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md65536

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Posts posted by md65536

  1. I would suspect, but I haven't looked into this at all, that the core of the building (or some part of its interior) collapsed first while the perimeter (or at least the part of the perimeter measured on the video) stayed pretty much in place. The core would have picked up some speed before it ripped down the perimeter around it. For a short time the perimeter would have collapsed not only from its own weight, but from the transferred momentum of the already-collapsing core.

    Yes, the video evidence is consistent with this idea.

    1) The top central part is seen beginning to fall before the surrounding part.

    2) The plot of rooftop height has a sharp initial change in velocity instead of the smooth curve of constant acceleration.

     

    This means that the outer part of the building actually fell faster than free-fall at the start, as it was pulled down. Since the outer part's average speed was roughly that of free-fall, it would have accelerated at a lower rate than free-fall later on. The inner core could fall slower than free-fall, consistent with NIST's report.

     

     

    This is consistent with controlled demolition. I think that it strengthens the case for controlled demolition. It means that the outer portion of the building was supported for longer than the inner core was supported. This would happen if only the inner main support was demolished, as is typically done with controlled demolition.

     

     

    If someone can provide a reasonable explanation for the official case, where debris from outside the building must have severely damaged the inner core of the building, but left the outer part structurally sound, that would certainly increase my confidence in the official story. As it stands, I must conclude that the official story requires either that debris weakened the core while leaving the exterior structurally intact, or that neither were significantly weakened by debris and that fire alone (using only the building and its contents as fuel) caused a near simultaneous structural failure of all of the building's interior supports.

  2. Part 4

    As I explained, there is, at best, evidence that if thermite was present, it didn't burn. Finding three of the commonest 5 elements on the planet is hardly evidence of anything. (oxygen, iron, aluminium)

    If it had been there and burned it wouldn't have done much, as shown by that video clip. In any event thermite isn't an explosive.

    What explosives? Is there actually any evidence of any?

    In particular is there evidence of the massive amounts that would have been needed?

    My previous post re. pools of molten metal suggest that it did burn.

    The previously posted video www.youtube.com/watch?v=DonpXB6gjPA#t=8m16s demonstrates that modest amounts of thermite can be shaped to cut through steel beams.

     

    The same video shows, as http://www.benthamsc...V002/7TOCPJ.pdf claims, that thermite can react explosively.

     

    I'm confused by what you mean by "the massive amounts that would have been needed". Needed for what? To produce the results that we saw on that day? If your argument is that the buildings fell solely from the impact of the planes and the burning of jet fuel and building contents, then why would any explosives be needed?

     

    To clarify, I'm not arguing that the planes and the fires didn't contribute to the towers' destruction. I'm not even arguing that it's impossible that the towers could fall from impact+fires alone. What I'm arguing is that the evidence indicates that they didn't, ie that there were other factors that conspired that day.

     

    part 3

    " The Bush administration destroyed evidence and fought against independent investigation. This is not evidence of anything in particular"

    You said it.

    As I have pointed out there is a perfectly reasonable explanation for this. They wanted the mess tidied up so the city could recover quickly. There was no evidence at that time to suggest anything other than a terrorist outrage so there was no reason to look for clues about the cause of the collapse. They fell because the planes (or debris) hit them. Why make things worse by delaying the clear up?

    Also, re " I don't accept as fact any scientific conclusion where the evidence is kept secret, destroyed, or made unscrutinizable" Logically you don't believe in a lot of things then. Do you believe that men landed on the moon? If you do the you have contradicted yourself. If you don't then people will draw their own conclusions.

     

    I'll accept that 3 can be scratched off the list because it's not a very sciencey argument.

    I don't accept that it was perfectly reasonable. The Bush administration had to fight a lot of people to keep information hidden, to stymie investigations, to keep things quiet. They didn't do it in the best interests of people "to tidy the mess" because they were fighting people who wanted the investigations done. Finding out the truth was in the best interests of the people.

     

    It's possible that there was a good reason that they had to lie and cover up -- perhaps it was in everyone's best interest -- but that would still fall under the category of "the official explanation is not the truth."

     

    Evidence of the moon landing wasn't quickly "tidied up" and destroyed.

     

     

     

    The collapse is difficult to see well on any video because it's dusty and the people often stop filming to run.

    [...]

