Room-temperature superconductivity?

[johanfprins]

We disagree about the twin leaving & returning, where it is the change in FOR, not the acceleration per se, that makes for the difference in elapsed time.

There is no difference in elapsed time since even acceleration does not affect the rate of time: It is only a perception within another reference frame that the time is slower within the moving reference frame while the latter is not the case. Thus, excluding any gravitational effects, the twins will be exactly the same age when they get together again: No matter which reference frame slowed down to reach the other. The latter is in either case a contradiction since both observers within the two reference frames will believe that it is the other reference frame that is slowing down to meet up with his/her reference frame.

[icarus]

So how did the muon cross the space? It should have decayed before it got here.

1) Was time going slower?
2) Does the distance it travels shorten?
3) Did it travel faster?
4) Was its decay process altered by the journey?

Imagine you are a muon tomclarke.

many arguments, incl this, are invalid because they assume time has some meaning independent of FOR. It does not, so "time going slower/faster" is meaningless without further qualification.

A clock travelling with the muon would appear to be going slower if observed from earth FOR. Also a clock on earth would appear slower from muon FOR. No contradiction.

So 1), 2), 3) or 4) or none of the above (with explanation if possible)?

[Aero]

Some of you folks debating here may find the original paper to be an interesting read.

http://www.casavaria.com/hotspring/2008 ... aper-1905/

I certainly found it interesting.

This paper is standard bedside reading matter for me. I would not have dared to criticize Einstein's derivation of length contraction without first studying what he has written in detail. A pity that most scientists at present do not extend the same courtesy to me.

Of course - you demonstrate by your writing that this must be so. Others however may be interested to read at the bottom of page 4 of the quoted paper, as follows:

The following reflexions are based on the principle of relativity and on the principle of the constancy of the velocity of light. These two principles we define as follows:
1. The laws by which the states of physical systems undergo change are not affected, whether these changes of state be referred to the one or the other of two systems of coordinates in uniform translatory motion.
2. Any ray of light moves in the "stationary" system of co-ordinates with the determined velocity c, whether the ray be emitted by a stationary or by a moving body.

If one makes the assumption that the twins are "physical systems," then it seems to me that Dr. Einstein has already answered the riddle by his reflection 1 above.

I have long been under the impression that special relativity describes the appearance of "things" in a remote reference system when view by the medium of electromagnetic radiation (light) from a local reference system. "Things" appear to become interesting when the reference systems are in relative motion.

[johanfprins]

If one makes the assumption that the twins are "physical systems," then it seems to me that Dr. Einstein has already answered the riddle by his reflection 1 above.

Bravo!!

I have long been under the impression that special relativity describes the appearance of "things" in a remote reference system when view by the medium of electromagnetic radiation (light) from a local reference system. "Things" appear to become interesting when the reference systems are in relative motion.

The reference frames need not be "remote": They can move intimately through and relative to each other with a relative speed v. If a twin within one reference frame ages faster or slower than a twin within the other, Einstein's first, and major postulate of relativity is violated.

[tomclarke]

If one makes the assumption that the twins are "physical systems," then it seems to me that Dr. Einstein has already answered the riddle by his reflection 1 above.

Bravo!!

I have long been under the impression that special relativity describes the appearance of "things" in a remote reference system when view by the medium of electromagnetic radiation (light) from a local reference system. "Things" appear to become interesting when the reference systems are in relative motion.

The reference frames need not be "remote": They can move intimately through and relative to each other with a relative speed v. If a twin within one reference frame ages faster or slower than a twin within the other, Einstein's first, and major postulate of relativity is violated.

To compare the times of two clocks they need to be co-located at two different times. If there is relative velocity you then need change in FOR (from acceleration) for the colocation ever to be repeated. This will either be symmetric - in which case no difference - or asymmetric, in which case the FOR change accounts for the time difference.

Think of it as world-lines in Minkowski space. Relativity only applies if they are geodesic: in absence of high gravitational curvature that means they will meet only once. If they meet twice the acceleration will define the relative time difference. Note that this is not as simple as time dilation from acceleration, it is bent world-lines that alter relative time.

Eitehr way, there is no violation of relativity.

[tomclarke]

So how did the muon cross the space? It should have decayed before it got here.

1) Was time going slower?
2) Does the distance it travels shorten?
3) Did it travel faster?
4) Was its decay process altered by the journey?

