Why is the Solar System Flat?

You might already be in shock looking at the question.

Well, it is, in fact, true that the solar system is (largely) flat. Not completely flat, but almost.

"But we live in a 3D world! Why would we have a 2D solar system?" You might ask. Well, here's the answer.

Our solar system started from a swirling group of dust and gas particles. Individually, these particles move randomly, and their motion can not be predicted. But as a whole cluster, this cloud of dust and gas always spins in one direction or another (this is as the cloud, held together by gravity, wants to spin about its centre of mass). This spinning happens on, as you would imagine, a flat plane.

But particles are not confined to spinning about on this flat plane. They could go up, or down, or wherever they wanted to. However, if they do move up or down, they are more likely to collide with other gas particles in the cloud, 'cancelling' each other out. Particles spinning on that flat plane don't collide with anything else, since everything else is also moving in the same direction, leaving them as the only particles remaining.

This explanation isn't limited to just our solar system's flatness, but also other planetary systems, black holes, Saturn's rings, quasars, pulsars, and entire galaxies.

If you found this article interesting, make sure to have a look at this video. It looks at why the whole universe is flat, and the explanation is a little more complicated than the one explained here.

Image: http://www.dailymail.co.uk/sciencetech/article-3306656/Did-solar-contain-DOZENS-Earth-like-planets-Simulations-suggest-rocky-worlds-kicked-gas-giants-billions-years-ago.html

https://www.youtube.com/watch?v=MTUsOWtxKKA

https://www.youtube.com/watch?v=Aj6Kc1mvsdo

https://www.youtube.com/watch?v=tmNXKqeUtJM

http://futurism.com/why-is-our-solar-system-so-flat/