Relativity revisited once more still again

Dunno Que but if the Universe is finite and one proceeds in what seems like a straight line he presumably returns to where he started

What got me going was the notion that relativity tacitly required a stationary reference, which my OP seemed to contradict--tho I'll be first to admit that somewhere along the line I might'v' stepped off the lory and from that point forward got everything wrong

Okay there's apparently something wrong with the "usual" supposition; but what

Tribute to Herbert Dingle


" It is ironical that, in the very field in which Science has claimed superiority to Theology, for example - in the abandoning of dogma and the granting of absolute freedom to criticism - the positions are now reversed. Science will not tolerate criticism of special relativity, while Theology talks freely about the death of God, religionless Christianity, and so on." H.Dingle

" It would naturally be supposed that the point at issue, even if less esoteric than it is generally supposed to be, must still be to subtle and profound for the ordinary reader to be expected to understand it. On the contrary, it is one of the most extreme simplicity. According to the theory, if you have two exactly similar clocks, A and B, and one is moving with respect to the other, they must work at different rates,i.e. one works more slowly than the other. But the theory also requires that you cannot distinguish which clock is the 'moving' one; it is equally true to say that A rests while B moves and that B rests while A moves. The question therefore arises: how does one determine, consistently with the theory, which clock works the more slowly? Unless the question is answerable, the theory unavoidably requires that A works more slowly than B and B more slowly than A - which it requires no super- intelligence to see is impossible. Now, clearly, a theory that requires an impossibility cannot be true, and scientific integrity requires, therefore, either that the question just posed shall be answered, or else that the theory shall be acknowledged to be false. But as I have said, more than 13 years of continuous effort has failed to produce either response. The question is left by the experimenters to the mathematical specialists, who either ignore it or shroud it in various obscurities, while experiments involving enormous physical risk go on being performed. "

equally true to say that A rests while B moves and that B rests while A moves…... [so] how does one determine…….which clock works the more slowly?

To me, maybe Que me only, that q doesn't make sense. Surely Einstein would reply, it depends upon from which reference frame you view it

For one to "really" establish which is slower would be to construct an absolute reference frame, which according to Albert there isn't any suc

what are you saying here?
To me, maybe Que me only, that q doesn't make sense. Surely Einstein would reply, it depends upon from which reference frame you view it

For one to "really" establish which is slower would be to construct an absolute reference frame, which according to Albert there isn't any such

In order for one clock to be running absolutely faster than another you'd have to find a special reference frame "at rest", which supposedly there isn't

Your analysis Bran pretty much agrees with mine, the apparent discrepancy doubtless arising from my oversimplifications. I probably shouldn't have had us taking off from "nearby planets"

Also I had inadvertently reversed our roles. Returning to the OP I see it was I who kept going. Blame my age, 84 day before yesterday, incipient Alz's

Anyhow it's the guy who accelerates who stays young

So instead here are you and I 20 years old, approaching Earth where A lives, also 20. You apply your retros, joining A for lunch, where we're all three of course still 20.

Much (much) later when I reappear (coming from the opposite direction?) A and you are very (very) old while I'm still 20

Sorry Bran if I was misunderstood. I am continually amazed at how easily misunderstandings arise

Incidentally I'd been making the assumption that my clock had stopped for my entire trip but I'm no expert.

Perhaps owing to the curvature of space, my movement slowly resumes, reversing at the "halfway" mark, in which case upon my return we're all three the same old age. Just wild speculation

Perhaps Ora you perhaps misunderstood my experiment. You and I are the same age, taking off eg from nearby planets opposite Earth.

Now ignore Earth. The instant after my takeoff you pass me going the other way, merely two observers traveling at (near) speed c with respect to one another. Yet next time we meet

Not if I travelled for some time near the speed of light. In this case, A might be much older, depending on the particulars.

Absolutely wrong,

and what does the curvature of space have to do with it?

You've been at this for a year and still know almost nothing

Taking off???………... "Suppose at the instant of our parting we had both been traveling, relative to the rest of the visible Universe, near c"

I've assumed that you are envisioning a finite universe that loops on itself, so that someone who travels far enough is a straight line will one day end up at the same spot. However, you've never confirmed this.

Note that the real universe is infinite. If these two guys travel in a straight line away from each other, they will never meet each other a second time.