    Also you make an assertion that is unsupported and doesn't make much sense "and if it's from the falling inertia of the floors, then they wouldn't fall at free-fall speeds."

    What other speed would they fall at?

     

    This video shows 3 things to address your comments:

    1) The collapse of WTC 7 is clearly visible on video. Granted, the twin towers were shrouded in pyroclastic clouds and your argument is acceptable for them.

    2) It really does show free-fall speeds.

    3) At 3:30 it explains what I meant -- if the energy used to destroy the beams was extracted from the inertia (or I should have said kinetic energy) of falling floors, then the falling floors would be slowed.

     

     

    Fundamentally, there isn't much difference between the two states. In one case you cut most of the supports with cutting charges and so the building falls- one layer lands on the one below it and that collapses. Those two land on the next one down and so on.

    In the case of the WTC, one floor was weakened by a massive fire. The weight of the floors above collapses that floor, and it lands on the one below. The impact smashes that and the whole lot carries on down pancaking the floors under it in turn.

     

     

    It's fairly clear you haven't read NIST's report on the subject, since they address this issue quite extensively. In fact, they specifically discount the "pancaking" theory.

    (To be fair I hadn't read it either.)

     

    "Pancaking" was the original official explanation, but when that was proven ridiculous they changed the official explanation.

     

    Now, if the best 5 reasons to believe the conspiracy are not valid, there's no point whatsoever looking at numbers 5 to 10 or 10 to 1000000.

    So, we can stop now.

    I think that 3 of the 5 remain valid.

    Also, OP's list of reasons yet haven't been shown to be invalid.

    I think we'd have to consider points 6 through 1000000 individually to determine their validity.

     

    Stop whenever. I think I have given a lot of evidence to back up OP's claims.

  3. You can't user thermite to cut verticle columns, gravity pulls the liquid iron down not sideways. Anyway, the amount of thetmite needed to cut hundreds if steel I-beams would be in the hundreds if tons, reference upon request.

    Both statements are incorrect.

    See www.youtube.c...XB6gjPA#t=8m16s

    (The link skips to several demonstrations of thermite cutting columns.)

     

    Part 2

    The simple answer is that normally, if there's a damn great fire in a skyscraper the whole fire service is mobilised to do something about it. In this case, they were busy.

    It's not realistic to compare that fire with an "ordinary" one. Apart from anything else, ordinary fires only have one "seat". The one in that building set lots of floors alight at the same time. There was not the usual supply of water or manpower to put it out,

    There's your assertion that "nor was its structure compromised by debris" which is odd. It was clearly hit by a lot of debris- there is no evidence that the debris didn't do any damage?

     

    The simple answer is invalid. "Fire service doing something about it" doesn't invalidate the evidence of other larger, hotter fires burning for much larger in other skyscrapers.

    No need to compare to "ordinary" fires. Here are several examples of multi-seat, multi-floor fires: http://911research.wtc7.net/wtc/analysis/compare/fires.html

    There are no examples of skyscrapers collapsing due to fire.

     

    The support structure of WTC 7 was not completely and uniformly compromised by debris.

     

     

    Now, if the best 5 reasons to believe the conspiracy are not valid, there's no point whatsoever looking at numbers 5 to 10 or 10 to 1000000.

    So, we can stop now.

    That's some good scientific reasoning there.

     

    No, just kidding.

     

     

     

    Part 5

    5) Testimony of individuals having foreknowledge that the towers would be demolished.

    Testimony isn't evidence I'm afraid. People are prepared to lie for any number of reasons.

    The art of "prediction" has been with us for a long time, but it was never very credible.

    It is evidence, but I agree we won't get anywhere with it (especially scientifically) so we can remove #5 from the list.

     

    That's very true that people lie for many reasons. This applies to both sides of the argument. So we won't present evidence that is just what someone (including NIST) says unless it can be backed up or verified or reproduced.

     

     

  4. What they didn't seem to find was the molten iron and alumina that you get after a thermite reaction.

     

     

    "Several tons of molten metal reported by numerous highly qualified witnesses" http://thermalimages.nfshost.com/index.php/World_Trade_Center_Hot_Spots

     

     

    Another dull fact is that people who know how to drop buildings use shaped charges. They don't use thermite to cut steel beams.

     

    I don't think anyone is claiming that anyone wanted it to look like a demolition. Obviously if it was a demolition then it was done covertly.

