Just a little question on orbits.

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Hi all,

Why is it that the planets in our solar system seem to orbit relatively in the same plane? ( or is it a misconception ?)

Why can't our planets orbit like this :

http://www.steve.gb.com/images/science/planetary.png" [Broken]

Thx.
 
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DaveC426913

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Because of the initial conditions under which the solar system was formed. The planets accreted from a rotating disk of dust and gas. This is also why they all orbit in the same direction.
 
389
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So it is not possible to have planets orbiting in such a fashion as shown in the picture i linked?
 

DaveC426913

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So it is not possible to have planets orbiting in such a fashion as shown in the picture i linked?
I cannot access the picture you've linked to, so I can't see it.

Nonetheless:

It IS theoretically possible, it just doesn't happen very much, and is unstable, so doesn't last very long, so even more rare to see.

Thing is, the system still starts off as a disc. It can't start off with planets going every which way - for several reasons. One: if an object were way off in a polar orbit it, could never accrete mass - it would never grow. Two: these orbits are very unstable. The overwhelming mass from the accretion disc will either draw it in to the plane or will cause it to plunge into the star.

What can happen though is, a planet can get knocked out of its orbit by another object - either a close pass or collision, and finds itself in an eccentric orbit. Pluto is 17 degrees off the orbital plane.

But you won't get a system with full-sized planets orbiting in multiple planes in the same system, no.
 
389
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hmm....... thx for the help
 

DaveC426913

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I'd still like to see that pic if you get it working.
 
389
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i don't have a problem accessing the picture actually. Anyway it is just a structure of an atom. (the conventional one, with electrons orbiting in dif. planes. Trying the illustrate my point with the structure of an atom.)
 

SpaceTiger

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i don't have a problem accessing the picture actually.
The error message is 403 (Forbidden), so since you posted it, it's not too surprising you can access it. Try submitting it as an attachment.
 
Because of the initial conditions under which the solar system was formed. The planets accreted from a rotating disk of dust and gas. This is also why they all orbit in the same direction.
Doesn't venus orbit the opposite direction.... or is that the rotation of it's axis?
 

Phobos

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Just to add to DaveC426913's explanation...
The original cloud of material was not a disk, but as it collapsed, it spun faster and material was spread out in a plane perpendicular to the axis of rotation (conservation of angular momentum)...thus forming the protoplanetary disk which aggregated (gravitationally) into the planets all orbiting the central sun in the same direction (since the whole disk was rotating that way to begin with).

Doesn't venus orbit the opposite direction.... or is that the rotation of it's axis?
It's rotation (on its axis) is retrograde (opposite direction of its orbit). Not sure why...perhaps a large-scale collosion early in its formational history?

Delzac said:
Anyway it is just a structure of an atom. (the conventional one, with electrons orbiting in dif. planes. Trying the illustrate my point with the structure of an atom.)
Note that electrons don't actually orbit that way (see quantum mechanics).
 

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