Twin Paradox - For and Against.
Extracts from
http://math.ucr.edu/home/baez/physics/Relativity/SR/TwinParadox/twin_vase.html
My text in red, Baez's text in black
[Physics FAQ] - [Copyright] -- I'm trampling all over that copyright, if Baez wants to sue me in a court of law he is welcome to try. I would enjoy the opportunity to challenge his fraud. Got any balls, Baez? Take me to court and I'll metaphorically castrate you there.
Original by Michael Weiss. (as if that mattered)
An old lawyer joke:
"Your Honor, I will show first, that my client never borrowed the Ming vase from the plaintiff; second, that he returned the vase in perfect condition; and third, that the crack was already present when he borrowed it."
Or to quote Shakespeare: "Methinks the lady doth protest too much."
Why so many different explanations? Because the whole thing is a pack of lies.
Are the relativists just trying to bamboozle their opponents? Yes, they are. This document will prove it.
To prevail, a defense attorney just has to stir up doubt about the plaintiff's case; she's not required to give her own theory of what happened. Then sue me if you have the courage, "Professor" Baez, I'm calling to a lunatic.
But a physical theory should tell a single coherent story. Stipulated to.
Relativity here pays the price of permissiveness. It says to us, "Pick whichever frame you like to describe your results, or use spacetime diagrams and don't choose a reference frame at all. They're all equivalent, I don't mind." No wonder that one explanation ends up looking like three or four.
Ladies and Gentlemen of the Jury, a "spacetime diagram" is an ordinary distance/time Cartesian graph with distance and time axes exchanged. "Spacetime" is a buzzword for children wanting to play at being astronauts and time travellers. Here are some examples of a spacetime diagram, before the time axis became vertical:
http://www.kettering.edu/~drussell/Demos/SHO/damp.html
http://webphysics.davidson.edu/physlet_resources/bu_semester1/c2_twocars_graphs.html
http://www.shodor.org/interactivate/discussions/fd5.html
http://www.mste.uiuc.edu/users/Murphy/DerivMod/RelDistToVel.html
Notice that in every case, the distance is vertical, time horizontal.
Most physicists feel that the Spacetime Diagram Explanation is the most fundamental.
Not so, Ladies and Gentlemen of the Jury. Most physicists do not use Confidence Trickster's terminology, or appeal to "feelings". Baez is not a physicist, he is a ranting, raving, lunatic schoolteacher.
It does amount to a sort of "Universal Interlingua", enabling one to see how superficially different explanations are really at heart the same.
Figure 1 is the basic spacetime diagram for our hero and heroine. By adding lines one way or another, we will get all the various explanations. (Oh yes: choose units so that c=1 throughout. So light rays graph as 45 degree diagonal lines in all our diagrams.) In whose frame of reference?
(http://interactive.usc.edu/projects/img/HBD_thumb.jpg)
Figure 2 is the diagram for the Doppler Shift Explanation. The red lines at 45 degrees are the pulses of light one twin sends to the other. (To reduce clutter, I've made two copies of the diagram. The left one shows Stella's pulses, the right one Terence's.)
The time dilation factor in the diagram is two: Terence ages twice as much as Stella. (Notice that Stella has time to send off a mere 16 pulses, while Terence fires off 32.)
The prosecution contends there is no such animal as time dilation, and Baez is no physicist or mathematician. He doesn't even understand f = 1/t. 
t = (t-vx/c²)/sqrt(1-v²/c²)
t = (t-uy/c²)/sqrt(1-u²/c²)
t = (t-wz/c²)/sqrt(1-w²/c²)
x = (x-vt)/sqrt(1-v²/c²)
h = (y-ut)/sqrt(1-u²/c²)
z= (z-wt)/sqrt(1-w²/c²)
Right or wrong, Ladies and Gentlemen of the jury?
I put it to you that if one equation is correct, they all are, if one is invalid they all are.
Einstein said :
h = y,
z = z
because he did not know how to move sideways or up, he was either an anencephalous cretin or a huckster. Either way, so is the defendant. He may enter a plea of insanity during sentencing, but I ask you find him guilty of fraud as charged.
The emissions are spaced evenly from the viewpoint of the respective senders; not so the receptions, which are redshifted or blueshifted according to the relative motion of sender and receiver. All pulses are properly accounted for; check out the Doppler Shift Explanation for full details.
