I love you, baby, but not like I love my guitar, Prince leers in”Guitar,” between blasts of heroically pointless Edge-style soloing.It’s his most slamming summer jam since “P Control” in the summer of’94, or “Alphabet St.” in the summer of ’88, or maybe “Delirious” in thesummer of ’83. What did people do for fun in the summer before Prince? Planet Earth is one of those albums he makes when he’s trying a littleharder than usual, if not hard enough to alienate his core audience,which loves him for indulging himself. “Planet Earth” and “Lion ofJudah” continue the hard-rock groove, while “Future Baby Mama” and”Somewhere Here on Earth” revisit his smooth R&B side. As for “Guitar,”he’s decided to jack the post-punk revival, so he swipes a guitar rifffrom U2 (“I Will Follow”) and a bass line from Duran Duran (the samesong that provides his album title). Wily bastard.