Time Travel is Science Fiction

[Farsight]

You can beat an egg, but you can’t beat a good movie. And there are some real crackers out there. The Terminator was a classic, with that remorseless skeletal T-800 that just won’t stop. Another cracker was 12 Monkeys, which featured a scary way to save the planet. Then there’s Men in Black3, Looper, and Lost in Space. Or Frequency or Déjà Vu or Source Code. And if chick-flick is your thing there’s Kate and Leopold, The Lake House, and The Time Traveller’s wife. They all feature time travel, and I loved them all, and more besides. One of my special favourites was Timescape starring Jeff Daniels, where he and his other self hammered the church bell to sound the warning. Dang Ding Dang. Brilliant. I loved it even though I know that time travel is science fiction.

Yes, science fiction. Time travel to the past is impossible. Not because of the grandfather paradox or the chronology protection conjecture. But because we don’t even “travel forward through time”. That’s just a figure of speech. So is “the flow of time”. If you open up a clock you don’t see time flowing through it like it’s some cosmic gas meter. You see little cogs and things, moving. In a grandfather clock there’s a pendulum swinging. In a quartz wristwatch there’s a crystal vibrating. In an atomic clock it’s the hyperfine-transition microwaves. Moving. Clocks always feature some kind of regular cyclic motion, and they clock this up to show you some kind of cumulative display that you call “the time”.

You must have seen some movie or TV program where somebody has a device that can stop time. Did you notice that the gizmo doesn’t so much stop time as stop motion? It’s the same kind of deal with bullet time. It’s not time going slower. It’s bullets going slower. Or just hold your hands up. See that gap between them? That's a space, and you can see it’s there, even though you can't see the space itself. Now waggle those hands. That's motion, and you can see that too. But can you see time? No. Can you see time flowing? No. Can you see any actual travelling through time? No.
Have you ever heard Hawking saying you can “travel” to the future on a superfast train? Imagine you’re on it. The train moves fast. Through space. And because it does, the local rate of motion in your body brain and clocks has to reduce. It’s called time dilation, but it’s all down to motion really. It occurs because the maximum rate of motion is the speed of light. If that train could move at the speed of light, your local motion would be zero. If it wasn’t, adding the train motion to your local motion would mean your total motion exceeds the speed of light. That’s a no-no. Special relativity says no, and the wave nature of matter says no. Time dilation doesn’t really mean you travel to the future faster. All it means is your local motion is reduced compared to mine, in line with Pythagoras's theorem. You never were actually travelling through time. You were travelling through space. And whilst you were doing that I could have watched you every step of the way. You could have looked out the window and watched me every step of the way too. You didn’t disappear up some time tunnel to start living your life in the middle of next week. You just fast-forwarded through the week. And when you step off the train it’s me who meets you. I don’t miss you by a week.

Public domain image by Mdd4696, see Wikipedia.

It’s the same kind of thing with gravitational time dilation. It's not quite the same, but it's still simple. It can be idealised via the stasis box, which is kind of like the ultimate refrigerator. Yes, it’s something out of science fiction too, just like time travel. But it’s kind of fun to fight fire with fire. No motion of any kind occurs inside this stasis box. So when I put you inside, electromagnetic phenomena don’t propagate. So you can’t see, you can’t hear, and you can’t even think. Hence when I open the door a week later, to you it’s like I opened the door just as soon as I closed it. And get this: you “travelled” to the future by not moving at all. Instead everything else moved. And all this motion wasn’t through time, or spacetime, it was through space. Yes, the stasis box is science fiction, but don’t forget, we can freeze embryos now. In the future maybe we’ll be able to freeze an adult. Then you could “travel” to the future by stepping into a glorified freezer. But you aren’t really travelling to the future. You aren’t moving. Instead everything else is.

