Apparently it really did take a little kid to point out to Obi-Wan and Yoda the obvious fact that if the planet is missing from the map and there's a mysterious blank region in the map where you expect the planet to be, that maybe the planet is actually there and the map has been tampered with. Seems like a pretty obvious deduction to make - eliminate the impossible and whatever remains, no matter how improbable, must be true, and all that - but then again we're not blessed with Yoda-like levels of intelligence and insight. If you're that smart, maybe it's obvious that it's not actually as obvious as it appears to be...

Transcript

Obi-Wan: Maybe if we look at a map, I can find the planet.
Yoda: How get a map will you? All information about planets by dogs eaten was, hmmm?
Obi-Wan: Perhaps I managed to retrieve a... memory marble.
Yoda: Yeees... But damaged, it appears. Bite marks, there are.
{Obi-Wan plugs the marble in, holographic star map appears and fills the room}
Yoda: No Kamino do I see. Just this blank spot.
J. K. Burtola: Oooh! Oooh! Just go there and you'll find it!
Yoda: Uh, no... anything there, there could be. There.
Obi-Wan: It can't hurt to check. Truly wonderful the mind of this child is.
Obi-Wan: {to youngling} Do you want to come along?
J. K. Burtola: I'm not a child!
Obi-Wan: No, but your character is.
J. K. Burtola: I'm going to go play Guitar Hero.
{beat}
Yoda: By the way, save the marble from the dogs, how did you?
Obi-Wan: Alimentary.