Conservation of angular momentum

In physics, angular momentum is the rotational counterpart of momentum. A spinning flywheel has angular momentum.

To calculate angular momentum of an object or system, a point is chosen, called the origin (often the centre of mass is used), and the distance to a part of the object is determined. This is then multiplied by the transverse component of the momentum relative to that origin; this gives the magnitude of the angular momentum of that part of the object.

So what those all this mean, well I'll try and explain it, the best thing to do is imagine a hurricane, when the storm that forms a hurricane is beginning it is a large mass of clouds. These clouds slowly start to spin as warm air and cold air meet each other and then the spinning becomes faster and faster as the clouds begin to contract and eventually when they are spinning really fast they create a hurricane.
What has this to do with anything? Well everything. It is because of this principle that we are here in the first place. The Conservation of angular momentum meant that the nebula from which all the stars and planets are made, could make all those stars and planets. these nebula eventually begin to move in the same way as storm clouds do and as such they get denser and denser until they form stars and such. Now.