So if there isn’t really any travelling forward through time, how are you going to travel back in time? Arrange for the big guy in the sky to press his cosmic rewind button? Whilst leaving your memories intact? Don’t think so. Besides, that’s not time travel. That’s just one up from dragging the bar on a YouTube video. And despite what you may have heard about closed timelike curves, that’s not time travel either. That’s just Groundhog Day, only you wouldn’t know it. The thing is, spacetime is a mathematical model. It presents the dimensions of space along with a time dimension, depicting all times at once. It’s like you film something with a movie camera, then develop the film, then cut it up into individual frames and form them into a stack. And because of that, it is static. It isn’t something you can move through. It isn't what space is.

Spacetime depiction by John D Norton, see Einstein for everyone course HPS0410

You cannot look up to the clear night sky and point to a world line or a light cone, because these things are abstractions, like spacetime is an abstraction. Yes, general relativity refers to curved spacetime, but only to give the equations of motion through inhomogeneous space. And the time dimension is in itself derived from motion, such as the motion of clocks, and the motion of light. So that time dimension just isn’t the same as the dimensions of space. You can hop forward a metre, but you can’t hop forward a second. And you can’t hop backward a second either.

You can read more about this stuff in A World Without Time: The Forgotten Legacy of Godel and Einstein. It’s a book featuring philosophy and relativity and what Einstein and Godel used to talk about in Princeton. It doesn’t say time does not exist, it’s more like time exists like heat exists. And just as you can’t literally climb to a higher temperature, you can’t literally travel forward in time. Or backwards. No way, no how.

Bear all this in mind next time you see some celebrity physicists talking about time travel on the Discovery Channel. Like those time-travel movies, it’s science fiction. Not physics. But a time travel movie can still be a great movie. There is no time travel, but there is no Santa Claus either, and you can still have a great Christmas.

 

[paddoboy]

Bear all this in mind next time you see some celebrity physicists talking about time travel on the Discovery Channel. Like those time-travel movies, it’s science fiction. Not physics. But a time travel movie can still be a great movie. There is no time travel, but there is no Santa Claus either, and you can still have a great Christmas.

If this isn't just another one of your incessant rants, then get it peer reviewed.

I prefer the Greene, Kaku, Tegmark, Kraus, take on the situation though.
Afterall, they do have credentials....You?, , with all due respect, I don't know you from a bar of soap.

 

[paddoboy]

Nearly fifty years after its inception, the Gravity Probe B satellite mission delivers the first measurements of how a spinning gyroscope precesses in the gravitational warping of spacetime.


The great blues singer Etta James’ signature song begins, “At laaasst, my love has come along … .” This may have been the feeling on May 4th when NASA announced the long-awaited results of Gravity Probe B [1], which are appearing now in Physical Review Letters [2]. Over 47 years and 750 million dollars in the making, Gravity Probe B was an orbiting physics experiment, designed to test two fundamental predictions of Einstein’s general relativity.

According to Einstein’s theory, space and time are not the immutable, rigid structures of Newton’s universe, but are united as spacetime, and together they are malleable, almost rubbery. A massive body warps spacetime, the way a bowling ball warps the surface of a trampoline. A rotating body drags spacetime a tiny bit around with it, the way a mixer blade drags a thick batter around.

The spinning Earth does both of these things and this is what the four gyroscopes aboard the earth-orbiting satellite Gravity Probe B measured. The satellite follows a polar orbit with an altitude of 640 kilometers above the earth’s surface (Fig. 1, top). The warping of spacetime exerts a torque on the gyroscope so that its axis slowly precesses—by about 6.6 arcseconds (or 1.8 thousandths of a degree) per year—in the plane of the satellite’s orbit. (To picture this precession, or “geodetic effect,” imagine a stick moving parallel to its length on a closed path along the curved surface of the Earth, returning to its origin pointing in a slightly different direction than when it started.) The rotation of the Earth also exerts a “frame-dragging” effect on the gyro. In this case, the precession is perpendicular to the orbital plane and advances by 40 milliarcseconds per year. Josef Lense and Hans Thirring first pointed out the existence of the frame-dragging phenomenon in 1918, but it was not until the 1960s that George Pugh in the Defense Department and Leonard Schiff at Stanford independently pursued the idea of measuring it with gyroscopes.

