Can someone truly build a working time machine?

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Val,

P.S.

Even if we assume only two bodies in the universe, i.e. the Earth with the twin and the rocket, there is still a solution to the problem of who will be effected by the time dilation. Because one individual is in fact stationary and one is not. That solution is as stated in the previous posts, the twin who has to slow down and turn around (an effect that could be measured) will be the one who has felt the effects of time dilation. It just does not matter how many other bodies are around. If there is two or two billion, this still remains a nonparadox because there is the above solution which is stated in many textbooks.
 
What this discussion about the twin 'paradox' comes down to is the conflict between special and general relativity. General relativity says nothing about acceleration, and using only it the spaceship twin is allowed to say the everything else is moving and he is staying stationary. Using only general relativity, it truly is a paradox. But what I meant when I said that special relativity 'solves' the puzzle is that SR takes change of reference frames into account. We can tell that the spaceship twin is accelerated and decelerated, because he experiences pseudoforces at certain points in his journey. Therefore he is shifting reference frames, and GR no longer fully applies.

There is a solution to the two-body problem, as DaveTrott says, but I just want to point out that one observer need not be 'stationary' for it to work. So long as both twins start and finish in the same reference frame, moving at any constant velocity, it will work. This eliminates the need for an absolute reference frame for the entire Universe.

PS: in my last post, I meant to say that the 'centrifugal' force is a pseudoforce, not the centripetal. That one's real.
 
Janus:
In my book of relativity writen by Einstein acceleration is an important part of the General Theory of Relativity. What book of relativity are you useing?
 
er... maybe it's the other way around, SR and GR. I always get the name mixed up
happy.gif


But the point remains the same - if you don't take shifting reference frames into account, the twin paradox is a paradox. If you do, it's not.
 
DaveTrott:

While I don't disagree with you in the principles and mechanics of the two body problem itself, it still can't be used to solve the problem of which twin is effected by what measurement of dilation. It isn't even needed and complicates the issue beyond what is required to solve it.

As I said before, In the two body problem itself, the solution becomes moot. But my scenario is in fact NOT a two body problem.

First, every other body in the Solar system also serves as well as a reference for the traveller AND the "stationary" twin. The traveller is moving at a velocity that is FASTER than every other body in the solar system, not just relative to the Earth itself. As such, his velocity CAN be measured to be relatively faster than the twin on Earth and therefore be shown to be the one who's clock slows down. In a classic tw0 body problem situation, this WOULD not be possible as you have pointed out in terms of "who is travelling faster than whom", but in the scenario I described, this is not the case. In fact, my scenario is really nothing more than an extrapolation of the clock experiments that have already been performed and proven to be true.

Your point is interesting tho, in solving just how one would determine which twin was experiencing "clock slowing" dilation since there would be no other frames of reference.

This particular form of the (two body) experiment is of course not do-able except as a mathematical exercise since we cannot eliminate the influence of all other frames of reference in the universe. All we can do is mathematically plot how it hypothetically WOULD be, if these other frames did not exist.

But in the case of the twins, the precise measurement of WHICH twin is undergoing which dilation is eminently do-able. And in fact has been done. For the very reason that there ARE so many frames of reference to determine just which one IS travelling "faster" relatively speaking.

Understand, I'm not trying to disagree with your concept of the two body problem, just that I don't agree that is has any application in the "twins paradox" as I have formulated it. The "twins" is really a very simple problem that has been confirmed by very simple experiments.

Peace.
 
Janus:

I don't THINK I've misunderstood you, but perhaps so. Message boards can be tough places to express oneself correctly, and easy places to jump to conclusions on. :-)

The reason I set up the scenario I did was to avoid the "shifting frames of reference" problem which WOULD be the case if the travelling twin voyaged OUTSIDE the realm of direct observation of the Earth bound observer. i.e. - Intergalatic space.

So I kept my traveller within the confines of the Solar System to make a point. He would ALWAYS be visible from Earth! :-)

Upon completion of acceleration, he would take up a controlled orbit of the Sun, of x distance from the center (pick any, even a very elongated one), and settle in for a long lasting journey. Say, 50 Earth orbits of the Sun, or 50 "years" by Earth time clocks. But...