     

    Re. the video: A guy in a wife-beater saying "You'd need a bucket of thermite" is not a credible expert or anything. If thermite is used to cut steel beams, it is not done by putting a loose pile of it on a beam. That's like lighting a pile of gunpowder on a cannonball, watching it not move very far, and claiming that "they don't use gunpowder to launch cannonballs".

     

     

     

    In short, the collapsing floors yanked the vertical columns inwards as they fell, so the vertical columns did not have to break for the collapse to continue.

    The vertical columns didn't break?

  5. MD65536,

    I have a suggestion.

    Rather than an endless back and to argument over this bit of data and that bit of data, can I ask you to provide your own personal "top 5" pieces of evidence for why you believe that the towers fell as anything other than a consequence of the impact from the planes and the subsequent fires?

     

    Just a list of 5 items - preferable with a link to put them in context but I can probably live without one in most cases.

     

    Also, can I ask for the rest of the contributors to the forum to hold fire for a few days or so in order to give him a chance to chose his "champions" and for me to offer a rebuttal.

     

    Okay, I like this idea. But this isn't a court case. If it were I would be very poor representation, and I can't "close the case" for others who think the official story is bull. I think others should be encouraged to contribute. Also "top 5" is arbitrary... it really only requires one piece of evidence. I haven't done the research, but it's fair to expect that evidence must be provided for any claims that I want to stand by.

     

    My top 5 pieces of evidence:

    1) All 3 buildings fell at near free-fall speeds. This is physically impossible if the "pancaking" floors had to counter any resistance to falling. The floors had to fall countering the resistance of vertical steel beams. This could be explainable if the floors were connected to the beams as weakly as possible, but then the floors would fall past the vertical columns. Either they slip past at near free-fall, or the energy required to destroy the vertical beams supporting each tower would have to come from somewhere, and if it's from the falling inertia of the floors, then they wouldn't fall at free-fall speeds.

     

    2) Building 7 wasn't hit by a plane nor was its structure compromised by debris. All 3 towers officially fell due to fires. WTC 7 didn't have jet fuel burning to explain it as an extraordinary fire or anything like that. No comparable building has ever collapsed due to fire, even though there are many examples of comparable buildings burning with larger fires burning for much longer, with NO complete structural failure. Existing evidence is that such buildings do not suffer complete structural failure due to ordinary fires.

     

    3) The Bush administration destroyed evidence and fought against independent investigation. This is not evidence of anything in particular, but it is suspicious. I don't accept as fact any scientific conclusion where the evidence is kept secret, destroyed, or made unscrutinizable. The Bush administration very literally was hiding something, which while unknown, makes their official "scientific" findings unreliable.

     

    4) Evidence of thermite and explosives was found, and including destruction of steel supports that can't be attributed to fire.

     

    5) Testimony of individuals having foreknowledge that the towers would be demolished.

  6. As far as I'm aware no significant explosives residues were ever found. (And, I know 'cos it's part of my job, that you can find explosives residues years or decades later if you look, so the fact that they cleared up first and studied later doesn't affect that fact)

    The scientific conclusion from that is that no explosives were present.

     

    He doesn't need evidence that no explosive residues were found. That's negative evidence and it's not evidence.

    That's true, but he made a "scientific conclusion" based on the statement of not being aware of any explosive residues.

     

    "I don't know if any explosive evidence was found, therefore I conclude that no explosives were present" is very different from "I am aware that there was a test made for explosives and it was negative, therefore I conclude that no explosives were present." I was asking for clarification on what he meant because it could be either.

     

    It's true, he doesn't need to provide evidence that no explosives were found, to argue against OP's claims or mine, but he does need to provide evidence to back up his own "scientific conclusions".

     

    I have demonstrated evidence of thermite found. This contradicts the conclusion that no explosives were present. -- Technically thermite isn't necessarily explosive so I might need to clean up my argument. It could be possible that the towers fell due to controlled demolition AND that no explosives were used in that process. However, 1) there is evidence of explosives, as seen in the video and witness testimony, and 2) the core argument of this thread is not limited to explosives, but rather "controlled demolition vs. structural failure directly caused by the planes". This is beside the point that anyone's "scientific conclusions" must be backed up.