The Gravity Probe B (or GP-B, in NASA parlance) gyroscopes (Fig. 2) are coated with superconducting niobium, such that when they spin, the supercurrents in the niobium produce a magnetic moment parallel to the spin axis. Extremely sensitive magnetometers (superconducting quantum interference detectors, or “SQUIDs”) attached to the gyroscope housing are capable of detecting even minute changes in the orientation of the gyros’ magnetic moments and hence the precession in their rotation predicted by general relativity.

At the start of the mission, the four gyros were aligned to spin along the symmetry axis of the spacecraft. This was also the optical axis of a telescope directly mounted on the end of the structure housing the rotors. Spacecraft thrusters oriented the telescope to point precisely toward the star IM Pegasi (HR 8703) in our galaxy (except when the Earth intervened, once per orbit). In order to average out numerous unwanted torques on the gyros, the spacecraft rotated about its axis once every 78 seconds.

GP-B started in late 1963 when NASA funded the initial R&D work that identified the new technologies needed to make such a difficult measurement possible. Francis Everitt, a physicist at Stanford and a lead author on the current paper, became Principal Investigator of GP-B in 1981, and the project moved to the mission design phase in 1984. Following a major review of the program by a National Academy of Sciences committee in 1994, GP-B was approved for flight development, and began to collaborate with Lockheed-Martin and Marshall Space Flight Center. The satellite launched on April 20, 2004 for a planned 16-month mission, but another five years of data analysis were needed to tease out the effects of relativity from a background of other disturbances.

Almost every aspect of the spacecraft, its subsystems, and the science instrumentation performed extremely well, some far better than expected. Still, the success of such a complex and delicate experiment boils down to figuring out the sources of error. In particular, having an accurate calibration of the electronic readout from the SQUID magnetometers with respect to the tilt of the gyros was essential. The plan for calibrating the SQUIDs was to exploit the aberration of starlight, which causes a precisely calculable misalignment between the rotors and the telescope as the latter shifts its pointing toward the guide star by up to 20 arcseconds to compensate for the orbital motion of the spacecraft and the Earth. However, three important, but unexpected, phenomena were discovered during the experiment that affected the accuracy of the results.

First, because each rotor is not exactly spherical, its principal axis rotates around its spin axis with a period of several hours, with a fixed angle between the two axes. This is the familiar “polhode” period of a spinning top and, in fact, the team used it as part of their analysis to calibrate the SQUID output. But the polhode period and angle of each rotor actually decreased monotonically with time, implying the presence of some damping mechanism, and this significantly complicated the calibration analysis. In addition, over the course of a day, each rotor was found to make occasional, seemingly random “jumps” in its orientation—some as large as 100 milliarcseconds. Some rotors displayed more frequent jumps than others. Without being able to continuously monitor the rotors’ orientation, Everitt and his team couldn’t fully exploit the calibrating effect of the stellar aberration in their analysis. Finally, during a planned 40-day, end-of-mission calibration phase, the team discovered that when the spacecraft was deliberately pointed away from the guide star by a large angle, the misalignment induced much larger torques on the rotors than expected. From this, they inferred that even the very small misalignments that occurred during the science phase of the mission induced torques that were probably several hundred times larger than the designers had estimated.

