Thanks. I totally forgot about that one.
PLEASE stop the way space stations ROTATE
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Thanks. I totally forgot about that one.
The Moon rotates slowly about an axis perpendicular to its orbit. A space station needs to spin rapidly for artificial gravity, but in the game needs to keep that same axis pointing to the planet. So it's quite different.
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And what game is this? Where a PhD Astrophysics quotes Wikipedia. God save us.
Edit: I quote you: 'Precession does not have to be 'natural'. Precession is simply the movement of the angular momentum vector of a rotating object. It does not have to be in response to an external force.'
God save us.
Edit 2: You must have seen a toy gyroscope precessing - yes? In response to an external force. You got it - gravity. PhD or not, you've got some serious swotting to do in tensor physics.
Edit 3: Your PhD is in metallicity / light curves / distance indicators. Worthy stuff - astrochemistry / astrometry, but nothing to do with orbital mechanics.
Regards.
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Wikipedia is not a final source; but it has plenty of completely valid information.
This is what I do for a living, for instance, and the wikipedia page is plenty accurate.
https://en.wikipedia.org/wiki/Type_Ia_supernova
I think you have an internal definition of precession which is simply a subset of what precession actually is. Precession is the movement of an object's angular momentum vector. That's the end of the definition.
What I am thinking of also comes from this lecture from a physics teacher at Simon Fraser University:
http://www.sfu.ca/~boal/211lecs/211lec26.pdf
Also, these lecture notes:
http://physics.ucsd.edu/students/courses/winter2008/physics110b/LECTURES/CH13_RIGID_BODIES.pdf
Also, this explains how part of Earth's precession is simply because it is not symmetric:
http://farside.ph.utexas.edu/teaching/celestial/Celestialhtml/node72.html
I haven't (and probably won't) sat down and worked out if it's possible to make these space stations have a moment of inertia matrix that can achieve the behavior of the stations in ED. But, at least, this should prove to you that your definition and thoughts about precession are not completely correct.
I don't have a PhD from anywhere but it does seem to me that you are both right - just arguing at different angles. Precession is movement in angular momentum vector and movement requires force so the only real sticking point is whether or not it is possible to have a starting force that causes the station to spin the way it does in Elite (not whether it's difficult - just if it's possible) or whether it constantly needs new forces to keep it aligned. I believe that it is possible but incredibly unlikely so some time related force is more likely to me. You're both smart - now kiss n make up 
Yep. I would read that, but I don't need to. I'm pleased you have made the effort to understand your own post.
Blocked.
Regards
I'm confused. Is the problem "you can't have a station that's tidally/gravitationally locked on a celestial body, while also maintaining a stable rotation about an axis perpendicular to that body's surface"? That would make sense to me - except we don't know that the station is gravitationally locked. It might just be periodically correcting via thrusters to maintain a "docking slot down" attitude. I don't see what that wouldn't be possible, with a fly-by-wire-esque thruster system to correct for any wobbles.
Why block me? That seems odd. I have only been respectful to this guy, and he's the one reacting poorly to having his position questioned. When my position was questioned, I found more sources that backed up what I was already saying; that you could setup a station in orbit that can precess properly without the need for constant torque supplied by thrusters. He has made zero attempt to refute my point.
I mean, literally, what I posted proves his point of view wrong, and continues down the same path of my previous posts. But whatever. I've seen so many physicists behave this way online. I usually refuse to participate in discussions with them. I will take his acting out like a petulant child as acknowledgement that he is uncomfortable being shown he is wrong.
Nah, Gyroscopes... Cheaper... Might even work out so that the net change in angular momentum would be zero over the orbital period of the planet, so no need to even dump off spinning flywheels...
Would that be so? Would it be the case that a gyroscope could spin up in one direction to compensate for a while, then it would be of benefit to slow down in order to rotate the other way?
I'd love for someone more competent (or even dangerous) to think about that...
Would that be so? Would it be the case that a gyroscope could spin up in one direction to compensate for a while, then it would be of benefit to slow down in order to rotate the other way?
I'd love for someone more competent (or even dangerous) to think about that...
I'll explain the problem - because it is an interesting one:
1. the stations rotate, deliberately, and quite rapidly, in order to provide artificial gravity.
2. there's a requirement in game that the slot faces the planet - not sure why! But that's sci-fi
3. if the station rotates about that central axis, it can represent a vector, if you wish, which is locked directionally along that axis - not by standard linear inertia, but by angular momentum.
4. As the station orbits, if that slot is to remain facing the planet, that axis / vector must rotate to keep pointing at the planet
(folks have been calling that 'precession' - but it is a total misuse of the term - oops - hence the controversy - but that aside - not important here
5. If that vector has to keep pointing inward to the planet, and rotated, a torque (turning effect) *has* to be applied by the space station.
6. That's about it - if the space station wants to rotate *in that manner*, and *still* have the slot facing the planet, there need to be thrusters firing.
That's the essence of it.
So, the space station's orbit - in that attitude - has to be *maintained* - with energy expenditure - it's not inertial.
Hope that helps.
(OK, an orbit is not strictly inertial - but the sense is clear enough I hope.)
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You're flying in a spaceship that has can exceed the speed of light in contravention of the theory of relativity, has magic space brakes that slow it down even when the engines are powered down, and for some reason can't exceed 450m/s... and you're complaining about the station rotation being unrealistic? Seriously?!
Called Olber's paradox - solved in part by the realisation that the universe is not static, but expanding.
This guy seems to have blocked me, but he is wrong about both the definition of precession and his absolute statement that an external torque must be applied. An asymmetric object will have different rotational rates about different axes with no need to continuously apply an external torque.
edit: whether or not an object can be designed with the right distribution of mass, I haven't worked out. But I assume it isn't impossible, and Space Fan most certainly hasn't shown that it's impossible.
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You can exceed the speed of light if the distance is measured in one reference frame, but time passage in another. It's only within a single reference frame that the rule applies.
To add on to this, Olber's paradox also implies that the universe cannot be infinitely old. That's the part that's key to me. But it really implies both a finite-age and expanding universe.
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I'm afraid it wouldn't help. Even with contra-rotating gyroscopes, the net angular momentum would just be the sum of the two; which could be zero. There are no ways around some of these basic problems.
LOL. From SC drop to hard dock, I can approach and doc with minimal time and direction of travel every time no matter rotation or orientation of the station. There is no issue lol. Just learn to fly more efficient (there is a way to approach the station/planet in a certain way in SC that gets you almost a straight in approach every time.) No extra entry points needed!