tashja
Registered Senior Member
I did. I provided him with a link to the thread.
Time Travel is Science Fiction
- Thread starter Farsight
- Start date
I did. I provided him with a link to the thread.
Can I suggest Billy T not be a moderator.?
Why would I want to part of a forum where he is a moderator?
Why would I want to part of a forum where he is a moderator?
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There are two conceptual errors here.
The first conceptual error is that traveling in time is anything like being frozen. Traveling in time is about a path through a geometry from one event to another, not merely the subjective experience of a being. A frozen being has some of the physical processes in their region slowed relative to others. Someone traveling in time has all of their physical processes going from one event to the other. Even a science fiction device like a stasis box takes a clear path from one event to another that is clearly different from what people mean when they speak of time traveling.
It is either an insult to offer a mistake like the one above or a sign of really poor thinking.
The second conceptual error is that anything in that passage is part of Einstein's relativity theory. As Godel showed, standard, vanilla GR allows for paths in spacetime that are closed causal loops.
Now one can, like Farsight, say that Einstein and Godel meant different things than they actually wrote, but that is not an honest way to discuss these issues.
The graphics below the x-p plane are abstractions representing the space and time relations for objects relative to the perception of observer U.
In the drawing observer U is in his (pseudo) rest frame. His perception of the world is a continuous sequence of incoming spheres of light. For simplicity, the spheres are replaced with 2-dimensional circles of simultaneity, forming a cone with a ct 'time' axis. An object e moves on a linear path at constant speed in the x-p plane, past U, offset a distance d. Its path traces a hyperbola on the light cone of U. Since the accepted convention is to consider a distant object in the past, eg, a star is 4 ly distant, object e moves in the -x direction from the past, to its closest approach d, then into the past. If perception/awareness of an event is always after the event, the object is always in the past, to varying degrees. This choice is consistent with a reversal of direction for e. It also supports the nature of time as it relates to distance.
Here are two reasons why there is no 'future' light cone in the drawing. The light path is discontinuous at U, since perception requires light detection. If there was a future cone, how would e at its closest encounter d, jump from one cone to the other?
The 'flow of time' is the incoming light from events that have happened elsewhere. In reality U is moving, therefore his path determines which events are perceived, and their order. The future for U is only possibilities.
Consulting the primary text, the dictionary, we find:
dilation: the stretching or extending of something.
Time dilation is then an extending of the time required for a process.
Anaut Al leaves Earth on Jan 2015 in a spacecan and returns Jan 2025. The speed of the spacecan was .3c with a brief reversal of direction. Upon return Al's clock reads Jun 2024.
If recording events as they become evident, implies moving in time, then Al apparently fell behind!
The fact is he observed every earth year as it occurred (after a light transit time). His event log for earth will match one from the earth, except the dates will show an increasing time difference. He could have compensated for this by adjusting a 2nd onboard clock to run about 5% faster when up to target speed, and synchronizing on departure.
The earth and Al are simultaneously in the year 2015. He and his clock ticked slower. If Al had truly moved ahead in time he would have gone from 2015 directly to 2025, skipping the intervening 10 yrs.
GR can define a supernova which is occurring now (2014) for a star 10 ly distant, as in the present (for the star), but in the future for earth. It's a relative thing.
dilation: the stretching or extending of something.
Time dilation is then an extending of the time required for a process.
Anaut Al leaves Earth on Jan 2015 in a spacecan and returns Jan 2025. The speed of the spacecan was .3c with a brief reversal of direction. Upon return Al's clock reads Jun 2024.
If recording events as they become evident, implies moving in time, then Al apparently fell behind!
The fact is he observed every earth year as it occurred (after a light transit time). His event log for earth will match one from the earth, except the dates will show an increasing time difference. He could have compensated for this by adjusting a 2nd onboard clock to run about 5% faster when up to target speed, and synchronizing on departure.
The earth and Al are simultaneously in the year 2015. He and his clock ticked slower. If Al had truly moved ahead in time he would have gone from 2015 directly to 2025, skipping the intervening 10 yrs.
GR can define a supernova which is occurring now (2014) for a star 10 ly distant, as in the present (for the star), but in the future for earth. It's a relative thing.
Can you quote a physics textbook?
My neighbours think I'm weird cause I have more than three.
My neighbours think I'm weird cause I have more than three.
Good stuff phyti. Time dilation is not time travel.