Imagine you are a muon tomclarke.

many arguments, incl this, are invalid because they assume time has some meaning independent of FOR. It does not, so "time going slower/faster" is meaningless without further qualification.

A clock travelling with the muon would appear to be going slower if observed from earth FOR. Also a clock on earth would appear slower from muon FOR. No contradiction.

So 1), 2), 3) or 4) or none of the above (with explanation if possible)?

None of the above. I just gave explanation. To repeat:
1) meaningless. Slower than what, and how are you measuring time? Give a precise question involving a clock whose position at all times is specified.
2) Also meaningless, but in earth FOR no.
3) no, it is travelling very close to c
4) no. Decay process is normal.

[Teahive]

So in earth FOR the muon clock ticks more slowly and it reaches earth before decaying, whereas in muon FOR clocks on earth would appear to tick slowly and the muon decays before it reaches earth?

What happens if you build a muon trap on earth that rapidly decelerates the muon? In earth FOR, would the muon age rapidly and decay before becoming stationary? In muon FOR, would earth clocks speed up massively, and if so, would it start before the muon decays?

To compare the times of two clocks they need to be co-located at two different times. If there is relative velocity you then need change in FOR (from acceleration) for the colocation ever to be repeated. This will either be symmetric - in which case no difference - or asymmetric, in which case the FOR change accounts for the time difference.

But if the clocks are not just co-located but stationary relative to each other at both comparison events, doesn't the situation have to be symmetric?

So in the case of the twin paradox, if one twin were to launch from earth and land on earth again, as opposed to flying by at close to c, wouldn't both their clocks have to show the same time?

[johanfprins]

To compare the times of two clocks they need to be co-located at two different times.

Any two or more clocks that are stationary within the same inertial reference frame, no matter how far they are spaced from each other, will keep the same time. If this is not the case two separated events within an inertial reference frame can never be simultaneous.

Furthermore, ignoring gravitational effects, and assuming that all clocks within the universe were set to t=0 at the instant of the Big Bang, all clocks within the universe must show exactly the same time within their respective inertial reference frames within which they are stationary. If this is not the case, the age of the universe will be different when measured relative to different inertial refrence frames: Perhaps 7 days!? There can only be one age for the whole universe no matter relative to which inertial reference frame it is measured. If this is not so, Einstein's first relativity postulate must be wrong!

[johanfprins]

So 1), 2), 3) or 4) or none of the above (with explanation if possible)?

None of the above. I just gave explanation. To repeat:
1) meaningless. Slower than what, and how are you measuring time?

It is not meaningless! The time rate measured for a cosmic ray muon to decay is slower when measured by the clock on earth than it is on the clock travelling with the muon.

[johanfprins]

So in earth FOR the muon clock ticks more slowly and it reaches earth before decaying, whereas in muon FOR clocks on earth would appear to tick slowly and the muon decays before it reaches earth?

Correct! But both the clock on earth and the clock with the muon actually tick at the same rate since both clocks are stationary within their respective inertial refrence frames.

What happens if you build a muon trap on earth

It is no use to slow it down after it has reached earth; but if you rapidly slow it down on its way to earth it will according to the clock on earth now decay faster and will thus decay before reaching the earth. Nonetheless, the clock with the muon keeps time at a constant stationary rate.

To compare the times of two clocks they need to be co-located at two different times. If there is relative velocity you then need change in FOR (from acceleration) for the colocation ever to be repeated. This will either be symmetric - in which case no difference - or asymmetric, in which case the FOR change accounts for the time difference.

But if the clocks are not just co-located but stationary relative to each other at both comparison events, doesn't the situation have to be symmetric?

Yes it has to be the case!

So in the case of the twin paradox, if one twin were to launch from earth and land on earth again, as opposed to flying by at close to c, wouldn't both their clocks have to show the same time?

Yes they will.

[D Tibbets]

Concerning light and time stopping in a Bose Einstein condensate (BEC), this author implies that the light does not stop, it is absorbed and it's characteristics are preserved. When the BEC is prodded to release the light ( stored information) it gives the illusion that a specific photon was stoped. No need for stopping time.

http://answers.yahoo.com/question/index ... 618AAjHuXz

Dan Tibbets

[tomclarke]

So 1), 2), 3) or 4) or none of the above (with explanation if possible)?

None of the above. I just gave explanation. To repeat:
1) meaningless. Slower than what, and how are you measuring time?

It is not meaningless! The time rate measured for a cosmic ray muon to decay is slower when measured by the clock on earth than it is on the clock travelling with the muon.

