My understanding of the current physical theories that best describe our world is that they seem to be bizarrely focused on the idea that the observer is somehow separate from the system being observed. Clearly this is false, and to me appears to be one of the problems with reconciling Quantum Mechanics with General Relativity. Special Relativity is partially based on knowledge of certain properties of the observer (velocity, mass); QM acknowledges that observation has certain effects on the system being observed. These are both steps in the right direction, so why is seemingly all of our physical research aimed at removing the observer from the picture?
My question is this: should physics research, both theoretical and experimental, be attempting to construct an explanation for reality that is ‘observerless’, or is from an observer’s point of view? Why should this be so?
It shouldn’t be observerless, but it shouldn’t get too hung up on the Copenhagen Interpretation either. Observation doesn’t affect a system so much as interaction with it. And the observer’s point of view isn’t always enough. Take length contraction for example. If you accelerate to a high speed, you see things as length-contracted. But it’s actually because you are “smeared out”. A star doesn’t flatten to a discoid just because you accelerated towards it. Instead you changed, along with your observations and measurements. The pole-and-the-barn paradox is important here. But people do seem to have issues with even the simple stuff. IMHO the issue is that people develop convictions, and find it difficult to shed them.
No problem Ed. Yes, I reject it. But only because Einstein rejected it.
He started with the constant speed of light as a postulate in 1905 when he was doing special relativity, but by 1911 he was getting into general relativity. That’s when he wrote On the Influence of Gravitation on the Propagation of Light, where he said this:
This is the speed of light c varying with gravitational potential. This variable c is counter to his postulate. And it wasn’t some one-off mistake, because in 1912 he said it again when he wrote “On the other hand I am of the view that the principle of the constancy of the velocity of light can be maintained only insofar as one restricts oneself to spatio-temporal regions of constant gravitational potential”. He repeated this in 1913 when he said: “I arrived at the result that the velocity of light is not to be regarded as independent of the gravitational potential. Thus the principle of the constancy of the velocity of light is incompatible with the equivalence hypothesis”. It’s repeated in Die Relativitätstheorie in 1915 where he says “the writer of these lines is of the opinion that the theory of relativity is still in need of generalization, in the sense that the principle of the constancy of the velocity of light is to be abandoned.”
Note that the word “velocity” in the above quotes is a mistranslation of “geschwindigkeit”, which literally means speed. This is reinforced by the way he talked about c, which is a speed rather than a vector-quantity velocity. I can send you some pages for context if you wish.
The bottom line is that Einstein abandoned his postulate, and I’m with Einstein.
I think you have mistakenly assumed that the Postulate of Relativity states that the speed of light is a constant. It really says that the laws of Physics are the same in all reference frames. (Initially it stated that the laws of physics are the same in all inertial reference frames).
Aside from that, it is my personal opinion that you put far too much stock in Einstein.
He has been wrong about too many things to quote him generally. That includes your quoted section where he uses the wrong formula.
Einstein wrote:
Wrong might be a little strong, but it is only valid in constant acceleration fields (fake fields) and it is not valid in naturally occurring fields.
If we constrain our attention to inertial reference frames, which would probably be simpler, your customary conversation would be about the cosmic microwave background radiation as an absolute reference frame.
I think it would be interesting if you expanded on that point.
[i]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.
As measured in any inertial frame of reference, light is always propagated in empty space with a definite velocity c that is independent of the state of motion of the emitting body.[/i]
Nobody’s perfect. The important point is that Einstein said his special-relativity postulate of the constancy of the speed of light didn’t hold where gravity was concerned. He said it repeatedly, as per my post above. He really did say the principle of the constancy of the velocity of light is to be abandoned.
See CMBR dipole anisotropy which mentions the reference frame of the CMB. It’s a de-facto reference frame for the universe, which is as absolute as you can get. If you’re in space but you can’t see any stars or galaxies, you can work out your motion through the universe from the CMBR. If it’s blue-shifted in front of you and redshifted behind you know you’re moving forwards. Of course if you’re inside a box you can’t see the CMBR. Then you can’t judge your motion through the universe because Lorentz invariance (the first postulate) holds.
Wait…I need to back up a second.
Light is considered independent of the state of motion of the locality in which it is traveling through when measured within that locality?
