Jump to content

Tides on moons of a gas giant - avoidable?


ruiluth
 Share

Recommended Posts

Hi everybody. So, one of my hobbies in addition to KSP is the creation of a fantasy world, and I was recently inspired to make my world a moon of a gas giant instead of its own planet. However, after reading this thread I realized that I might have daily 50 foot tidal waves if I do that. So my question is, can I position my moon in such a way that it avoids this? I had planned to have five other large moons in the sky, with this world being the fourth of the six, but I'm open to changing that. Would placing it farther out lessen the tidal effects of the other moons? Would placing it closer to the gas giant's gravity well have the same effect? I am planning to have this world tidally locked, by the way, so I believe that should eliminate tidal waves caused by the planet itself, even if it makes for some weird oceans. Any help on this would be appreciated, so thank you in advance!

Link to comment
Share on other sites

http://astronomyonline.org/Science/TidalForces.asp

I assume you want to keep it simple and not take into account for the influence of different bodies. Looking at the formula, just keep the distances large. You can't do much about the masses and radii since density is a feature of the the material which is rock (2.5 to 3.5 g/cm³) or iron (around 8g/cm³) or a combination.

Don't use KSP as a guideline. Bodies are far too small and far too close together, just keep the distances large like irl and you're fine with your fantasy world :-)

Edit: here is a better version of the formula, since i feel the first link doesn't make clear that there is a difference in forces between near and far on the bodies.

Edited by Green Baron
Link to comment
Share on other sites

1 hour ago, Green Baron said:

Don't use KSP as a guideline. Bodies are far too small and far too close together, just keep the distances large like irl and you're fine with your fantasy world :-)

One thing I should mention is that my world is 1/7 the size of earth with similar gravity, so I'm already handwaving a bit of physics here... I suppose the best solution might be to handwave even more, but keeping distances large relative to mass does make sense if I'm trying to keep it as close to reality as possible.

Link to comment
Share on other sites

22 minutes ago, ruiluth said:

One thing I should mention is that my world is 1/7 the size of earth with similar gravity, so I'm already handwaving a bit of physics here... I suppose the best solution might be to handwave even more, but keeping distances large relative to mass does make sense if I'm trying to keep it as close to reality as possible.

Why would you need it so small? 
Lower density moons, think mars would work better as they will look larger. If you want easy spaceflight use 0.75-0.5 g gravity, 

Only constrain is that an far orbit gives longer days, it can easy become very long ones. Europe has 3.5 days, Ganymede has an week, 

Link to comment
Share on other sites

8 minutes ago, magnemoe said:

Why would you need it so small? 
Lower density moons, think mars would work better as they will look larger. If you want easy spaceflight use 0.75-0.5 g gravity, 

Only constrain is that an far orbit gives longer days, it can easy become very long ones. Europe has 3.5 days, Ganymede has an week, 

This is a really good point if I do want tidal locking. The main reason for making is so small is because my world map just happened to scale out that way when I started overlaying latitude lines on it :P Although I already know that this planet is highly magical, so I'm wondering if it might be better to just say that it isn't affected by its system. It's also hollow with a habitable interior surface, so there's already a ton of weirdness going on with it... That would actually lead to some interesting storytelling opportunities too, if this one moon behaved differently from every other moon in the system.
So I suppose I've answered my own question :sticktongue: Thanks guys!

Link to comment
Share on other sites

2 hours ago, ruiluth said:

This is a really good point if I do want tidal locking. The main reason for making is so small is because my world map just happened to scale out that way when I started overlaying latitude lines on it :P Although I already know that this planet is highly magical, so I'm wondering if it might be better to just say that it isn't affected by its system. It's also hollow with a habitable interior surface, so there's already a ton of weirdness going on with it... That would actually lead to some interesting storytelling opportunities too, if this one moon behaved differently from every other moon in the system.
So I suppose I've answered my own question :sticktongue: Thanks guys!

Ok, it sounds like the planet doesn't even try to adhere to the laws of physics, so I really wouldn't worry about tidal forces! After all, what does it add to the story?

Link to comment
Share on other sites

This thread is quite old. Please consider starting a new thread rather than reviving this one.

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...