I have some questions

[MeGaBlitz]

Hello!

I am from Austria and tomorrow i am having a presentation about Blu-ray and HD-DVD. But i have so many questions and if i know something there will be tow more questions *lol* Please can someone answer the following questions?

1. Why is the protection layer of a Blu-ray disc smaller. Ist a HD-DVD safer than a Blu-ray disc? And if not, why is HD-DVD having a 0.65 mm layer? For what hat ist this layer using?

2. I have a list where is standing that the Numerical Aperature(NA) is 0.85. But what? mm? And i really don't know what it is. In another threat Marwin worte: "A unitless measure of the ability of a lens to gather and focus light." I don't understand this sentence. I can't translate it in German. Can someone describe this sentence for me?

3. Why will HD-DVD only be in a double-layer disc. Why not also multi-layer?

4. Which format releases first? HD-DVD or Blu-ray?

5. Is it right that Windows Vista will only be compatible for HD-DVD?


I would be so happy if someone could answer this questions for me. Thanks!
meGa