Upon returning to Earth, the traveller would have aged only 5 years, say. All the while being within the view of Earth, and having Earth within HIS view. What happens is that the traveller still sees the Earth go around the Sun 50 times, but it is HIS biological clock that has slowed, making an orbital revolution of the Earth no longer a definition of 1 biological "year" for HIM. The deceleration of return, or the acceleration of leaving are negligible effects in this scenario. He's orbiting the Sun at near the speed of light for 50 Earth Years. All frames of reference remain constant and always usable AS a frame of reference. But the time dilation effect STILL occurs.

It's nothing more than a further technological advancement of experiments that have already been performed and proven to be true.

In my mind, it also proves that even with shifting frames of reference, there is still no paradox, since we now know the effect occurs anyway. Even if we COULDN'T provide constant frames of reference to measure it by. It's an effect of Relativity, regardless of whether we can measure it correctly or not. Just like Gravity. It exists even if we don't know what causes it. And we DO NOT know what CAUSES time dilation. Only that it is so. We can say that relative velocity differences "cause" it, but we do not know why.
 
Time02112:

"Frame Dragging" refers to the effect of rotating gravitational bodies.

For starters may I suggest you begin at:
http://www.spacesciences.com/af/23apr98/iskast2/

...where a very thourough explanation is presented as we now believe it to be. (Notice it's a NASA site.)

Near the bottom, you will find a link to the "Gravity Probe-B" project NASA is engaged in for the purpose of measuring the strength of the Earth's effect in this endeavour.

Hope this helps.
 
As absurd as it sounds, if you don't take into account the acceleration of the traveller, he can just as easily say that the Earth, the Sun, the rest of the Solar System, indeed the entire universe, are moving, rather than himself. There is no absolute frame of reference generated by these objects.

I think you're mistaking something like 'fields of vision' for 'frames of reference'. An inertial reference frame is basically one in which Newton's laws apply (as you said earlier). That is, one which is not being accelerated. This has no connection to the traveller's proximity to the Solar System.

We know what is being accelerated, because that body experiences pseudoforces. And it is this accelerating body whose time frame is slowed down. Regardless of whether there are only two bodies in the problem, or the entire Universe, it's the acceleration that matters, not position relative to other objects. This is what has been proven experimentally.

And, by the way, I'm curious as to what your last five questions were. This thread has sort of devolved into talk about reference frames, and your challenge never was completed.
 
Janus:

yes, :-), I do think we may be deteriorating into a misunderstanding here, unintentionally. Now we have come to the point where it seems we might have to debate the meaning of the word "acceleration" as applies to the "change in motion" sense or the more common "keep going faster" one. Heh Heh. I really don't want to do that. Suffice it to say that while acceleration IS INDEED a factor in my scenario, it is negligible in the long run in the same scenario since the traveller moves at a constant rate for most of the journey. And Time Dilation still occurs while this is going on. We could probably take the debate on "reference frames" to another board if you like, but your point on the original premises of "why I think it's impossible to build a Time machine" is well taken.

Question # 5 was "Why?"

A cynical question to be sure, but rooted in philosophy. If ANY Time Machine were ever possible, the inevitable resultant paradoxes FORCE me to ask this.

In truth, I'm not willing to say "Time travel is impossible." But...

All scenarios involving "Time Machines", "multiple universes", "matter transporters", and "reversing black holes" are simply not going to cut it for me. I believe I can disprove, thru Physics, Quantum Theory, and just plain logic, that THESE scenarios cannot be a way it could ever be done.

If it is ever to be, it has to come from something we haven't even concieved of yet that is being overlooked. Nothing in the debates anywhere on any of these TTI boards has offered even a reasonable and logical thought that is even close to what this might be.

As you've seen by now, I dismiss the "cranks" who claim to have already done this, or the "wannabes" who think they can snow us with double talk and allegedly impressive proclamations to their "knowledge" they either refuse to reveal or just plain cop out on the issue when cornered by reasonable discussion.

