Ringworld / Sphereworld |
If I understand correctly, they are the same things, right?
Also, I believe I read somwhere here on the forums that they can only be colonized by Rock Colonizer ships. Is that also correct?
Thanks
Although apparently not THAT
Although apparently not THAT much bigger, which makes it a bit odd. You'd think a sphere, with its obviously superior surface area, would be larger than merely twice a ringworld.
Thanks
Ringworld = a ring, sphereworld = a sphere. One is bigger than the other, and takes more tech.
_______________________
There are 10 types of people in the world:
Those that understand binary, and those that don't.
Thanks, Rilbur, I can see the distinction now. 
That takes care of the first question, what about the colonizing thing? And can you provide a bit more information? It would be appreciated.
To the comment about a
To the comment about a sphere world needing to be more than twice the capacity of a ring world:
Not really. If you notice the spin on the sphere worlds. The only reason for that spin is to simulate gravity. The closer you get to the top and bottom of the sphere the less gravity there will be and it will feel all sorts of screwey. So I guess a gaint portion of that sphere would be uninhabbitable.
Are there any indepth
Are there any indepth explanation of sphereworlds/ringworlds?
I remember you could make them in SE4 but I never quite figured out how.
Trying to figure out how you go about making one, what type of planet its considered for colonizing purposes (Rock, ice, gas?) and the techs you need.
What you need is...
Trying to figure out how you go about making one, what type of planet its considered for colonizing purposes (Rock, ice, gas?) and the techs you need.
What you need in SE5 is a single star system with nothing in the 6 hex radius around it. You need high levels of stellar Manipulation (80+ in stock game), and lots of ships loaded down with lots of materials like a Ring World/Sphere World Placement Generator, 10 planetary gravity plating, and 10 Hyper Dense Cables.
Progress isn't made by early risers. It's made by lazy men trying to find easier ways to do something.
-- Robert Heinlein
GREAT! Thanks!
Trying to figure out how you go about making one, what type of planet its considered for colonizing purposes (Rock, ice, gas?) and the techs you need.
What you need in SE5 is a single star system with nothing in the 6 hex radius around it. You need high levels of stellar Manipulation (80+ in stock game), and lots of ships loaded down with lots of materials like a Ring World/Sphere World Placement Generator, 10 planetary gravity plating, and 10 Hyper Dense Cables.
Progress isn't made by early risers. It's made by lazy men trying to find easier ways to do something.
-- Robert Heinlein
Thank you VERY MUCH, Dragagon, that wa by far the most complete answer yet!
Do you also happen to know about the proper type ship needed for colonization and perhaps the maximun number of colonies that can be established?
Ring/Sphere colony
Do you also happen to know about the proper type ship needed for colonization and perhaps the maximun number of colonies that can be established?
You actually have to construct it yourself. by building ships large enough to hold the 2000kT parts (thats per Plating and Cable). You ship it all over to one spot next to the star, then, using the ship with the Generator you "Build" the ring/sphere. It creates a planet that "should" be your original planet selection (rock if you started with rock) and the atmosphere you breath (oxy, meth, whatever). From there I'm not certain but i believe you then colonize it like any other planet. Only 1 colony, but its absolutely huge in size. To the point that most players consider the game won when they have just one of these (against an AI anyway).
Dragagon
Progress isn't made by early risers. It's made by lazy men trying to find easier ways to do something.
-- Robert Heinlein
Thanks Again!
Thanks again, Dragagon - I'll be giving it a try (several hours from now, though).
Gravity and Rotation
Not meaning to be picky, but i believe the reverse is actually true. The spinning creates centrifugal force, which is opposing gravity. The closer you get to the top and bottom of the sphere, the more the effect of gravity would be felt. (and it would be a LOT, considering the proximity to the star). The result would be the same of course, ie: these zones would be less habitable than the equatorial regions.
