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Obscure Questions

  1. Jul 31, 2006 #1
    i had a brainwave this morning, i just was wondering about things

    these are my obscure questions about Lagrange points:

    Would a body with sufficient mass possitioned in a lagrange point affect the tides of earth?

    Would a body with sufficient mas positiond in a lagrange point create other Lagrange points?

    Condider a system; a star with a gas giant, and a H congrouous planet. The rocky planet is positioned in the Lagrange point of the gas giant, would it realy beable to suport life, even if it were positioned in the "Life band"?

    Thanks
    Joe
     
  2. jcsd
  3. Jul 31, 2006 #2

    Garth

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    Hi Joe! I did some work on Trojan orbits and Lagrange points some time ago, The Orbits of Trojan Asteroids, I'll see what I can remember.....
    Interesting question. No, not at first. Assuming you are talking about a large body placed in co-rotating orbit at the Earth's stable Lagrange points L4 or L5. The Earth would be at the new body's mirror Lagrange point. There would be no net gravitational potential on the Earth from the new body. The overall gravitational force on the Earth would still be from the Sun and its tides, together, of course, with the Moon's tides. However, after many orbits the Moon, which is not exactly at the new body's L4 or L5, would be perturbed from its orbit and that eventually would change the tides on the Earth.
    Yes, you can have a (contrived) stable system of six bodies in the same orbit 600 apart around a star, all in each others' Lagrange points
    I don't really know what you mean by a "H congrouous (congruous?) planet", but assuming you mean a Earth type rocky planet, then yes it would be capable of bearing life if the system were in the habitable zone around the star.

    Garth
     
    Last edited: Jul 31, 2006
  4. Jul 31, 2006 #3
    i was more intrested in a orbit at L1? maybe
    I don't really know what you mean by a "H congrouous (congruous?) planet", but assuming you mean a Earth type rocky planet, then yes it would be capable of bearing life if the system were in the habitable zone around the star.[/quote]
    yes
    would it beable to rotate?

    in L1?

    Would a planet in a L4 or 5 position with a gas giant affect the gas giants orbet?



    would the moon eventualy move into a new orbit?
     
  5. Jul 31, 2006 #4

    Garth

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    Orbits at L1 are unstable, after about 100 orbits they would slowly slide off into a 'horseshoe' orbit. If both planets were of more or less equal mass they would end up doing a dance with each other like some of the shepherding satellites in Saturn's rings.
    Nothing would prevent either planet from rotating
    No - not if the second planet were put in an exactly co-rotating orbit at L4 or L5.
    Yes, perturbations on the Moon, and the reaction to the Moon raising tides on the Earth, are already perturbing the Moon into a new orbit - it is steadily receeding from the Earth.

    Garth
     
  6. Jul 31, 2006 #5
    i actualy meant if they were diferent sizes
    or doesnt that mater

    would you beable to have a star and a gass giant orbiting in a pair?
    maybe even around a biger star?

    is it posible to crate an highly eratic orbit around a black hole?
    even between 2 black holes orbiting each other?
     
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