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In the world I'm building, there is a race of people whose main shtick is that they can detect the magnetic fields of their planet and use them to navigate. In one of their cultures, the people are nomadic and use the same "roads" to travel to different historic or religious sites in their culture. What's even more interesting is their sense of these lines, which is widely perceived as being innate knowledge. Members of this culture may not know where these paths lead, but their existence is widely known and understood to them, even if they've never followed them far or at all.

However, what these ley lines really are has been difficult to pin down. I am essentially looking for a phenomenon that can explain the following traits:

  • Ley lines can be felt, but cannot be seen with the naked eye

  • They will continue to be present regardless of terrain or manmade constructs, and can be tracked going “through” things as well

  • Ley lines can be of varying length

  • They do not have to intersect, although this would be preferred if possible

  • The shape of the line is of little consequence, but straighter lines would be preferred if possible

  • Their existence is part of some natural force that does not need to be taught

  • Ley lines are not the magnetic field of the planet, although they may be related to magnetic forces

  • Ley lines are not a phenomenon caused by any extinct cultures or anything like that; this is a natural force of the world

  • They are also not a creation of the gods or magic

In essence, I am looking for a natural phenomenon or something that could be a widespread phenomenon on some other world to use in this setting that meets most if not all the criteria above.

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    $\begingroup$ One main issue is going to be why your people evolved an ability to sense these lines. They'd have to point to something useful or otherwise offer a survival advantage, and it's not immediately clear to me how "historic or religious sites" meet that criterion. $\endgroup$ – imallett Mar 19 '18 at 4:52
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    $\begingroup$ If hey follow the same paths year after year, why would they need an esoteric navigation system? Polynesians confidently voyaged to destinations no one had visited in generations just using stars and other guides. $\endgroup$ – Kilisi Mar 19 '18 at 5:39
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    $\begingroup$ Are the lines always fixed, or can they shift? $\endgroup$ – Monica Cellio Mar 19 '18 at 12:52
  • $\begingroup$ Do you have to explain how it happens? They could be like salmon, which make their way back to the stream they were born in to spawn, but we're not exactly sure how. $\endgroup$ – HopelessN00b Mar 19 '18 at 13:40
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    $\begingroup$ @imallett historic and religious sites wouldn't cause ley lines, but intersections of ley lines could easily cause historic and religious sites - like how major cities form at the intersections of bodies of water, or highways, or railroads. $\endgroup$ – Tin Man Mar 19 '18 at 19:54
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What about Lodestone paths?

Some birds can handle long range migrations through being able to 'detect' magnetic fields; I don't know the specific mechanics of how they do that, but let's assume that your people have some iron-based 'sensors' in their minds, allowing them to detect the presence of small magnetic fields, or at least disruption of the primary one around the planet. This would likely only occur at short range, and may be felt at a subliminal level. They go a particular way because it 'feels' right.

Lodestone is effectively just naturally magnetised Magnetite, and this can be created by volcanic activity for one. So, what I'm thinking is that you have a world that was very volcanically active at an earlier stage, and that there was a large amount of lodestone created during that period. What happened however was that the lava ran along the many gullies and ditches that had been formed on the planetary surface, leading to a criss-crossing pathway of lodestone rich lava 'tubes' or 'lanes'. Over time, granite and other 'softer' stone breaks down and becomes soil that covers the surface a little more evenly. Your tribe naturally settle such areas of the planet because what igneous rock that does break down in addition to the granite makes the soil very nutrient rich meaning that agriculture thrives in such areas.

But, many of these paths (particularly the deeper or larger ones) still exist under the surface, and your tribe can detect the interference pattern that results from the minor magnetic field overriding the planetary one.

This gives you a reason why the paths would exist, a reason for your people to live close to them in the first place and has the added benefit of using minerals and science that currently exists.

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    $\begingroup$ Similarly, nodules of lodestone could form in a random distribution over the floor of a shallow ocean, then become covered by silt etc. This ocean floor, subsequently raised and drained, becomes navigable by sensing the buried natural magnets. - Same as your answer except with detectable vertices instead of detectable edges. $\endgroup$ – A. I. Breveleri Mar 19 '18 at 0:38
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    $\begingroup$ This was my first thought when I saw the question in the sandbox. $\endgroup$ – EveryBitHelps Mar 19 '18 at 13:48
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    $\begingroup$ IIRC humans actually do have a remnant of an iron "sensor" in our nose bridge, and it's theorized it developed to help us navigate as we spread out across the planet. To be honest though, that's really old info and I have no idea if it's accurate. $\endgroup$ – thanby Mar 19 '18 at 17:18
  • $\begingroup$ I absolutely love, love, love this response. I didn't even know something like this existed; that's why I love this site. Thank you very much! $\endgroup$ – Pleiades Mar 21 '18 at 23:55
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    $\begingroup$ @thanby We do, it's a tiny crystal of magnetite in our ethmoid bone where our nasal bones connect with the bone between our eyes. $\endgroup$ – Carduus Mar 27 '18 at 13:02
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It's the migratory birds.

