I don't think space is expanding.

[Ziggurat]

I'm saying that if the light approaches a mirror at 0.5c, but reflects at c, based on what is actually observed, we really wouldn't know what speed the light was before it hit the mirror.

You're using Snell's law and a non-existent medium to describe what would happen to a photon moving at c - H * D in a vacuum.

I have explained all of this already. The presence or absence of a medium is irrelevant. All we need is region with one velocity and a region with another velocity. That's all that's required. It's generally discussed in the context of a medium, because usually you need one to change the speed of light. But it's not actually any part of the derivation.

By invoking Snell's law, we would assume the light as traveling at less than c because it's being "re-emitted by atoms".

No, Mike, we wouldn't. That paper details how an absorption and re-emission model will still produce Snell's Law, but it's not a necessary part of it. Hell, Snell's Law was derived hundreds of years before quantum mechanics was invented.

 

[Mike Helland]

Lastly, if you're referring to the very first CMB temperature predictions being wrong as evidence that the standard model is wrong, well, no. As I already explained, the CMB temperature isn't something that can be predicted absent experimental measurements, since it isn't constant. Getting it wrong at a point in time when those measurements were, well, not very good isn't an issue. There are issues with the standard model, but not that.

No argument there.

If the Big Bang Theory predicted a CMB with a temperature of 2.8K, and that's what was discovered, that would be pretty darn impressive. But that's not what happened.

Sometimes that's what it sounds like what happened, so I'm just setting the record straight.

Isn't that enough?

Just trying to be complete.

 

[Mike Helland]

That paper details how an absorption and re-emission model will still produce Snell's Law, but it's not a necessary part of it.

If the absorption and re-emission of light by atoms is not necessarily part of it, how do you describe the speed of light being less than c in a medium at the atomic level?

 

[Ziggurat]

If the absorption and re-emission of light by atoms is not necessarily part of it, how do you describe the speed of light being less than c in a medium at the atomic level?

You don't need to describe why light goes slower than c for Snell's Law. It suffices that it is different. Again, the fact that it was derived hundreds of years before quantum theory should tell you that it's not necessary.

 

[Mike Helland]

You don't need to describe why light goes slower than c for Snell's Law. It suffices that it is different.

Aren't the properties of the medium what makes it different?

 

[Ziggurat]

Aren't the properties of the medium what makes it different?

Usually. But those properties are irrelevant to Snell's Law, only the velocity matters. You have posited a change in the velocity of light absent any change in the medium. Snell's Law will still apply, because the velocity change is enough. That's the only thing that goes into the equation. If other properties of the region were relevant, they would appear in the equation. They do not, because they are not.

 

[Myriad]

Usually. But those properties are irrelevant to Snell's Law, only the velocity matters. You have posited a change in the velocity of light absent any change in the medium. Snell's Law will still apply, because the velocity change is enough. That's the only thing that goes into the equation. If other properties of the region were relevant, they would appear in the equation. They do not, because they are not.

My understanding is that Snell's Law would even apply to robots with two drive wheels, if they were programmed so that each wheel independently speeds up or slows down the moment it reaches a boundary line. Crossing the line makes the robot's speed decrease or increase. But when a robot hits the line at an angle, the wheel on the acute angle reaches the line first and speeds up or slows down before the other wheel does, thus changing the trajectory of the robot, and (if everything works perfectly i.e. no skidding or anything) the trajectory changes would match Snell's law.

 

[Reformed Offlian]

100 years ago, the universe and Milky Way were one in the same.

Then we got big telescopes and discovered everything outside the Milky Way.

We went from a hundred thousand light year across observable distances, to billions.

We discovered redshift.

Either redshifts indicate some limit to inertia which is only observed with 20th century technology, or they indicate expansion and dark energy and all the rest.

The redshifts are actually observed, so I don't see the harm in examining a hypothetical universe where cosmological redshifts are fundamental, rather than an effect of some other fundamental cause.

The astronomers of the 20th century felt the expanding theories get the job done with the least amount of fuss.

In the 21st century, there's now quite a bit of fuss.

The redshift was observed. It wasn't made up by someone who didn't understand Snell's law or aberration because he didn't like dark energy.

You don't even know what all has to be wrong before it's even possible that you're right.

You're not Galileo. Get over yourself.

 

[Mike Helland]

Usually. But those properties are irrelevant to Snell's Law, only the velocity matters. You have posited a change in the velocity of light absent any change in the medium. Snell's Law will still apply, because the velocity change is enough. That's the only thing that goes into the equation. If other properties of the region were relevant, they would appear in the equation. They do not, because they are not.