As i said, i don't mean to be picky, but I had this out with a friend who believed that if the earth stopped spinning, there would be no gravity, and would not believe me when i insisted that gravity was based on mass, not rotation.
I had to dig up some web pages to prove him incorrect, as he was so sure of himself. Here is one such page:
http://www.newton.dep.anl.gov/askasci/phy99/phy99x82.htm
(OMG, i'm such a geek lol)
-Noc-
Mind benders
it's really kind of a mind bender... Gravity pulls you towards an object, the object has to have enough mass to generate that gravity. I'm not sure a hollow sphere would have that mass. you can't count the entire sphere's mass into account, because most of that is pulling you from above you (if your on the inside of the sphere, which is were you should be if you want any sun exposure).
I think that it would be the spin that holds you to the inner surface of the sphere world. The radius of this sphere would have to be close to 93 million miles (1AU), around our sun, other stars would produce more heat and light so they'd have to be either dampered down or a larger sphere...
So the question remains what happens at the internal pole regions. If it is spin that holds you and the atmosphere in against the sphere then there wouldn't be any spin at the pole areas. walking towards the poles I think it would be like climbing a mountain, the atmosphere would get thinner and then you'd reach an area where your weight would reduce, if you put on a space suit and continued walking, you would eventually reach a point were you would fall towards the star...
I think the spin of the earth does have something to do with the electromagnetic fields around our planet...
The faster you spin...
... the greater the force applied. You rely on Cetrifugal force to simulate gravity. The inside of the Sphere or Ring is where you live, not the outside shell. There would be less 'gravity' at the equator than at the poles with a Spehere. A Ring world is actually more manageable since the area you have to engineer for is smaller - let alone all the material you save. If any part of a sphere world cannot be effectively used, then you are better served with a ring world. I would imagine you would have to engineer a sphere world so that the rotation decreases as you reach the poles.... hmmm....
Ya
I think people were going on the fact that you lived on the outside. But, you really live on the inside of it, unlike a conventional planet, therefore the spin would be causing the gravity. There are references to this being put to work in sci-fi novels and shows, which, while fictional, usually have some basis in fact on how physics work.
Larry Niven
...read Ring World by this guy. Fun book.
Yep, you live on the inside since 'life' pretty much needs sunlight. You won't have enough localized mass to really satisfy your gravitationl needs if you lived on the outside of the sphere.
Point of Sphereworld is to fully utilize all the sunlight
Exactly. You live on the inside of the sphereworld. In theory, if you have the tech to build a sphereworld, you also have the tech to fully convert all that sunlight to power. Oh, and yes, I heartily recommend the Ringworld books by Niven. Also, there is a Star Trek: The Next Generation episode that features a wormhole. If you are interested, do a search for the episode title 'Relics'. That particular episode features James Doohan playing the same role from the original series.
My mistake.
I was indeed assuming that you live on the outside. I should have known better, having seen and read vast amounts of sci-fi over the years. Disregard the bulk of my last post lol.
Depends....
Depends on how "thick" the ringworlds ring is. Or is that wide?
_______________________
There are 10 types of people in the world:
Those that understand binary, and those that don't.
Sphere World Gravity
I doubt sphereworlds would generate their gravity Via. spinning, as that leaves the obvious hole of the poles having next to no gravity.
_______________________
There are 10 types of people in the world:
Those that understand binary, and those that don't.
more power!
True, you would have quite a bit of power from that. I was thinking in terms of livable space.
Spinning would be the simplest way to generate gravity. Also, as raynor points out: not all the sphere is necessairily used for living so having gravity uniform is not important.
Interesting
This whole thread has become interesting (and a bit amusing at times) because it's pretty obvious that we've got some folks here that haven't spent much time studying physics, astrophysics, or the concept of the Dyson Sphere.
First, just to be clear even though it's already been mentioned a few times, the colony is on the inside of the sphere. Second, the spin, through what we call "centifugal force" (though it really isn't a true force and is merely a product of inertia) indeed does produce the gravitational effect. And the rate of spin could be adjusted to produce any amount of apparent gravity you wanted.