The native birds use a stinging agent to digest almost any food available on your world. And by using terrestic navigation and magnetic fields to find their path, millions and million of years of continous bird droppings concentrated the stuff in the earth, embedded it in the trees and water.

The stuff can be immediately felt because it works as a very weak contact poison. But it is not stable, so it needs constant replenishment to be active.

Your population knows that birds are following the ley lines, but they got it wrong: They think the birds are using the leys for navigation while in reality the birds are the origin of the lines.

It also explains neatly why the nomads are following the lines: Birds also need food, water and rest, so the ley lines are guaranteed to provide them. Bird meat is raw inedible, so cooking is necessary, but the agent is destroyed by heat which also explains why people do not recognize the ley line feeling when eating birds.

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  • $\begingroup$ Upvote for creativity. This is such a bizarre response, and even though it doesn't really fit the overall theme of my world, this is still a very unique answer. $\endgroup$ – Pleiades Mar 21 '18 at 23:56
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    $\begingroup$ @Pleiades Nothing is as easy to overlook than the unthinkable. Dogs mark their territority with smell and we are completely ignorant of their invisible markings although it is very real in the dog world. There are also many chemicals which in very diluted form cause irritation, but are not consciously felt. $\endgroup$ – Thorsten S. Mar 22 '18 at 8:06
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Crustal cracks, and a radioactive core

Your planet could have cracks in it's crust, hidden by top soil and geologic layers deposited in the last few million years by rivers and wind.

These cracks could be caused by large moons (see this article about cracks on the Moon caused by the Earth's gravity), or by ancient meteor strikes during the planet's formation.

Some of these cracks may be associate with volcanic activity, but they don't all need to be. They could be thinner areas that don't go all the way through to hot magma underneath, or there could be another layer underneath that confines the lava.

The point is, that your planet has a radioactive core, and the crust has elements in it that shield the surface. At these points where the crust is thin, there is a measurable increase in radiation. Species on your planet evolved in this environment and aren't harmed by the radiation. In fact, in the very distance past this radiation was an energy source that assisted biota in developing into complex life and your creatures have a residual attunement to finding it. Think of the way plants on Earth absorb the sun's radiation and use it for food rather than other ways that radiation tends to harm us.

These crustal weak points could run long distances. Any formed by meteor impacts would probably lead to a number branching out from a single location and stopping after a certain distance (potentially hundreds of kilometers), while cracks due to large moons might go around the whole planet.

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  • $\begingroup$ The radioactivity wouldn't really help though, for one the plants are basically using harmless radiation, plus the only reason it's harmless to trees is that because they don't have much activity - they don't move, or digest anything, which means their cells aren't constantly replenished, meaning diseases caused by mutation (which will definitely be a result of increased radioactivity) like cancers are harmless to them. $\endgroup$ – somebody Mar 19 '18 at 10:57
  • $\begingroup$ what radiation is harmful/beneficial will depend entirely on your biology. Example: superman, yellow sun and kryptonite vs humans $\endgroup$ – Sir Adelaide Mar 20 '18 at 0:43
  • $\begingroup$ eh, well Superman isn't based very much on science, so as long as you're based on DNA nuclear radiation will be harmful. $\endgroup$ – somebody Mar 20 '18 at 0:55
  • $\begingroup$ @somebody fungi containing melanin show an increased growth when exposed to radioactivity - the mechanism is not very well understood, see radiotrophic fungus. A mechanism like that might work. $\endgroup$ – Arsenal Mar 20 '18 at 13:56
  • $\begingroup$ @Arsenal Well sure but if you have something that actually needs to actively move the negative side effects quickly outweigh the positives. Unless you don't mind making their average lifespan really short of course. $\endgroup$ – somebody Mar 20 '18 at 22:31
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A giant fungus or slime mold network.

The fungus is growing below the soil and tries to reach points of interest for it (source of nutrients basically). The network is highly optimized and uses lines to connect the important points.

Along those lines and at the nodes spores of the fungus will be present. Usually people won't notice them but the nomads have developed a method of sensing them although they are too small to be seen - microscopic analysis might discover them but spores are everywhere, so it might be hard to get down to this specific fungus.

