Why all planets occupy the same orbital plane around? The best guess is that all astronomical move in the same orbital plane because they were born of one and the same flat disk of matter.
Theories suggest that the solar system was originally a huge mass of rotating gas and dust, which was perhaps initially spherical. At some point in this process of condensation and becoming more pronounced rotation,
the centrifugal effects eventually break off a piece of matter in the equatorial plane. This torn piece of matter, representing a small percentage of the total, a large flat disk formed around the main central portion of the cloud. One way or another (for the details there is much less a general consensus) is a series of planets condensed from that album, while the bulk of the cloud became the Sun followed planets spinning in the region formerly occupied by the disk, and that is why they all revolve more or less the same plane of the solar Ecuador.
It is believed that the exceptions to this rule are due to violent events long after the general formation of the solar system. The planet Pluto rotates in a plane forming an angle of 17 degrees with the plane of revolution of the earth. No other planet has an orbit so inclined. Some astronomers have speculated that perhaps Pluto was once a satellite of
Neptune that broke free through some unspecified
cataclysm. Current satellite of Neptune, the principal, which is Triton, does
not rotate in the equatorial plane of Neptune,
which is another sign that some cataclysm struck the planet.
Jupiter has seven small and distant satellites that rotate in the plane of
The outermost satellite of Saturn is in the same case. It is likely that these
satellites were formed in their present position, at the time of birth of the
solar system, but are captured asteroids long after by those giant planets.
Many of the asteroids revolving between the orbits of Mars and Jupiter are very inclined orbital planes. Again, it seems a disaster. It is possible that the asteroids were originally one small planet revolving in the shot. Long after the formation of the solar system, an explosion or series of explosions that May unfortunate fragmented world, placing the fragments in orbits that, in many cases differed greatly from the overall orbital plane.
Comets revolve all possible planes. Now there are astronomers who believe that too outside the solar system, like a light year from the Sun, there is a sparse cloud of comets. These comets may have condensed from the outermost portions of the original spherical cloud, before the overall contraction and before forming the equatorial disk.
In such circumstances, when occasionally a comet leaves the layer spherical precipitates in the inner regions of the solar system (perhaps as a result of the gravitational influence of distant stars), its plane of rotation around the Sun can be anything.