Physics is not “silly,” in my opinion. Go and show this link to a niece or a nephew of a younger age, and see what happens.
Thanks for making my point. (And your's is not an opinion, it's a fact, Jack.) The silly part is the premise of a 0.9c baseball in a dense atmosphere. It would have burned up long before ever getting to 0.9c. Ever see a small piece of space debris entering the thin outer atmosphere at 0.0000...c? Poof. Shooting star. Gone. You cannot suspend basic physics, go on to construct some "what if?" scenario, and then claim it's still covered by physics.
Oh, as to your suggestion, I would not knowingly subject any young relatives of mine to silly stuff like that before they had a firm grasp on the real principles of physics.
(That’s what public schools are for, anyway. Heh.)