Empty query on Google

Google prevent users from typing nothing in the search engine. It's a pity, I'd be curious to know what should come out from a research on an empty query.

Why the hell an empty query would be important in a search engine? At first glance, it's a weird idea because if you go to a search engine, it's basically because you want to look up something on the information superhighway. But why not allowing people to search for nothing? This lead to the question of leaving a blank space on a query. On some platforms it could be used as starting point to have an overview of the situation; for example, on a map engine, it could be a way to have the overall representation of the earth; or in an address book it would be an easy manner to get the whole list of people. The problem is that we've google, the domain's huge. I would have expected an empty query to bring me on some sort of representation of the globality as described by Google. They actually do have a good representations of what's available on the noospherian web, so why not providig the users with a sort-of depiction of this? I also expect it to be more elaborated and revealing than the Google Zeitgeist.