Have no idea is a phrase appears many times in the book We have no idea: A guide to the unknown universe, for example in the title, or in this sentence:
It's the biggest chunk of reality, and we almost have no idea what it is
My question is: What does the phrase "have no idea" mean? Can we understand it literally that people haven't got any idea about something or it means that people don't know about something?
I know that it's quite confusing and may be trivial question, but I'm translate from English to my native language, so I have to find the most exact words to describe that phrase, so please help me.