Of course there's all sorts of things wrong with the idea that blowing up the moon will prevent the geysers from erupting on time. Beginning with the idea that the moon can cause geyser eruptions in the first place... But never mind that.

Take Earth for example. If you blow our moon up a little bit - just enough to bust it into pieces - it won't have any major effect on the tides. The centre of mass of the moon fragments will still be in the same place, and that's what really matters. If you blow it up a bit more - enough to bust it into pieces that fly apart fast enough to overcome their own mutual gravitational attraction and spread throughout Earth orbit - you will affect the tides, but not immediately. It'll probably take a few days for them to settle into a new pattern. If you blow the moon up even more - enough to send the pieces flying away from the vicinity of Earth altogether - you'll eliminate tides on Earth, but again it'll take some time for the effects to settle down. You certainly won't notice the tides doing anything weird in the next couple of minutes. If you blow up the moon with ridiculous amounts of sci-fi technobabble - say instantly convert the entire mass into energy, or send it into another dimension or something - then the forces that generate the tides will vanish instantly, but the inertia and momentum of all that water sloshing around Earth's oceans isn't going to stop suddenly. It'll probably be hours to days before you'd even notice, if you were only measuring the tides and not checking to see if the moon was still there by other means.

And because we're blowing up moons, it would be remiss of us not to mention:

• The Endor Holocaust
• A Detailed Rebuttal to The Endor Holocaust (saved copy, since the original site is now dead)

We present these to demonstrate inarguably that there are people who spend more time analysing Star Wars, to greater levels of geekiness, than we do.

Transcript

Captain Tarpals: Wesa outnumbered!
Jar Jar: Wesa has to fight on. Throw mesa da explodey soap bubble!
GM: Captain Tarpals throws badly. Make a fumble check.
Jar Jar: 14!
GM: You catch it.
Jar Jar: Mesa throws it at da driver droid!
GM: The tank careens out of control.
Captain Tarpals: General Jar Jar! Look! The moon! It's asplode!
Jar Jar: Oh nosa! Everyone take cover!
{Jar Jar hides under a vehicle}
R2-D2: So much for the geysers. We're screwed.
Jar Jar: Wesa surrender! Gungans, lay down yousa weapons!
Combat Droid 1: All right!
Combat Droid 2: Now we can all go back to the drop-ship for a pint of oil.
Captain Tarpals: Mesa knew we couldn't win...
Jar Jar: {softly, to Tarpals} It'sa okay. Wesa take them by surprise later. Mesa knows how to make them break down.
Obi-Wan: I don't think droids eat sashimi, Sally.