Typical Y Combinator Interview Questions says:
Where is the rocket science here?The question might be simple for Americans, but I am outside USA, and I haven't found a reliable answer. I need a clarification because I plan to translate it into Chinese for knowledge sharing.
I guess from posts containing rocket science in this site that it may mean silver bullet (a term used in saying "no silver bullet" from a book named The Mythical Man-Month ).
Can I say that rocket science means something over-complicated that still makes people feel like magical, although it is a step-by-step science?
I would imagine that in this instance it's a reference to the phrase "It's not rocket science" used to mean that you do not think that something is very difficult to do or to understand.
So what they are asking is "What's the difficult / complex part of this business?".
What's going to stop N thousand other companies copying you and doing it better.
The answer has been accepted by questioner, and for those who are interested, here is an excellent explanation from English Language Learner: http://ell.stackexchange.com/questions/6922/what-does-the-rocket-science-refer-to-in-this-question-about-startup/