Light from stars really from billions of years ago?

[excreationist]

0:45 ....In 1978, a physicist by the name of John Archibald Wheeler proposed a thought experiment, called
delayed choice. Wheeler’s idea was to imagine light from a distant quasar which is billions
of light years from earth, being gravitationally lensed by a closer galaxy. As a result, light
from a single quasar would appear as coming from two slightly different locations, because
of the lensing effect of gravity from a galaxy between earth and the quasar.

Wheeler then noted that this light could be observed on earth in two different ways. The
first would be to have a detector aimed at each lensed image. Since the precise source
of this light was known, it would be measured as particles of light when viewed. But if
a light interferometer was placed at the junction of the two light sources, the combined light
from these two images would be measured as a wave because it’s precise source would
not be known. That’s the way quantum mechanics should work.

This is called a delayed choice because the observer’s choice of selecting how to measure
the particle is being done billions of years from the time that the particle left the quasar.
So presumably the light would have to be committed to either being a particle or wave, billions
of years before the measurement is actually made here on earth.

This quasar experiment isn’t practical, but modern equipment allows us to perform
a similar experiment in the lab, where the decision to measure a particle or wave is
done at random after the quantum system is “committed.” And indeed his thought experiment
is confirmed – that even if measured at random, when the path information is known,
the light is a particle. When path information is erased by using an interferometer, the
light is a wave. But how could this be?...the light began its
journey billions of years ago, long before we decided on which experiment to perform.
It would seem as if the quasar light “knew” whether it would be seen as a particle or
wave billions of years before the experiment was even devised on earth.
Does this prove that somehow the particle’s measurement of its current state has influenced
its state in the past?.....
​

I suspect I am in a simulation. I don't believe this simulation explicitly simulated billions of years of history before our modern history.

The simulation would know how the star was being viewed. It would generate an output of the star based on that. It is easy for the output of the star to be generated when it is viewed today. An alternative is that a message from the present is sent back billions of years.... ???

 

[DBT]

There are several interpretations. Objective collapse is one;

''There are possible explanations – theorist Roger Penrose at the University of Oxford has suggested that gravity drives the process, for instance – but no consensus. The tweaked Schrödinger equation was also not relativistic; it did not work for particles moving at close to the speed of light, a basic requirement of any modern theory.''

''That began to change around five years ago, when theorists including Daniel Bedingham of the University of Oxford and Roderich Tumulka of Rutgers University in New Jersey formulated the first relativistic objective collapse models. Still the idea had few takers. For Tumulka, that’s because persuading physicists to go for any option besides the Copenhagen interpretation is like Copernicus trying to persuade people in the 16th century to give up Ptolemy’s Earth-centric view of the universe. “The difference is that Ptolemy’s theory made perfect sense. It just happened not to be right,” he says. “But Copenhagen quantum mechanics is incoherent, and thus is not even a reasonable theory to begin with.”

Work that Sudarsky and his collaborators have been doing recently might begin to turn the tide. It shows that objective collapse might explain not only how structure began to appear in the universe, but a host of other cosmological problems, too.''

''Spontaneous wave function collapse makes stuff, too. When a wave function disappears, something new appears in its place – a definite position, a piece of information, a tick of energy. Each collapse can only generate a minuscule amount of energy, so we wouldn’t notice it on any everyday scale. But in the universe as a whole, this energy creation could be rather significant – and perhaps solve the biggest cosmological conundrum of all.''

 

[bilby]

Photons travel at c, and therefore experience no time, and no distance.

An observer with zero rest mass would see no distance between origin and destination, and experience no time for the journey, regardless of the distance and time observed by another observer, such as a human being, with a finite rest mass, and therefore a velocity of less than c. To the second observer, the first is a massless particle moving at c.

It may take billions of your years for a photon to travel from a distant quasar to your observatory on Earth. But it takes zero seconds in the photon's reference frame, and the quasar and your observatory are in the same location.

There's no time or distance when you're a photon. So 'delay' is meaningless.

 

[excreationist]

There are several interpretations. Objective collapse is one;

''There are possible explanations – theorist Roger Penrose at the University of Oxford has suggested that gravity drives the process, for instance – but no consensus. The tweaked Schrödinger equation was also not relativistic; it did not work for particles moving at close to the speed of light, a basic requirement of any modern theory.''

