Room-temperature superconductivity?

[johanfprins]

Resolution of the paradox in special relativity

The standard textbook approach treats the twin paradox as a straightforward application of special relativity. Here the Earth and the ship are not in a symmetrical relationship: the ship has a turnaround in which it undergoes non-inertial motion, while the Earth has no such turnaround. Since there is no symmetry, it is not paradoxical if one twin is younger than the other.

This assumes that acceleration can dilate time. Since the strength of a gravitational field is proportional to the acceleration of a body with mass, it has been assumed that acceleration caused by engines on a spaceship will have the same effect. This has NEVER been proved experimentally, and I am convinced that when such an experiment is done within gravity free space, it will be found that aceleration does not affect the time rate of a clock that is being accelerated.

Nevertheless it is still useful to show that special relativity is self-consistent, and how the calculation is done from the standpoint of the traveling twin.
Special relativity does not claim that all observers are equivalent, only that all observers at rest in inertial reference frames are equivalent. But the space ship jumps frames (accelerates) when it performs a U-turn. In contrast, the twin who stays home remains in the same inertial frame for the whole duration of his brother's flight. No accelerating or decelerating forces apply to the homebound twin.
There are indeed not two but three relevant inertial frames: the one in which the stay-at-home twin remains at rest, the one in which the traveling twin is at rest on his outward trip, and the one in which he is at rest on his way home. It is during the acceleration at the U-turn that the traveling twin switches frames. That is when he must adjust his calculated age of the twin at rest.

This pure and unadulterated BS.*

As far as your diagram is concerned I would like to repeat that the one twin does experience the other twin's clock to slow down; even though this clock does NOT actually slow down within its own inertial reference frame. Both twins are stationary within their respective inertial reference frames so that both their clocks must keep the same time within their respective reference frames within which they are stationary. Thus there is no actual time-dilation caused by relative motion: Only apparaent time-dilation within YOUR reference frame of your twin's clock when he moves past you: However, this time dilation does not actually occur within your twin's reference frame: Within HIS refrence frame HIS clock keeps exactly the same time that YOUR clock keeps within YOUR reference frame. Thus it is impossible for you and your twin to age at different rates.

* I apoligise for being blunt above. At least bringing in acceleration when discussing the two twins is in effect an acknowledgement that a constant speed does not change the time rate of any clock which moves relative to another reference frame, within its own reference frame.

[rcain]

So what do you think about these tests where atomic clocks are synchronized and then one of them is flown around?
...

To be truthful, Teemu, it probably means i don't properly 'understand' it myself. but i hope to get there some day.

certainly the evidence for 'asymmetry' of recorded clock ticks seems incontrovertible, and despite initially agreeing with Johan's logic, i might just be forced to accept the orthodox view again on the theory of SR(/GR), simply in order to get the right (asymmetric) numbers out of the examples i was trying to consider.

certainly, the examples i provided above are 'out' in a few significant details. (i will try again at some point).

in any event, i've been reacquainting myself with some of conventional theory, and have the root of SR asymmetry explained (eg: - David Malament 'Geometry and Spacetime (lecture notes) - http://www.socsci.uci.edu/~dmalamen/cou ... cs/GST.pdf - esp. 'proposition 3.1.8' p37 and '3.2 Minkowskian Geometry – Physical Interpretation' p39 onward - which I'm finding helpful) - and hope to get back here soon with a revised interpretation.

(Sorry Johan - but please continue - i would still be very interested to arrive at a proper conclusion, by unconventional means, as it were )

[sparkyy0007]

Here is a thought experiment that may help to hopefully clear some confusion.
Regarding the twin paradox, the observer (let's call him Sam) on earth has a device to measure
the speed of light coming from a distant star. His brother Bob also has a similar device mounted
in his spaceship. Bob and Sam synchronize their respective clocks and say goodbye.
During Bobs journey to the star Sam keeps a record of the speed of light and spectrum from the same star
while Sam in his space ship does the same.
Bob during his trip, accelerates to 0.5c for a year and returns at the same speed.
Sam and Bob compare their data to find that Bobs spectrum was blue shifted for the first half and red shifted for the return, compared to Sams data.
However the speed of light was the same in both instances .
Now, how could the speed of light have been measured to be the same for both Sam and Bob if Bobs clock was actually running slower than Sams.
You need an accurate clock to measure the speed of light and according to Einstein, that speed must be c for all observers in an inertial frame.
If Bobs clocks were running slower, he would measure variations in c and we know this doesn't happen.

