Banned because black holes or the destruction of the Sun will eventually destroy the planet before anyone has the chance to take over, but probably not before a meteorite, solar flare, another planet, or something of the sort comes our way and extincts the human race. We might even hit another ice age before any of that happens.
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"I got to keep you on your toes. When you think I'll zig, I'll zag. Then when you think I'm gonna zag, I do zag, just to mess you up for the next time, when I might zig" - Lorelai Gilmore