And last, there would be NO poles present at all. If the sphere is perfectly centered, the artifical gravity produced and the anount of radiation (heat from the sun) would be equally uniform over the entire inner surface.
In order to experience a reduction in 'gravity" you'd need only to rise above the surface - towards the sun. And yes, there would be a point between the surface and the sun where all the forces would be nullified - very much like the LeGrange points between the Earth and our moon.
Hope that helps clear things a little.
...
No offense, but "poles" in this case would still exist. It doesn't matter HOW you stack the dice, you have to have an axis of rotation and where that axis meets teh surface of the sphere, the centrifugal force (yeah, what a lovely misnomer...) would virtually vanish (and at the point where they touhc, it WOULD cease to exist). Unless of coures, you want to rotate along two or three axis at once, and I think that'd have some major problems associated with it too (and they only do it in once axis-in game!).
Personally, I suspect that they'd use gravity generators of some kind... after all, they already have unobtanium, why not be able to play with gravity?
_______________________
There are 10 types of people in the world:
Those that understand binary, and those that don't.
No Offence Taken
Personally, I suspect that they'd use gravity generators of some kind... after all, they already have unobtanium, why not be able to play with gravity?
_______________________
There are 10 types of people in the world:
Those that understand binary, and those that don't.
Absolutely no offence taken. But true Dyson shpere actually would be made to rotate in two planes at the same time - completely eliminating poles in order to prevent exactly what you and others have mentioned so that the entire inner surface is habitable.
And I wasn't talking about the game. But you're certainly correct that they would most likely have unobtanium along with isotopes of yacantgettium so that they could do all sorts of strange and wonderful things. (Like Heisenberg Compensators, for example.)
But in the meanwhile, I'll stick with 'normal' physics and what's known to work - just as I described it.
In that case...
Given that spherworlds rotate in one axis in game, how do they keep the atmosphere decent? 
edit:
And, while I haven't done the math, wouldn't rotating in 2 axis still leave a few places where the "gravity" ends up weak, in the places between each pole? Or maybe right on each pole...
Or is it one of those weird things, and the losses caused by leaving one pole are gained through another? I don't THINK you'd have that -- if only at the place at a right angle to each axis you'd end upw ith double compared to the "poles" themselves, I think -- but anything is possible.
_______________________
There are 10 types of people in the world:
Those that understand binary, and those that don't.
No Beans Allowed
By not allowing the agriculture units to produce beans.
And, while I haven't done the math, wouldn't rotating in 2 axis still leave a few places where the "gravity" ends up weak, in the places between each pole? Or maybe right on each pole...
Or is it one of those weird things, and the losses caused by leaving one pole are gained through another? I don't THINK you'd have that -- if only at the place at a right angle to each axis you'd end upw ith double compared to the "poles" themselves, I think -- but anything is possible.
No, but rather than drag you through all the calculus and the intergrations, I'll simply say that the choice of rotational planes can be made so that there aren't any nulls or additive-effect points.
This thread has sparked my
This thread has sparked my interest, so i've just been doing a bit of light reading on the subject. It seems that the dyson sphere that everyone pictures is actually a "rigid dyson shell", as a true dyson sphere is not one solid ball but many independent collectors in a spherical formation around the star.
As i'm very tired, i'll steal a couple of interesting paragraphs directly from one text i've just read:
(for the complete text go here: http://www.nada.kth.se/~asa/Hx/dyson.html)
A nonrotating dyson shell would have just two sources of gravity: the shell itself and the star. As mentioned above, on the inside only the gravity of the star would be felt and everything would fall down into it, while on the outside there would be weak gravity (for a 1 AU sphere centred around the sun, the gravity would be 6e-3 m/s2).