What ensued during the data analysis phase was worthy of a detective novel. The critical clue came from the calibration tests. Here, they took advantage of residual trapped magnetic flux on the gyroscope. (The designers used superconducting lead shielding to suppress stray fields before they cooled the niobium coated gyroscopes, but no shielding is ever perfect.) This flux adds a periodic modulation to the SQUID output, which the team used to figure out the phase and polhode angle of each rotor throughout the mission. This helped them to figure out that interactions between random patches of electrostatic potential fixed to the surface of each rotor, and similar patches on the inner surface of its spherical housing, were causing the extraneous torques. In principle, the rolling spacecraft should have suppressed these effects, but they were larger than expected. The patch interactions also accounted for the “jumps”: they occurred whenever a gyro’s slowly decreasing polhode period crossed an integer multiple of the spacecraft roll period. What looked like a jump of the spin direction was actually a spiraling path—known to navigators as a loxodrome. The team was able to account for all these effects in a parameterized model.

The original goal of GP-B was to measure the frame-dragging precession with an accuracy of 1%, but the problems discovered over the course of the mission dashed the initial optimism that this was possible. Although Everitt and his team were able to model the effects of the patches, they had to pay the price of the increase in error that comes from using a model with so many parameters. The experiment uncertainty quoted in the final result—roughly 20% for frame dragging—is almost totally dominated by those errors. Nevertheless, after the model was applied to each rotor, all four gyros showed consistent relativistic precessions (Fig. 1, bottom). Gyro 2 was particularly “unlucky”—it had the largest uncertainties because it suffered the most resonant jumps.

When GP-B was first conceived in the early 1960s, tests of general relativity were few and far between, and most were of limited precision. But during the ensuing decades, researchers made enormous progress in experimental gravity, performing tests of the theory by studying the solar system and binary pulsars [3]. Already by the middle 1970s, some argued that the so-called parameterized post-Newtonian (PPN) parameters that characterize metric theories of gravity, like general relativity, were already known to better accuracy than GP-B could ever achieve [4]. Given its projected high cost, critics argued for the cancellation of the GP-B mission. The counter-argument was that all such assertions involved theoretical assumptions about the class of theories encompassed by the PPN approach, and that all existing bounds on the post-Newtonian parameters involved phenomena entirely different from the precession of a gyroscope. All these issues were debated, for example, in the 1994 review of GP-B that recommended its continuation.

The most serious competition for the results from GP-B comes from the LAGEOS experiment, in which laser ranging accurately tracked the paths of two laser geodynamics satellites orbiting the earth. Relativistic frame dragging was expected to induce a small precession (around 30 milliarcseconds per year) of the orbital plane of each satellite in the direction of the Earth’s rotation. However, the competing Newtonian effect of the Earth’s nonspherical shape had to be subtracted to very high precision using a model of the Earth’s gravity field. The first published result from LAGEOS in 1998 [5, 6] quoted an error for the frame-dragging measurement of 20 to 30%, though this result was likely too optimistic given the quality of the gravity models available at the time. Later, the GRACE geodesy mission offered dramatically improved Earth gravity models, and the analysis of the LAGEOS satellites finally yielded tests at a quoted level of approximately 10% [7].

Frame dragging has implications beyond the solar system. The incredible outpouring of energy from quasars along narrow jets of matter that stream at nearly the speed of light is most likely driven by the same frame-dragging phenomenon measured by GP-B and LAGEOS. In the case of quasars, the central body is a rapidly rotating black hole. In another example, the final inward spiral and merger of two spinning black holes involve truly wild gyrations of each body’s spin axes and of the orbit, again driven by the same frame-dragging effect, and these motions are encoded in gravitational-wave signals. Laser interferometric observatories on the ground, and in the future, a similar observatory in space, may detect these gravity waves. So there is a strong link between the physics Gravity Probe B was designed to uncover and that describing some of the most energetic and cataclysmic events in the universe.

Even though it is popular lore that Einstein was right (I even wrote a book on the subject), no such book is ever completely closed in science. As we have seen with the 1998 discovery that the universe is accelerating, measuring an effect contrary to established dogma can open the door to a whole new world of understanding, as well as of mystery. The precession of a gyroscope in the gravitation field of a rotating body had never been measured before GP-B. While the results support Einstein, this didn’t have to be the case. Physicists will never cease testing their basic theories, out of curiosity that new physics could exist beyond the “accepted” picture.

http://physics.aps.org/articles/v4/43




http://science.nasa.gov/missions/gravity-probe-b/

 

[billvon]

Time Travel is Science Fiction

Agreed, as is manned travel to Mars. Although in 1950, human beings on the Moon was science fiction as well.