     

     

     

     

    Do you have evidence no unicorn horns were found in the rubble? A great amount of what they call gypsum dust covered the site--they said it was from drywall, but calcium sulfate is also an important component of unicorn horn, which supports my unicorn theory.

    Then perhaps you have stronger evidence for unicorns than the Bush administration had for their explanation.

     

    However in your case, the "it was from drywall" explanation is reasonable and scientifically possible. I'm not aware* of any reasonable explanation that would explain the evidence of thermite in the rubble other than the use of demolitions.

     

     

    * (and if you challenge me on that, it would be up to me to provide evidence if I wanted to back up my claim that there's no explanation in the official story, for the evidence of thermite.)

     

     

     

    Unresolved fact: WTC 7 did not collapse due to a plane crashing into it. That explanation alone is invalid.

     

    I truly believe that you have to either trust the scientific integrity of the Bush administration over previous scientific understanding, and/or you have to ignore scientific principles altogether and accept what the state tells you (even if it's that 2+2 sometimes equals 5), in order to accept the official account of what happened.

  7. What the **** has that got to do with the issue?

    Are you claiming that the planes didn't hit the buildings?

    That's what happened.

    There's no question that we know what happened. Some people flew aircraft into the buildings.

    I'm saying that "planes hit the buildings" is not enough sufficient evidence for the official explanation (which is dubious, for example that a building can fall at near free-fall speeds while "pancaking").

    Occam's razor is not a law, and it doesn't state that "The simplest explanation is always the correct one."

    I think that "Planes hit the buildings, therefore that is the reason that they collapsed" is unscientific.

     

    As an example, yes I will claim that a plane didn't hit building 7, yet it collapsed in less than a day with *complete* structural failure. Therefore "planes hit the buildings" is not a sufficient explanation.

     

     

    "Do you know of any scientific evidence that contradicts the controlled demolition theory?"

    As far as I'm aware no significant explosives residues were ever found. (And, I know 'cos it's part of my job, that you can find explosives residues years or decades later if you look, so the fact that they cleared up first and studied later doesn't affect that fact)

    The scientific conclusion from that is that no explosives were present.

    The scientific conclusion from that is that explosives were not used to destroy the building.

     

    Do you have evidence that no explosive residues were found, or are you just not aware of it?

     

    Here are references to evidence of explosives:

    http://www.ae911truth.org/en/news-section/41-articles/351-advanced-pyrotechnic-or-explosive-material-discovered-in-wtc-dust.html

    http://911research.wtc7.net/wtc/evidence/metallurgy/index.html

  8. the fact is that the science doesn't support the idea of a demolishion

    Does this mean that there is a lack of or insufficient evidence to support the idea of demolition?

    Or does it mean that there is scientific evidence that opposes or rules out the idea?

    Do you know of any scientific evidence that contradicts the controlled demolition theory?

     

     

  9. Oh, so a bloke who "feels it's odd" is now evidence is it?

    No. How someone feels is not evidence. The qualifications of someone who has an opinion is not evidence. Sorry for making you waste your time posting stuff that you know is nonsense.

     

    A lot of AE911Truth is devoted to calling for an investigation and stuff. Its not all "evidence". I too don't want to waste my time reading everything on the site either, so how about just the points on the right side of http://www.ae911truth.org/? I've removed a few points that might be argued "not evidence".

     

    ----

     

     

     

    WTC Building #7, a 47-story high-rise not hit by an airplane, exhibited all the characteristics of classic controlled demolition with explosives:

     

    1. Rapid onset of collapse

    3. Symmetrical "structural failure" – through the path of greatest resistance – at free-fall acceleration

    4. Imploded, collapsing completely, and landed in its own footprint

    5. Massive volume of expanding pyroclastic-like clouds

    7. Foreknowledge of "collapse" by media, NYPD, FDNY

     

    In the the aftermath of WTC7's destruction, strong evidence of demolition using incendiary devices was discovered:

     

    8. FEMA finds rapid oxidation and intergranular melting on structural steel samples

    9. Several tons of molten metal reported by numerous highly qualified witnesses

    10. Chemical signature of the incendiary thermite found in solidified molten metal, and dust samples

     

    WTC7 exhibited none of the characteristics of destruction by fire:

     

    1. Slow onset with large visible deformations

    2. Asymmetrical collapse which follows the path of least resistance (laws of conservation of momentum would cause a falling, to the side most damaged by the fires)

