The Dark Matter hunt continues

[xelasnave]

I think this clears it up

The combination of these two relativitic effects means that the clocks on-board each satellite should tick faster than identical clocks on the ground by about 38 microseconds per day (45-7=38)!

alex

[Zuts]

Originally Posted by xelasnave

I think this clears it up

The combination of these two relativitic effects means that the clocks on-board each satellite should tick faster than identical clocks on the ground by about 38 microseconds per day (45-7=38)!

alex

A microsecond is an eternity (just ask my 3 gigahertz cpu) and easily measured which is why Bojan says the proof is on your gps...

Paul

[xelasnave]

Originally Posted by Zuts

A microsecond is an eternity (just ask my 3 gigahertz cpu) and easily measured which is why Bojan says the proof is on your gps...

Paul

I was not trying to be cute...

what I was saying was.. I think I am seeing how they arrive at the math overview of the situation..that there are two theories to be considered, one adds a bit and one takes away..please believe me when I say that I believe differences in time no matter how insignificant from a human experience view of the Universe are absolutely important..

and given my recognition that I am probably hard to understand at times due to verbosity I am trying to state the position in my way hoping that if I am getting it wrong someone will be good enough to point out what I am missing...which happens from time to time when some kind person like Bojan overlooks their frustration with my ignorance and helps me out showing me something that I need to know… and so I upgrade my ideas to fit a new understanding of a concept.

I lay awake for about three hours last night thinking this through... and it is not the first time... firstly I am never really sure what any theory really says sometimes and what it does not say.. folk express things differently and each expression of the same Idea can sound different... and at the end of every thought a little voice at the back asks me …” yes but what does that really mean...”

So is there a Doctor in the house... a condition where there is no delusion about the prospect of any reality being a delusion…it is not easy not to believe in anything and question everything.

The time dilation thing I think that is probably where I get the difficulty in understanding is the "twin paradox" ..

there is something there that seems "wrong" and I can not put my finger on it ..and until I settle whatever it is confusing me I will go around and around until I accept the idea or can overthrow it... not for any reason other than for my own understanding...

and ask that I not be grouped with all the crackpots out on the net... Once I though I was like them but they are usually just trying something to get recognition... I may have been similar once in appearance and direction but I finally realize that all I want is to understand personally and that is for me not others...so there will never be a book as they say…

I have an obsession with all this stuff..gravity mainly.. and it shows I know that.. but I find physics and particularly General relativity and Special relativity not easy to understand...its like that 3 shell game with the ball under one of the shells. every time I think I have it really worked out. and look under the shell the ball is under another... I don’t care so much where the ball is but I sure want to know how the guy moving the shell can make that ball appear under any shell he likes .......

alex

[xelasnave]

look at this... someone has become obsessed and written a book I dont know that it has got him or science any further ahead..

http://home.alphalink.com.au/~jdx/muller.htm

anyways still reading other stuff about it and probably more confussed..but this was a little off track and humerous given my earlier coments about crack pot approaches ...
alex

[xelasnave]

Is this a fair coment??? from the above site.....

In search for a causal reason of Time Dilation the author is wasting his time. Regardless of what our century believes, Einstein never gave a causal explanation of anything. The plea for a "why" concerning Time Dilation is, therefore, a futile one.
An authoritative relativist like Nobel laureate Max Born clearly expressed this when he wrote: the (length) contraction, (and time dilation), are "only a way of our way of regarding things and is not a change of a physical reality. Hence (they) do not come within the scope of the concepts of cause and effect". They are "circumstantial companions of motion", (1). No wonder John Doan could never find a rational explanation. There is none! Relativity Theory must be "swallowed" as an entire package.


alex

[xelasnave]

Is this a reasonable statement?

