Name one. I'll will suggest it to him (or better yet, you tell him how he does not need to deny the existence of QM and free will.)
Time Travel is Science Fiction
- Thread starter Farsight
- Start date
The professor agrees that the laws of physics and GR do not forbid time travel, as does the vast majority of mainstream cosmology, and as such remains open to possibility by any sufficiently advanced civilisation.
Live with it
Tashja, I cannot easily quote from quotes on an iPad so...
The Professor in this response introduced Simutaneity, I take as a reference to the relativity of simutaneity... Which in the context of the discussion as I understand it, is a different animal altogether. Though a similar confussion may be at the heart of some of the disagreement. His response here seems to me to support my interpretation of his earlier comment as consistent with my later post below,
If his responses are to only those specific portions of the discussion you deam important and not the discussion's context as a whole you do him a dis-service and us.
Most of the comments made in any single post carry with them some context developed in earlier posts... Or clarified by subsequent posts.
I don't believe the Professor's comments were made with a full understanding of the disscussion!
No "X not forbidden" does not equal "X is possible" In most cases the laws of physic do not mention X. That is the case when X = time travel.
GR allows (and suggests) that the behavior of particle, past, present and future can be described in 4D space time with "time indexed" by the integers along the particle's 3D trajectory. No mention of any actual ability for observers to move differently than that.
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I'm certain though that the professor realises the factual content in what I did say.
Plus, I'm sure according to the two posts tashja sent the professor, [one of mine and one of Billy's] plus the link to this forum, that he would and did have a good understanding of the discussion.
Billy, please accept the facts of this thread....[1] The inference of the title of this thread is wrong and a misnomer...Sci/Fi now, yes, Sci/Fi tomorrow?? Maybe not[2] Time travel is not forbidden by the laws of physics and GR...and the relevant equations support that possibility ...[3] No one has said it is indeed 100% possible.
Yet you continue to put words in people's mouths.
What words have I put in your mouth?
But let me note more on fact "X is not forbidden by the laws of physics" is not equal to: "X is possible."
by noting that the laws of physics have evolved since Newton's day (and before) by experimentation and observations. They try to precisely summarize how the universe behaves. Pleople do, as you have done, speculate on possible extensions of them. QM events span "multiple universes," etc. Witter of good science fiction try not to violate them, but when they are slient on some X being possible or not, these writers tend to use X in their stories if that will sell more copies of their books.
The laws of physics codify what is observed into theories that they can test. When not theory falsifying test turns up and many confirmations have, we then see what else is consistent or can be predicted form the theory. For example the currently accepted theory predicts that magnetic monopolies not only could exist but that they should (and tells that they would be much heavier than a proton if they did exist.
This is an interesting case where not the laws of "do not prohibit" magnetic monopoles they actually predict them, yet magnetic monopoles do not seem to be possible.
Again "not prohibited" is not equal to: "Is possible"
tashja
Registered Senior Member
OnlyMe, I always send the post(s) in question with an attached link to that specific page where the posts are so that there is no misunderstanding of what is being discussed. Do the Profs. follow the link? That I cannot tell you. The thread is already 56 pages deep, so I doubt they have enough time to go through each post. But like Paddo said, they don't seem to have any trouble understanding the core issue of the discussion.
Again, stop putting words in my mouth.
I fully stand by the claims I have made, that is totally aligned with the mainstream position on the possibility or otherwise of time travel.....
The way I see it, is that the discussion is a debate about what is real. One side defending science fiction as real.., occasionally by just saying it might be real sometime in the future. The other side saying science fiction is science fiction.
It gets more complicated because there has as far as I can tell been no agreement on exactly what is meant by time-travel, which leads to riduculus ideas like just waking up in the morning is time travel... The word time-travel has a very specific lay meaning, which includes some kind of jump from one time frame to another without experiencing any time during the jump. That would not include waking up day after day or even the situation in the twin paradox, because in both cases all observers experience an uninterrupted experience in their own frame of reference.
Where the Professor clarified his position by introducing simutaneity of relativity, worm holes and grandfather paradoxes, as argument.., as far as I am concerned he proves my point. The simutaneity of relativity is a whole separate discussion and worms holes, warp drives and time machines are things of theoretical speculation and science fiction, until they have been realized in reality.
No one including the professor has presented a clear definition of just what time-travel is.., that has then been accepted, as a baseline consensus for the discussion. are we talking about time-travel as depicted in science fiction, or just waking up in the morning?
Actually, me too, though he was far from a fan :shrug:I miss AlphaNumeric terribly.
And again I ask you for an example of me putting words in your mouth. Back up your accusation with at least one case - telling the post number where I did that, of course. (Or apologize for making false statement about me.)
No, that was the other thread about time.
This is about the possibilities of time travel, and no one, least of all me, is defending Sci/fi as real. But to deny what may be possible in the future, taking into account that the equations of GR support scenarios, applicable to time travel, is very short-sighted.
That is the way I see it, and I challenge anyone to show me differently.
Me three...although I do see a tendency for some of our more respected knowledgable contributors, as having had a gut full of the unsupported claims that Farsight is apt to make, as well as others.
Your inferences are obvious, and no, like the other accusations you have thrown my way, they are all false...so no apologies and I'll leave the rest up to anyone that takes the time to read post 1105 and 1108, being the most recent.
And no apologies necessary on your part for your false accusations...Afterall, this is just a science forum, and certainly not any vehicle for mainstream peer review or anything near that dramatic..
then again for the third time, quote me putting words in your mount - just saying it is "obvious" that I did is not a "quote."
And BTW, I am only responsible for what I actually say, not what you "infer" from my words.
Here is post 1105, in its entirety:
No "X not forbidden" does not equal "X is possible" In most cases the laws of physic do not mention X. That is the case when X = time travel.
