In order to account for an immense amount of technological and cultural disparity, I have been attempting to figure out ways that the world in a setting could be extremely hostile to travel. The idea I came up with was to have a planet that is majority-water with two moons that have extreme effects on the tides of the world, thus making sea travel (and even coastal living) an arduous task.

  1. What is the effect that two moons would have on the planet's tides?
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  • $\begingroup$ Welcome to worldbuilding. Please narrow down to a single specific worldbuilding question, according to our help center $\endgroup$ – L.Dutch - Reinstate Monica Jan 12 at 19:45
  • $\begingroup$ Please specify. How big and or close are the moons? $\endgroup$ – 11Bravo Jan 12 at 19:53
  • $\begingroup$ However big and however close they need to be to cause the desired effect. $\endgroup$ – Rick Jan 12 at 19:58
  • $\begingroup$ Can you explain more about the desired effect that causes problems for sea travel? For example, are you imagining giant waves at sea frequently washing ships away? $\endgroup$ – TheUndeadFish Jan 12 at 20:58
  • $\begingroup$ I was thinking something like that, very large waves that present a serious risk of capsizing, waters that are hard to navigate, sudden extreme low tide causing hulls to slam into rocks and coral that would otherwise be harmless. As well as the issue of extremely high tides washing away or just flooding coastal structures. $\endgroup$ – Rick Jan 12 at 23:00

Tides are predictable.

The thing about predictable hazards is that they are less hazardous. If you know it is dangerously cold you can prepare for the cold. If you know there a fierce beasts you can come armed and in strength.

Tides are eminently predictable and seafarers have been using knowledge of tides for millenia. Super high tides would not make it more difficult to live on the coast because you would live above high tide, as people do. Super low tide would not make it hard to sail around because your boats would sit on the bottom and you would sit in the bar until the tide came in.

Until they aren't...

I am thinking of 2 moons in a stable orbit like Phobos and Deimos. But what if they weren't? What if 100 years before a new moon showed up. The old moon was thrown into an elliptical orbit. Now you have some adventure possible. The 2 moons are not in a stable orbit and are jockeying for position. High tides when both are closer are higher than anything in recorded history. Low tides expose the ocean floor for miles.

It would be very tough to predict what tides would do. That might work for your story. Plus if the arrival of the moon were historically recent the shock of unpredictable tides would impact society harder.

  • $\begingroup$ Sounds very similar to the unpredictability of Game of Thrones LongNight/LongSummer $\endgroup$ – EveryBitHelps Jan 13 at 0:15

with how Willk says it there is little else to say, but one thing here is that you could get the moons in a type of twin orbit, but with a twist, one moon orbits the other sometimes, this could make the tides very, very high, or very very low, if the moons are at a sufficient distance you wont have to worry of the second moon crashing into your planet, and there are more variable key factors, such as the pull of the moons, their size, the gravity of your planet, the sun, the atmosphere gasses, and so much more, also another factor is the actual water, is oxygen diluted in it, is salt? etc.

edit: i forgot the size of the star, the type, the zone you are in farther or closer, and the actaul size of your planet : )

i know this is not the answer you were looking for, but i hpe this helps, also this would do great on the astronomy and physics stackexchanges also, for this kind of questions you need to add the hard science tag


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