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Quote from: timey on 05/04/2018 10:08:10Yes " the energy loss equals the gravitational potential difference between the source (KX) and the observer (STV or CAM)", but the blueshifted clocks at the stations are also equal to the gravitational potential difference. But note that the redshift of the light (train) is 'measured' via the clock at the station.as is the redshift of the clock at the lower potential, when seen from the higher potential. It doesn't matter whether you send me a photon, a train, or a carrier pigeon: if you are at a lower gp than me, it will be redshifted on arrival compared with a carrier pigeon born in Cambridge.

Yes " the energy loss equals the gravitational potential difference between the source (KX) and the observer (STV or CAM)", but the blueshifted clocks at the stations are also equal to the gravitational potential difference. But note that the redshift of the light (train) is 'measured' via the clock at the station.

Light is redshifted in comparison with a photon generated by the same process at the receiver. Whether you calculate the redshift by considering kinetic energy loss, or time dilatation as measured by identical clocks, you get the same answer

If this were not so, you could generate free energy.

However it does not escape my notice that time dilation and kinetic energy loss are phenomenon that are both occurring simultaniously. Therefore if you calculate only via kinetic energy loss, or only via time dilation, then 'one' is negating half of the story...leading to a special relativity conversation, but never mind.

Let's change tack...This is interesting:Quote from: alancalverd on 05/04/2018 20:57:24If this were not so, you could generate free energy. Can you describe your understanding of why "if this were not so, you could generate free energy" ?

@Colin2B I don't know why you have to complicate the matter.

Place 10 clocks at 1 metre elevation apart in the gravity potential, and at each elevation the clock there will tick faster than the clock below. ie: blueshifted.So at each position of elevation in the gravity potential the clock at that position is blueshifted, and at each position of elevation in the gravity potential, when the light arrives there, the light is redshifted.

Now tell me that light that is escaping a gravitational well behaves the same as a clock placed at elevation in the gravity potential of a gravity well. I double, triple, dare you. (Chuckle)

However, what I really want to discuss is the fact that the elevated clocks are ticking faster, and that this affects the measurement of the observation of the arriving light.

So at each position of elevation in the gravity potential the clock at that position is blueshifted, and at each position of elevation in the gravity potential, when the light arrives there, the light is redshifted.

Quasars emit x rays and gamma rays. Speculating once a blackhole has lost enough mass/energy due to hawking radiation can it become a quasar or supernovae?

They would only be ‘negating’ if one was working in opposition to the other, which they are not. They are different sides of the same coin.Remember that any measure of energy will involve time in the equation, if time changes so does energy, it all works together.

“10 clocks at 1 metre elevation apart in the gravity potential, and at each elevation the clock there will tick faster than the clock below. ie: blueshifted.” - here you are comparing each stationary clock with the onebelow.“when the light (from light source on ground) arrives there, the light is redshifted” - only when observed by a clock above the photon source.You are using different reference clocks and getting different answers, surprise, surprise.

Remember that any measure of energy will involve time in the equation, if time changes so does energy, it all works together.

Yes I agree. However, if one makes a calculation of it all working together, including changes in energy as per the difference in gravity potential between source and receiver, and also including changes in time as per the difference in gravity potential between source and receiver... Then within the calculation, one has used the fact of the difference in gravity potential between source and receiver twice, when the physicality of the difference only occurs once.

Quote from: Colin2B on 06/04/2018 08:37:15Remember that any measure of energy will involve time in the equation, if time changes so does energy, it all works together. If the difference in gravity potential between source and receiver is being used twice in the calculation, it is little wonder that general relativity gives twice the curvature of Newton.

@evan_au , just read your post, think I've addressed the points you mention in the post above answering Colin.

A light source or a clock elevated in the gravity potential are observed to be "less redshifted (ie: blueshifted)

Quote from: timey on 07/04/2018 00:01:58"So here I have given specifics from the 3rd clocks perspective where:"A light source or a clock elevated in the gravity potential are observed to be "less redshifted (ie: blueshifted)"And:Electromagnetic radiation escaping upwards in the gravity potential is observed by clock 3 to be "more redshifted (ie: redshifted)" than clock 2 below is measuring of the light". No. blueshift is in the opposite direction to redshift. The comparison is always and only with the receiver reference. Forget clocks, think about pianos. If you are on the moon and there are two pianos playing C, one on the ground and one in low earth orbit, you will hear Bb and B respectively, but never C#.This may be the basis of your misunderstanding. Remember every measurement is made relative to the local clock/Mossbauer linesource/piano/whatever.

"So here I have given specifics from the 3rd clocks perspective where:"A light source or a clock elevated in the gravity potential are observed to be "less redshifted (ie: blueshifted)"And:Electromagnetic radiation escaping upwards in the gravity potential is observed by clock 3 to be "more redshifted (ie: redshifted)" than clock 2 below is measuring of the light".

Rubbish.

Alan, Evan and myself have said the same thing, the points don’t need to be ‘addressed’.

Can you provide a worked example of a calculation which uses GP twice?

Think of it this way. The photon never changes. When it starts its journey it is being measured by a time dilated clock. So the frequency appears high. As the photon moves out of the gravity well the clocks are getting faster so that they record lower and lower frequencies. If you don't understand time dilation properly then you can get into all sorts of trouble.

Clock 3 will observe clock 2 as less redshifted (ie:blueshifted) than it observes clock 1 to be, and it observes electromagnetic radiation from light source on ground as more redshifted, (ie: reshifted) than clock 2 will observe that light to be.

I don't know why it is that you guys seem to get so defensive.

The GR equations 'are' using a double dollop of the difference in gravity potential, in that they are accounting for time being faster in the higher gravity potential, via the difference in gravity potential between source and receiver, and they are accounting for the frequency change due to kinetic energy loss for light via the difference in gravity potential between source and receiver.

shift implies that the frequency of a single source has changed, you can’t use it to describe differences in frequency between separate sources.

@alancalverd Huh? If you told me to go 'less left' I'd have to steer to the right a little.Clock 3 observes clock 2 to be less redshifted than it observes clock 1 on the ground to be. Clock 3 can then deduce that clock 2 is blueshifted compared to clock 1.

Calculating via the difference in gravity potential between source and receiver is using a determined physicality, (physicality (a)), to determine the 'magnitude' of a physicality.By using the 'magnitude' of the determined physicality (a), that occurs only once in the observation process, in order to calculate both the 'magnitude' of the faster ticking clocks in the higher potential, (physicality (b)), and the magnitude of the frequency drop due to kinetic energy loss for electromagnetic radiation escaping into the higher potential, (physicality (c)), physicality (a) has been used twice to describe the 'magnitude' of physicality (b) and the 'magnitude' of physicality (c).There is a distinction between the way that physicality (a) is being used twice in the GR equation, once on the left, and once on the right.In the left side of the GR equation clocks in the higher potential are used as ticking faster via the difference between source and receiver and this extends the hypotenuse for the GR geometry.In the right side of the equation electromagnetic radiation is calculated as losing frequency in the higher potential due to kinetic energy loss via the difference in gravity potential between source and receiver. And is done so on the basis that each observer in his reference frame observes his clock to be ticking 'normally'. (ie: no energy change for the clock)

But that is exactly what Jeff, and Evan suggested doing when they said that the shifted clock is measuring the shifted photon. (remembering that electromagnetic radiation itself is a separate phenomenon from a source of electromagnetic radiation)

Anyway, I've got my paper to be getting on with now, so I don't have time for this thread anymore really.