[Teemu]

The kinematic change in time must ALWAYS be a decrease in the time of the "moving" clock within the reference frame of the stationary clock; and must thus be negative for both the eastward and westward flights.

If I understood correctly, in their calculations it would decrease also if the plane was fast enough (twice the rotational speed of the Earth?). But why do the applications of this special relativity, to at least 4 tests of this type, and GPS, etc. work?

[Teemu]

Lets go from twins to triplets.

Triplets are in a gigantic merry-go-around, going in counter-clockwise direction. First they are all in the middle, they synchronize three atomic clocks, and put them in their backpack. One of them, lets call him A stays at the center, other two get bored, and walk a distance 6000x from the center. At this point, their cross-radial velocity is 5v. One of them just starts to sit at that point, his name is B, and another one, C, decides to go a little further, at the distance of 6010x from the center, and starts to walk the merry-go-around in either counter-clockwise or clockwise direction, at speed 1v.

Now if triplet C choosing the counter-clockwise or clockwise direction relative to the triplet B wouldn't matter, then the time dilation of the clocks of the triplet B and C would always be negative related to the triplet C going at speed 1v faster than the triplet B. But relative to the triplet A, the time dilation would be clearly dependent of the direction, so the time dilation would be negative, either related to 4v or 6v velocity, depending on the direction of triplet C.

If the direction of C relative to the triplet B didn't matter, if the speeds were high enough, or if the speed of light came down in that universe suddenly, then when the triplets meet again, the triplet C would be "youngest" from the triplet B's viewpoint always. But from the center triplet, A's, viewpoint the triplet B would be the youngest if C chose clockwise direction, but from triplet B's viewpoint the triplet C would be still the youngest. So in their meeting again ages or tick of the clock would be:
from C's perspective A>B>C
from A's perspective A>C>B

I think based on that, the direction the triplet C relative to B triplet has to matter.

If the triplet A and his atomic clock got kidnapped from the middle by the alien kidnap ray, and whether the outer triplets get the information of this kidnapping or not, can't change the calculations. The relationship between the triplet B and C, which at point 6000x, before C went to 6010x and started to walk at 1v, their atomic clocks were synchronous, just like the atomic clock left to the earth and the atomic clock taken to the flight, were synchronous before the atomic clock was taken to the flight. Based on this I think the rules for calculating the time dilation for flying clock related on the clock left behind can't be dependent on the fact that there is no initially synchronized atomic clock at the center of the earth.

[MSimon]

Muons decay slower if they travel faster. It would seem that the muons do live longer if they are moving faster. This was at one time considered strong proof of time dilation.

[DeltaV]

Muons decay slower if they travel faster. It would seem that the muons do live longer if they are moving faster. This was at one time considered strong proof of time dilation.

"Seem" is the operative word.

Mendel Sachs gives a concise clarification here:

The Lorentz transformations are not cause-effect relations, They are not dynamical relations, they are only kinematic relations.

"Time and age are not the same thing."

Time is a "geometrical" quantity dependent on which frame the observer is in. Age is an intrinsic quantity of the observed.

[johanfprins]

Owing to limited time, I have decided to jump all the other comments, each of which is interesting in its own right and can be argued separately, to the following comment:

Muons decay slower if they travel faster. It would seem that the muons do live longer if they are moving faster. This was at one time considered strong proof of time dilation.

This does prove that time dilation has a real effect, but it does not prove that one twin can age faster than another twin moving with a speed v relative to the first twin.

The muon lives longer within the earth's reference frame but not within its own reference frame. A clock travelling with the muon will measure exactly the same decay time than one will measure for a muon generated within a laboratory on earth. This means that the clock travelling with the muon is keeping time at the exact same rate as the clock within the laboratory on earth.

This will also be the same for the clocks carried by the two twins: THEREFORE it is impossible for one twin to age slower than the other.

The fact that within the reference frame of the earth, the clock of the travelling twin keeps slower time, does not mean that the clock with the travelling twin keeps slower time within the reference frame of the travelling twin. Thus, although the twin on earth when communicating with the "moving twin" must take time dilation into account (just as the travelling twin must do the same when communicating with earth, since the time rate on earth is slower within his reference frame), the time rates of the two stationary clocks within the respective reference frames of the two twins are EXACTLY THE SAME. So how can one twin actually age slower than the other twin?