As fungi get their nutrients by decomposing other stuff, the nodes are places where something is living for the fungus to decompose, so it's likely that people could find something useful for living or surviving there as well.

Depending on the weather the path of the last year might not be optimal for the fungus anymore, so the lines the fungus is taking might shift from year to year.


Real world example:

Here is a video of a slime mold forming a network resembling the train network of Tokyo: link The cities are made up as source of nutrients, after some time an efficient network has grown.


Building upon this idea, there could also be an explanation for religious sites along the network. On especially big nodes you could have high enough spore concentration for mild intoxication to occur (maybe inside a cave or something). This could lead to hallucinations which are seen as a message from The Great Funghu - a nomad deity.

If you need them to be magnetic, make that fungus absorb magnetic material in high enough concentration - it's not uncommon for fungi to absorb specific elements. After Tschernobyl some fungi were found to have a very high content of radioactive Cesium-137.

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  • $\begingroup$ I was thinking of something along those lines. But my thought was that their method of sensing them might actually be an allergy, so they get itchy feet or cold like symptoms when following the right track. I just wasn't sure it would fit with the requirement that it isn't affected by terrain or man made constructions. $\endgroup$ – adaliabooks Mar 20 '18 at 9:40
  • $\begingroup$ @adaliabooks yeah an allergy would work as well, but usually you try to avoid getting it... As for the question with terrain and man made structures, that might disqualify this depending on how hard that requirement is. I think it would be possible for the lines to go around a building because they are getting fed by the nodes, so they wouldn't die, but take a small detour. $\endgroup$ – Arsenal Mar 20 '18 at 9:44
  • $\begingroup$ it wouldn't have to be a particularly strong or debilitating allergy, just a tingling in your feet or your nose say. Something tangible (but possibly not understood) that lets them know they are following the right path. $\endgroup$ – adaliabooks Mar 20 '18 at 10:19
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Underground rivers

One of the many theories for what creates lay lines are flowing underground rivers and streams. These might be deep enough that normal construction would never alter them. Just as with load-stone or iron or veins laid by ancient lava pipes (which could now have water in) these would be invisible to the eye from the surface but produce faint electromagnetic lines.

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  • $\begingroup$ Would the field from an underground river be strong enough to detect, when it's on top of the planet's own field? $\endgroup$ – Draconis Mar 19 '18 at 16:38
  • $\begingroup$ Underground rivers only exist where you have karstic limestone. Everywhere else, you just get groundwater filling up the soil pore space until you hit solid bedrock. $\endgroup$ – Sir Adelaide Mar 20 '18 at 0:41
  • $\begingroup$ @SirAdelaide True, but the people in question would presumably live in an area with correct geology for their ability. So, maybe? $\endgroup$ – Ville Niemi Mar 20 '18 at 9:35
  • $\begingroup$ @Draconis Fields do not vanish from being within the influence of one another. Someone or something sensitive enough should be able to detect it. It could be a very large river if you need the field strength to be high. $\endgroup$ – TafT Mar 21 '18 at 10:28
  • $\begingroup$ @TafT They don't vanish, no, but it seems like they'd be looking for stars in the daytime. $\endgroup$ – Draconis Mar 21 '18 at 17:46
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Infrasound.

Those people are folowing The Hum. On our own Earth there is nothing conclusive about that, but it is not a stretch for it to be a real thing in a fictional world.

What matters there is that the nomads either feel the minute planetary vibration on their skin rather than hearing it, or if they do pick it up with their ears, their brain processes it differently.

Or they might be "feeling" the vibrations of tectonic plates, crushing against each other - the paths could exist along fault lines (and maybe magma plumes);


As an alternative, rather than sounds, their ears might be picking up variations in the gravity of the planet itself (through the vestibular system). Our Earth's gravity is not homogeneous throughout the planet, though we are not sensitive enough to detect its variations. The nomad people in your story might be different from us in that aspect.

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Meteor impacts and vulcanism have created iron deposits that disrupt the smooth flow of the world's magnetic field. Instead of world-circling arc, pole-to-pole, there is a general 'polar' field that is significantly disrupted by what are in effect giant lodestones. These 'pinch' the magnetic field, so depending on where you are starting from you would take a different path to get to the lodestone - and then have choices for where to go next (which lodestone).

Knowledge of which path connected to where would be important and the destruction of a lodestone could have major impact. Maybe someone who had connected this navigation to celestial navigation skill could become significant in the event of lodestone destruction (volcanic action, earthquake or maybe creation of a new lodestone).

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