    3. Evidence of fire temperatures capable of softening steel

    4. High-rise buildings with much larger, hotter, and longer lasting fires have never collapsed.

     

     

     

    As seen in this revealing photo [http://www.ae911truth.org/], the Twin Towers' destruction exhibited all of the characteristics of destruction by explosives:

     

    Destruction proceeds through the path of greatest resistance at nearly free-fall acceleration

    Improbable symmetry of debris distribution

    Extremely rapid onset of destruction

    Over 100 first responders reported explosions and flashes

    Multi-ton steel sections ejected laterally

    Mid-air pulverization of 90,000 tons of concrete & metal decking

    Massive volume of expanding pyroclastic-like clouds

    1200-foot-diameter debris field: no "pancaked" floors found

    Isolated explosive ejections 20–40 stories below demolition front

    Total building destruction: dismemberment of steel frame

    Several tons of molten metal found under all 3 high-rises

    Evidence of thermite incendiaries found by FEMA in steel samples

    Evidence of explosives found in dust samples

    And exhibited none of the characteristics of destruction by fire:

     

    Slow onset with large visible deformations

    Asymmetrical collapse which follows the path of least resistance (laws of conservation of momentum would cause a falling, intact, from the point of plane impact, to the side most damaged by the fires)

    Evidence of fire temperatures capable of softening steel

    High-rise buildings with much larger, hotter, and longer-lasting fires have never collapsed.

     

    Yeah well, that could be some weird conspiracy, but did anyone consider that

    1 they wanted to get the city moving again and (perhaps more importantly)

    2They knew what the failure was.

     

    Sorry, but that doesn't justify a lapse of scientific rigor.

     

    Would you accept similar reasoning if there was a claim that cold fusion was real, but the experiment was kept secret and then destroyed before it could be analyzed by others (even if there was a video of it working)? Would you accept findings in climate science if the result was "what everybody knows" but the data was not open to scrutiny?

     

    I think that the point I'm trying to argue is that if one needs to provide irrefutable evidence that the official 9/11 story is incorrect, that implies that the official story is accepted science. I would say that it is an appalling failure of science if the official story can be considered accepted science, the way that it came about.

     

     

     

    Edit: I suppose that I must accept that any claim needs to be backed up by evidence. It doesn't matter "what side it's on". A claim of "the Bush administration got it right" would need to be backed up by evidence. Arguing that the evidence is insufficient is NOT an argument that a counter-claim is correct. Similarly, I think we could all benefit from accepting that lack of evidence for one claim is not evidence for a counter-claim. Conversely, evidence for a counter-claim is (or can be?) evidence against a claim.

     

    In other words, a lack of evidence is not going to win any arguments either way (and unfortunately this case is wracked with missing evidence). However, arguing that the OP is wrong because there IS evidence against OP's contention, would require evidence.

  10. How about the evidence provided here: http://www.ae911truth.org/

     

    Part of the problem is that the government prevented a proper investigation, so a lot of the missing evidence was hidden and destroyed.

    There was a conspiracy. The government implemented a HUGE cover-up.

    That's not evidence that anything specific was covered up, but when the details of such a huge crime are hidden by the ones supplying the official story of what happened, that's extremely suspicious.

    Accepting the official story, when the evidence doesn't support that version, is as scientifically wrong as accepting the conspiracy theory without evidence.

     

    A proper investigation needs to be done, before the OP's post can be judged correct or not.

  11. And the same apply to every planet in the solar system. For this reason, all the planets are orbiting in the same direction, not because they wanted to, but because they are forced to by the orbital force of the Sun. And the same force cause the Sun to rotate in the same direction as well.

    Sorry, I don't fully understand your post or the replies, but I agree that there is a "natural" direction of rotation.

     

    Things nearer to a gravitational mass orbit at faster speeds than things that are farther.

    So if you imagine the sun surrounded by a homogeneous cloud of dust orbiting it in circles, the inner circles are spinning faster than the outer ones.

     

    Imagine connecting two rocks at different orbits by a string, as a primitive model of the Earth. The rock closer to the sun travels faster than the other; tension on the string pulls the rock to a farther orbit while pulling the second rock to a closer orbit; the second rock ends up with an "inner track" and overcomes the first rock, and so on: These two rocks rotate in their orbit in the opposite direction that the Earth and other masses rotate.