Cool that we are starting to learn how things like time travel (Tipler cylinder) and faster than light travel (Alcubierre drive) might be possible though.

 

[Russ_Watters]

A discussion on how time works can't start with a rejection of what it is, Farsight. You can't reject the starting premise of a line of logic and then continue to pursue it. You need to do some work defining time and getting people to agree before you even start. Start by convincing us that time doesn't flow and time travel to the future doesn't happen.

In the meantime, I'll just sit here proving you wrong.

 

[paddoboy]

Farsight....
If you are proposing something different to what the more reputable mainstream advocates propose, you do realize you are in the wrong forum, don't you?
You should be in "Alternative Theories" at least, or maybe even "Pseudoscience"

We had another anti mainstream poster make that mistake a week or so ago.
We'll see how it pans out though.

 

[Beer w/Straw]

Farsight, man, saying time travel isn't possible is ultra lame.

It'd be like me writing a PhD Thesis: Gravity is attractive.

 

[Secret]

Some of my questions related to this topic were posted in Time is Dead but the others are too busy feeding the crank(s) and/or to notice it/bother answering it

Basically about time travel, one thing just really confuse me is how in general relativity spacetime is basically a block universe nature, that is, the past present and future all coexist as events in this spacetime block http://en.wikipedia.org/wiki/Spacetime_in_General_relativity

But in daily life, we seemed to experience something like "time has elapsed", and then there's the arrow of time. How do all of these be produced within the spacetime model proposed by general relativity?

I am not proposing anything or objecting the mainstream science, it's just I don't understand how some of the daily things we experienced can be produced by these models. It really gives me a feeling that quantum mechanics is not as confusing (though it is still quite confusing and non intuitive) as the nature of time, or even spacetime

An aside: As for the nature of time, I think this experiment might provide some clues, although this paper by Bruno seemed to suggest it is unlikely to be possile ,despite jury is still out
http://phys.org/news/2013-08-physicist-impossibility-quantum-crystals.html

The bottom line is, I think, in order for time travel to be possible, it seems past present and future has to coexist somehow in a spacetime "block"

Based on my preliminary understanding about special relativity, two observers in relative motion in general will not agree with whether two events are happening simultaneously, their clocks and length of objects. Going to general relativity and putting in closed timelike curves (CTCs):

http://plato.stanford.edu/entries/time-travel-phys/

From what I understood about the analysis of CTCs in this website, I found the following:
1. That presence of CTCs in the future light cone does not provide any constraint to the information (or states?) allowed on the present (the quasi cauchy surface), which if I understood it properly, seemed to suggest there is no way to detect beforehand whether spacetime we live in contains or will contain CTCs

2. On the other hand, in general there are infinite solutions within a CTC that can satisfy the boundary conditions imposed by the CTC, which (again if I have understood it correctly) seemed to suggest that time travel 'paradoxes' such as bootstrap/ontological paradox and predestination paradoxes are not only possible, but likely to be very commonplace. The author(s) of this analysis also mentioned this result in a scenario of "you don't know what will came out of a time machine" given there are so many states that can give the same observed outcome outside the CTC (A bit later I checked wikipedia, and found a term cauchy horizon, which describes this kind of phenomenon)

And then there's this hybrid view (which sort of mix presentism and eternalism (block universe))
http://en.wikipedia.org/wiki/Growing_block_universe

(There might be mistakes in what I mentioned after this, given my incomplete understanding and huge curiosity which not many are bothered to answer (asthey seemed to be too busy feeding trolls)
Since in special relativity two observers (A and B) in relative motion does not in general have agreement on when and where events occurs (thus one might be in the past light cone of another), if we put these into the growing block view mentioned above and put in CTCs, then one of the observer's (e.g. A's) future had not happened yet, thus B cannot travel back to A, but in B's frame, A is in its past, thus it is perfectly possible for B to travel back to A. Wouldn't this creates a contradiction?