Thus, relativity theory, as established by Einstein can never be experimentally proven. Einstein himself admitted this. But a single experiment against it would totally disprove it. Based on this Popper created his entire philosophy of scientific falsification: theories can only be disproven, not proven

alex

[Zuts]

Hi Alex

I think time dilation is a proven fact, there are countless illustrations. Another example is the decay rate of cosmic rays (mesons). In the labratory they decay at a certain rate, however when they measure the number of particles above the earths atmosphere with those actually arriving at a detector on the surface there is a discrepancy. The 'extra' particles arriving can be accounted for by time dilation. That is in the frame of reference of the particle it is 'living' slower and has not had time to decay.

Max Born died at 88 in 1970. Well before all these 'proofs' became readily apparent. I think had he been alive today he would tell a different story.

The whole point of my mention of time dilation is simply to point out that things which appear far fetched can be absolutely true. Also, unfortunately as our knowledge of things increases and regarding many things in science, quantum mechanics, black holes etc our 'common law' understanding of what the average man thinks is reasonable no longer holds water.

What possible experience can a man have of the interactions of electrons for example, or things acting on plank scale. When dealing with the realities of these types of things our common sense cannot possibly guide us. What was possible to the Greeks regards their simple armchair philosophy of understanding everything through thought experiments alone, these days is sadly impossible.

Whether Einstein is right or wrong is moot. The fact is that time dilation is readily apparent and observable, it wont go away if Eintein is proved wrong. People in the 19th century thought the Sun gave out heat because it was a gigantic lump of Coal. Of course they were incorrect; but not about the Sun giving out heat.

Please feel free to come up with some other explanation for time dilation, however since it is completely outside the realm of everyday human sensation i dont see how you could find one that average humans would say 'oh thats obvious i see that everyday, why didnt i think of that'. Unfortunately to understand certain things these days you need a grounding in maths and physics. Once you have this grounding, exceptional individuals amongst us move on from there and conceive of things like 'dark matter'.

Paul

[xelasnave]

Dam I lost one of those long replies Paul.
I thank you for a well thought out reply.
I cant come up with a specific as to the twin thing I tried once in this forum actually but no one bought it..
Dark matter maybe there no doubt we cant "see" air yet it is there so the fact we cant see it does not by logic exclude it... however could there be alternatives to it ... the search has not been encouraging and ceratinly Hubble has some shots showing why they think it is there...

If there is a real force behind the notion of a cosmological constant maybe that produces an effect we can not yet understand... anyway a situation that we have an alternative to dark matter..

I have been reading as much as I could to day still none the wiser but a nice way to past the day nevertheless
alex

[xelasnave]

Here we go heaps of the stuff ..still cant see it however
http://www.sciencedaily.com/releases...0221121109.htm
alex

[Karls48 (Karl)]

Few people stated previously that time dilation is a proven fact. It certainly is not. What is proven is that physical forces can slow or speed up clocks (and physical processes). It was known long before Einstein that rises in the temperature will lengthen pendulum and therefore slow the clock. Is it time dilation? And how does it differ from the clock on board of spaceship travelling at high speed. If I stand close to the pendulum clock that I heated up, is the time for me flowing slower? I don’t think so. That does not prove that the time itself actually slows down. No one knows what time is and if it actually exists. It may be just our invention to describe sequences of events happening.
As for GPS being practical example of GR, not really as it is using the Earth-centred inertial frame (universal frame) of reference to synchronise clock on the satellites. This is more in agreement with Lorentz relativity then GR

[bojan]

Originally Posted by Karls48

Few people stated previously that time dilation is a proven fact. It certainly is not. What is proven is that physical forces can slow or speed up clocks (and physical processes). It was known long before Einstein that rises in the temperature will lengthen pendulum and therefore slow the clock. Is it time dilation? And how does it differ from the clock on board of spaceship travelling at high speed. If I stand close to the pendulum clock that I heated up, is the time for me flowing slower? I don’t think so. That does not prove that the time itself actually slows down. No one knows what time is and if it actually exists. It may be just our invention to describe sequences of events happening.
As for GPS being practical example of GR, not really as it is using the Earth-centred inertial frame (universal frame) of reference to synchronise clock on the satellites. This is more in agreement with Lorentz relativity then GR

Karl,
we were not talking about temperature or whatever dependency of time base. This is an effect easily accounted for within classical physics.
We should not confuse those two totally different effects.