     

    However, the solar system isn't a homogeneous mass. If you have 2 rocks on opposite sides of the earth, the rock farthest from the sun experiences the most gravitational acceleration relative to the sun, because the gravitational pull of the sun and the earth are in the same direction. The rock on the side nearest the sun is actually being pulled away from the sun by the earth's stronger (at this distance) gravitational pull. The result is that the natural circular orbit speed around the sun of a rock on the farther dark side of the earth is faster than the circular orbit speed around the sun of a rock on the bright side of the earth. Mass on the dark side is constantly overcoming the average speed of the earth, being pulled to a sunnier orbit, and slowing down relative to the sun, and being pulled to the dark side again, as if the sides of the earth are constantly leap-frogging each other around the sun.

     

    A tidally locked body is also rotating in this "natural" direction; it is just doing it slowly enough that its revolution time matches its orbit time.

     

     

     

    BTW, I have a feeling that I got the idea right but screwed up the physics somewhere in this explanation.

     

     

     

     

    A large object with small enough mass, such as a huge but thin spherical shell, might naturally rotate in the opposite direction. If so, then I think this contradicts your idea. It would be the mass of the orbiting object, and not just that of the mass it's orbiting, that determines its natural rotation rate???

  12. Btw, on another subject, it is very strange to be still taking fire in a thread "the present time" on things like my definitions (not physics) in which I am not allowed to reply unless it's physics related.

    You posted erroneous information.

    You didn't post any retractions or corrections, and the misinformation remained.

    People were confused by accidentally taking it at face value.

    Another user was then compelled to point out the error.

    The rules prevent you from repeating the misinformation.

    Which part do you find strange?

     

     

    I'm getting off topic... I'll try to get back to ontology of time...

     

    I don't have a clue how time works I'm just asking questions of you because you claim you do, or at least you claim to know how time does not work.

     

     

    Are you saying the delayed choice quantum eraser experiment results should be ignored because they don't fit your concept of "now" or are you saying the result is wrong?

    I second this sentiment.

     

    I'm wrong to say the experiment is off-topic -- that assumes that there is no on-topic explanation of the experiment.

    But I'm actually quite interested in how the results of the experiment might be explained using (or consistent with) the ontological arguments.

     

     

  13. What trips me is thinking that entropy is not time symmetric, but it is nonetheless derived from the equations of motion which are time symmetric. The arrow arises more from the boundary conditions of the system than the underlying physics. I tried to say this earlier in the thread but mangled it horrifically.

    I also think this has something to do with gravitation. If I remember correctly, the laws of gravity don't have a meaningful notion of time symmetry in GR. Personally I don't think gravity is time-symmetric.

     

    But even if it were, relativity of simultaneity messes things up.

    Suppose you could "reverse the universe" at a particular instant, run it backwards for a time of t, and then forward for t, and suppose it's possible to end up at the same state as the instant you began reversing it.

     

    That instant won't be the same for other observers. Others will see different parts of the universe reverse at different times, for different lengths of time, and as a whole it would never end up in a state that was identical to a previous state. Everyone's observations would be consistent with your observations (in which a true hypothetical time reversal took place), but relativity of simultaneity would give everyone different experiences of it.

     

    I think that because time is relative, time-symmetry must also be relative. So if you're speaking of an arrow of time and whether it has a fixed direction, I don't think you can talk about a universal arrow of time. This is before even needing to consider entropy.

     

    That is, the underlying physics of relativity do imply that a system that can't be universally synchronized, can't be universally time-symmetric, even if entropy is ignored. I think.

  14. The delayed choice quantum eraser seems strange to me because at the time the photon that will make an interference pattern (or not) hits the target the entangled photon has not been directed to erase (or not) the path information. How does the photon "know" where to land on the target before the path info has been erased or preserved? How can an event that occured in the past be affected by current events?

    I don't think that that experiment is on-topic nor would I expect a satisfying answer here. It'd probably be best to ask in a new thread in the Quantum Theory forum instead of Speculations.

     

    But I think the answer to your question is essentially that the intuitive aspects of time, regarding that experiment, involve causality. The experiment doesn't violate causality. So if you understand why causality isn't violated by the experiment (I couldn't explain it because I only have a vague understanding, just enough to accept that it's true!), then you'll probably find that while the experiment isn't explained by "common sense" (aka. causality in this case), it also doesn't contradict it.

