I had to blow up the pic to see that the stargate actually doesn't have any carvings on it, but that sure IS an enterprise-shaped cloud formation over Hogwarts!!

If you looked at ALL the covers, the one you linked to is by far the best one, the US cover being very blah and only SLIGHTLY more interesting than the UK adult cover (hm, wonder if the ADULT edition is rated R for the naughty bits??) ^0^