Full details by the prosecution: Stella's "worldline" is shown at the top, Terence's "worldline" at the bottom.
Note that the red and blue lines leave at 45 degrees, as required, but do not arrive at 45 degrees.
Figure 3, the diagram for the "GR" Explanation, adds lines of simultaneity (in blue) instead of light pulses.
Ladies and Gentlemen of the jury, these lines are not parallel and do not represent simultaneity shown by the vertical grey lines in the prosecution's diagram. Stella has counted the same number of events as Terence and simultaneously with Terence, ergo Stella is the same age as Terence. The time dilation factor in the diagram is two: Terence ages twice as much as Stella. (Notice that Stella has time to send off a mere 13 pulses, while Terence fires off at least 13.) GR is as false and fraudulent as SR, and I put it to you that "Professor" Baez, who claims to be a mathematician and physicist, is a fraud and a nincompoop who could not count the fingers and toes he has.
These lines represent collections of events that all happen simultaneously, according to Stella.
Stella's view is subjective, ladies and gentlemen. Science is objective, it is not laissez-faire. We are not concerned here with when Stella receives a birthday card from her twin brother, her birthday is his birthday, they are twins. Stella is sensible enough to know it will take time for her card to be delivered and for her to receive one from her brother, unless she is totally stupid. Baez is totally stupid.
You can see how the lines are closely bunched near Stella, and spread apart near Terence.
Can you really see that, Ladies and Gentlemen of the jury? I see a fraud, deliberately perpetrated by the defendant. Yes, the received lines are spread out and bunched, that is known as Doppler shift and clearly shown in the prosecution's diagram. It is also symmetrical for both parties.
This is a graphical representation of "gravitational" time dilation. If we pretend that Stella's notion of simultaneity is the Truth (just for a moment!), we'd have to say that Stella's clock is running much faster than Terence's during the Turnaround. But we are not all quite that stupid.
Do you really want to pretend, Ladies and Gentlemen? I ask that you find this huckster Baez and his chronies guilty of fraud as charged.
Modify Figure 3 slightly, and we have a portrayal of the Time Gap Objection (Figure 4).
Here we have let the Turnaround become instantaneous. On the Outbound Leg Stella uses one frame of reference, and one notion of simultaneity. On the Inbound Leg she switches to another. The "gap" (the section of Terence's worldline devoid of blue lines) is a consequence of this abrupt switch.
These are just a few of the ways we can decorate our simple diagram with extra lines. In the laissez-faire (a philosophy or practice characterized by a usually deliberate abstention from direction or interference especially with individual freedom of choice and action, devil-may-care) spirit of General Relativity, we could cover the diagram with almost any network of grid lines, and base a description on the resulting coordinate system. (I hasten to add that there are some pitfalls for the unwary: see Section 6.3 of Misner, Thorne, and Wheeler for the fine points.)
Thorne is the same drooling imbecile that backed the cretin Hawking and lost his bet with John Preskill.
One territory, many charts. Which read "Here be dragons"..
"But a physical theory should tell a single coherent story." --Baez
The pitfalls are those deliberately created by Baez and his time shifting chronies to cheat you out of your hard-earned taxes and destroy science.
Indeed, nothing in any of Baez's papers suggests that he really understands 2AB/(t'A-tA) = c = 0, Einstein's theory, or Mathematical Vector Spaces. I'm reasonably familiar with all these topics, and as far I can tell, all he writes about is a mishmash of superficially plausible sentences containing stupid buzzwords in approximately the wrong order. There is no logic or cohesion in what he writes.
Since his papers make no sense, what is his intention in writing them? By now it seems clear that he is not staging a Sokal-type hoax to show up defects in the refereeing and Ph.D.-granting process. He has lost too much face for this to be a plausible course of action! The main remaining options are 1) that he is engaged in some sort of trick, or 2) that he honestly believes in what he's doing.
New lawyer joke:
"Your Honor, I have shown first, that my client stole the physics from Sir Isaac Newton; second, that he returned the physics in shattered condition; and third, that the crack was already present in the crackpot's head. I ask that he be stripped of his status as a 'Professor', fined and be remanded to a mental institution for correctional treatment"
R.I.P. Einstein's Relativity. Let sanity prevail.
A -5 point starting credit.
1 point for every statement that is widely agreed on to be false.