  15. You didn't. No problem. It is good to raise yet again the questions, "can the past be changed (or even 'visited')?"... and "can the future be visited?"

    I would really like to hear from those who say "yes" to either or both vis-a-vis my last post.

    Alright I'll give it a shot because I'm obviously a glutton for punishment.

    I'm not a physics expert.

     

     

     

     

    If you have a simple enough system (say, two simple particles), its state (ie. the state of the particles including relative to each other) may return to the same state it had at some point "in the past".

    If the two states are theoretically indistinguishable, and there is no possible measurement of time (within the system) elapsed between the current state and its previous state, then there may be no difference between saying that the particle traveled "forward in time" or backward, in an oscillation, or that it moved forward but then returned to the past time. Deciding that it is one but not the other involves attaching false meaning to the physics, and is a common pitfall in metaphysics.

     

    This applies only to that one particle's time relative to the other particle. In a more complex system, the rest of the components can continue on independently... it is unlikely that a particle will ever return to the same state relative to all the other particles in -- for example -- an egg. In fact it's statistically impossible. It's the laws of statistics that make a fried egg a one-way process, not some fundamental universal physical aspect of time that applies at every scale.

     

    The statistical laws can be encoded as physical laws with the concept of entropy. It is entropy that prevents a fried egg from becoming unfried. If your description of time is not separated from your description of entropy, then time is one-way. If you separate the two concepts, and talk about time independently of entropy (which you might only be able to do in a small enough, simple enough, and/or perhaps a meticulously organized enough system), then it's possible to have things moving backward and forward through time without problem.

     

     

     

     

     

    Philosophically, if you consider the passing of time to be "moving into the future", then manipulation of time dilation could be considered time travel to the future. That is, if all movement "through time" involves traveling through time, then it can be done at different rates (forward only though, when entropy is involved).

    Since you can't go backward, you can't "visit" the future with the implication of "returning to the present".

    Whatever your concept of time-travel might be, you'll always be in "your present". All that says is "wherever you go, there you are."

  16. Perhaps someone could take up the banner of discussing how "the present" (or "it's always now") isn't a tautology and can be quantified, in keeping with sound physics principles

    I disagree with this.

     

    The phrase "it's always now" implies a moment referred to by "it", which is implicitly "now".

    "Now is always now" is a tautology, as long as "now" is defined.

    Further, "now" or "the present" is defined relative to an observer and a specific observation (ie. a point in spacetime and a frame of reference for the observer whose lightcone's apex is at that point). Anywhere that an observer can make a statement about the present (referring to the spacetime location of the observer), the present is defined.

    So it's a tautology according to any observer.

    Experimentally, how could you ever find a counterexample???

     

     

    On the other hand...

     

    It can easily be made not a tautology, but to do so you must speak of two different possible "presents"... ie where "it" refers to something other than "now", for example to different spacetime points or frames of reference.

    "Tomorrow is now" or "Tomorrow will soon be now" is not a tautology (tomorrow's present can be observed in different ways depending on the observer's frame of reference and won't be the same as today's present).

    "Your present is my present" is not a tautology.

    But I think these cases are excluded by the implicit meaning of "the present" (which is that it refers to some single moment or Cauchy surface which is not universally experienced).

     

     

    Technically, a person does not have one single spacetime location and frame of reference, and so just as "the present" isn't the same for different people, it's not the same throughout a person. So while we can define a "present" for a person by a single point, that present is only approximate for the whole person.

  17. So, there is no such thing as a "universal present" which makes "presentism" rubbish..

    Who said that presentism implies a universal present?

     

    Isn't there some middle ground, where we can say that the universe as a whole cannot be described with presentism, because there is no one "knife edge" surface separating the past and the present. But any single observer can describe the universe observationally using presentism, because they have defined (or can choose?) such a surface?

     

    I don't think it's a problem that presentism may or may not be compatible with reality depending on what you're talking about, because a "universal" description of time (as part of a 4d manifold or whatever) is very different from time as defined by an observer or observational point of view? And isn't "the present time" only defined relative to a specific frame of reference?