But if we accpet the block universe view (the one suggested by general relativity), then all that has happened and will happen is already there as some points in spacetime, but then how does this "elapse of time" that we commonly experienced can be produced/explained by this model?

 

[Russ_Watters]

Secret, that is far too broad/vague, not to mention grammatically incorrect, to warrant a direct reply. Or to put it another way, I see no problems like that which you vaguely describe. Can you please ask more succinct/direct questions.

 

[Secret]

Ok let me try again
The key question is the following:

How to reproduce the effect of "time elapsed" and "causality" in general relativity, which basically every event is a point in the manifold of spacetime, thus in certain sense the events are like static objects on a piece of malleable cloth?

 

[Beer w/Straw]

Didn't Bob and Alice have an argument like this before, yet never agreed?

 

[Secret]

I don't get what you are saying. Specifically which argument as Bob and Alice have a lot of arguments spanning from general relativity to quantum mechanics?
I knew that bob and alice did not agree on when events happened simultaneously, the measurements of their clocks due to time dilation, and then the length of objects due to length contraction

Actually if time is a dimension in the manifold known as spacetime, and locally every patch behaves like miminkowski spacetime, and in general relativity devices known as clocks measuring time. But motion is just a curve in spacetime (the worldline) where does the notion of "time elapsed" came into play?

 

[Beer w/Straw]

The one where Alice falls into a black hole and Bob watches from a distance.

 

[Secret]

I rmb that one,

If my memory serves
Bob will measure it takes Alice a infinite amount of time to reach the event horizon, thus effectively she is frozen, while for Alice it takes a finite amount of time to cross it
*Browsing in more details*
http://en.wikipedia.org/wiki/Event_horizon

This is well beyond my understanding...

 

[Beer w/Straw]

And now it is probably currently beyond everybody on the forum.

I didn't read all of this blog but meh

http://www.nytimes.com/2013/08/13/s...n-a-firewall-paradox.html?pagewanted=all&_r=0

:EDIT:

Published: August 12, 2013! This internet sucks...


http://www.universetoday.com/108870/why-hawking-is-wrong-about-black-holes/

 

[Secret]

Few months ago, there's this Firewall paradox and the idea of entangled particles are connected by wormholes, even going as far as saying spacetime is basically born from quantum entaglement

And then in these recent months, event horizons become apparent horizons, hawking radiation is not in a pure state because it always involve an entangled particle within the black hole

Interesting stuff came out from the theoretical physicists, as always

What I don't understand, as mentioned in another thread some time earlier, that if these wormholes and those from general relativity are one and the same kind, then why when physicists entangle many pairs of photons and sometimes even bose einstein condensates when they carry out their quantum computing researches, why doesn't spacetime get warped out of shape, as wormholes does have some geometry that is clearly not flat, so if you have a bunch of speghetti of them, then shouldn't locally spacetime will become so warped?

As for the topic of time travel, I remembered that some black hole solutions (Kerr solution?) does permit CTCs within them

But the "one way property" of event horizons are so confusing. Like say we have a black hole in 2D spacetime, what does the shape of the event horizon look like when it is embedded in 4D spacetime. It cannot be look like a well as it is commonly depicted in the rubber film analogy of spacetime as the event horizon seems to have a perculier property that once passing through it, all directions lead to the singularity, but it is not the case before you pass through it, how can one visualise such structure as in geometry there is no kinds of topology that can give such "one way zone" like effect, or are they?

 

[Farsight]

Cool that we are starting to learn how things like time travel (Tipler cylinder)... might be possible though.

Cool? It's woo. And you don't understand it. But you can understand the OP. And you can't fault it.

