Recent content by sphyrch

Thanks for the response! But I'm sorry @Ibix I couldn't follow - I think I did not frame my question very well. My doubt isn't why one index is up and the other is down - it's why the indices are staggered in that particular way. There are three paragraphs in my OP, first para I'm pretty sure...

I'm reading Liang's book on General Relativity and Differential Geometry, and came across this part: I just want to have a crystal clear understanding of why this notation is chosen. Basis transformation would be an automorphism from ##V## to ##V##, and there's a result saying that the set of...

I see your point. Any random person (like me) can come up with a vague qualitative hypothesis, but working out details and following all the way through is what matters. Thanks for the wake up call and I understand that I should work out concrete details before presenting to others

Could you elaborate please?

I wanted to ask about a potential difference between general relativity and quantum mechanics phenomena - that we are observing them at different moments in time. Because causality has a speed limit (##c##), every point in space where you observe it from will be the closest to the present...

It like this? If front ship moved extra ##x## dist by the time (say ##t##) light reached, then ##ct-z=ut+at^2/2##. and then we say ##u<<c## so we ignore, and we say that time taken is super short so we ignore ##t^2## too. So every thing gets ignored and we get ##ct-z=0##. This the author logic?

I'm reading book from here. Suppose two rockets are accelerating with the same acceleration ##a## and are separated by some distance ##z##. At time ##t_0## the trailing rocket emits a light pulse. The book tells that pulse reaches leading box after time ##z/c## as seen in background frame. But...

On this note, some claims that Einstein makes in his booklet are from the inertial frame's perspective then? For example, he says From what I understand, his point is that in a Euclidean continuum (as assumed in non-relativistic classical physics), a Cartesian system of coordinates represents a...

Ah, understood.. But the last para in my last post (#42) is fine, right? I'm just combining whatever I've seen from the posts in this thread.

Thank. I think I got the source of my major misconception. I was wrongly assuming that a "theoretical argument" should just be some thought experiment that doesn't involve measurements. But even from ##A##'s PoV, just saying that the disc is rotating and hence ##B## is moving w.r.t. him...

Which is to say that w.r.t. ##A## (who's the observer in the inertial frame you mentioned), ##B##'s and ##C##'s clocks tick at a different rate - this conclusion is what you're saying can be derived based on SR only? Could you elaborate or give a hint so that I can try to work it out myself first?

Sorry for the delayed response. So then it seems that there's no way to theoretically conclude that ##B## and ##C## clocks are ticking at different rates based solely on SR. Either they'll have to do measurements using, e.g. , ring laser gyroscopes, OR the equivalence principle will need to be...

I gave it some thought. Can I say that since ##B## is at more distance from the disc center (say ##R##) than ##C## is (say ##r##), ##B## will have more tangential velocity at any given moment (##\omega R>\omega r##). So then ##C## should observe ##B## moving at a non-zero velocity w.r.t. him (in...

Got it, sorry for not responding to your earlier post. I'll study that wikipedia page in more detail asap

@PeroK : First off thanks for the replies and clarifying a few things for me. Yep that's very much clear. Just want to state that when I say that they consider the disc not to be rotating, I don't mean that they consider the disc inertial. So once and for all I'll say that I'm not under the...