However, Einstein and Farsight do not believe that statement to be true in a gravitational field.
Intuitively, to me anyway, it appears that, when gravity causes light to wander around, the speed of light will change. i.e. Farsight and Einstein are right.
However, this is a complex matter, where “wandering around” is determined by metrics. An argument can be made that distance/time will equal distance’/time’ where distance and time are the original position in a weak or null field, and distance’ and time’ are arbitrary positions in stronger gravitational field.
It dates from about 300,000 years after the big bang, when the universe “cleared”. It is light, red-shifted about a thousandfold due to the expansion of the universe.
I don’t think so. I think it is light.
As far as I know space is isotropic on a large scale, and the laws of physics are the same in all inertial reference frames. If you were moving fast through the universe, you still measure the speed of the CMBR light as c in all directions, but you see a blueshift in the direction of your motion, with a redshift behind. So it gives you a “working” reference frame for the whole universe. But you have to look outside of your box to do this. You typically select your reference frame according to your motion and surroundings. If you’re on earth you ignore the rotation of the Earth and use latitude and longitude. If you’re in the Shuttle you’d probably use the Earth itself as your origin, if you were in a Voyager/Pioneer type spacecraft you’d probably use the Sun. If you were in a starship you’d probably use the Milky Way. If you were flitting between galaxies you’d probably be using the CMBR and hoping that the universe isn’t that much bigger than the observable universe. That’s where the buck stops, that’s as absolute as you can get. But it’s not that different to looking out of the window and saying “I’m falling to Earth”. If you don’t, you can’t tell whether you’re in free fall or floating weightless in free space. You have to look outside your box to gauge your motion. You can’t gauge it from what’s happening inside the box.
I suppose it is in a way. But it would be a little like the force of gravity, which isn’t “really” a force.
I’d say the CMBR is redshifted by the expansion of the universe rather like the way light is redshifted climbing out of a gravitational field. It’s subject to a scale change rather than a force in the Newtonian sense. It’s a different type of scale change, involving spatial expansion, or space “dilation” as opposed to gravitational time dilation, but since we talk of spacetime in relativity, I think there are important parallels.
Have a nice trip.
Edit:
I’d say it’s the other way around Ed. A concentration of matter-energy “conditions” the surrounding space, altering its properties. The result is a gradient in the coordinate speed of light, and this causes gravity.
Count me on their boat then.
The other interpretation breaks countless laws of physics.
Ah, so:
Translates:
Within any given ocean area, a wave is always propagated throughout the ocean with a definite velocity that is independent of the state of the motion of the ship that caused the wave.
Far more sensible translation, thanks.
At first it was causing me to pull a dog’s confused look.
Mind you oceanic surface waves aren’t the best analogy because the velocity varies with wavelength, see this hyperphysics page. But light waves are light waves, not “bullets”. Their speed depends upon the local properties of space, not on the speed of the emitter. Hence c=√(1/ε[size=85]0[/size]μ[size=85]0[/size]), where ε[size=85]0[/size] is the permittivity of free space and μ[size=85]0[/size] is the permeability of free space. The common idea that photons are “bullets” is a misconception, the quantum nature of light is a wave phenomena, as betrayed by E=hf. Planck’s constant applies to waves. IMHO it’s simpler than people think, relating to displacement current. Here, have a look at this picture of the electromagnetic spectrum. See the various frequencies? Regardless of frequency, E=hf always applies. Yes it’s only a picture, but once you look at the dimensionality of action it kind of jumps out at you: what’s common across all frequencies?
Right, amplitude - essentially.
The proportion of energy is constant in ratio to the frequency of the wave.
The scale may change, but not the ratio; I deal with this every day at work.
Yep. And h is action, and action is momentum x distance. If the photon’s E=hf energy is greater so is the p=hf/c momentum. But the distance always stays the same. All electromagnetic waves share the same displacement. Light waves are essentially alternating displacement current, impedance is resistance to alternating current, hence vacuum impedance. This alternating current is more fundamental than the conduction current you get when you wrap it up as an electron or a positron then move the damn thing. Space is like a lossless line, see en.wikipedia.org/wiki/Characteristic_impedance.
I work in technical support, but by consequence, it really helps if you can fully imagine signal propagation in analog and digital formats in your mind.
