What are these white dots i see?

i have looked around on the internet and have found alot of people claiming to see what i am seeing. they are little very tiny white dots that shoot back and forth. there are alot of them you might be able to see them also if you go outside and look at a blue sky just to get the focus right on them. what i find weird is that they go in and out every quickly but some tend to do circles and some are brighter than others. there is no conformity to them at all. so basically i am wondering what the science behind them are.