Here we are talking about time dilatation, the relativistic effects.
BTW, Lorenz or GR, this is the same thing, the same formulas apply, if I remember correctly my grammar school classes (maybe I do not? )

[Karls48 (Karl)]

Quote: In SR, the Lorentz transformations apply to time, space, and mass. By contrast, in LR, they apply only to clocks, meter sticks, and momentum. This is a subtle but important distinction. For example, increasing the temperature slows a pendulum clock and increases its length, yet this does not mean that something happens to time or space. Only the attempted measures of time and space using the pendulum clock, but not time and space themselves, are affected by temperature. In a similar way, in Lorentzian relativity, only the attempted measures of the dimensions time, space, and mass are affected by speed, but not the dimensions themselves. (In general relativity we find that measures of time by clocks are also affected by gravitational potential.) So in LR, equation set relates clocks and meter sticks in the preferred frame (X,Y,Z;T) to those in any relatively moving inertial frame (x,y,z;t). Time and space themselves are simply dimensions (concepts), and cannot be changed by motion, by potential, or by any material entity.
Because time is never affected, LR recognizes a “universal time” applicable to all frames, and a universal instant of “now”. In SR, all inertial frames are equivalent, so the Lorentz transformations apply reciprocally (both ways between two frames); whereas in LR, the local gravitational potential field constitutes a preferred frame, and the Lorentz transformations work just one way from the preferred frame to any inertial frame with a relative motion, but not reciprocally.


To me this theory of relativity is more logical then SR. As far I can find out it has been experimentally proved as much as GR has been. The GPS network uses preferred frame to synchronise satellites clocks, so there is some practical example of its validity.

[bojan]

As I said, both use the same mathematical expressions to calculate the effects.
BTW, this is where Einstein started from, and build his GR which is complete theory, which LR is not.
Temperature has absolutely nothing to do with this.

[Zuts]

Originally Posted by Karls48

[FONT=Times New Roman][SIZE=3]Quote: In SR, the Lorentz transformations apply to time, space, and mass. By contrast, in LR, they apply only to clocks, meter sticks, and momentum. This is a subtle but important distinction. For example, increasing the temperature slows a pendulum clock and increases its length, yet this does not mean that something happens to time or space......

So LR applies only to clocks and not time? Well the human body can be considered to be a clock as can many other things. Thats the point, frames in relative motion as viewed from each other appear to be living at different rates by their clocks. Of course in there own frame of reference this affect is not visible.

The pendulum is a bad example, as with respect to other objects it is different from say an unheated pendulum next to it. In an intertial frame the clock is accurate in all parts of the frame however when viewed from other inertial frames it is different.

My heart beats at 70 beats a minute so i choose that as my clock. If I measure the heartrate of someone who normally has my heartrate right next to me and it is the same then if they move (somehow) to another inertial frame and now the heartrate is different then to me that is time dilation.

There are no forces involved here to account for the difference (unless you wish to invent one) simply bodies in relative motion.

Paul

[bojan]

Originally Posted by Zuts

Paul

This is well said..
BTW, Lorentz just tried with his transformations to explain the Michaelson-Morley's experiment result (the measured speed of light turned to be equal in all directions), while still retaining the "ether".
That is why the math is the same.... but the philosophy behind it was definitely not.

[bojan]

Originally Posted by Karls48

.....
It certainly is not.

More on this..
It certainly is the case.
As it was mentioned before, the relativistic mesons that are reaching the surface of the Earth, they would not be here if not for time dilatation, which (from our point of view) prolongs their half-life and enables them to penetrate deeper int our atmosphere before they decay.
Also, time dilatation it is the routine for people working with particle accelerators, in the same sense as is the mesons presence.