- #106
PeterDonis
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name123 said:when looking at it from the B-Team's perspective are they considering the A-Team to be going at ##-v##,##-w##?
Yes.
name123 said:when looking at it from the B-Team's perspective are they considering the A-Team to be going at ##-v##,##-w##?
name123 said:Now does have an absolute meaning for you personally though doesn't it? And would have for the next team A observer down. So can you see how it could true that simultaneously to you experiencing, a team A member was experiencing simultaneously to the team B member opposite to it who was experiencing simultaneously with another team B member experiencing who was simultaneously experiencing with you in the future?
PeterDonis said:If by "now" you mean "what is happening to me at a given reading on my clock", then yes, of course. But I don't see what that has to do with the rest of what you said.
name123 said:while I can imagine all the clock times that I will be alive for, there will only ever be one "now"
name123 said:Are you saying that you think the way that "now" should be understood given relativity, is that any clock time in your life has equal right for the claim of being now?
name123 said:with your understanding of relativity would it be true to say that everything the human you experience being has ever done exists in spacetime
name123 said:in theory if you could travel to those spacetime coordinates you could see yourself?
PeterDonis said:But which clock time is "now" to you, on this definition of "now", is continually changing.
name123 said:Are you saying that you think the way that "now" should be understood given relativity, is that any clock time in your life has equal right for the claim of being now?
PeterDonis said:No. It's true that, since each of them is your "now" when it's your "now", each of them has an equal claim to the term "now". This concept of "now" is just a label that means "whichever instant of my clock time I'm experiencing". But none of this has anything to do with relativity. Your entire worldline is represented in the spacetime model used in relativity; which instant you want to label "now" has nothing to do with the model.
name123 said:Also with your understanding of relativity would it be true to say that everything the human you experience being has ever done exists in spacetime, so in theory if you could travel to those spacetime coordinates you could see yourself?
PeterDonis said:In theory, yes. But the "if" there is a big "if". Traveling to spacetime coordinates that you've already visited once requires what are called "closed timelike curves", and while they are possible mathematically, pretty much all physicists believe that they aren't physically possible. Spacetimes which include them have a number of properties that don't appear to be physically reasonable.
name123 said:The way I mean it if I were to always wear a watch (which had the date and always kept time) only one of its times would ever be "now".
name123 said:Reality has to do with what instant I label "now".
name123 said:What is moving along your worldline in the spacetime model used in relativity?
name123 said:Can my history change? (without me visiting it again)
The first statement is obviously wrong, and the second is just philosophy. Since you have resolved your physics questions, it is a good time to close the thread.name123 said:if I were to always wear a watch (which had the date and always kept time) only one of its times would ever be "now".
Reality has to do with what instant I label "now".