I think I disagree with Jerry. After Arda became round*, Valinor isn't any longer part of the planet. Its unclear if it is another planet/moon now or if it just floats there in space.
The Valar seem very comparable to the Ones from the Mortis arc in The Clone Wars. They are definitly magical entities = Force entities, so I think the Death Star wouldn't affect them. ("The ability to destroy a planet is insignificant next to the power of the Force.") It wouldn't completely destroy Maiar like Sauron either, I guess. Sauron's spirit escaped from Numenor** after all, so he might be lingering around in space an it might even be easier for him to find the ring, which is also floating around in space.
But what if some Jedi (many Jedi) created a permanent Wall of Light around the Ring? Would it become useless for Sauron, because he couldn't connect with it anymore?
*For those who haven't read it: the World with middle earth on it was once flat. But then some humans wanted to conquere Valinor because there the immortal Valar and Elves were living and they thought they could steal Immortality from them. Iluvatar (=God) buried them under some mountains, sunk their home (the Island Numenor) into the sea and removed Valinor from Arda, while giving Arda planet shape.
**Sauron was on Numenor during this time. He fell into the abyss and his physical form was destroyed. But his spirit got out of it, taking the ring with him.
Interesting. The discussion didn't continue on much passed Jerry putting that in the FB thread so I'm going to defer to the two of you if this question ever swings my way again. Been way too long since I've kept up on LOTR continuity with the EU stuff.