"The many-worlds interpretation is an interpretation of quantum mechanics that asserts the objective reality of the universal wavefunction and denies the actuality of wavefunction collapse. Many-worlds implies that all possible alternate histories and futures are real, each representing an actual "world" (or "universe"). In lay terms, the hypothesis states there is a very large—perhaps infinite[2]—number of universes, and everything that could possibly have happened in our past, but did not, has occurred in the past of some other universe or universes. The theory is also referred to as MWI, the relative state formulation, the Everett interpretation, the theory of the universal wavefunction, many-universes interpretation, or just many-worlds".
It's tosh. Garbage. Nonsense. Pseudoscience. And it's way past its sell-by date. But people love their woo, they lap it up, and professional physicists use it to gain media attention and promote themselves. The more outrageous, the more air time they get, and there's no such thing as bad publicity.
OK thanks. But I don't think he's read it.Any chance you could draw the OP to his attention and ask him if he can point out where it's wrong?
That's woo too tashja. See what Wikipedia says:
"The many-worlds interpretation is an interpretation of quantum mechanics that asserts the objective reality of the universal wavefunction and denies the actuality of wavefunction collapse. Many-worlds implies that all possible alternate histories and futures are real, each representing an actual "world" (or "universe"). In lay terms, the hypothesis states there is a very large—perhaps infinite[2]—number of universes, and everything that could possibly have happened in our past, but did not, has occurred in the past of some other universe or universes. The theory is also referred to as MWI, the relative state formulation, the Everett interpretation, the theory of the universal wavefunction, many-universes interpretation, or just many-worlds".
It's tosh. Garbage. Nonsense. Pseudoscience. And it's way past its sell-by date. But people love their woo, they lap it up, and professional physicists use it to gain media attention and promote themselves. The more outrageous, the more air time they get, and there's no such thing as bad publicity.
Yep, and that's just one methodology of how time travel can occur.
I can also go at 99.999% "c"and return to an earth 230 years hence, while I have only aged 1 years. Just one method of time travel, as Kip, Sean, Carl, Michio, Lee, and all tashja's links to expert professors have agreed.
What you propose is no more than a cop out.
Pray tell us again, about the best bit of woo I have heard in my time at this forum.
You know the one...where you claim you have rewritten 20th/21st century cosmology and have a ToE? Can we hear it again?
Or is that past its "use by date" and only used by yourself to gain media attention, which thankfully it has failed.I'm waiting.
The following are 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% achievable.
The problem with the proven delusional Farsight [he's the one who claims to have a ToE] and others in this thread, is that strangely they find it impossible to accept any thinking that on face value is counter-intuitive. Do these same naive people accept the other two aspects of GR, time dilation and length contraction? Do they accept BH's? DM? DE?
Cosmology and the Universe does not worry about what is or what is not intuitive.
The accepted mainstream accept situations based on observational, and experimental data, along with some purely theoretical data. eg: Abiogenesis, in light of any non scientific magical deity explanation, is logically the only explanation for life in the Universe. We all were born in the belly of stars, as they say. Still we have no concrete evidence of such.
Time dilation in anyone's language is time travel, especially when we get to relativistic speeds and extreme gravity.
The problem with the proven delusional Farsight [he's the one who claims to have a ToE] and others in this thread, is that strangely they find it impossible to accept any thinking that on face value is counter-intuitive. Do these same naive people accept the other two aspects of GR, time dilation and length contraction? Do they accept BH's? DM? DE?
Cosmology and the Universe does not worry about what is or what is not intuitive.
The accepted mainstream accept situations based on observational, and experimental data, along with some purely theoretical data. eg: Abiogenesis, in light of any non scientific magical deity explanation, is logically the only explanation for life in the Universe. We all were born in the belly of stars, as they say. Still we have no concrete evidence of such.
Time dilation in anyone's language is time travel, especially when we get to relativistic speeds and extreme gravity.
Here is an example for the wormhole. This paper does an analysis for the Casimir wormhole. The good esoteric stuff.
http://www.kicc.cam.ac.uk/news/wormholes-negative-energy
The paper
http://arxiv.org/abs/1405.1283v1
The Casimir effect shows that a violation of the weak energy condition is possible. The issue becomes how can we get a big enough violation to hold the wormhole throat open or the walls of Prof Alcubierre warp spacetime from collapsing.
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This is hardly an argument for or against - a bald and ignorant assertion.Farsight said:
Consider this. Given a Hermitian operator acting on a state function, itself an element of an infinite-dimensional Hilbert space, the set of all available eigenvalues for this operator is called the spectrum for this operator. In the infinite-dimensional case this spectrum is (usually) continuous.
So a measurement of the said state is simply a determination of one of the many possible eigenvalues of the operator in question. Another measurement might easily yield a different eigenvalue. But the MWI simply says that all other eigenvalues are still available "out there" What is so outrageous about that?