Ok.

I think I understand your point well enough.

Snell's Law says a photon traveling at less than c will reflect and refract in noticeably obvious ways with our instruments and the atmosphere, effects which are not supported by observation.

 

[Mike Helland]

The redshift was observed. It wasn't made up by someone who didn't understand Snell's law or aberration because he didn't like dark energy.

You don't even know what all has to be wrong before it's even possible that you're right.

You're not Galileo. Get over yourself.

It's just a hypothesis. And the big bang is just a theory.

I'm pretty sure being skeptical that the universe inflated in a nanosecond, an invention needed to save the big bang theory in the 1970's, is perfectly healthy.

 

[Reformed Offlian]

It's just a hypothesis. And the big bang is just a theory.

I'm pretty sure being skeptical that the universe inflated in a nanosecond, an invention needed to save the big bang theory in the 1970's, is perfectly healthy.

Being attached to an hypothesis that has already been falsified is not. You are not a skeptic; you are a believer. In an idea that has already demonstrably failed. You'd still be wrong even if mainstream cosmology were also wrong.

 

[Mike Helland]

Being attached to an hypothesis that has already been falsified is not. You are not a skeptic; you are a believer. In an idea that has already demonstrably failed. You're wrong even if mainstream cosmology is also wrong.

I mean, the big bang has failed many times. That's why inflation was invented.

It's failing pretty hard on measuring the expansion rate right now.

Fails on the Tolman surface brightness test by predicting too high of an exponent.

Fails on CMB that's the same temperature north and south.

Let's keep things in context.

There's plenty of multiverse, varying speed of light, negative gravity ideas going on because ideas are needed.

My child like notion is that light doesn't travel at c to infinity... or even a trillion light years. That seems pretty consistent with observation to me.

 

[Reformed Offlian]

I mean, the big bang has failed many times. That's why inflation was invented.

It's failing pretty hard on measuring the expansion rate right now.

Fails on the Tolman surface brightness test by predicting too high of an exponent.

Fails on CMB that's the same temperature north and south.

Let's keep things in context.

There's plenty of multiverse, varying speed of light, negative gravity ideas going on because ideas are needed.

My child like notion is that light doesn't travel at c to infinity... or even a trillion light years. That seems pretty consistent with observation to me.

Like I said, even if it were as bad as you say, you're still wrong even if BBT is also wrong. Your model is falsified by such observations as aberration, annual Doppler shift, the asteroid occultation study Myriad linked earlier.

Also, as Ziggurat has pointed out, your model doesn't even get right the one thing it aspires to: the red-shift distance relationship. Your model would give different answers for different observers. Nor does it offer an explanation for that thing. "Photons just do that, I guess" is not an explanation. It is a posit with no rationale.

 

[arthwollipot]

Ok.

As I said in my first reply, in standard cosmology, there's this thing called Hubble Limit/Length/Volume/Sphere:

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

The idea that our observable region is not the whole universe is widely accepted and uncontroversial.

Still not an answer to my question.

If the big bang theory is correct, then there is no wave front. Space itself exploded while filled with matter, it wasn't matter exploding into space. If the universe is finite, then it wraps around like a 4D balloon inflating. If it is infinite, the it is filled with matter everywhere as well. In neither case do you get any wave front.

Yeah, I actually know this, but I was having trouble expressing what I actually meant. In a flat spacetime I figured that you'd eventually reach some kind of limit but at that point my brain broke and I defaulted to an incorrect assumption. Thank you for the correction.

 

[Mike Helland]

Like I said, even if it were as bad as you say, you're still wrong even if BBT is also wrong. Your model is falsified by such observations as aberration,

Assuming that Snell's law still works for a photon in a vacuum. I can conceptually understand how I would add Snell's law to the model, by adding atoms for the photon to interact with. But that doesn't test the hypothesis of speed of light in a vacuum.

annual Doppler shift,

I think that's a good test, and I'll need to find Hubble data on high z galaxies on the horizon at opposite sides of the sun to confirm the hypothesis is falsified.

the asteroid occultation study Myriad linked earlier.

Yeah, I think that's a good. It'd be good to compare the results they got with a low z galaxy to a high z galaxy.

Also, as Ziggurat has pointed out, your model doesn't even get right the one thing it aspires to: the red-shift distance relationship.

Well, if that's the case, let's get down to brass tacks.