''That began to change around five years ago, when theorists including Daniel Bedingham of the University of Oxford and Roderich Tumulka of Rutgers University in New Jersey formulated the first relativistic objective collapse models. Still the idea had few takers. For Tumulka, that’s because persuading physicists to go for any option besides the Copenhagen interpretation is like Copernicus trying to persuade people in the 16th century to give up Ptolemy’s Earth-centric view of the universe. “The difference is that Ptolemy’s theory made perfect sense. It just happened not to be right,” he says. “But Copenhagen quantum mechanics is incoherent, and thus is not even a reasonable theory to begin with.”

Work that Sudarsky and his collaborators have been doing recently might begin to turn the tide. It shows that objective collapse might explain not only how structure began to appear in the universe, but a host of other cosmological problems, too.''

''Spontaneous wave function collapse makes stuff, too. When a wave function disappears, something new appears in its place – a definite position, a piece of information, a tick of energy. Each collapse can only generate a minuscule amount of energy, so we wouldn’t notice it on any everyday scale. But in the universe as a whole, this energy creation could be rather significant – and perhaps solve the biggest cosmological conundrum of all.''

This is the "delayed choice" experiment. What you wrote doesn't seem relevant....

 

[excreationist]

Photons travel at c, and therefore experience no time, and no distance.

An observer with zero rest mass would see no distance between origin and destination, and experience no time for the journey, regardless of the distance and time observed by another observer, such as a human being, with a finite rest mass, and therefore a velocity of less than c. To the second observer, the first is a massless particle moving at c.

It may take billions of your years for a photon to travel from a distant quasar to your observatory on Earth. But it takes zero seconds in the photon's reference frame, and the quasar and your observatory are in the same location.

There's no time or distance when you're a photon. So 'delay' is meaningless.

This is about "delayed choice" -

https://en.wikipedia.org/wiki/Wheeler's_delayed-choice_experiment

It is about how information about the observation seems to travel back in time... (though not in my simulation thought experiment)

A related thing is the delayed-choice quantum eraser:
https://en.wikipedia.org/wiki/Delayed-choice_quantum_eraser

Though:

While delayed-choice experiments have confirmed the seeming ability of measurements made on photons in the present to alter events occurring in the past, this requires a non-standard view of quantum mechanics. If a photon in flight is interpreted as being in a so-called "superposition of states", i.e. if it is interpreted as something that has the potentiality to manifest as a particle or wave, but during its time in flight is neither, then there is no time paradox. This is the standard view, and recent experiments have supported it.


​

https://en.wikipedia.org/wiki/Retrocausality

Retrocausality is sometimes associated with the nonlocal correlations that generically arise from quantum entanglement, including for example the delayed choice quantum eraser. However accounts of quantum entanglement can be given which do not involve retrocausality


​

That's a pity because I thought I had come up with good evidence for a simulation - though it also says:

In quantum physics, the distinction between cause and effect is not made at the most fundamental level and so time-symmetric systems can be viewed as causal or retrocausal
​

 

[bilby]

Photons travel at c, and therefore experience no time, and no distance.

An observer with zero rest mass would see no distance between origin and destination, and experience no time for the journey, regardless of the distance and time observed by another observer, such as a human being, with a finite rest mass, and therefore a velocity of less than c. To the second observer, the first is a massless particle moving at c.

It may take billions of your years for a photon to travel from a distant quasar to your observatory on Earth. But it takes zero seconds in the photon's reference frame, and the quasar and your observatory are in the same location.

There's no time or distance when you're a photon. So 'delay' is meaningless.

This is about "delayed choice" -

https://en.wikipedia.org/wiki/Wheeler's_delayed-choice_experiment

It is about how information about the observation seems to travel back in time... (though not in my simulation thought experiment)

There is no absolute time.

One observer's past is another observer's future.

Photons don't experience time, so there's no such thing as a delay, or a delayed choice, for a photon. Everything that happens to a photon happens at the same time, in the photon's frame of reference.

 

[excreationist]

There is no absolute time.

One observer's past is another observer's future.

Photons don't experience time, so there's no such thing as a delay, or a delayed choice, for a photon. Everything that happens to a photon happens at the same time, in the photon's frame of reference.

So are you saying that it isn't meaningful to say the earth seems to be 4.5 billion years old or that the universe seems to be about 13 billion years old?

 

[skepticalbip]

There is no absolute time.

One observer's past is another observer's future.

