The difference between OpenSolaris and Linux

What's the difference between OpenSolaris and Linux?

opensolaris is a UNIX system provided by Sun Microsystems which is Solaris version 10 or greater, when Solaris became opensource. It has been around far longer than any Linux distrubution, and generally used by enterprises rather than as a desktop system, as it is highly stable & reliable and very well documented.

Linux orgin's come from the GNU project and has always been opensource. Linux is UNIX like but cannot be called UNIX