The only ways to make a rigid Dyson shell habitable on the inside would be either to provide it with some sort of antigravity (which is unlikely) or to rotate it, which would make only the equatorial band habitable unless the interior was terraced. A rotating dyson sphere would be under immense strains; see the section about the ringworld for a simple calculation. Niven pointed out that if you want to spin a Dyson sphere, it is better to build it like a film canister for reasons of structural strength, and then you have a Ringworld.
It has been suggested that one could live on the outside of the sphere, especially if the interior star is rather cool; it appears that a terrestrial environment is possible around M stars just at the end of the main sequence.
And also
After reading a bit about the subject I see a few possibilities as to how the sphere worlds in the game would be feasible (by stretching the imagination a bit).
One possibility would be the "shell within a shell" method, whereby people would live on the outside of an internal shell.
Another idea is that, since gravity plating is used in the construction of the sphere world, the game's technology may be advanced to the point where gravity can be negated entirely, either through artificial means (gravity dampening fields or some other sci-fi technobabble BS) or by using superdense materials with extreme mass and therefore their own gravity.
Anyway, it's late, and my brain hurts, but hopefully I will read more interesting thoughts on the subject from you guys tomorrow.
I think my brain just
I think my brain just exploded trying to imagine how you could rotate a sphere along 2 axes...
I Can Understand That
Ha-ha! I understand because I remember how I felt the first time I came across it over 40 years ago.
But it's not so bad at all. Picture it this way: Think of of it rotating on a single axis. Remember that it has an axis but NO axle. So there's nothing to keep it from rotating around a second one perpendicular (90 deg) from the first. Both movements are totally independent of each other. Even skydivers can do it - they can fold their legs and arms in and tumble head over heels while also rolling their torso.
And once you visualize that, you'll next realize that there's nothing at all to keep the sphere from rotating in any number of planes at the same time.
2 but not 3...
Whew, i can get it to 2 planes. thats really no big deal. I am trying to visualize the 3rd plane of rotation but it is tough with the first 2 already moving as well... heh
Dragagon
Progress isn't made by early risers. It's made by lazy men trying to find easier ways to do something.
-- Robert Heinlein
Non-Euclidean Geometry
Uhh... the basic tenets of geometry would indicate that it is still only rotating along one axis at a time; you are just changing the axis of rotation. Planes and axes are completely fictional constructs designed to make analysis easier; they are arbitrarily oriented to suit the situation at hand. If you apply a (equal to the original in magnitude) force at a 90 degree angle from the original axis of rotation, the sphere would begin rotating along an axis that is 45 degrees from the original axis. It is no longer rotating along the initial 0 degree axis, and is not rotating along the 90 degree axis.
Rotating along 2 axes at once would require some bizarre non-Euclidean geometry...
Thank you cosmic marvel for
Thank you cosmic marvel for that explanation of the multi axis rotaion, I can picture it in my mind now.
my question would be... does that exsist in space, or is that theoretical... my point is, do we have any planets in our solar system rotating on more than one axis, or does some other physical thing stop that and force one axis rotation?
Fayron - I imagine it's kind
Fayron - I imagine it's kind of like braking up linear motion into vectors. you can have a horizontal componet and a vertical component. They do add up to a third dirrection.
With rotation you have one spin, and another spin, they can be analized separately, but in reality they add together to produce a third spin... I think....
Gyroscope
So you are telling me its nothing like those 3 axis gyroscopes you can latch people into and utilize 2 axis? i imagine i can spin in one axis of rotation, causing gravity on the insides of my ribs, but not at my head or feet. But what do you think happens when i begin to spin head over heals at the same time? there is no independent pole at that point. Yes some areas experience more force than others but no place has 0 force applied to it.
Dragagon
Progress isn't made by early risers. It's made by lazy men trying to find easier ways to do something.
-- Robert Heinlein
meep
Horizontal, vertical, etc. vectors in linear motion are also completely imaginary tools for analysis. The object isn't actually moving horizontally and vertically, it is only moving in one direction. You can simply reorient your axes to get the motion being a straight line along the x axis, for example.
