Moving particles down


I’m trying to understand how particles are generated but need some help. I have this code where it is generating raindDrops and moving them down but it only moves 100 of them and after that the raindrops don’t move.

Can someone tell me how can I make this to run forever and move all rainDrops?

I was also wondering if the objects need to be removed after moved all the way down or flash will remove them automatically? If yes, how (using null or something like that)?

Thank you very much!

var rainDropArray = new Array();

this.addEventListener(Event.ENTER_FRAME, addDrops);

function addDrops(event:Event):void {
var rainDrop:RainDrop = new RainDrop();
rainDrop.scaleX=Math.random() * .2;

this.addEventListener(Event.ENTER_FRAME, moveDrops);

function moveDrops(event:Event):void {
for (var i:int=0; i<100; i++) {