Tidal Bulge

[Space_Goose]

Hello, in doing some more research for the story I am writing, I learned that not only does the moon cause high tide on the side the earth facing the moon, but the moon also causes high tide on the opposite side of the earth facing the moon at the same time.

I was wondering if a gas giant would have a simular affect on a moon. I assume the affect on tides would be greatly enhanced by a gas giant compaired to our moon because of the great gravitational pull, but I was wondering if a gas giant would also cause a hi tide on opposite side of the moon at the same as the side of the moon facing the gas giant. Again, incase you didn't see my other post, my moon is tidally locked to its gas giant and is very swamply and full of lakes and shallow seas. So being that my moon is tidally locked, would it still have a tidal bulge on both sides and if so, would this cause two sides of the moon to be nothing but shallow seas at all times?

Thanks,

 

[origin]

Hello, in doing some more research for the story I am writing, I learned that not only does the moon cause high tide on the side the earth facing the moon, but the moon also causes high tide on the opposite side of the earth facing the moon at the same time.

I was wondering if a gas giant would have a simular affect on a moon. I assume the affect on tides would be greatly enhanced by a gas giant compaired to our moon because of the great gravitational pull, but I was wondering if a gas giant would also cause a hi tide on opposite side of the moon at the same as the side of the moon facing the gas giant. Again, incase you didn't see my other post, my moon is tidally locked to its gas giant and is very swamply and full of lakes and shallow seas. So being that my moon is tidally locked, would it still have a tidal bulge on both sides and if so, would this cause two sides of the moon to be nothing but shallow seas at all times?

Thanks,

Sounds right to me. The seas would only occur where there are not highlands of course.

 

[Space_Goose]

Well, in doing my discription of the moon and how it worked, I took Saiph's advice and according to Saiph if my moon was tidally locked to a Gas Giant, It would be reletivly flat, marshy and full of lakes. My moon doesn't have plat techtonics but it does have a molten iron core which creates a magnetosphere which helps protect the wild life from the radiation of the Gas Giant. This Iron core would also mean that I have to account for volcanic activity as well. In my discription, this mainly takes place in the form of Gysers and geothermic vents in the seas but it would be unrealistic I think to have a moon with an Iron core that doesn't have ANY volcanos. So I suppose, even though their are not really any highlands on my fictious moon, there could be Volcanic islands in the shallow seas in fact I think this scenerio is probably very likely. But for the most part, I think it would be more scientifically accurate for the main land mass or contenents/countenent to be on the sides of the moon (in respective on which side faces the gas giant) The side that faces the gas giant and the side directly opposite of this are mainly shallow seas with puhaps a few volcanic islands.

If any one doesn't agree with the above, please let me know. I appreciate everyone's help and responses.

Thanks

 

[MeteorWayne]

One problem I see is that an iron core that is not rotating at a substantial speed would not create a magnetorsphere.
The iron core is not a magnet, rather it creeates a self sustianing dynamo. Not sure how to make that happen in a tidally locked planet, unless it's close enough to broil everything (and leave no liquid water) and the orbital period is a day or two. I don't think it would work even then.

Pondering....

 

[Space_Goose]

Thanks MeteorWayne for the comment. That is a good point, am certainly not an expert in this field which is why I am bowing to everybody on the forums superior knowledge and am looking to learn the science to make my moon work.

I do think I am going to keep the molten Iron core though because the release of heat through the geothermal vents and gysers along with the thick atmosphere my moon has is how my moon stays warm even though it orbits a gas giant beyong the goldielocks zone. So basically my moon is creatiing it own heat and the atmosphere prevents the heat from escaping so that the moon is warm even when it is on the opposite side of the Gas Giant from its star. My moon is actually very geothermically active but as I said mainly gysers and geothermic vents.

But MeteorWayne, doesn't Jupiters moon Ganymede have a magnetosphere and isn't it tidally locked?

And also do all Gas Giants produce radiation like Jupiter? If not then I can eliminate this by simply making the moon orbit a gas giant that doesn't omit radiation.

Also the intelligent race on this moon, have very thick skin and spins and plates much like some of earths dinosaurts to help protect them from some of the radiation.

 

[Shpaget]

Remember, the magnetosphere and the ozone layer are not here to protect us form radiation. They just happens to be around. It is the life on Earth that evolved in this shielded environment and is so spoiled that it can't survive without its protection.

You can make your lifeforms naturally resistant to radiation. It is SF and as long as you provide a good reason why they should be unaffected by it, it's OK (or more precisely, it's all right as long as you don't offer a bad explanation).