In which message was that said? Did I miss it?

The redshift-distance relationship is equal to the standard model for the near universe, and lower than the standard model for the far universe, which agrees with the latest measurements. Here's H74, green=hypothesis, white=standard model.

Your model would give different answers for different observers.

Only in a Newtonian context. In relativity, it's still all the same.

Relativity already sort of takes care of this, when the light cone is depicted like this:

In relativity, you start with a light cone (v_light = c) and you add the expansion of space (v_galaxy = H * D) and that closes the cone.

My suggestion does the same thing in one step (v_light = c - H * D).

In my hypothesis, special relativity produces the red-shift, by upgrading the 2nd postulate to be the speed of light is c - H * D.

Or, you could do it the standard way, where H * D comes in due to the expansion of space.

In either case the light cone looks the same.

Nor does it offer an explanation for that thing. "Photons just do that, I guess" is not an explanation. It is a posit with no rationale.

We observe redshifts.

The suggestion is that they are how nature works.

If they aren't how nature works, the universe inflated in a nano second 14 billion years ago.

Dark energy does sound cooler.

 

[Mike Helland]

Still not an answer to my question.

Yeah, I actually know this, but I was having trouble expressing what I actually meant. In a flat spacetime I figured that you'd eventually reach some kind of limit but at that point my brain broke and I defaulted to an incorrect assumption. Thank you for the correction.

One of the reasons I gave was that the standard model had a theoretical size limit, and we observe things much larger than theoretical size limit; this means the theory is in conflict with observation; if we change the theory so there is no size limit and the universe extends beyond the observable region, then the theory wouldn't be in conflict with those observations; some people find resolutions to theory and observation valuable, and that would be something positive gained.

You said that doesn't answer your question, which probably means your subjective values are not what I had assumed them to be. That being the case, I hope you find what you're looking for.

 

[Reformed Offlian]

Assuming that Snell's law still works for a photon in a vacuum. I can conceptually understand how I would add Snell's law to the model, by adding atoms for the photon to interact with. But that doesn't test the hypothesis of speed of light in a vacuum.

Your model doesn't work with Snell's law.

I think that's a good test, and I'll need to find Hubble data on high z galaxies on the horizon at opposite sides of the sun to confirm the hypothesis is falsified.

Hope you do. That's progress.

Yeah, I think that's a good. It'd be good to compare the results they got with a low z galaxy to a high z galaxy.



Well, if that's the case, let's get down to brass tacks.

In which message was that said? Did I miss it?

Message #407ff. And, no, you didn't miss it, because you responded to it. And you already implicitly admitted that you can't reconcile this with relativity because you tried to appeal to some sort of emission theory.

*snip*

Only in a Newtonian context. In relativity, it's still all the same.

No, it isn't. Light is only invariant for all inertial observers if it's at c. For a particle traveling at less than c, velocity addition rules apply. And the fact that you tried to bring up emission theory to save your model in response to Ziggurat shows that you can't reconcile it with relativity, and suggests to me that you already know it, but don't want to admit it in so many words.

 

[arthwollipot]

One of the reasons I gave was that the standard model had a theoretical size limit, and we observe things much larger than theoretical size limit; this means the theory is in conflict with observation; if we change the theory so there is no size limit and the universe extends beyond the observable region, then the theory wouldn't be in conflict with those observations; some people find resolutions to theory and observation valuable, and that would be something positive gained.

You said that doesn't answer your question, which probably means your subjective values are not what I had assumed them to be. That being the case, I hope you find what you're looking for.

Allow me to repeat my question, as it is quite a simple question:

What benefit is there to proposing the existence of something when it is impossible to verify?

 

[Mike Helland]

Allow me to repeat my question, as it is quite a simple question:

What benefit is there to proposing the existence of something when it is impossible to verify?

Do you consider fixing a problem between theory and observation a benefit?

If no, then I don't think there is any benefit. It will not give you a back rub, or take you out to lunch.

If yes, then by postulating a universe infinitely beyond the observable region, the theoretical size limits go away, and a problem between theory and observation has been fixed.

 

[arthwollipot]

Do you consider fixing a problem between theory and observation a benefit?

If no, then I don't think there is any benefit. It will not give you a back rub, or take you out to lunch.

If yes, then by postulating a universe infinitely beyond the observable region, the theoretical size limits go away, and a problem between theory and observation has been fixed.

Thank you for finally answering. My next question is "is this really a problem?" but rather than asking it I'll just go back to lurking.