Since we've beat this "two body problem" issue to death like a dead horse, wanna talk about why I think "time" is an ill concieved concept in the first place? And that you cannot therefore "travel" within, thru, or around something that doesn't even exist except in the minds of as yet primitive humans? Einstein talked of this. If it's good enough for him, I can deal with discussing it, since he remains one of my personal heroes, among others. :-)

Peace.
 
Now just think real hard about what you said here,..." If it is ever to be, it has to come from something we haven't even concieved of yet that is being overlooked."

* The missing element of suprise is no suprise at all, in fact the answer is staring right at you, and yet you still do not see. Of course it has been "Overlooked" otherwise you would not be asking these questions, am I right?

You also said,..." Nothing in the debates anywhere on any of these TTI boards has offered even a reasonable and logical thought that is even close to what this might be.

Reasonable? or Logical Thoghts, none of which have any merit to help in any way to bring us any closer to those questions we seek answers to? ..Oh Really now! I think you should retract that statement, you could be asking for trouble here.

Read this!..........

Everything is interconnected, but in ways that even elude, or deviate from the norm of the most common practicality,of "Mainstream Science"
All mass contains particles, and all particles generate their own internal rotating electromagnetic fields.
a good example is in that of an observer examines the Planetary, (REMF) also notices the same effects occuring within the molecular (REMF) as the electrons & neutrons are spinning around an atom, and the effects of quarks & gluons on yet another minute scale that displays the same effects.

Now would not it be rather ignorant to discount the effects of planetary REMF have upon the body's internal molecular REMF ?
and I am not speaking of natural occurences here!

what really begins to happen, when we start manipulating atoms in ways that enable us to change shape, or structures of mass, to tranverse transportation barriers such as "FTL" or Time~Travel, that might have been otherwise been impossible to have crossed if they had remained in their original state of matter?



------------------
"Everything you know,...is Wrong!
soon we shall all discover the truth."

p)'i4q4
 
Time02112:

Sorry, but I'm afraid you happen to be one of the "cranks" I was referring to earlier. You offer "doublespeak", mumbo-jumbo, and no REAL explanation of ANYTHING.

You didn't even get the definition of "Frame Dragging" right. I trust you investigated the site I provided and educated yourself a little. (Or perhaps you are now going to declare the scientists at NASA "daff" for how thay are going about measuring this effect.)

I wasn't going to name names in the "crank" department, but your previous post forces me too.

Frankly, you don't have the faintest idea what you are talking about and you know it.

You just want us to think you do. Sorry, there are some people on this board who actually DO know what they are talking about.

You just don't happen to be one of them.

P.S. Your continued useage of that smug little saying you always sign off with speaks volumes about your over-inflated self image.
 
Well, I think it's about time to start a new thread. The Nature of Time - that'd be a nice topic, if we can keep it basically targeted on the physics, and not delve too much into the metaphysics and philosophy.

If only there were kill-files on HTML boards...
 
Janus:

"Well, I think it's about time to start a new thread. The Nature of Time - that'd be a nice topic, if we can keep it basically targeted on the physics, and not delve too much into the metaphysics and philosophy."

I'd LOVE it. You're a member here. Go for it. I'd LOVE some reasonable debate/discussion/brainstorming on the topic with people who truly understand the laws of physics and are happy to explore the problem of time travel in a concientious adult manner. If it turns out to be we think it's impossible, so be it. If it turns out we think we can find a way for it to actually BE possible, all the better!

We need not try to impress anyone with anything. Let the laws of Quantum theory, Physics, Astrophysics, and Cosmology be our guides. Let it be a truly scientific thread where claims are required to backed up with solid references. Web sites, published articles, theories from respectable people, etc.

But at least we can "cut to the chase" and toss out the bull crap. (Actually, the "bull crap" has a way of becoming apparent on it's own accord huh.)

Peace.
 
No need to be a member to post a new thread. Anyone can. I think it'd start the thread off better if you'd give the gist of your ideas, to give us something to start from.

