[chiralSPO]

Space is curved by massive objects. Light goes "straight" within that space. This is very different from the force of gravity on other massive objects.

[mxplxxx (OP)]

Space is curved by massive objects. Light goes "straight" within that space. This is very different from the force of gravity on other massive objects.

So massive objects attract each other as well as "falling" towards each other via space curvature. A double whammy?

[mxplxxx (OP)]

 

my emphasis. Note "has" , not "is". I have £10 in my pocket, I am not made of money!

But the $10 note IS made of money.

[yor_on]

MP "  I would say that nothing that moves at the speed of light can be measured. "
Not really, you  measure photons daily by your senses. Seeing is one.

Not single photons it would seem http://math.ucr.edu/home/baez/physics/Quantum/see_a_photon.html.

No, Baez is interpreting the statistics, but the experiment did prove that a human eye can see a 'photon', and if you think of a highly energetic 'photon' (gamma) it should even leave a mark.

[yor_on]

:)

Yes, wordings can be tricky. Still, energy densities seems a accepted term for it, if we now use language. At least it puts it as the energy of 'something' becomes a 'density', which can be interpreted as something defined through a limit, measurably containing a 'mass' of sorts, be it relativistic or not. Although I have such a grave problem seeing what should be defined as 'containing' that relativistic mass, as it isn't locally definable.
=

It would have been so much simpler if we by measuring a light in a 'black box scenario' could prove for example a 'relative speed'. Then we all could sit back and smile, as the universe started to make sense :)

[yor_on]

Depends on definitions. A geodesic isn't a 'force', in Einsteins terms it is more of the 'straightest path' something can take. Any deviation from said geodesic needs a acceleration, which then should cost 'energy'. But throw one kg in the air, and stand under it as it comes down, that you will define as a 'force' acting upon you, as you and Earth acts upon it.

But then you also have to remember that in Einsteins terms, Earth is constantly and uniformly 'accelerating' at one gravity approximately. So, standing on a accelerating object 'hitting' that kg? That gotta hurt.
=

Thinking of it we have three terms at least for what a motion is. Acceleration is the easiest one to define as it acts locally measured.

Then we have 'relative (uniform) motions'. There you have two types, one becomes a 'real motion' as defined relative something else, but on another tentacle it also can be defined as 'locally' still. This should be read that if you only have two objects on a collision course in a space, then you're free to define your and his 'relative motion' any way you like, him moving or you, or both. There exist no locally definable proof of you moving. Neither does it exist for the other object but as you see, you're still on a collision course.

And when you hit the energy released from that collision will be more than if both had been 'still'. That's also called a 'potential energy' of something happening. You can have a untold magnitude 'potential energies' simultaneously just by introducing more objects coming at you in that space, it all depends on your frame of reference.

although, if we introduce distance over time, you will be able to define who's going to hit first, and by that introduce only one 'outside' frame of reference existing creating your 'potential energy'.

Doing so you're still bound through observer dependencies though as with a higher 'relative speed' the universe around you must change both 'clock rates' as well as contract.

But if we now go back to the first postulate in where you locally has no way to define a relative motion at all, except relative another frame of reference? What then is your 'relative speed'? Relative what? A suns blueshift?
=

Actually, presuming you to be alone with just another object in a space, hurling against each other relatively, close to the speed of light. You're still unable to define who's 'moving'. So, you're free to define yourself in any way you like, from you speeding away to not 'moving' at all.

So, what happened to those 'clock rates'?
solve that one :)

==

If we look at it another way we can use NIST experiments with 'gravity' and elevations. There we find 'clock rates' to change relative ones wristwatch, by changing the elevation of those atomic clocks they use. That is a result of different 'accelerations' in Einsteinian terms, as 'gravity' then is a equivalence to a acceleration.

Against it we have that different relative motions (uniform motions) can be proven to exist, and will introduce time dilation's as well as LorentzFitzgerald contractions.

Now imagine the atomic clock resting on a shelf, showing you a time dilation relative your wristwatch. Then let the atomic clock fall of that shelf. As it does it's no longer in a 'acceleration', it's in a 'free fall', aka a 'geodesic', aka 'being still, aka being in a 'relative (uniform) motion, even though you find it to gravitationally accelerate. But that 'acceleration' you give the atomic clock is in Einsteins terms a result of Earth constantly uniformly accelerating at one gravity. So one could look at it as the clock passing different 'gravitaional potentials' in its 'free fall'.

Still, the clock is now in a 'relative motion' versus Earth, aka being 'still' in a geodesic. What happens to its 'clock rate'? Do you think it will change? Will it matter for the 'clock rate' measured in that geodesic how many 'gravities' it formerly accelerated at, resting on the shelf? Give that clock a really long 'free fall' and imagine that you have a way to see its dials.

No matter what 'accelerating gravity' it had, do you think the dials will present different readings in that geodesic (free fall) towards a floor?

Is gravity transformed away?
===

a third way is to use 'black box scenarios'. Doing so we encase the the atomic clock, you inside, placing ourselves at rest with it following its 'free fall'. Did your wrist watch ever change its 'clock rate' relative that atomic clock in our 'free fall' towards the floor?