You are right, the rotation thing is just like vectors; both are imaginary constructs to make math simpler, but they are not actual physical properties. Being able to break the rotation of a sphere into two components along chosen axial planes for analysis is nice and all, but it doesn't mean that the sphere is in reality rotating in two different ways, creating different "centripetal forces" than if it was "rotating on one axis." If you look at the broken down rotations, the "centripetal forces" involved will be component vectors of the "centripetal force" created by the real single rotational axis.
In reality, a sphere can only rotate along a single axis of rotation, which can of course be oriented in way you choose. As soon as you apply force to "add" a spin in a different direction, you change the axis of rotation. There are not multiple axes, there is just one. The "centripetal forces" change direction, yes, but the net result is identical to the old axis of rotation (assuming overall speed is the same, just in a different direction). You have the same type of apparent gravity, you've just change where the poles are and what planar circumference is the equator.
In fact, you don't even have to add another axis rotation of rotation to get subcomponents... just reorient your xyz axis, and go from there.
You're Welcome
my question would be... does that exsist in space, or is that theoretical... my point is, do we have any planets in our solar system rotating on more than one axis, or does some other physical thing stop that and force one axis rotation?
You're very welcome, Rilo.
To answer your question directly, no - planetary bodies generally have only one axis of rotation. And yes, there is a physical reason (in one sense, anyway) for that being the case.
To explain, we need to delve into astrophysics for just a brief moment. Planetary bodies, indeed, even galactic bodies, are formed from/in what is called an accretion disk. That plane has a single axis which is usually a star or the galactic center. The bodies that are formed obtain their spin from the angular momentum present in the orbiting debris in that disk as the various bits and pieces coalesce into a larger body, such as a planet.
On the other hand, asteroids, comets and other rather rogue bodies can and DO exhibit spins in multiple planes. Cosmologists and astrophysicists even have a highly technical term for that motion - they call it "tumbling." Ha-ha! Seriously, that IS the correct word which stands in contrast to simply "rotating."
And equally seriously, any free-floating object (which a planet is obviously not) can exhibit that behavior. That's why I was careful to point out that an axis WITHOUT an axle (like a wheel often has - think of a car or a gear) has nothing to restrain it from other independent coexisting motions. (And even an automobile wheel can do that when it becomes detached from the road surface. Picture the vectors involved if a car tumbles sideways down a cliff while the wheels are still spinning in was was their original direction of travel.)
Tumbling
Ha-ha! Seriously, that IS the correct word which stands in contrast to simply "rotating."Yeah, that caught me off guard by our PhD Math Teacher at the university until he explained that due to gravity the object is "falling into" the other object. Thus tumbling becomes an appropriate term.
Dragagon
Progress isn't made by early risers. It's made by lazy men trying to find easier ways to do something.
-- Robert Heinlein
Not a Gyroscope
Plus, I don't think you can necessarily apply the effects of strapping into a Gyroscope to the inner surface of the (inner) sphere. Let's say you have a 2 sphere gyroscope. Rotate the outer one along the xy plane, so that the z axis is your axis of rotation. Now, add a rotation of the inner one along the yz plane, so it's axis of rotation is the x axis. What does this add up to on the inner surface of the inner sphere?
If you use the same speeds for the two spheres, I think you'd get the same exact effect of just rotating a single sphere along an axis that exits at 45 degrees from all planes, since the rotations would effectively combine linearly. Which two opposite 3d quadrants this axis passes through depends on the directions of the two rotating spheres. Each subcomponent of the overall centripetal force vectors along each xyz axis being applied by the rotation of each sphere would simply add together linearly.
