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#82
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In article ,
(AA Institute) wrote: Herb Schaltegger wrote in message ... In article , (AA Institute) wrote: If the perigee of the asteroid's orbit is 40,000 km and say the apogee is 200,000 km then that may be a safe option. If the apogee goes much above 250,000 km then there's the Moon's perturbing influence to worry about, since it orbits at around 380,000 km. There's ALWAYS the Moon's perturbing influence to worry about. Have you ever done any three-body problems? There's a reason they can't be done analytically, you know. Especially when one of the objects is massive enough to cause tides on the other object from 225,000 miles away, as well as influence menstrual, mating, spawning and behavioral patterns of a good deal of the life on it. I'm serious that a ring will be created around the Earth at some point in the future and I need some equations to simulate the event. I want to be able to analytically demonstrate the long term stability of such a ring system and all I get is joke after joke on this thread... I will try more analytical groups like sci.math and physics. Abdul What I wrote isn't a joke. Do you understand ANYTHING about gravity and the three-body problem? You CAN'T solve it analytically; you have to do it computationally. You might start by doing a literature search on the Saturn ring system to get an idea of the complexity involved. You seen to be thinking like a science fiction writer or futurist; try thinking like an engineer or scientist instead. Stop talking grand generalities and start talking equations and numerical methods for analyzing complex (e.g., chaotic) systems. -- Herb Schaltegger, B.S., J.D. "Never underestimate the power of human stupidity." ~ Robert A. Heinlein http://www.angryherb.net |
#83
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"AA Institute" wrote in message om... Alan LeHun wrote in message .. . In article , says... You didn't spot the three dots I put after I wrote the word "heartless"; that means I was joking. Not to most people. That's a new usage for an ellipsis. New to you perhaps. we could have just used an ellipsis... What is an ellipsis? I've heard of an ellipse but never an ellipsis. You didn't even try to look the word up before posting. No one takes you seriously because you don't do your own homework. They post joke responses to you because they can tell you're not yet worthy of anything substantive. |
#84
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"AA Institute" wrote in message
om... Herb Schaltegger wrote in message ... In article , (AA Institute) wrote: If the perigee of the asteroid's orbit is 40,000 km and say the apogee is 200,000 km then that may be a safe option. If the apogee goes much above 250,000 km then there's the Moon's perturbing influence to worry about, since it orbits at around 380,000 km. There's ALWAYS the Moon's perturbing influence to worry about. Have you ever done any three-body problems? There's a reason they can't be done analytically, you know. Especially when one of the objects is massive enough to cause tides on the other object from 225,000 miles away, as well as influence menstrual, mating, spawning and behavioral patterns of a good deal of the life on it. I'm serious that a ring will be created around the Earth at some point in the future and I need some equations to simulate the event. I want to be able to analytically demonstrate the long term stability of such a ring system and all I get is joke after joke on this thread... I will try more analytical groups like sci.math and physics. If you're talking about a solid ring, I believe a quick and simple analysis should prove it to be unstable. Try looking at it from the opposite perspective. Even a solid spherical surface is only metastable, in the sense that there is no net gravitational field inside it to stabilise the position of a centrally located body. I would expect a ring (I can do the math if you insist, but you should be able to do it yourself) to pull objects away from the centre radially. Newton's third law then tells you that a centrally (but not perfectly centrally) located body would pull a ring away from a stable position. Grim |
#85
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"Grimble Gromble" wrote in message ... I'm serious that a ring will be created around the Earth at some point in the future and I need some equations to simulate the event. I want to be able to analytically demonstrate the long term stability of such a ring system and all I get is joke after joke on this thread... I will try more analytical groups like sci.math and physics. If you're talking about a solid ring, I believe a quick and simple analysis should prove it to be unstable. Try looking at it from the opposite perspective. Even a solid spherical surface is only metastable, in the sense that there is no net gravitational field inside it to stabilise the position of a centrally located body. I would expect a ring (I can do the math if you insist, but you should be able to do it yourself) to pull objects away from the centre radially. Newton's third law then tells you that a centrally (but not perfectly centrally) located body would pull a ring away from a stable position. Grim It's been done. Google for references to an analysis that a math class did for Larry Niven's ringworld. The math works regardless of the scale of the system. It's not stable. Our large moon makes it damned near impossible. AA: If you even think about responding to this posting, do it with some serious mathematics. If you can't do that, you're wasting my time. MK |
#86
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T wrote in message . com...