Furthermore, did you notice it change on the shelf?
In what way did you then transform gravity away?
===

the one with defining yourself as being still will hold no matter how many objects you introduce, as well as defining some other frame of reference to be the one not moving.

[mxplxxx (OP)]

There exist no locally definable proof of you moving.

Except the fact that is blindingly obvious that you ARE moving:)

[yor_on]

Well MP, that's what I would call a 'global approach' to the puzzle. You do that one by introducing two objects and yourself in a space, at different speeds. Doing so you find that even though any motion is 'relative' different speeds do exist. Locally though there exist no proof of a difference between different relative speeds. That one you prove by using Einsteins famous 'black box' in where there is no way to differ between them, including testing by making 'repeatable experiments'.

[mxplxxx (OP)]

Locally though there exist no proof of a difference between different relative speeds. That one you prove by using Einsteins famous 'black box' in where there is no way to differ between them, including testing by making 'repeatable experiments'.

But the world is not a black box?

[yor_on]

No, not frames of reference interacting. But most of what you do and see is 'observer dependent', probably all. An observer dependency is always local, with the 'universe' being the place where you act, and get acted on, observer dependently.

[Bored chemist]

Except the fact that is blindingly obvious that you ARE moving:)

Not, for example, to an ant walking around through the hair on your head.

[mxplxxx (OP)]

Not, for example, to an ant walking around through the hair on your head.

The ant is aware it is moving (if ants can be aware and can process movement!)

[Bored chemist]

No, the ant thinks it's sitting still on your head. It may think that other things which it can see are moving. For example, it might see a bird fly past and think the bird is moving. But it's sure that you are stationary.
It's the same issue as the geocentric/ heliocentric view of the universe.

[syhprum]

It is indeed possible to measure the frequency of a photon with a ruler ,photons come in all shapes and sizes they are not all in the nanometre range.
In the early days of amateur radio one of the techniques for measuring the frequency was to measure the distance between null and peak voltages on an unterminated air spaced transmission line.   

[mxplxxx (OP)]

It is indeed possible to measure the frequency of a photon with a ruler ,photons come in all shapes and sizes they are not all in the nanometre range.
In the early days of amateur radio one of the techniques for measuring the frequency was to measure the distance between null and peak voltages on an unterminated air spaced transmission line.   

It is energy I am interested in measuring. I do not want to calculate energy, I want to measure it.

[Bored chemist]

I want to measure it.

Then I strongly urge you to look again at this post.

Somewhere ikn the last 50 years, I forgot about the GeLi gamma spectrometers we used to use to calibrate x-ray sources. Wikipedia has a good explanatory article that I won't repeat here, but the key is that you can use a gamma emitter with a narrow spectrum to locate a single point on the resultant spectrum and thus measure the energy of any photon against your calibration point.

Getting down to single photon detection with GeLi is a bit of an art form but since we know photons are indistinguishable, if we find a narrow line on a spectrum we can say that it does at least represent the average energy of a few photons.

It's interesting that the questioner persists in telling us that something can't be done, in the face of the experience of those who have done it for a living.  Unshakeable faith in one's prejudice can be dangerous, but as a forlorn gesture of friendship I'll advise people not to play with fire or walk in front of moving buses.

[alancalverd]

It is not only well understood (though often poorly explained) but completely demonstrated by experiment. Problem is that gravitational lensing is not dependent on photon energy.

[esquire]

each photon carries with it seperate waves of intensity from gamma to am. each of these seperate waves are subject to reflective elongation which in turn determines the strentgh of the intensity present in its 9 separate spectum waves of energy, momemtum, non-mass. also, the fact that its waves can be absorbed via different elements, presents another conundrum of being able to accurately measure the energy weight of a photon. so, there is an elongation issue that alters the wave's value. there is an absorbtion factor that alters it's value strength. there is also the speed of light momentum issue. that via the uncertainity principle can only provides an approviamation of single variable, which renders any determination scientifically invalid.

[esquire]

this image is of an attempt to weight a proton and difficulties this presents. the proton waves actually breaks apart into multiple waves in liquid hydrogen or helium. the attempt was to weight the bubble mass as the proton wave  cycled through the cylinder. the experiment fails because the proton wave, breaks into multiple wave of varying sized bubbles, never of the same size.  scientist remain stumped for an explanation. 

https:  //www.gettyimages.com/detail/news-photo/photograph-of-a-bev-proton-from-the-cosmotron-colliding-news-photo/929284356

[Bored chemist]

this image is of an attempt to weight a proton

No it isn't.

scientist remain stumped for an explanation.

No, they are not.

each photon carries with it seperate waves of intensity from gamma to am. each of these seperate waves are subject to reflective elongation which in turn determines the strentgh of the intensity present in its 9 separate spectum waves of energy, momemtum, non-mass. also, the fact that its waves can be absorbed via different elements, presents another conundrum of being able to accurately measure the energy weight of a photon. so, there is an elongation issue that alters the wave's value. there is an absorbtion factor that alters it's value strength. there is also the speed of light momentum issue. that via the uncertainity principle can only provides an approviamation of single variable, which renders any determination scientifically invalid.

Was that a quote from the script for Star Trek?