True, but the statement I replied to did not specify how measured, and was therefore meaningless.

[tomclarke]

To compare the times of two clocks they need to be co-located at two different times.

Any two or more clocks that are stationary within the same inertial reference frame, no matter how far they are spaced from each other, will keep the same time. If this is not the case two separated events within an inertial reference frame can never be simultaneous.

True, as long as both clocks are always in the same FOR. But the inconsistency you claim is not for two clocks always in same FOR.

Furthermore, ignoring gravitational effects, and assuming that all clocks within the universe were set to t=0 at the instant of the Big Bang, all clocks within the universe must show exactly the same time within their respective inertial reference frames within which they are stationary. If this is not the case, the age of the universe will be different when measured relative to different inertial refrence frames: Perhaps 7 days!? There can only be one age for the whole universe no matter relative to which inertial reference frame it is measured. If this is not so, Einstein's first relativity postulate must be wrong!

There is no gloabal universe time. You can draw a spacelike surface which joins all clock world-lines with clocks showing identical times. But to say the clocks must show the same time beggars the question of how simultaneity can be defined in different FOR. It cannot.

[D Tibbets]

The Cosmic background radiation (CBR) is a phase change, but it is not a beginning. The information about the early universe is already present in the plasma. And the information in the plasma was in the preceding quark soup. It was present (and greatly magnified) at the end of inflation, and it was present at the instant (instant after?) of creation. This is the whole point of inflation. Quantum uncertainty allowed for the ridiculously tiny variations in the heat of the Big Bang Fireball that did start out as a point (at the Plank length). Before that ( if time and space can even apply) we know nothing and cannot know nothing, er... anything. So if there was a collapse/ boundary layer change it was at this point. Alternately it is the point at which the physics laws were set/ created that allows for subsequent processes and predictions of those processes to proceed. The CBR is the ashes of the fire, not the fire itself. We just cannot see earlier because of the opacity of the plasma (at radio frequencies). Only when the plasma had cooled enough that recombination resulted in neutral atoms is the transparency great enough that we can see it. And, If you accept the balloon surface analogy(perhaps a stretching sheet of cellophane would be less confusing, but it introduces the idea that you can find the center of a flat sheet while you cannot do so on a sphere's surface. A compromise is to imagine a balloon that is so large that we cannot see everything. Only what is above our horizon (observable universe). When the Earth was believed to be flat, some believed that the center was Jerusalem. Once it was recognized (accepted ) that the Earth was a sphere, it is obvious that there cannot be be a center so long as the 2 dimensional perspective is maintained. this deceit is obvious, but useful for describing the universe, at least for laymen.
There may be mathematical models that describe the 3D space of the universe and it's expansion, but this apparently does not lend itself to visual representation, except for the shapes used for describing whether the universe' expansion is closed or open or balanced on the cusp.

Dan Tibbets

[D Tibbets]

I started to write a lengthy rambling message but my circular arguements only increased my confusion, who knows what it would do to others. Instead I will condense it to a few items.

If a frame of reference is centered on a partical, it will have vero velocity- it will be at rest. No mater how the time is manipulated the answer will always be 0 because the numerator is always 0. But this is a classical view. With quantum mechanics velocity can never be 0 because you never can measureit to such absolute acuracy. Plank length and Plank time (? if time is quantitized). In a clasical system, instead use a frame of reference where the velocity of the particle is not zero, but some tiny velocity, like 1 micrometer / second. Now the numerator is not zero. Does this allow for distance compression?

There has been mention of acceleration and gravity as not tightly linked or equivalent to relativistic speeds. Is it accepted that distance compression occurs near black hole event horizons. Certainly the acceptance of tidal forces seems to imply so (spegetti effect). Would Fredrick Pohl's Hechii (sp?) from the Gateway novels be able to camp out near the event horizon of a black hole as the rest of the universe passes by (time dilation from the perspective of the rest of the universe?). If you continuously accelerate on your trip (accelerate to the midpoint then decelerate) will the age paradox not apply? Since you are spending only a small part of the trip at near the maximum relativistic speed, the effect would be less extreme, so a longer trip might be needed for the effect to reach the same magnitude. This could be couched in acceleration terms (just like gravity).

I still do not comprehend how this thread answers the Muon issue, or the real measured time differences (elapsed time) of an airplane carried atomic clock compared to a non flight atomic clock.


Dan Tibbets