"Till" is completely valid synonym of until. "'Til" is an informal contraction (and was probably meant to be the actual word "till"). If you're gonna be aggressively prescriptive, at least pick an actual battlefield instead of attacking innocent folks.
DarthFreyr
joined 2 years ago
I think that mental model only works if you imagine the parabolas as reaching to infinity in a finite space so that both ends are parallel, ie having identical vertical slopes of +/- infinity. At that point, easier just to call it "half an ellipse". To me, it's much easier to imagine a parabola as the end of an infinitely long ellipse.
Your intuition and the KSP example are correct though. If you imagine the plane and cone for a parabola, you wouldn't notice any significant change to the shape (at a finite distance) if you tipped the plane ever so slightly into forming an ellipse (or a hyperbola, for that matter) since it's all smooth changes.
Anyway, the size of the elliptical (I think hyperbolic would have a different sort of energy state) arc that'd be formed by a thrown object would be so large relative to human scale as to basically be infinite, equivalent to a parabola. I imagine the difference might become significant once you are launching something a decent way around the Earth, but with that much energy in play I don't think it makes much difference where exactly the projectile "lands".