Re: Physics for ex-farmers

Thus spake Oz <Oz@xxxxxxxxxxxxxxxxxxxx>
>Charles Francis <charles@xxxxxxxxxxxxxxxx> writes
>>Thus spake Oz <Oz@xxxxxxxxxxxxxxxxxxxx>
>>>Charles Francis <charles@xxxxxxxxxxxxxxxx> writes
>>>>Thus spake Oz <Oz@xxxxxxxxxxxxxxxxxxxx>
>>>
>>>>it doesn't change with distance.
>>>
>>>yes it is because it has changed from the start of the BB and is a
>>>solution to GR.
>>>
>>>>If it were a true
>>>>acceleration it would shift the planets away from their Newtonian
>>>>orbits, and it doesn't.
>>>
>>>Now who is getting confused between co-ordinate systems?
>>
>>Need you ask? You are. Actually getting confused between Pioneer Blue-
>>shift and Cosmological red shift, although as no one understands Pioneer
>>blue shift I'll forgive you.
>
>You said it yourself, the blue shift is fictitious and in effect due to
>cosmic expansion.

The blue shift is measured, hence real. Classically it would correspond
to acceleration, but I say the acceleration is fictitious. It is related
to expansion, but appears only in quantum coordinates.
>
>>The classical analysis of cosmological redshift is as you explain, it is
>>equivalent to a Doppler velocity and gets larger in proportion to
>>distance. It is perfectly meaningful in classical gtr, and does not show
>>up in a bound system like the solar system or the galaxy because no
>>expansion is visible in the solar system. If you had two space craft in
>>deep space (ignoring local gravity) both following geodesics from the
>>big bang then they would be drifting apart and would observe
>>cosmological redshift. According to classical gtr, if the two spacecraft
>>are close the cosmological redshift will be equal to the Doppler shift
>>due the velocity at which they are moving apart, according to the
>>formula Hd.
>>
>>According to me, they are only moving apart at half that rate.
>
>Yes. The doppler redshift is misinterpreted.
>
>>I am sure
>>you feel a twin paradox coming on. It is resolved because strictly we
>>can't define a Minkowski frame containing both spacecraft. If some great
>>cosmic being were to come and place a huge ruler between the space craft
>>so that their actual velocities could be measured, analogous to
>>measurement of Doppler on Earth, my claim is that that would change the
>>measurement such that only half the redshift was observed.
>
>I think that is where you are wrong. You don't have to have a paradox.

Then how do you account for Doppler measurements on earth coming out
right. Cosmological element too small to measure. Yes, you could be
right. More pondering required, I think.
>
>>The pioneer blueshift is quite different. It is a constant acceleration,
>>Hc (or close) toward the "sun" (from I think 20AU to about 120AU or
>>whatever is a bit bigger than the solar system). Other possible
>>directions are toward Earth, along its spin axis, and in its direction
>>of motion. My claim is that it is toward the origin of coords, i.e. to
>>the earth, and they had better come up with that when they do the next
>>mission or I'm stuffed. Also this experimental value for Pioneer has to
>>converge with direct measurements of Hubble.
>>
>>Hd is a velocity. Hc is an acceleration. The two effects are distinct,
>>though linked.
>
>Hang on though.
>In the galactic rotation curve you associated the apparent inwards
>acceleration with a VELOCITY.

The inward acceleration of a body in orbit is given by v^2/r.

>>From what I remember this was related to
>cosmic expansion.

Yes, but in a different way. This is due to acceleration in time, which
appears in quantum coordinates. Uniform motion in quantum coordinates is
non uniform in real coordinates.

>
>>>>If it were present
>>>>in a bound orbit then it would increase with each orbit.
>>>
>>>Well, it might, b
>>
>>No, I was lying again. This redshift is equivalent to an acceleration.
>>In a bound orbit one would expect a very slight constant shift in
>>redshift because the acceleration is perpendicular to the motion. I
>>think the shift corresponds to a shift of 1/4 km or so in the orbit of a
>>planet. I suspect that is rather less than Pound-Rebka measured in an
>>earth based lab.
>
>Hmmm....
>
>>The trouble with thought
>>experiments is that you don't have the results to guide you!
>
>Maybe, but one should at least be consistent.

Absolutely. If you can show there is only one consistent result to the
experiment, then you don't actually need the experimental result to
establish the theory. That is what Einstein did. I can't understand why
more people don't try working the same way.

>IMHO the universe is expanding everywhere and if theory says (or rather
>protagonists argue) it only happens where nobody is or can look then I
>am not convinced.

Nor I. The questions are to do with what is expanding, and what it means
to say it is expanding. Empty space is a sort of non-concept, because
you can never look at it, you can only look at objects on the other side
of it. And if a space is truly empty you can never measure a point in
it, because if you were measuring it wouldn't be empty.

>Just as I am not convinced by putting arbitrary
>amounts of dark matter in a galaxy to obtain the 'correct' rotation
>curve.
>
>I think you are groping your way towards being consistent.
>
That is the purpose of the exercise. I strongly suspect there is
essentially only one possible consistent structure for the universe,
perhaps governed by a few parameters. I don't believe the universe can
be inconsistent with itself, but its obviously bloody difficult for a
human being to be consistent.


Regards

--
Charles Francis
Please reply by name
.

Relevant Pages

  • Re: Physics for ex-farmers
    ... >shift and Cosmological red shift, although as no one understands Pioneer ... >The classical analysis of cosmological redshift is as you explain, ... >measurement such that only half the redshift was observed. ... >>>in a bound orbit then it would increase with each orbit. ...
    (uk.business.agriculture)
  • Re: Physics for ex-farmers
    ... shift and Cosmological red shift, although as no one understands Pioneer ... The classical analysis of cosmological redshift is as you explain, ... measurement such that only half the redshift was observed. ... >>in a bound orbit then it would increase with each orbit. ...
    (uk.business.agriculture)
  • Re: Mathemagickal Dullskuggery
    ... The predicted shift is way above measurement ... MONDian acceleration at 1.8a_0, ... Pioneer shift is a tiny effect seen on a very ... only a classical prediction is made ...
    (uk.business.agriculture)
  • Re: Farmers in orbit
    ... Systems will not result in a MONDian shift. ... Pioneer anomalous acceleration is sunwards. ... Hubble shift represents a recession velocity exactly equal to Doppler ... Distant galaxies have their rotation curves measured. ...
    (uk.business.agriculture)
  • Re: Kalman Filter and INS
    ... Why is acceleration a state? ... If the higher-order inputs and dynamics are unknown then you probably want to treat acceleration as a measurement, ... acceleration with respect to your vehicle frame of motion, ... Or find a good treatment of a mixed continuous/discrete Kalman filter, extend it to a multi-rate filter, and find how you can avoid a lot of computations when you're not getting position fixes. ...
    (comp.dsp)
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