Newtonian Mechanics are valid, just not as accurate as Relativity. Relativity is, in essence, a more accurate version of Newtonian Mechanics. It refines it, but the basic conclusions are very similar, save for extreme circumstances. Though relativity is more accurate, it's much more complicated, so most people will calculate things with N.M. It works fine at human-experienced scales, speeds and distances. Creationism is entirely different from evolution. It in no way refines the idea for more accuracy, it just throws the whole damn concept out the window and says "We know, and we're right because we said so." And it should be noted that Einstein, unlike the evolution-deniers, backed up his claims with math, logic and science, rather than just anecdotal evidence. Fact checking when you are an informed person or scientist is one thing, saying something is wrong because you don't get it and some old book told you it's wrong is entirely another, invalid, way of thinking.