Imagine a point that exists on the intersection of the spheres with the positive y axis. If you just rotate the sphere clockwise along the xy plane, that point moves around the circular intersection of the sphere with the xy plane, in a clockwise direction. If you just rotate the sphere clockwise (relatively) along the yz plane, you get the point moving around the circular intersection of the sphere with the yz plane. Now, if you have the two nested (and somehow connected) spheres rotate as described previously, the point will move along both the xy and the yz planes simultaneously. In reality, they will move along a perfectly circular path that orbits the new axis of rotation (the axis 45 degrees from the planes above).
If you have the two spheres move at different speeds, and somehow manage to keep the spheres connected so that the motion of the outer sphere effects the inner sphere, the axis of rotation will be tilted away from the 45 degree axis, depending on the speeds. I think you will still get an essentially circular orbit, but it will just be tilted as well. It gets difficult to explain without graphs at this point.
If you want to try 3 concentric spheres, you will get the same type of linear combination effects, I think...
Good Point
Thats a good point Fyron. oh well. I'll leave it up to those more inclined to care at this point. I concede.
Dragagon
Progress isn't made by early risers. It's made by lazy men trying to find easier ways to do something.
-- Robert Heinlein
double take
Re: Ringworld / Sphereworld
ok...let me see if i understand this from my highschool only point of view.
lats say we have a sphere and want to rotate it along its axes. i will call axis 1 "up and down" and axis 2 "left and right".
i am going to mark a spot on the sphere so i can keep track of its location as the sphere rotates.
1st i will apply 100 units of force along axis 1 (up and down) as i watch the marker i see it travel up the sphere, lose sight of it as it goes behind the sphere and then i see it go from the bottom of the sphere and back over the top over and over.
now i will stop the sphere and apply 100 usits of force along axis 2 (left and right) and i watch the marker go towards the left, around the back and come from the right side of the sphere and travel to the left over and over.
this time i will exert 100 units of for along both axis 1 and axis 2. as i watch the marker it travels up and left along the sphere at an angle 45 degrees to both axes. around the back and then comes up the bottom right "corner" up the sphere travelling towards the upper left "corner"...continues doing this over and over.
from my point of view all i have effectively done is applied force at a 45 degree angle. and that is where my centrifugal force appears to be also. correct?
i can express this in terms of force in each axis and say it is "tumbling" along 2 axes. or i can say it has x amount of force along a new axis, axis 3 which i will call "diagonal"...........
i admit i have been out of highschool for about 20 years and have not done much with math and science since then....but does this sound vaguely right.
Re: Ringworld / Sphereworld
Ok, i just skipped a few things because i'm tired and my brain is starting to shut down. But i've always thought that people lived in the platings. Soooo.... They dont live on the inside near the sun or outside near space, but they live imbetween both. Do you get what i'm saying?
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WHY SHOULD I FEAR WHAT WRONG I HAD NOT DONE?
~Ardius (me)
Re: Ringworld / Sphereworld
A ringworld's shaped sort of like a gigantic, spinning car tyre. The spin is to push things towards the inside of the tyre, effectively simulating gravity. The tyre-shape is to prevent leakage over the sides of the ring; in other words, there's walls so stuff like atmosphere and/or rollerskates don't fly off into space - which they would, being accelerated to extreme speeds by the spin of the ringworld.
A sphere world is a lot of radically different things. First of all, it can be identical to a ringworld, but with the addition of great big 'sails' to soak up energy from the star, effectiveely making the ringworld spherical.
A second favourite is a solid/Dyson sphere. It's pretty much the same as the above, but the entire shell has a regular surface, and either gravity is generated artificially, or the thing is spinning and only habitable around equator (like a ringworld).
A third is v.2.0 of the Dyson sphere, aka. the not-so-solid sphere. Here you have the sphere 'sails' from above, but instead of a ringworld or other mega structure, there's a mesh of largely independent little satellite worlds in orbit, like pearls on strings - habitable on any convenient plane.