A discussion on how time works can't start with a rejection of what it is, Farsight. You can't reject the starting premise of a line of logic and then continue to pursue it. You need to do some work defining time and getting people to agree before you even start. Start by convincing us that time doesn't flow and time travel to the future doesn't happen.
In the meantime, I'll just sit here proving you wrong.

You haven't proved me wrong Russ! I can demonstrate that time doesn't flow by opening up a clock. You can't find fault in that demonstration. Nor can you demonstrate that time does flow. Now try to read the OP and point out where it's wrong. When you can't, concede.

Farsight, man, saying time travel isn't possible is ultra lame.

That's where it starts, Beer. Come on, you know you agree with me. Don't dig yourself into a hole just because you don't want to admit I'm right.

 

[Farsight]

...Basically about time travel, one thing just really confuse me is how in general relativity spacetime is basically a block universe nature, that is, the past present and future all coexist as events in this spacetime block http://en.wikipedia.org/wiki/Spacetime_in_General_relativity...

Spacetime is an abstract methematical space. It isn't what space is. It's the map, and the map is not the territory. Our world is one of space and motion. Worldlines are abstract things that do not actually exist, as are lightcones, as is the block universe. The past present and future do not all coexist. The present exists. The only time is now, whatever you deem it to be. And there is now way no how that you can go to the middle of last week.

But in daily life, we seemed to experience something like "time has elapsed", and then there's the arrow of time. How do all of these be produced within the spacetime model proposed by general relativity?

You drop one dimension to convert 3D space into a 2D plate in a 3D block universe, then you raise the plate at a uniform rate. The time now is the height of the plate, but then you have to adjust for speed and gravitational potential. The main thing is to appreciate is that spacetime is a mathematical model. It isn't space.

The bottom line is, I think, in order for time travel to be possible, it seems past present and future has to coexist somehow in a spacetime "block".

Well, they don't. So it isn't.

Based on my preliminary understanding about special relativity, two observers in relative motion in general will not agree with whether two events are happening simultaneously, their clocks and length of objects.

Sure. No problem with that.

Going to general relativity and putting in closed timelike curves (CTCs)...

...Wouldn't this creates a contradiction?

Yes. A closed timelike curve is like a looping worldline. In the block universe. Only a worldline doesn't actually exist. And nor does the block universe. These things are abstract mathematical things. And in the real world things do not move in magic loops to obligingly put themselves back where they were yesterday.


ETA:

Few months ago, there's this Firewall paradox and the idea of entangled particles are connected by wormholes, even going as far as saying spacetime is basically born from quantum entanglement.

And then in these recent months, event horizons become apparent horizons, hawking radiation is not in a pure state because it always involve an entangled particle within the black hole

Interesting stuff came out from the theoretical physicists, as always...

I'm afraid some of it is Emperor's New Clothes pseudoscience quackery. What isn't, is the OP. Read it. Understand it. Ask me about anything you're not clear on. If you can find fault with it, please point it out. I don't think you'll be able to. So you'll have to accept it. Then when the penny has dropped about what clocks really do you'll get better at spotting the pseudoscience quackery. Note that I'm a relativity guy. I'm with Einstein. By and large, those "theoretical physicists" are not.

 

[Motor Daddy]

I can demonstrate that time doesn't flow by opening up a clock.

Please start a new thread on this so that we can all learn.

 

[Farsight]

I've already started a new thread, and here we are. Let's open up a quartz wristwatch. Inside it do we find time flowing? No! We find a crystal oscillator:

"A crystal oscillator is an electronic oscillator circuit that uses the mechanical resonance of a vibrating crystal of piezoelectric material to create an electrical signal with a very precise frequency..."

But woo, clocks are supposed to be measuring the flow of time? Only there ain't no time flowing through 'em? Read the OP, MotorDaddy. A clock is not some cosmic gas meter. But time travel is science fiction. And if there's anything you aren't clear on, ask me about it, and I'll clear it up.