     

     

  18. I believe the phrase should read, certain types of subatomic particles can be treated mathematically AS IF they were travelling backwards through time. I don't think Feynman ever suggested that anti-particles really travel bacwards in time, nor that tachyons actually exist ( but, hey, stranger things have been discovered to happen ).

    Yes, I think you must be correct.

    The best reference I could find so far is here: http://vega.org.uk/video/programme/47 If you skip to 92:23 (and watch to the end), Feynman answers a few questions concerning time. He mentions some topics that are probably very useful to an understanding of time, and related to the questions of this thread, but I don't see any unambiguous answers that couldn't be interpreted either way.

     

     

    Note: 92:23 specifically addresses causality.

  19. Yes, Mystery111, you have said 'time doesn't have a flow' many times now. But, I don't know , what's the minimum number of times you need to say it before it automatically becomes correct ???

     

    We are having a discussion, an exchange of ideas if you will. The ideas I present are based on my limited knowledge, and are of course, opinions or best educated guesses ( based on GR ). Of course I cannot absolutely prove the assertions I've made, but at least I realise that. I also realise you cannot prove the assertions you've made, yet you claim that, since you've repeated them several times, they must be true.

     

    An open mind is a terrible thing to be missing.

    It cannot just be replaced by a donkey named Pompous.

    It doesn't become correct; either it was correct the first time, or not.

    Perhaps if you explained what you mean when you're speaking of "the flow of time" then it might be possible to figure out if those ideas are correct or not.

    Better yet, by explaining it as precisely as you can, you should be able to better understand your own ideas, and to tell if they are even meaningful and/or make sense. Then, if "flow" is the best word for your idea, you could explain its meaning. If not, you might find more meaningful words to express your ideas.

     

    The ability to reason about things that you don't fully understand is a sign of an open mind. Avoiding understanding by hiding it behind possibly meaningless words, whether they're your words or others, is not.

     

    Do you wish to continue being pedantic, or are you interested in a serious discussion?

    I don't think pedantry is a bad thing in a conversation like this. At best everyone would be using words that have the same meaning to everyone. More common, not only are people using words that mean different things to different people, but often don't even mean anything useful to the person using them.

     

    An "exchange of ideas" is good. It's not as useful if nobody knows what anyone is talking about.

     

     

  20. blue screen suddenly appeared

    computer suddenly re-booted itself

    couldn't load

    it was behaving quite slow

     

    This is all normal Windows behavior.

    It doesn't sound like a virus to me, but if you want to remove it, popular Linux distributions give you the option of removing Windows or leaving it and installing Linux with dual boot options.

     

     

     

  21. I was thinking way too hard on that one. Probably should have stayed a little closer to the problem. Good puzzle.

    Thanks! :)

    I thought of it trying to find a situation in which "small bang"'s similar puzzle could ever be not answered with "yes".

    The trick is probably in remembering some other riddle that involved the words themselves and not the meaning of the words, and then your brain like switches modes or something.

     

     

  22. You are a letter in the puzzle.

    You were on the right track here. I am! But it's not a specific answer to the riddle because it doesn't agree with the statement "But I'm not in a box, nor a house.", when interpreting each of the statements in a consistent way.

  23. I believe the phrase should read, certain types of subatomic particles can be treated mathematically AS IF they were travelling backwards through time. I don't think Feynman ever suggested that anti-particles really travel bacwards in time, nor that tachyons actually exist ( but, hey, stranger things have been discovered to happen ).

    The phrase should be a proper Feynman quote! I was referring to how interactions on Feynman diagrams can be pointed backward through time.

     

    But yes, I think we're making the same point. At a quantum level, the behavior of things in time is described mathematically using the sums of probabilities of all possibilities (or whatever it is). At a macroscopic level it can be described the same, though you'll find that the probability of certain possibilities approach 1 and others approach 0, so you can also describe the behavior of macroscopic things in time with simplified math and deterministic equations.

     

    There are different mathematical representations of time, I suppose... but then, how can you describe "what time is" using say only one representation and ignoring another? Ie describing time based on large bodies moving through space relative to each other, while ignoring quantum interactions?

     

    I think that any "true" metaphysical understanding of time would have to correspond well with all "valid" mathematical representations of time.

    As that pertains to the topic of this thread, my point is, I suppose, that assumptions about time that are made based on a limited domain, may only apply to that limited domain, and don't necessarily tell you anything about time across its entire domain.

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