This is of course unrelated to time travel. I would simply point out the following analogy - assuming it makes sense to talk about "the present", and assuming that in some sense "the future" is determined by the present one would say that the relation between the two is highly non-linear. Deterministic non-linear processes are generally referred to as "chaotic". Does this mean a choice of which "future" you travel to (if you could) would be the same every trip you made? Given the caveat "if", I say not.
Conversely, we are where we are. We are connected to the past via a similarly chaotic process, but this process "choses our now" from all other possible "nows". So to travel back in time (assuming again it is possible), and assuming the rule of causality is irreversible, this would place very severe restrictions on how you could influence the "now" you have traveled back from
T
That is why I added theoretical speculation, to science fiction above, and I think in another instance I used the combination of fringe or cutting edge... Personnally I hope something comes from his work, but I have a hard time seeing it right now.
Yes. In the entire universe now, there certainly are in each passing second more than a trillion, trillion possible and different ways to have observations (any interaction of mixed quantum state with a macro scale system, nothing to due with humans looking or even existing) being resolved to particular Eigen states. The "many universes" theory that each and ever possible Eigen state does happen, but creates another separated universe is nearly an "equally improbable fantasy." I say "nearly" as the "many universes" theory does not postulate that all these "futures" currently already exist somewhere that you could "time travel" to. - It just creates them as needed.
That is an untrue statement! On more than one occassion in this thread I have associate time dilation, I. Terms of the twin paradox, with waking up in the morning.... And I am not the only one in this thread who has disagreed with your definition. Thus the statement as quoted, is false.
I think you are referring to Feynman Diagrams - a tool for calculation particle interactions, especially scattering cross section even with new particles or gammas produced. It is just the set of all possible current interactions that one sums over. If you are referring to something else - don't know what it might be - please give a link. Here is link to discussion of Feynman Diagrams and brief quote form it:
http://en.wikipedia.org/wiki/Feynman_diagram said:
It's another name for Feynmans quantum electrodynamics. The diagrams were invented for QED.
I have made the same point several times. Time dilation is only a comparison of clock rates in a frame moving wrt to your stationary clocks and completely symmetric - the person you see moving with high speed also see your clocks as going slow wrt to his. If either of you transfer to the other's frame, you will be less aged by the clocks of that frame.
Any process, including traveling fast and then returning to Earth, that lets more earth time laps before you die can be called "time travel", but that is deceptive as definitely that is not the way that term is used in science fiction. In those stories the time traveler goes into an already existing different time, not just ages more slowly so lives longer than he would if he did not used some process to slow his rate of aging as measured by earth based clocks.
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Paddoboy's calling it a "sum over histories," especially in this thread, made me think he might be talking about some thing else as how to calculate cross sections is not much on thread, but if history were involved it would be.
Not in my opinion, otherwise I wouldn't state it.
http://en.wikipedia.org/wiki/Time_travel#Time_travel_to_the_future_in_physics
Time travel to the future in physics[edit]
Twin paradox diagram
There are various ways in which a person could "travel into the future" in a limited sense: the person could set things up so that in a small amount of his own subjective time, a large amount of subjective time has passed for other people on Earth. For example, an observer might take a trip away from the Earth and back at relativistic velocities, with the trip only lasting a few years according to the observer's own clocks, and return to find that thousands of years had passed on Earth. It should be noted, though, that according to relativity there is no objective answer to the question of how much time "really" passed during the trip; it would be equally valid to say that the trip had lasted only a few years or that the trip had lasted thousands of years, depending on the choice of reference frame.
This form of "travel into the future" is theoretically allowed (and has been demonstrated at very small time scales) using the following methods:[30]
- Using velocity-based time dilation under the theory of special relativity, for instance:
- Traveling at almost the speed of light to a distant star, then slowing down, turning around, and traveling at almost the speed of light back to Earth[59] (see the Twin paradox)
- Using gravitational time dilation under the theory of general relativity, for instance:
- Residing inside of a hollow, high-mass object;
- Residing just outside of the event horizon of a black hole, or sufficiently near an object whose mass or density causes the gravitational time dilation near it to be larger than the time dilation factor on Earth.
- then it says.....
- Additionally, it might be possible to see the distant future of the Earth using methods which do not involve relativity at all, although it is even more debatable whether these should be deemed a form of "time travel":
- """"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
- Now I realise this is only WIKI, but Thorne expresses the same Ideas, as does Carroll.
- And no I didn't contribute to the WIKI article and in fact never have.
- So please, don't say its false when it is not false in the eyes of many professionals, and is the view of mainstream in general, from what I have read, and the many additions from the many professors that tashja has been so good to obtain for us.