Because if you can, then you can quickly reduce the possible issues that a customer may be having from n to, say for example, 3.
Simply imagining like this, for example, can shoot me to understanding that if someone tells me channel 3, 14, and 25 (numbers don’t truly matter) are all out but every other channel they like to watch works fine, then I can easily verify that these 3 channels all emit from the same SEM/QAM and therefore ride the same analog frequency, therefore meaning that, say for example, frequency 189MHz is not propagating through their box.
I can then have them flip to a series of channels that all ride a relative MHz 6 dBmV away from 189 (or as close as I can get if the standard 6 dBmV minimal MHz space of frequency is not used for the next set) and see if the frequency is intact there.
If so, then I know that it might be possible to pull the signal back in by refitting the coaxial connection on their box or wall socket because the frequency in question is so isolated and small that a slight depression on the contact could throw it off.
It’s handy.
It’s also handy to know this kind of stuff with the more obscure calls…like the gentleman that called up with distorted picture in both digital artifact and analog scrambling, which resulted in figuring out that the only way this was possible (through asking questions about the imagery and channels effected) was by having a massive introduction of electromagnetic charge near the coaxial line.
When pressed, the gentleman wasn’t sure if he did or did not, but then informed me that he had two actively running DC generators roughly 3 feet from the coaxial line on either side of the on-top-of-the-ground coaxial line parallel to each other.
Sometimes, in my line of work, you have to use a massive amount of imagination to figure out what the hell could be the cause of their issues that you can’t physically see yourself.
Knowing some science of frequency behavior helps.
Interesting stuff, Sky man! Amazing to think that that coaxial cable is carrying waves, and it’s made of electrons and protons etc …and they’re made out of waves too.
More amazing is to tangibly grasp how that batch of electromagnetic frequencies turns into an incredibly articulated image and sound on your screen.
We literally telaport a moving facsimile of real things.
To truly grasp this, you have to understand that we take light and convert that into binary information, which then itself is converted into electromagnetic frequency, which is then retranslated into binary information, which is then reconverted back into light.
Gosh, it all seems to have gone a bit off topic, but never mind: very interesting to read.
Allow me to refine what I mean, then. As far as I can see, observation involves two entities: the observer, and the observed system. The act of observation involves particles/waves being transferred from the system to the observer: essentially, energy moves from the system and interacts with the observer in some way. So, in a more general sense, I think that the laws of physics should be based upon a “viewpoint” that belongs to one system which is “viewing” another; equivalently, the observer can be considered to be a system, and the observation is then merely an interaction between, say, system A and system B.
On the contrary, I think that an observer’s point of view is all that we will ever have. E.g. all of relativity is based upon points of reference, which are observational points of view.
But then how do we “know” what a star looks like when we’re not accelerating towards it? By observation.
Agreed, though, that convictions and doctrines are pretty non-beneficial and even harmful. Science and knowledge are about evolution: our understanding of things will necessarily change as our observations encompass more of the Universe.
I find what you mentioned about the CMBR absolute reference frame to be quite interesting, as it’s not something I’ve thought of before. Very cool! And it doesn’t violate the mathematics of relativity?
What does everybody else think of the observer/observerless physics? I’m starting to believe that it’s impossible for any of our physical theories not to be from an observer’s point of view.
I don’t know, Mermaid. I think it would be better to be able to appreciate what’s going on with this observation. As if we’re a disembodied observer observing the interaction of observation, if you know what I mean.
There’s a way to get past this.
Yes, by observation. But when we’re all moving towards it from different directions and it looks flattened to all of us, we compare notes, and we know that it isn’t flattened in all those directions. We compare observations and extract more by doing so.
Agreed.
Actually I don’t agree with that. Convictions and doctrines prevent people seeing the bleedin’ obvious. I’m serious about this.
Not a bit. Setting gravity aside to keep it simple, the mathematics of special relativity is bang-on correct. But what it doesn’t tell you is that “we are made of light”. Pair production and annihilation are the evidence of this, along with things like electron diffraction. That’s why that mathematics applies. Have a read of The Other Meaning of Special Relativity by Robert Close. The bottom line is this: when you’re made of waves, you can only measure wave velocity in terms of wave velocity. So you always measure it to be the same.