 

[Space_Goose]

by Shpaget » Sun Dec 13, 2009 4:16 pm
Remember, the magnetosphere and the ozone layer are not here to protect us form radiation. They just happens to be around. It is the life on Earth that evolved in this shielded environment and is so spoiled that it can't survive without its protection.

You can make your lifeforms naturally resistant to radiation. It is SF and as long as you provide a good reason why they should be unaffected by it, it's OK (or more precisely, it's all right as long as you don't offer a bad explanation).

You are right of course. I suppose for my story as long as I just made it clear that humans had to wear protective gear to visit the moon due to the high radiation. I will also add in that aliens of the moon have thick skin with plates and spines to help with protection from Radiation and leave it at that.


I still think during my research that I read somewhere that Jupiters moon Ganymede has a magneotsphere, in fact I think I read it is the only moon in our solar system that has one. It also happens to be the biggest moon. But my made up moon is even bigger, larger than the planet of Mars. I mention that because, I am not sure if Ganymedes size has anything to do with it having a magnetosphere and being that my moon is bigger...... But as Shpaget said, I suppose it doesn't really matter.

Thanks guys.

 

[Shpaget]

It is true, Ganymede has magnetosphere and it is the only moon in solar system to have one, however, it is several orders of magnitude weaker than Earth's.
Wiki has a rather extensive articleabout Ganymede, including somewhat complicated magnetic field it creates.

Oh, just a suggestion, if I may.
If your species is intelligent (approx human level or higher), it might not be wise to give them thick scales. Look at the humans and other primates. We're pretty weak, soft and fragile compared to other animals on this planet.
Why not give them protection at sub-cellular level? That is if you chose to build them from cells.
Gamma radiation is dangerous to us because it alters and breaks DNA, but if you don't give your species a DNA, you don't have to worry about it.
One other example would be if radiation is so ever-present, an intelligent species would have hard time detecting it. It took humankind a long time to realize that there is air all around them.
So they can be completely ignorant of radiation's existence until human explorers/conquerors/heroes arrive and start dying from extended radiation exposure (humans would probably be aware of it, but accidents happen).

 

[Space_Goose]

That is a good suggestion, the problem I see in that, is if they do not have DNA..... how do their bodies work, how do they pass on genetic information? If I go that route, I will have to enter a whole new science that I know even less about. And, this moon is and its people are not the only civilization in the universe, I still have other planets to research. So, if they didn't have DNA, how would it all work. I still do want them to be very brutish and phyically intemidating. In my short story, these aliens were friendly. However, since I have decided to continue writting and expand my story. I have made these people not so friendly. They are intelligent but while they do have the technology to space travel and such, they are still very brutish comparied with the other aliens in my story.

 

[Shpaget]

Than you can just give them a gene for radiation resistance. Natural selection and evolution should make sure it happens.

It's hard to judge and suggest anything with so little information and I really shouldn't impose my ideas and thought. It's your story, you're the only one that knows what's it all about and how will things work.

 

[Space_Goose]

No worries, I appreciate any input ideas or suggestions. Basically, I am just trying to make sure that my ideas are scientifically accurate. The good thing about dealing with a ficticious moon is that you can alter and change the story slightly to make it fit with science. I am actually enjoying reading all the comments even if I choose not to use an idea. I actually wanted to go into astronomy when I was in college but I let my parents pressure me into going into a field that was "in more demand" and that "paid more money". So I have always been interested in all of this. If only someone could invent a time machine and I could go back and talk myself into it. But oh well too late now. Thank you for your suggestions.

 

[SpaceTas]

Too late for your story but ...

The tides are due to the difference in gravity between where the water is at and the Earth. The surface of the oceans on Earth try to match an equi-potential surface. The force of gravity is equal everywhere on this surface. Think of 3d version of a contour level rather than a slice through a hill. The shape of this surface is an ellipsoid. On earth the ellipsoid doesn't line up with the moon because of friction with the rotating Earth. So the tides lead the moon. The solid ground of the moon and Earth also show a tidal bulge (about 6cm on the Earth). This solid bulge also is not lined up along the Earth-Moon axis because each is in orbit about the other. Torques on this bulge allow transfer of momentum from rotation to orbits. Hence at the moment the Earth's rotation is slowing down and the Moon's orbit is getting larger.

I suppose your moon would have even larger tides but only if the water moves around freely (Oceans). There would be larger movements in the ground.