My initial question is "Why not do the same thing on the Moon itself?"; lots of room to tunnel underground, etc. I have since highlighted some of the attractions like surface minerals, easy reach from Earth, artificial gravity, robotic excavation, etc. http://uk.geocities.com/aa_spaceagen...arth-ring.html otoh, I like the general idea of a ring around the planet but it sounds unstable with the Earth/Moon binary setup; other ringed planets have a much greater difference in the Moon to Planet ratio. Again, I have done some thinking around the precession rates for non-polar orbits and it appears the *safest* option is to stick the whole ring system in the Earth's equatorial plane. I think that is one of the easiest lessons from all the outer planetary rings. The only shame with this arrangement is we will not experience the thrills of 'ring rise' and 'ring set', the dream view will be slightly weakened... AAI |
#87
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"Bootstrap Bill" wrote:
"Derek Lyons" wrote in message ... B2 didn't work because far more attention was paid to ecological mysticism than to science and engineering. I'd not use it as 'proof' of anything one way or another. Is there any chance that another similar project will be attempted in the near future? I don't know one way or another. I'd have to say that the spectacular failure of B2 mitigates against someone getting the gumption and cash together for another try. D. -- Touch-twice life. Eat. Drink. Laugh. -Resolved: To be more temperate in my postings. Oct 5th, 2004 JDL |
#88
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#89
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AA: If you even think about responding to this posting, do it with some
serious mathematics. If you can't do that, you're wasting my time. In light of your very dangerous fore-warning... I am being a bit brave here! Are you familiar with this equation (quoted by Henry Spencer on sci.space.tech a while back):- An Earth circling satellite orbit will precess along the equator over time according to the equation:- -3/2 * J2 * (R^2 / p^2) * n * cos (i) [Where J2 is a constant related to Earth's flattening, R is the Earth's eq. Radius, p = a*(1-e^2) (in which a is the orbit's semi-major axis and e is its eccentricity), n is the mean motion and i is the orbit's inclination.] ??? AAI |
#90
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"AA Institute" wrote in message
om... AA: If you even think about responding to this posting, do it with some serious mathematics. If you can't do that, you're wasting my time. In light of your very dangerous fore-warning... I am being a bit brave here! What's brave about wasting someone else's time? Are you familiar with this equation (quoted by Henry Spencer on sci.space.tech a while back):- An Earth circling satellite orbit will precess along the equator over time according to the equation:- -3/2 * J2 * (R^2 / p^2) * n * cos (i) [Where J2 is a constant related to Earth's flattening, R is the Earth's eq. Radius, p = a*(1-e^2) (in which a is the orbit's semi-major axis and e is its eccentricity), n is the mean motion and i is the orbit's inclination.] Being familiar with an equation is not the same as understanding it. That the earth's flattening is involved suggests that this precession is caused by tidal influences experienced by the satellite as it orbits above and below the earth's equatorial plane. That there is no term relating to the lunar and stellar masses, suggests that this is a very simplified analysis in which all other influences have been ignored. Is there any reason you introduce this (idealised particulate) satellite into a discussion on earth rings? Perhaps you are comparing the effect on an orbiting satellite of the earth's equatorial bulge to that of an independently orbiting ring? You do realise that there are significant electromagnetic forces operating between the 'equatorial' bulge and the 'spherical' earth? Grim |
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