GR allows (and suggests) that the behavior of particle, past, present and future can be described in 4D space time with "time indexed" by the integers along the particle's 3D trajectory. No mention of any actual ability for observers to move differently than that.
-----------------------------
Here is post 1108 in its entirity:
What words have I put in your mouth?
But let me note more on fact "X is not forbidden by the laws of physics" is not equal to: "X is possible."
by noting that the laws of physics have evolved since Newton's day (and before) by experimentation and observations. They try to precisely summarize how the universe behaves. Pleople do, as you have done, speculate on possible extensions of them. QM events span "multiple universes," etc. Writers of good science fiction try not to violate them, but when they are slient on some X being possible or not, these writers tend to use X in their stories if that will sell more copies of their books.
The laws of physics codify what is observed into theories that they can test. When no theory falsifying test turns up and many confirmations have, we then see what else is consistent or can be predicted form the theory. For example the currently accepted theory predicts that magnetic monopolies not only could exist but that they should (and tells that they would be much heavier than a proton if they did exist.
This is an interesting case where the laws of physic not only "do not prohibit" magnetic monopoles they actually predict them, yet magnetic monopoles do not seem to be possible.
Again "not prohibited" is not equal to: "Is possible"
--------------------------
Again: where do I even quote you, much less put any words in your mouth? (tell me - fouth time I ask)
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http://timetravelphilosophy.net/topics/relativity/
http://www.spacedaily.com/reports/T...eral_relativity_to_quantum_mechanics_999.html
http://www.astro.umd.edu/~miller/teaching/astr380f09/lecture26.pdf
Above are three more interesting links that talk about time travel, it's possibilities, and the fact that it is not forbidden by GR.
http://www.spacedaily.com/reports/T...eral_relativity_to_quantum_mechanics_999.html
http://www.astro.umd.edu/~miller/teaching/astr380f09/lecture26.pdf
Above are three more interesting links that talk about time travel, it's possibilities, and the fact that it is not forbidden by GR.
My virus protection blocked opening Paddoboy's first link in post 1119, but this is a quote from the second:
"The properties of quantum particles are 'fuzzy' or uncertain to start with, so this gives them enough wiggle room to avoid inconsistent time travel situations," he said."
Clearly marked as an opinion by the "he said" and another link to this said he was a graduate student. That may explain his idea about QM being Fuzzy. More accurately it has uncertain or probabilistic results. But more important is that QM predicts the same result when time, "t" in the equations is reversed (replaced by -t) IF either P (parity) or C (charges) but not both are reversed too. I. e. physics is invariant if any pair of CPT are changed in sign. (There may be an exception to this rule in the case of a few reactions with the weak nuclear force - as I recall these "CPT violations" have even been observed and were once (still?) used to explain why the current universe appear to be so dominated by mater instead of equal mount of both mater and anti-mater.
The other and some what obvious thing to know that this was all just computer simulation study - they certainly did not have any "worm hole" as they have never been observed - are only speculative (and very complex math) extensions from GR. They even admit that they only simulated a photon finding its self going around the worm hole the other way round as illustrated in this drawing:
Sorry. It will not copy. Go to link 2 to see.
Paddoboy's third link, concludes with the observrion that worm holes probably can not exist, but if they did sending any normal mater into them would very rapidly destroy them (and presumably any one trying to "time travel" thur one, although as this is all just speculative math, lets assume not - assume that they are now in another space time - some other universe.)
Dirac once, in jest, I think, explained why all electron are identical. Because there is only one existing. I.e. in the future some clever physicists reversed T & C of so there was a negative charge travelling back in time (as it passes thru our "now" going into the past we recognize it as a positron.) When it gets further back in the past it scatters with a second change in T & C so becomes an electron that travels to our "now" etc. a zillion times and "low and behold" you have in our now a zillion completely identical copies of the one electron that really exist in our now. I forget how Dirac got rid of the equal number of positrons, if he did.
"The properties of quantum particles are 'fuzzy' or uncertain to start with, so this gives them enough wiggle room to avoid inconsistent time travel situations," he said."
Clearly marked as an opinion by the "he said" and another link to this said he was a graduate student. That may explain his idea about QM being Fuzzy. More accurately it has uncertain or probabilistic results. But more important is that QM predicts the same result when time, "t" in the equations is reversed (replaced by -t) IF either P (parity) or C (charges) but not both are reversed too. I. e. physics is invariant if any pair of CPT are changed in sign. (There may be an exception to this rule in the case of a few reactions with the weak nuclear force - as I recall these "CPT violations" have even been observed and were once (still?) used to explain why the current universe appear to be so dominated by mater instead of equal mount of both mater and anti-mater.
The other and some what obvious thing to know that this was all just computer simulation study - they certainly did not have any "worm hole" as they have never been observed - are only speculative (and very complex math) extensions from GR. They even admit that they only simulated a photon finding its self going around the worm hole the other way round as illustrated in this drawing:
Paddoboy's third link, concludes with the observrion that worm holes probably can not exist, but if they did sending any normal mater into them would very rapidly destroy them (and presumably any one trying to "time travel" thur one, although as this is all just speculative math, lets assume not - assume that they are now in another space time - some other universe.)
Dirac once, in jest, I think, explained why all electron are identical. Because there is only one existing. I.e. in the future some clever physicists reversed T & C of so there was a negative charge travelling back in time (as it passes thru our "now" going into the past we recognize it as a positron.) When it gets further back in the past it scatters with a second change in T & C so becomes an electron that travels to our "now" etc. a zillion times and "low and behold" you have in our now a zillion completely identical copies of the one electron that really exist in our now. I forget how Dirac got rid of the equal number of positrons, if he did.
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