Let me end by asking a few questions:

1) Do stationary clocks all keep the exact same time? YES or NO?
2) Is a clock travelling with an inertial reference frame stationary within this inertial reference frame? YES or NO?
3) Are all clocks travelling within different inertial refrence frames stationary within the inertial reference frames with which they are travelling? YES or NO?

If you answered YES on all these questions you must agree that all clocks moving relative to one another MUST keep the same time within their respective reference frames. Therefore the clocks with the two twins MUST keep time at the same rate. So how is it biologically possible for one twin to age slower than the other twin?

[MSimon]

Muons decay slower if they travel faster. It would seem that the muons do live longer if they are moving faster. This was at one time considered strong proof of time dilation.

"Seem" is the operative word.

Mendel Sachs gives a concise clarification here:

The Lorentz transformations are not cause-effect relations, They are not dynamical relations, they are only kinematic relations.

"Time and age are not the same thing."

Time is a "geometrical" quantity dependent on which frame the observer is in. Age is an intrinsic quantity of the observed.

The muon decay results seem to point to the fact that differential aging is possible. Although the fast muon it its frame of reference lives as long as the stationary muon in its frame.

[DeltaV]

A multi-valued age would be meaningless.

[MSimon]

A multi-valued age would be meaningless.

Why? I don't see any problem with a fast muon aging slower (in my frame) than it does in its frame. And in fact that is what is observed.

And this all revolves about meaning vs observations?

Explain the observation then we can work on meaning if that is even important. The deal is: the flow of time is not a universal constant the way the speed of light is. Time is not invariant.

Say I'm traveling close to c. Why does it bother you that under those circumstances that I may have aged 67 years while the Earth (stationary relative to my frame) has aged millions of years?

Is it still early 1905?

http://hyperphysics.phy-astr.gsu.edu/hb ... /muon.html

[johanfprins]

The muon decay results seem to point to the fact that differential aging is possible. Although the fast muon it its frame of reference lives as long as the stationary muon in its frame.

Can you not see that you contradict yourself? You admit that the lifetime of the muon is the same within both reference frames; YET you then conclude that "differential aging is possible?

A human is also a biological clock and if my biological clock is running at the same rate as my twin's biological clock runs even though he is moving with a speed v relative to me then it is impossible for him to age slower than I do.

How many times must I repeat the fact that what the events which are actually ocurring within a passing reference frame is NOT the same in position and time after they have been transformed into your reference frame. If they were, one would not require coordinate transformations at all.

Consider again an object that, within the reference frame of your twin moves perpendicular to the direction that your twin is moving relative to you. Within your twin's refrence frame the object is moving along a straight line. After doing a coordinate Lorentz-transformation from your twin's reference frame into your reference frame, the object is observed within your reference frame to follow a curved path. It is obviously totally WRONG for you to now conclude that the object is also following a curved path within your twin's reference frame.

It is equally WRONG to assume that the TRANSFORMED time-rate of your brother's clock within your reference frame, which gives your twin's clock AS VIEWED FROM YOUR REFERENCE FRAME a slower time rate, is the same as the actual clock rate within your twin's reference frame. It is not! The time-rate on your clock is exactly the same as on your brother's clock. Thus your twin cannot age at a slower rate when moving relative to you, neither can you age slower relative to your twin.

Stephen Hawking is thus writing total claptrap within his book "A brief history of time that: “In other words the theory of relativity puts an end to the idea of absolute time! It appeared that each observer must have his own measure of time, as recorded by a clock carried by him, and that identical clocks carried by different observers would not necessarily agree.”

The clocks carried by you and your twin brother MUST have exactly the same time rate; or else Einstein's very first postulate on which he based his Special Theory of Relativity MUST be wrong. Einstein's Special Theory of Relativity DOES THUS NOT PUT AN END TO ABSOLUTE TIME; as Hawking claims!!

[MSimon]

Johan,

If you buy relativity time is not invariant. I will live 100 years (say) if I am traveling near the speed of light or am sitting in my chair on Earth.

However, my aging near the speed of light will be slower relatively than my aging sitting in my chair on Earth.

Muon decay is the proof of this.

If you are going to come up with a different theory you need to explain the muon numbers.

Start here and explain the results:

http://hyperphysics.phy-astr.gsu.edu/hb ... /muon.html

[MSimon]

BTW Johan,

I'm not saying you are wrong. I'm saying you haven't explained the muon results:

http://hyperphysics.phy-astr.gsu.edu/hb ... /muon.html

[mvanwink5]

I thought the muon results were because the measurement takes place in a gravity field, not because of the velocity.
Best regards