Photons don't experience time, so there's no such thing as a delay, or a delayed choice, for a photon. Everything that happens to a photon happens at the same time, in the photon's frame of reference.

So are you saying that it isn't meaningful to say the earth seems to be 4.5 billion years old or that the universe seems to be about 13 billion years old?

It is meaningful to us humans because we share an inertial reference frame but would be meaningless to a photon. Also some critter traveling at close to c with respect to us would see the Earth and universe as having a different age than we do.

 

[excreationist]

So are you saying that it isn't meaningful to say the earth seems to be 4.5 billion years old or that the universe seems to be about 13 billion years old?

It is meaningful to us humans because we share an inertial reference frame but would be meaningless to a photon. Also some critter traveling at close to c with respect to us would see the Earth and universe as having a different age than we do.

Well I'm talking about experiments done by humans not conscious photons...

 

[DBT]

There are several interpretations. Objective collapse is one;

''There are possible explanations – theorist Roger Penrose at the University of Oxford has suggested that gravity drives the process, for instance – but no consensus. The tweaked Schrödinger equation was also not relativistic; it did not work for particles moving at close to the speed of light, a basic requirement of any modern theory.''

''That began to change around five years ago, when theorists including Daniel Bedingham of the University of Oxford and Roderich Tumulka of Rutgers University in New Jersey formulated the first relativistic objective collapse models. Still the idea had few takers. For Tumulka, that’s because persuading physicists to go for any option besides the Copenhagen interpretation is like Copernicus trying to persuade people in the 16th century to give up Ptolemy’s Earth-centric view of the universe. “The difference is that Ptolemy’s theory made perfect sense. It just happened not to be right,” he says. “But Copenhagen quantum mechanics is incoherent, and thus is not even a reasonable theory to begin with.”

Work that Sudarsky and his collaborators have been doing recently might begin to turn the tide. It shows that objective collapse might explain not only how structure began to appear in the universe, but a host of other cosmological problems, too.''

''Spontaneous wave function collapse makes stuff, too. When a wave function disappears, something new appears in its place – a definite position, a piece of information, a tick of energy. Each collapse can only generate a minuscule amount of energy, so we wouldn’t notice it on any everyday scale. But in the universe as a whole, this energy creation could be rather significant – and perhaps solve the biggest cosmological conundrum of all.''

This is the "delayed choice" experiment. What you wrote doesn't seem relevant....

It is relevant to QM, ie, objective p wave collapse as a way that matter/energy may possibly work.

 

[Wiploc]

Photons travel at c, and therefore experience no time, and no distance.

People keep saying that, but I don't understand why.

 

[skepticalbip]

Photons travel at c, and therefore experience no time, and no distance.

People keep saying that, but I don't understand why.

Maybe they say it because understand relativity and time dilation. t = t₀/(1-v²/c²)^1/2.

Then again, if they don't understand relativistic time dilation, maybe they are just repeating what they heard someone who does understand it has said.

 

[excreationist]

Photons travel at c, and therefore experience no time, and no distance.

People keep saying that, but I don't understand why.

Maybe they say it because understand relativity and time dilation. t = t₀/(1-v²/c²)^1/2.

Then again, if they don't understand relativistic time dilation, maybe they are just repeating what they heard someone who does understand it has said.

What if the photon was in water (0.75c or 225,000 km/s)? Would it experience any time?

 

[skepticalbip]

Maybe they say it because understand relativity and time dilation. t = t₀/(1-v²/c²)^1/2.

Then again, if they don't understand relativistic time dilation, maybe they are just repeating what they heard someone who does understand it has said.

What if the photon was in water (0.75c or 225,000 km/s)? Would it experience any time?

No. c is not just the speed of light in free space. c is determined by the permittivity and permeability of the medium you are talking about so electromagnetic radiation travels at c (as established by the medium it is traveling through). People generally talk about c being the speed of light in free space because they are generally talking about light traveling through free space.

 

[bilby]

So are you saying that it isn't meaningful to say the earth seems to be 4.5 billion years old or that the universe seems to be about 13 billion years old?

It is meaningful to us humans because we share an inertial reference frame but would be meaningless to a photon. Also some critter traveling at close to c with respect to us would see the Earth and universe as having a different age than we do.

Well I'm talking about experiments done by humans not conscious photons...

