I suppose it's too late to ask for a deeper explanation. I must admit I'm puzzled on this one; these are principles that were taught to me very early on and never questioned since. I can remember by physics teacher along the lines of "physics is exact, if your experiment fails it's not the theory that's wrong, it's you!" and students were expected to make the experiment work for a good grade. If education grades can be subornated to the certainty that carefully designed experimental protocols should work within margins of error, this goes to show how confident we are that valid theory is valid... I don't know.

As for the scientific theory it was taught to me even in History class, it's just a set of principles.

Astrophysics, as far as I know, do not contradict existing theory? However it very much shows the limits thereof — but what's beyond this limit is not part of our undertanding of physics, of our theory, yet or ever. Maybe you can solve gravitation at the quantum level, maybe not, either way our accepted current theory work and keep being confirmed afaik.

Genuinely curious to know why the downvotes to GP.