Why are the planets on the same orbital plane (more or less) as opposed to very diffrent planes?
92655
Because the gas that originally formed the solar system spun as gravity pulled it together, centrifical force forced it into a flattned disk shape.  This meant that as the gas pulled together to eventually form the plannets (and sun) they all revolved generally in the same orbital plane.
884425
well the path of the planets is different for each due to the size but the are similar to a oval type shape, gravity hold the planets in orbit and as far as the asteroids they are freely moving until caught by a gravitational pull of a larger object
51021
No. Planets orbit stars.  The earth is a planet orbitting its star, the Sun.
250788
Because they are tilted with respenct to both the earth's orbit and with respect to Saturn's orbit. This means that we sometimes see them edge-on. But when Saturn has gone about 90 degrees further in its orbit, we will see the edges from a more open viewpoint.
643880
Most of the orbits are set (initial point and direction) so that they don't crash into each other, but even if they didn't, the amount of surface area (of satellites at the same altitude) is so great that there is an extremely small chance that they would crash into each other even if they were set randomly.  Imagine a thousand people placed randomly around the world, blindfolded and told to walk around.  Think of how low the probability that two people would run into each other would be.
520855
We think that the planets all formed pretty much at the same time. However the sun probably formed first. The leftover gas and dust remained in a disk around the sun. In this disk, stuff began to clump and form "planetesimals" (pronounced pla-ne-TE-si-mals). These are small rocky bodies, something like asteroids. They crashed into each other and eventually formed the inner planets. At the same time, planetesimals formed the cores of the outer planets Jupiter and Saturn. Because of their strong gravity, they swept up a lot of gas. Uranus and Neptune did this too, but there was less gas around because Jupiter and Saturn got it first. The asteroid belt may be left-over planetesimals that never formed a planet because Jupiter's strong gravity nearby kept it from forming.
29403
The planets were formed by the same cloud of swirling rocks and dust, so when they came together and formed the planets they were all going the same direction. And actually, since the sun was made from the same stuff, it actually rotates in the same direction, though it is hard to tell because there are no surface details to see from earth without assistance to see the movement of the sun. I think astronomers see the rotation of the sun by watching sun spots. \n\nAnd actually they do not all lie in a flat plane. There is actually a small difference between the orbital planes of each of the planets.
806566
Oops. There is a problem with the question. You used the words smaller and larger. These may usually be the appearance of planets and moons, but in fact, these are the wrong words when you ask about objects in orbit.\n\nThe variables that determine orbital paths are mass, relative vectors and speeds. \n\nSize (smaller or larger) is not one of the variables. It may be true that a larger object - of the same material - has more mass than a smaller one, but not always. A large steel bucket has less mass than a cannon ball that can fit inside it.\n\nA dwarf star could be very small. Smaller than the Earth. A planet the like the Earth would orbit the star, even if the star was smaller. \n\nPlanets and moons are in orbit around each other. An orbit is a kind of ellipse. An ellipse is a kind of like a circle, but it has two centers rather than one. The objects travel around one of the centers. If the two objects are exactly the same mass and speed and in orbit, the two centers could be exactly between them and the orbits would be circular. Their size would not matter. \n\nHowever, in the real universe, most objects are made of plasma, iron, silicates, and other materials that cause them to form stars, planets, asteroids, planetoids, comets, and gas and dust clouds. In most cases, the larger ones - the most massive ones - are orbited by smaller ones - the less massive ones. But is some cases the larger ones are very tenuous and although larger, they still orbit the more massive object. \n\n;-D The huge Oort cloud is about 6 light years in diameter. It is in orbit around our little Sun!
1184119
Jupiter is further from the sun, and has a larger orbital path.  That is why it takes longer (it has to travel further to go around)
181847
Because planets are actually moving in relation to stars.  They are orbiting the sun.  They are also a lot closer to us than stars.  For example, when you drive, you see mountains in the distance.  You are passing those mountains at 65 miles an hour.  They appear to be going by very slowly.  But when you pass a light pole right next to you at the same speed, it appears to whizz by really fast even though it's the same speed.
905767
You are making it needlessly hard on yourself.  The planet has the same mass as the earth, and someone on it weight the same as on earth, therefore the surface of the planet is the same distance from its center as the earth radius, i.e. this planet has the same dimension as earth.\nSo, the radius of the planet is 6,372.797 km, same as earth's.\nYou don't need to compute anything.  The orbital velocity of the planet has nothing to do with it.\nIf the weight was different, you only need to scale it remembering that the weight would vary as an inverse of the square of the radius.
91699
Stars are burning like our sun. Planets aren't burning like our earth. Planets usually orbit around suns.
746784
The orbital plane has planets slinging out from the middle of a rotating sun, as the rings of Saturn do around its middle, because of a flow that is slung out from the rotating body that thence returns into the rotating body at the poles. The planets in the orbital plane slung out from the middle of the sun are thus held away by this sling. \n\nPlanets do not flow with the sling round to the poles of the sun, because this would involve a trip too far away from the sun, a gravitational giant, before the trip back. The gravitational draw here can be envisioned as a string from the center of the sun to the planet. \n\nPlanets move, in concert, in a clockwise or counterclockwise direction around a sun due to sweeping arms that reach out from the core of the rotating sun, brushing the planets before them. These sweeping arms can be envisioned as the spokes of a wheel. \n\nPlanets stay in the orbital plane and do not drift to either side because of what we will refer to as eddy currents. The sling out is not solely at the waist of the rotating sun but slings out at a diminishing rate on either side, but the rate outward is greater at the waist. Thus, when the material being slung out from the middle of the rotating sun tries to escape to the sides, it is caught and pulled back by the slower pace of the material at the sides, creating a circular eddy current that returns it to the waist of the rotating sun. This eddy current can be envisioned as flotsam on a river and the manner in which this gets drawn into the center of the river, where the fastest flow occurs. \n\nPlanets find their niche in all this based on more than gravity or magnetism factors, as there are thousands of forces that affect the placement of bodies free to move about in space. The entry of a new planet into the orbital plane would results in a bumping outward or compressing inward of existing planets as this new planet encountered the others during their journeys around the sun, until no further adjustments were required and an equilibrium was established.
250088
Larger planet has a stronger gravitational pull than a smaller planet.
224788
Orbital obliquity is probably influenced by the sun in some way during the time when the planets were forming, but I don't think we have any solid idea exactly what factors were involved.  It's clear that most of the planets' axis are more or less vertical, though Venus in fact rotates the opposite way (so its obliquity is considered to be nearly 180 degrees).  The big exception is Neptune, which is nearly lying on its side.\n\nIf the Earth was similarly lying on its side as you suggest, then yes, it could spin the same and have light and dark "sides" that only change as it moves around the Sun.  See Neptune for details of this exact mechanism.
111203
I think the current theory is that it comes from the origin of the solar system as a spinning mass of material. This material had a certain angular momentum, which was retained as the material coalesced into the sun and the planets and moons and other bodies. So there are only a few planets and moons whose orbital and rotational angular momentum vectors are not aligned with each other (like Neptune, and Venus, Triton and a few of the smaller, more distant moons of Jupiter and Saturn).
515806
The earth rotates on its axis (spins) the same way as the sun does on its axis, since the planets all formed out of the proto-solar disc when the sun was forming.  All of the planets spin the same way, EXCEPT for Venus, which rotates (very slowly, once every 243 days) in the opposite direction.  Some planetary scientists consider this evidence that Venus at one time collided with another large body early in its lifetime, which caused the retrograde rotation.