Photons don't need to be conscious for us to understand that they exist for zero time in their own reference frame, and that as a result it is incoherent to describe any event for a photon as 'delayed'. A photon is emitted by a distant quasar, and absorbed by whatever detector you are using, simultaneously in the photon's reference frame. In your reference frame, these events are separated by many billions of light years of space, and many billions of years of time, but that's irrelevant - neither frame is preferred, both are correct and mathematically equivalent, according to the rules of general relativity as set out by Einstein, Lorentz, and others. You can do all your calculations in whichever frame makes them easiest, or in whatever frame takes your fancy, and then convert to any other frame to see how the same circumstances would appear to an observer in that other frame.

The question 'how does the photon "know" when it is emitted what measurement will be made to it when it's absorbed?' is most easily answered by understanding that in the photon's frame, these are simultaneous events, so there's no mystery, and no strange effect of the future on the past - a photon has neither future nor past. We do; But we're not moving at c, so we are able to experience time and distance. Photons are, so they can't.

 

[bilby]

Photons travel at c, and therefore experience no time, and no distance.

People keep saying that, but I don't understand why.

Photons don't have time or space, because they travel at c. They travel at c because they don't have mass. They don't have mass because they have been excommunicated by the Pope.


(sorry, it's been a long day, and my seriousity has evaporated).

 

[excreationist]

It is relevant to QM, ie, objective p wave collapse as a way that matter/energy may possibly work.

https://landing.newscientist.com/department-for-education-feature-3/
It doesn't seem to have many fans and is "still at an exploratory stage".

Anyway the objective collapse theory rejects that the cat is simultaneously alive and dead - that it is either alive or dead before the observation....

I wonder how it would work with the quasar... that it would involve particles or waves.... from what I've read of objective collapse theory it could collapse to particles itself sometimes.... but that might not match the observations of the experimenter....

 

[excreationist]

.....The question 'how does the photon "know" when it is emitted what measurement will be made to it when it's absorbed?' is most easily answered by understanding that in the photon's frame, these are simultaneous events, so there's no mystery, and no strange effect of the future on the past - a photon has neither future nor past. We do; But we're not moving at c, so we are able to experience time and distance. Photons are, so they can't.

What if the experiment was done using electrons instead of photons?

This seems to talk about the "delayed choice quantum eraser" and electrons:
https://www.preposterousuniverse.com/blog/2019/09/21/the-notorious-delayed-choice-quantum-eraser/

Would using electrons still imply retrocausality? Also electrons apparently only move at about 1% of the speed of light...

 

[skepticalbip]

It is relevant to QM, ie, objective p wave collapse as a way that matter/energy may possibly work.

Anyway the objective collapse theory rejects that the cat is simultaneously alive and dead - that it is either alive or dead before the observation....

Exactly. The Copenhagen interpretation is not data, it is one of several attempts to understand the nature of the quantum world from the data. In the thought experiment, when the box is opened the cat will be found to be either alive or dead. What was the state of the cat before opening the box? Bohr, by the Copenhagen interpretation, says the cat would be in a state of superposition but Schrodinger (who posed the thought experiment to show the absurdity of that interpretation) says the cat would either be alive or dead. There were many physicists at the time and there still are many physicists who reject the Copenhagen interpretation.

I wonder how it would work with the quasar... that it would involve particles or waves.... from what I've read of objective collapse theory it could collapse to particles itself sometimes.... but that might not match the observations of the experimenter....

I think a major problem in trying to understand is that we don't really know the true nature of the QM world. Electrons and photons aren't really either particles or waves but using those descriptions is the only way we can currently make any sense of (or even describe) the results our measurements. The term wavicle has been coined as a term to replace particles and waves but it doesn't really help since we don't really know the true nature of 'wavicles'.

 

[Jayjay]

Exactly. The Copenhagen interpretation is not data, it is one of several attempts to understand the nature of the quantum world from the data. In the thought experiment, when the box is opened the cat will be found to be either alive or dead. What was the state of the cat before opening the box? Bohr, by the Copenhagen interpretation, says the cat would be in a state of superposition but Schrodinger (who posed the thought experiment to show the absurdity of that interpretation) says the cat would either be alive or dead. There were many physicists at the time and there still are many physicists who reject the Copenhagen interpretation.

I think that to connect Copenhagen interpretation with Shrodinger's thought experiment is incorrect. For example, the many-worlds interpretation also says that the cat is in a superposition of dead and alive.