If you can give me a scenario where such asteroid that obliterated Earth would not render SHA256 obsolete I'd love to hear it.
Well, just from the top of my head, SHA256 is pretty good so I bet alians also use it.
The rest of your post is simply silly.
I agree the OP post has lots of nonsense in it. It is already stated that to hack bitcoin they must hack the sha256 system, and hacking so if succesful will not only compromise bitcoin security but all of banking security in the world. He keep pushing precious metal, i can say we hear you, and somehow agree that one shouldn't put all his egg in 1 basket.