The third model is the only semi-realistic one, but it still requires a species capable of converting most or all of the bodies in the star system into raw materials, and the ability to push surplus junk out of the system entirely (or risk them falling into, and obliterating, the sphere world). Of course, it also yields the least habitable space, but it's pretty much a moot point, as the space available will still be incredibly much more than even a species of 50 feet tall super-fertile, hypersexual rabbits could reasonably be expected to need. Ever.
Re: Ringworld / Sphereworld
I thought the point of a dyson sphere was a theoretical means to capture all the energy of a star. This would essentially be an enormous power station. Basically capturing all the released energy of the star.
Since this would be the theoretical idea behind a dyson sphere, there would be very little population living there (there is no saying what effects solar flares would have on people living there).
The game is presenting a sphere/ring world idea. A sphere world could be a modified dyson sphere where you would effectively be using 50% of the surface for living areas (30 degrees above and below the equator) and the other 50% would be used for solar panels, etc.
@desdinova the best way to figure out your rotation issue would to calculate the vectors created by the applied forces. That would give you a force at 45 degrees with a total force of roughly 141.42 units in the new vector (100 * sqrroot 2).
Re: Ringworld / Sphereworld
I'm a tad rusty with geometry but if you combine two rotations of a sphere then you get another rotation (the rotations are just elements of a group which is closed under its operation for those that know what that means). Since the group of these rotations - SO(3) if I remember correctly - is noncommutative (ie. the order you do the rotations matters) I'm not sure whether it's possible to rotate around two different axis simultaneously since you have to specify one first then the other. There is a more technical way involving the instantaneous rotations but there's noncommutativity in the Lie Algebra too...but I don't want to go there.
For those who didn't take group theory think of it this way: pick up any old book and hold it with the front cover facing straight up, kinda like if you were getting ready to pop it open to read. That's the starting position. If you rotate the book 90 degrees and two different axis in two different orders you will get a different result (having a book helps clarify the difference since it's kinda hard to tell when rotating a sphere). One axis will be the one going straight up and down - you're rotating around a vertical line running through the center of the book. The other axis will be one running horizontally from you to the book.
Rotate around the first axis 90 degrees clockwise first and the top of the book is now on your right hand side with the cover facing up. Now rotate around the second axis 90 degrees clockwise. The front cover is facing to your right and the top of the book is facing down.
Now back to the starting position and do the rotations in the other order. Rotate around the 2nd axis 90 degrees clockwise. The front cover is facing to your right with the bindings of the book facing up. Now rotate around the first axis 90 degrees clockwise. The binding is facing up with the front cover facing you with the top of the cover to your right.
Assuming I explained that properly you should be able to see that doing those two rotations in different orders leads to totally different results. So when you talk about rotating a sphere around two different axis it is a rotation but you have to specify which order you're doing it in. So basically you can't rotate around two axis simultaneously in the sense of simultaneously spinning in two different ways. You're still ultimately rotating around one axis no matter how you do it - even if that axis is hard to picture (not 100% on that though).
There is also (I think...it's been a while) a fixed point thereom for SO(3), namely no matter how you try to rotate a sphere there is always at least one point that stays the same. That point is different for each rotation but there always is some point. So basically no matter how you choose to rotate the sphere there is going to be a point (namely the poles) that are staying still. These points will not experience the weird inertia effects of centripetal/centrifugal "force" so they will only experience the gravitational pull of the sun.
Edit: Adding a link: http://en.wikipedia.org/wiki/Rotation_group
Re: No Offence Taken
Personally, I suspect that they'd use gravity generators of some kind... after all, they already have unobtanium, why not be able to play with gravity?
_______________________
There are 10 types of people in the world:
Those that understand binary, and those that don't.
Absolutely no offence taken. But true Dyson shpere actually would be made to rotate in two planes at the same time - completely eliminating poles in order to prevent exactly what you and others have mentioned so that the entire inner surface is habitable.
And I wasn't talking about the game. But you're certainly correct that they would most likely have unobtanium along with isotopes of yacantgettium so that they could do all sorts of strange and wonderful things. (Like Heisenberg Compensators, for example.)
