Which creature aliens? Maybe or after the destruction of the earth by humans, what will be left, living micro-organisms? I was wondering, if Mars or other planet would be discovered to be indeed livable, will not human beings destroy it also? Everything is coming to an end, the world and everything in this world is degrading, human lives are becoming shorter, shortage of food and scarcity of everything is there so human lives will eventually come to an end no matter how technology tries its best to to find solution to revert aging and spoil death i don't believe they'll be successful.