But I'd recommend registering anyway. That way, at the very least, no-one can post under your name.
 
Janus-
I know you said that explaining all your ideas on how you think time travel could be possible would be too long to explain-
but how about ONE of them -how about the wormhole one. will you share your ideas of this?
happy.gif
or is there one you favor above the others?

<This message has been edited by pamela (edited 15 June 2000).>
 
Janus:

First, there is never any need to register on a board that is managed the way this one is. Being a "member" actually means nothing unless TTI chooses to install the board's password option. If it chooses to do this, I may or may not continue. Like my father before me who used to be a regular poster here, he also never registered. But he turned me onto this board and I have chosen to participate. He's a Systems Professional and true renaissance thinker. I am but a humble, barely graduated, lab worker in the field of aerospace research. I work a menial job in a shop that builds guidance systems for experimental aircraft. My father is a Ph.D, MS in Computer science and BS in Astronomy. I am but a lowly graduate student of Fluid Dynamics Engineering. I don't claim to be a geek, an egghead, or even smart for that matter. But don't try to snow me. I can spot a phoney from a mile off.

I figure a person's words are their bond and the words one uses are signature enough for valid ideas.

If someone chooses to "imitate" me here, I will first point out that this is occurring and then switch to a new handle. I prefer to let the readers here be the judges of what is real and what is "bull crap".

But... YOU suggested the "new thread", therefore I suggest YOU start it. I would think you know what my Ideas are by now, at least enough that I don't have to re-state them redundantly, and bore everyone here by doing so.

Pamela:

Actually, I think Janus has done a pretty fair job so far in the "two body problem" discussion. I don't see that he has it quite right just yet, (which is beside the point), but he is putting up a reasonable argument as to what he THINKS it is.

I respect that.
 
Valkerie:
Just wondering why a Fluid Dynamics Engineer is working on aircraft guidance systems.
 
Valkerie, Read "your comments" here, and give me an answer, as to what the Hell is wrong with this picture?

Valkerie Said.......

* "I prefer to let the readers here be the judges of what is real and what is "bull crap".

* "Time02112:
Sorry, but I'm afraid you happen to be one of the "cranks" I was referring to earlier. You offer "doublespeak", mumbo-jumbo, and no REAL explanation of ANYTHING."

* "I wasn't going to name names in the "crank" department, but your previous post forces me too.

* "Frankly, you don't have the faintest idea what you are talking about and you know it."

* "You just want us to think you do. Sorry, there are some people on this board who actually DO know what they are talking about-
---You just don't happen to be one of them."

* "P.S. Your continued useage of that smug little saying you always sign off with speaks volumes about your over-inflated self image."

My response.........

Valkerie, you bring new meaning to the word "Paradox" for you, yourself are full of your own "Doublespeak! (Listen to yourself!)

I really hope that you, or anyone likewise, never gets the vote to represent the state of the Time~Travel research community, otherwise we all might as well give up now!

---------------<W H Y ?>--------------------

Because we would certainly fail, before we ever get started.

In the words of your dear friend "Janus" I say unto you likewise;--------

"I will no longer be reading or responding to any posts you make on any topic. So go hurl insults and preach your beliefs to someone else; I won't be listening."

Since both of you appear to be "Birds of a feather, why don't you take your "parroting misconceptions." elswhere; a place in which they are more likely to be accepted by others that think like you.

I refuse to appologize for who I am, and just because I cannot, or refuse to exist within the restrictive confines of your your neat little box, does not give you any right to impose, or pass judgement upon me!...you have know idea who I am, moreover, if that makes you uncomfortable, or socially unacceptable, by your standards, then you know what you can do with your little box!

I don't need to be patronized, mocked, or insulted by you, or anyone else on my own free time.

p)'i4q4
 
Valkerie,
You must admit Time02112 has a point. You are just as much guilty, if not more of what you claimed him to be. So recognize =).

And you Janus, you have only 1 friend here. To bad he's also a buffon like you =P.

Have a great day,
Javier C.
 
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