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Gravity effect the tilt too

  1. Dec 12, 2006 #1
    I still cannot find any concrete explanation for tilt of planets like mars and neptune.
    These planets must be taken into account to make theory much stable regarding tilt of planets.
  2. jcsd
  3. Dec 16, 2006 #2


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    Mars' 'tilt' or inclination of equator to orbit (240) is very similar to the Earth's (23.50) and Neptune's is not too different either (28.80). Uranus is the planet with the greatest inclination (980) i.e. it leans over backwards!

    The planets formed from collisions and mergers of proto-planets, as these impacting bodies grew from asteroid to small planet sized objects the impacts had greater and greater effects.

    The final state of each planet, its orbital elements and rotational motion, is the total sum of all the mass, energy and angular momentum delivered to them by these proto-planets, giving them an overall pro-grade rotation at some inclination to their orbits.

    The large inclinations can be explained by the collision of an extra large proto-planet late in the process, for example, it is thought a Mars' sized planet collided with the Earth forming the Earth, the Moon and maybe Mars as well from the debris. Uranus must have had an extra large body colliding with it, and this may have left its mark on one of Uranus' moon's Miranda.

  4. Dec 17, 2006 #3
    That's the principle to which i stick too, but regarding Brunini's new finding the tilt of giant planets is the result of "neutral gravitation interaction" which tempts each of the jovian planets to tilt at some constant angle which doesn't tend to change till any exospheric thing doesn't collide with the concerned planet.

    Now same finding also suggests that these planets were much closer before and thus by gravitational interaction got their tilt angle.
    Now my problem was about the jupiter-mars system and the uranus-neptune system,If they are carefully considered through the acquired knowledge of evolution of solar system then these systems appear to be contradictory, and to satisfy this finding and contracdiction we have to add some new structures to solar system.
    That's why i said that this topic must be taken into consideration.
  5. Dec 17, 2006 #4


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    I am not aware of Adrian(?) Brunini's "new finding"; reference?

  6. Dec 17, 2006 #5
    However there are more forces at work. gravity between spinning objects tend to cause axial and orbitual perbutations, precession cycles and obliquity cycles. On Earth currently 26,000 and 41,000 years. Those two cycles interact which each other causing them to exchange momentum. Laskar (Fr) has figured out that when the precession and obliquity cycle are about equal in frequency then a chaotic resonance can send the spin axis to extreme obliquities and this may have been the main cause for the loss of rotation of Venus.

    Obviously the moon is causing a rather rapid precession cycle which will preclude the Earth from having the same fate as Venus.

  7. Dec 18, 2006 #6
    I read it in a newspaper about 1-2 months ago.
    Googling the word "cosmic Dance" or this thread's title might help u to get the reference.
    If problem persists then i will give u the report itself.
  8. Dec 18, 2006 #7


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    I Googled for '"cosmic dance" Brunini' and got nothing.

    Googling for "cosmic dance" got a lot on the 'dance of Shiva' and similar.

    Googling for '"Gravity effect the tilt too"' simply found this thread.

    Last edited: Dec 18, 2006
  9. Dec 19, 2006 #8
  10. Dec 19, 2006 #9


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    Thank you, yes there is a lot we do not know about planetary formation. The discovery of lots of 'hot jupiters' has thrown the whole field into the melting pot (literally!).

    How these beasts formed is a mystery IMHO, and if our Solar System formed in a similar way with the gas giants originally very close to the Sun then, yes, inter-planetary interactions would have to be taken into account.

    I find it difficult to believe Uranus' inclination can be explained in this way though.

  11. Dec 19, 2006 #10
    Yeah! that uranus for me too acted as a hurdle in understanding this.
    I was also thinking of Saturn.
    Look i have a got a logic here, if this finding is true then it contradicts many facts relating jupiter and saturn and mars.

    #1 Was there asteroid belt at that time?after decided this,think about the existence of jupiter with so less amount of rings than saturn.

    #2 Ok! no asteroid belt ,then how is such gravitational interaction possible.

    #3 Let it be possible again,then isn't jupiter that much fat to effect the tilt of mars which is already so near and dear to it.
  12. Dec 24, 2006 #11
    Logic19,ur second point doen't co-relate with other point,u can't continue with that wrong point in the middle, u should again consider that.
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