This page will try to explain the dynamics of our solar system. I know, I know, this can be confusing, but... none the less I will make it clear.

First: The solar system is like you spinning a rock on a string - all the planets orbit in a plane called the 'ecliptic'. This is a flat plane that all the planets are orbiting, that is, not the outer Kuiper belt objects that do have elongated or tilted planes like Pluto, which is about half the size of our Moon. Speaking of rocks, try this without hitting yourself - if you spin a weight on a string around in circles does it go only in one 'orbit'? [I'm betting yes] What if you add another? Do they both go in the same plane? [same answer] Now you know that the planets are like those theoretical rocks in that the Sun is flinging the planets around it in a flat plane. How else would you be able to see them every year in their predicted orbits if they were just going every which way?

Second: Mars will never move in its orbit toward any other planet. It will never be any bigger than half of the size of Earth and it will never appear bigger than our Moon. Every two years Earth and Mars, being in a 2:1 resonance with each other, come close enough that Mars seems to be larger than before. Naturally this is because it is closer relatively speaking since the last closest approach was only 39 million miles! That's close for planets, but it's still pretty darn far away!

Third: Neptune will never hit Pluto or vice versa. Pluto is in a elongated orbit that does go inside the orbit plane of Neptune, but due to the nature of the orbits of the two planets, they won't hit. Remeber space is not like our 2 dimensional representations!

Fourth: The Sun coalesed from the matter and gasses in a nebula of a previous star. This cycle is ongoing. The rotation of the Sun, every 25 days, comes from the cloud of gas condensing in as the center was moving and thus created rotation. So the rotation of the Sun then created the rotation of the remaining dust and rocks to form planets that now orbit the Sun in that same direction. Everything is now orbiting the same diection around a rotating central star. Interesting that the Sun rotates every 25~ days, but the outer planet Neptune takes 165~ years.

Fifth: Earthlings are like gnats of the solar sytem! We are tiny! The sizes of planets and distances between are so vast that our normal far away is the same point for all intents and purposes. It's hard to grasp the true scale of the solar system never mind the size of the Sun, which is a small yellow dwarf star, as stars go. The Sun is 99.8% of the matter in the system and our little planet nor what we do on it will ever match or come the tinyest bit close to what the Sun's output could and does to it for warming and cooling. If the Sun's output changes in its normal cycle, we gnats can't do a darn thing about it.

This should start to clear up any douts about these areas. We will keep you posted if any changes occur or new questions need resolving.

Also you can visit this solar system simulator to see the planet rotation too. http://astro.unl.edu/naap/pos/animations/kepler.swf