But in the meanwhile, I'll stick with 'normal' physics and what's known to work - just as I described it. :)
Re: Ringworld / Sphereworld
Yes centrifugal force is perpendicular to the axis of spin but the amount experienced at the poles is 0: centrifugal force http://en.wikipedia.org/wiki/Centrifugal is proportional to the radius from the axis. At the pole your distance from the axis is 0 so it's constant x 0^2 = 0. So the only non-zero force acting on someone at the pole is gravity.
Anyways, there are Anti-grav ground thrusters in game so any race who can make a sphere world almost certainly would have that tech too.
Re: Ringworld / Sphereworld
Oh yeah.... I forgot that. I suppose about halfway between the equator and the pole would be worst then. Enough for decent gravity but at a 45° angle.
Re: Ringworld / Sphereworld
It is possible to have an opbject rotating around three different perpendicular axes at once. The end result us far different than having it rotating around a single axis.
What y'all have been neglecting to consider is that for this to happen, the axes needs to be static in relation to the rotating object, but mobile in 3D space - and mobile in relation to the surface of the object.
Take a styrofoam sphere. Insert two pins, along the same axis. If you rotate the sphere using those two pins, the sphere is rotating along one axis. Now take some wire and make a C shaped mounting for the styrofoam sphere, set the sphere to spinning, and then start rotating the mounting along an axis perpendicular to the one the sphere is spinning.
Your sphere is now rotating along two different, 90 degree apart axes. And it is not behaving as though it was rotating along one axis 45 degrees off of the first axis of rotation.
To achieve such a rotation in space would require some sort of forces not, I'd expect, commonly found outside of a Hollywood asteroid belt. As far as what sorts of effects such a rotation would have on an atmosphere of a planet or construct of that size, I couldn't begin to guess.
Re: Ringworld / Sphereworld
Combining two different rotations is ultimately a rotation around a new axis (see the links) so no matter how you do it it's just one axis you're rotating around.
a in SO(3), b in SO(3) means ab is in SO(3)
For a more proper approach the Lie Algebra so(3) is needed but ultimately the result is the same (you're using the commutator but so(3) is still closed under the bracket).
Of course finding the new axis can be a giant pain even in the simplest cases, but there is one. Then near the poles the centrifugal force is zero (see above).
Re: Ringworld / Sphereworld
You are wrong and right at the same time Spencer. You get one direction of rotation at a specific moment, but that direction would change all the time because of the second rotation axis. In the end the race living in such a sphereworld would get very dizzy : ). What this means is that rotating a sphereworld on two or more axis is not the wisest thing to do unless you love being throwed around all the time and gargantuan storm fronts, electric discharges (lightnings) and so on. Including continuous and moving floods if you have water on the inside surface of the sphereworld. Anyway unadvisible. It's obvious by the statements here that a lot of the participants have troubles with 3d visualization : ). As one person here has already said tumbling is different than rotating. For example the Earth DOES tumble. It's just very small. What this means is that the Earth actually rotates on two axis, but on one of them the movement is very slow, so actually you get the movement of a spinning toy. Don't remember the actual name in english (may be top?). Look at this link to visualize:
http://en.wikipedia.org/wiki/Precession
"The Earth goes through one complete precession cycle in a period of approximately 25,800 years, during which the positions of stars as measured in the equatorial coordinate system will slowly change; the change is actually due to the change of the coordinates. Over this cycle the Earth's north axial pole moves from where it is now, within 1° of Polaris, in a circle around the ecliptic pole, with an angular radius of about 23.5 degrees (or approximately 23 degrees 27 arcminutes [1]). The shift is 1 degree in 180 years, where the angle is taken from the observer, not from the center of the circle.
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No
They are not the same things.
Ringworld = a ring, sphereworld = a sphere. One is bigger than the other, and takes more tech.
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