2 points for every statement that is clearly vacuous.
3 points for every statement that is logically inconsistent.
5 points for each such statement that is adhered to despite careful correction.
5 points for using a thought experiment that contradicts the results of a widely accepted real experiment.
5 points for each word in all capital letters (except for those with defective keyboards).
5 points for each mention of "Einstien", "Hawkins" or "Feynmann".
10 points for each claim that quantum mechanics is fundamentally misguided (without good evidence).
10 points for pointing out that you have gone to school, as if this were evidence of sanity.
10 points for beginning the description of your theory by saying how long you have been working on it.
10 points for mailing your theory to someone you don't know personally and asking them not to tell anyone else about it, for fear that your ideas will be stolen.
10 points for offering prize money to anyone who proves and/or finds any flaws in your theory.
10 points for each new term you invent and use without properly defining it.
10 points for each statement along the lines of "I'm not good at math, but my theory is conceptually right, so all I need is for someone to express it in terms of equations".
10 points for arguing that a current well-established theory is "only a theory", as if this were somehow a point against it.
10 points for arguing that while a current well-established theory predicts phenomena correctly, it doesn't explain "why" they occur, or fails to provide a "mechanism".
10 points for each favorable comparison of yourself to Einstein, or claim that special or general relativity are fundamentally misguided (without good evidence).
10 points for claiming that your work is on the cutting edge of a "paradigm shift".
20 points for emailing me and complaining about the crackpot index. (E.g., saying that it "suppresses original thinkers" or saying that I misspelled "Einstein" in item 8.)
20 points for suggesting that you deserve a Nobel prize.
20 points for each favorable comparison of yourself to Newton or claim that classical mechanics is fundamentally misguided (without good evidence).
20 points for every use of science fiction works or myths as if they were fact.
20 points for defending yourself by bringing up (real or imagined) ridicule accorded to your past theories.
20 points for naming something after yourself. (E.g., talking about the "The Evans Field Equation" when your name happens to be Evans.)
20 points for talking about how great your theory is, but never actually explaining it.
20 points for each use of the phrase "hidebound reactionary".
20 points for each use of the phrase "self-appointed defender of the orthodoxy".
30 points for suggesting that a famous figure secretly disbelieved in a theory which he or she publicly supported. (E.g., that Feynman was a closet opponent of special relativity, as deduced by reading between the lines in his freshman physics textbooks.)
30 points for suggesting that Einstein, in his later years, was groping his way towards the ideas you now advocate.
30 points for claiming that your theories were developed by an extraterrestrial civilization (without good evidence).
30 points for allusions to a delay in your work while you spent time in an asylum, or references to the psychiatrist who tried to talk you out of your theory.
40 points for comparing those who argue against your ideas to Nazis, stormtroopers, or brownshirts.
40 points for claiming that the "scientific establishment" is engaged in a "conspiracy" to prevent your work from gaining its well-deserved fame, or suchlike.
40 points for comparing yourself to Galileo, suggesting that a modern-day Inquisition is hard at work on your case, and so on.
40 points for claiming that when your theory is finally appreciated, present-day science will be seen for the sham it truly is. (30 more points for fantasizing about show trials in which scientists who mocked your theories will be forced to recant.)
50 points for claiming you have a revolutionary theory but giving no concrete testable predictions.
38. Gamma points for claiming v = 0.99xxxxxxxxxxxxxxxxxxxxxxxxxxxxxc where x is the digit claimed and gamma = 1/sqrt(1-v2/c2)
39. 100 points for claiming to be a physicist who accepts Einstein's definition of time.
40. 1,000 points for claiming to be a mathematician who believes 2AB/(t'A-tA) = c
41. 10,000 points for claiming to be a Professor interested in mathematics and physics that include 39 and 40.
© 1998 John Baez -- screw your copyright, Baez. Sue me for damages if you dare.
http://www.newsroom.ucr.edu/cgi-bin/display.cgi?id=1229
RIVERSIDE, Calif. www.ucr.edu UC Riverside Chancellor France A. Córdova testified before a joint State Senate-Assembly hearing at Pasadena’s Jet Propulsion Laboratory on Friday, Jan. 20, about the need to attract more young people to mathematics and science careers and to improve the preparation of those who choose to teach those subjects in public schools.
Heaven help the students!
Androcles Dumbledore, Headmaster, hogwarts.physics.