Use Apache's mod_alias module to perform a permanent redirect like:

RedirectPermanent / "http://world wide"

Put the redirect within the blank subdomain's virtualhost block or root level .htaccess file.

The trailing / on "http://world wide" is vital.

I'll add an alternative choice here that I have accustomed to permit other specific hosts too. For instance should you wanted a along with a site additionally for your world wide site, put this inside your root level .htaccess file:

RewriteCond % .

RewriteCond % !^

RewriteCond % !^

RewriteCond % !^

RewriteRule (.*) http://world wide$1 [R=301,L,QSA]