Destroying the earth may be easier than most people think, now I'm going to start off by saying I'm not a trained professional by any stretch of the imagination, but I do know a little bit about physics and I think I have one that's within our technological reach (not developed fully but could be if this was for whatever reason necessary[don't ask me why]), but basically the concept revolves around essentially creating a micro-singularity(miniature black hole) and forcing it to the center of the earth, which would cause the core to collapse and (atleast hypothetically) cause the crust to either get thrown off into space or collapse inwards... So problems= 1.Creating a micro-singularity (miniature black hole) Surprisingly... not really that far out of our grasp, we already know that the LHC is capable of producing black holes not even remotely strong enough to destroy anything at all mind you, and they dissipate so fast that it's as if they were never there, but that's not all we know for a fact that we can use magnetic fields to crush matter together to fuse, so all we really need is a massively scaled up Fusion reactor(like this) with additional power or... a massively scaled up version of the LHC to accommodate now this will certainly require some effort to fine tune, but it's most certainly not outside of our reach. 2. Stabilizing the micro-singularity to avoid premature dissipation. For this all we really need to do is scale up, more material, more energy... essentially a larger black hole should do the trick.. how large is problem... but not my problem... I'm sure if (for whatever reason) we're doing this, that we're using the top scientists and well... they'll figure it out 3. Getting it to the center of the earth... This I'm not sure about, my assumption is that it'll sorta pull itself down there and that gravity will do a damn good job of pulling it in, but the most mass it accumulates the more matter will actually distance itself, so we may end up (if I'm not overthinking this) with a sorta bowling ball finger hole in the side of the earth. So once the black holes formed we may have to give it a good magnetic kick in the pants to get it to the core. 4. Once at the core.. we run into another problem... keeping it there and can we make it large enough to cause the core to collapse as opposed to just boring a nice big tunnel, again I Suspect gravity may be a help here, but for stopping it... perhaps just let it go and let the accumulating mass slow it down... or potentially send two down in such a manner that they gravitational interact and launch themselves off in opposite directions (hopefully the increased mass from the 2nd pass would cause them to crash into each other on the 2nd pass) 5. Motivation... Because F**k you, that's why! and finally we have it we 'should' have made the earth essentially go either nova or black hole-i-fied