. There’s a reason why Hansel and Gretel found a witch in the deep woods: it was a forbidden place beyond the pale.

As with the gap between mountains and forest, the tedium of drawing (or plopping down forest symbols) is one reason why there tend to be too few forests on maps. But probably a bigger reason is that we have been trained by earlier fantasy maps and by modern landscapes to expect an unforested world where the opposite is the natural order of things.

Missing Swamps

Thanks to a thousand years of land reclamation projects, we don’t tend to realize that much low-lying land used to be swampy. Glastonbury Tor used to sit in the middle of fens, not farmland. Same for east Anglia, much of the Lowlands, parts of Poland. A combination of dykes and gates to drain low land at low tide or canals to drain a higher marsh have been used over the centuries to reduce or eliminate what used to be large swampy tracks. These were never as vast as the primeval forests but they were huge, the places where kings on the run used to hide out. In fantasy settings, they are places where nature (or monsters) rule.

Swamps and marshes tend to be omitted out of oversight: large ones are less common in our modern world so we forget to add them to our fantasy world.

Curiously, if mankind disappeared, most of the swamps wouldn’t come back. Sea-dykes would rupture and flood lands at sea level but otherwise, what was once swamp would probably stay dry: the canals remain to drain them and centuries of farm use have raised the level of the land to where it might not get so soggy again, even without human intervention.

Missing People

It is perfectly reasonable to have empty fantasy worlds. Populous orc tribes, dragons, ogres, giants, all these things could exert enough pressure on the civilized peoples that they cannot spread-out over nearly ever biome as humans have on earth. Therefore, there is nothing wrong with having a kingdom here and another there, a wilderness in between.

The trouble arises when your setting presupposes lots of contact with other peoples. Take the Gyre from the Thomas Covenant series. I haven’t read these books in 25 years so I’m a little hazy but I remember at the time being quite annoyed with the Gyre: it’s a large trading city at the edge of a desert. It had a harbor packed with ships from all over. These ships must have brought food because, unlike Carthage or Alexandria, there was no fertile hinterland to feed them (I think). But regardless of a hinterland, where were these other lands that the Gyre traded with? The Thomas Covenant world felt rather empty to me with implied “large populations elsewhere” that were never shown. It all felt rather sloppy.

Empty worlds are fine but the interactions the characters experience should be appropriate. For instance, there might still be trade (something like the old silk road linking civilizations across a lot of emptier space) but it would not be high volume and the distant lands would be little known and have little influence on each other. China never went to war with Europe. Neither knew much about the other, even after Marco Polo.

In your world, if you have small kingdoms separated by large wilderness, they won’t have much reason to fight with each other or even have much to do with each other. This can actually be a boon for the writer: you don’t need to flesh out the far away places until your heroes get there. But it also means you probably shouldn’t have powerful merchant families running the show.

Tolkien gets some of this right in Middle Earth: Rohan is alien to all but a few of the more traveled folk of Gondor. Lothlorien is entirely isolated, as is the Shire. But other parts don’t really ring right for me. Laketown trades with “people to the south” but on the maps there doesn’t really seem to be anyone close enough to justify such a trade oriented settlement. And while I love the imagery of Rohan and the Rohirrim, they are modeled on iron age Germanic tribes whose culture and trappings arose from tribes rubbing shoulders with other tribes. It doesn’t feel right to me for something exactly like a Germanic tribe to arise in isolation without warfare with other tribes to help shape it.


As with many tropes, most of the items above seem to be accepted by fantasy readers. They aren’t reading your opus for your ability to model trade routes in a world ravaged by dragons. And while a few do stick out as probably something better avoided (all north-south rivers, for instance), most of the rest can be overlooked because no one seems to be particularly disturbed by them. But as with momentum in teleporters or energy density in laser weapons, you can use an awareness of these elements to make your map stand apart from the countless fantasy maps we’ve all seen.