Did Hubble can it wrong?

[vorlon13]

Absorption features are also noted on those spectra you are citing, and those features are due to intervening diffuse gas clouds. Clearly they won't exhibit gravitational redshifting due to their diluted state, yet those absorption features correlate to consistent distances derived from Hubble expansion relative to the luminous galaxies also.

So you're still wrong.

[Surgenator]

You misunderstood me. I said there is evidence to support the the hubble constant that is independent of the wavelength shift, i.e. paralax, standard candles, etc... I was NOT saying that the universe is not expanding nor the redshifts are unrelated.

Okay, thanks for the clarification.

Yes, if we go through the route of parallax, standard candles, etc... we get that the universe is accelerating. If you read my blog carefully, the point I'm making is that this acceleration can be derived theoretically strictly from GR - that the observation through the route of parallax, standard candles, etc confirms that is obviously a good thing otherwise GR is in trouble. So you've got two pictures: one is that the universe is expanding, labelled that the Doppler Effect; the other is that the universe is not expanding, but the photon still exhibit a redshift due to the fact they are moving against gravity. On first appearance, these two pictures seem to contradict each other, but Einstein Equivalent Principle says they are equivalent -- you can trade one with the other, the equations describing them are the same.

Gravitational redshift has a limit of how much redshift there can be. This limit is constrained by the mass of the star and its radius. If we took two identical stars that are at different distances from us, the amount of gravitational redshift should still be the same if we're sufficiently far away. If the universe was not expanding, then this gravitation redshift would be the main component for the redshifts and we would see the same redshift. However, we see different redshifts.

Also, if you look at whole galaxies that have different total mass but are at the same distance away from you, you would expect different amount of redshift if the universe was not expanding. We see the same amount.

[Alex K]

I'm confused: cosmological redshift and doppler redshift are different phenomena, no? One measures the relative speed during emission, the other the total expansion of the universe since the emission. In GR far away galaxies don't really move away in space, but the in between space expands according to the friedmann equations. Or do you claim that both are equivalent?

[little_monkey]

If we took two identical stars that are at different distances from us, the amount of gravitational redshift should still be the same if we're sufficiently far away. If the universe was not expanding, then this gravitation redshift would be the main component for the redshifts and we would see the same redshift. However, we see different redshifts.

The gravitational redshift depends on the difference of the gravitational potential. If two identical stars are at different distances, they will be in different gravitational potential, hence will exhibit diffrent redshifts.

Also, if you look at whole galaxies that have different total mass but are at the same distance away from you, you would expect different amount of redshift if the universe was not expanding. We see the same amount.

If you look at equation 10, d = H Δv, you need to know the mass and the size of the source. And so my argument is that this will be the same for every galaxy. I've put an appendix on my blog to illustrate that. Check it out again: http://soi.blogspot.ca/

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I'm confused: cosmological redshift and doppler redshift are different phenomena, no? One measures the relative speed during emission, the other the total expansion of the universe since the emission. In GR far away galaxies don't really move away in space, but the in between space expands according to the friedmann equations. Or do you claim that both are equivalent?

Yes, both are equivalent, since they both are described by the same equations.

[vorlon13]

Does the medical community ever get 'cranks' that come in out of the blue and declare all the appendectomies done in the last 100 years were done improperly, and the surgeons have overlooked some big glaring obvious factor, and if they would start doing appendectomies 'correctly' everything would be wonderful from there on out ??

[Surgenator]

If we took two identical stars that are at different distances from us, the amount of gravitational redshift should still be the same if we're sufficiently far away. If the universe was not expanding, then this gravitation redshift would be the main component for the redshifts and we would see the same redshift. However, we see different redshifts.

The gravitational redshift depends on the difference of the gravitational potential. If two identical stars are at different distances, they will be in different gravitational potential, hence will exhibit diffrent redshifts.

At the large r limit (when the source is very very far away from the observer) the gravitational redshift are identical for identical stars. It doesn't matter that one of the one of the stars is 100 billion lightyears further away. Read the link I provided and look at the 2nd equation in the article.

Also, if you look at whole galaxies that have different total mass but are at the same distance away from you, you would expect different amount of redshift if the universe was not expanding. We see the same amount.

If you look at equation 10, d = H Δv, you need to know the mass and the size of the source. And so my argument is that this will be the same for every galaxy. I've put an appendix on my blog to illustrate that. Check it out again: http://soi.blogspot.ca/

Two words: statelite galaxies. If the masses of each galaxies would be the same, then you shouldn't have any satellites. A satellite requires a central mass that is much heavier than itself to orbit around.

Your claim doesn't hold up to the observations.

[Alex K]

If we took two identical stars that are at different distances from us, the amount of gravitational redshift should still be the same if we're sufficiently far away. If the universe was not expanding, then this gravitation redshift would be the main component for the redshifts and we would see the same redshift. However, we see different redshifts.

The gravitational redshift depends on the difference of the gravitational potential. If two identical stars are at different distances, they will be in different gravitational potential, hence will exhibit diffrent redshifts.

Also, if you look at whole galaxies that have different total mass but are at the same distance away from you, you would expect different amount of redshift if the universe was not expanding. We see the same amount.

If you look at equation 10, d = H Δv, you need to know the mass and the size of the source. And so my argument is that this will be the same for every galaxy. I've put an appendix on my blog to illustrate that. Check it out again: http://soi.blogspot.ca/

---

I'm confused: cosmological redshift and doppler redshift are different phenomena, no? One measures the relative speed during emission, the other the total expansion of the universe since the emission. In GR far away galaxies don't really move away in space, but the in between space expands according to the friedmann equations. Or do you claim that both are equivalent?

Yes, both are equivalent, since they both are described by the same equations.

I don't see it yet. Do you talk about cosmological redshift via spatial expansion at all in your notes?

[little_monkey]

The gravitational redshift depends on the difference of the gravitational potential. If two identical stars are at different distances, they will be in different gravitational potential, hence will exhibit diffrent redshifts.

At the large r limit (when the source is very very far away from the observer) the gravitational redshift are identical for identical stars. It doesn't matter that one of the one of the stars is 100 billion lightyears further away. Read the link I provided and look at the 2nd equation in the article.

I have read your link and nothing in there contradicts my blog. Secondly, there is no reference to two identical stars, so I have no clue where you get that. Simply put, galaxies at different distances will have different redshifts. It doesn't matter what their masses are. What matters is the mass of the source of gravity. In the first figure, the source is the earth, but in the appendix, it's an infinite number of galaxies.

If you look at equation 10, d = H Δv, you need to know the mass and the size of the source. And so my argument is that this will be the same for every galaxy. I've put an appendix on my blog to illustrate that. Check it out again: http://soi.blogspot.ca/

Two words: statelite galaxies. If the masses of each galaxies would be the same, then you shouldn't have any satellites. A satellite requires a central mass that is much heavier than itself to orbit around.

I'm not talking about satellites. Your point is irrelevant.

Your claim doesn't hold up to the observations.

You haven't shown that so far how my claim doesn't hold up. I believe you did not understand my blog. Let me give a short synopsis. Historically Hubble discovered his eponymous law through observation, not theory. He concluded that all galaxies were moving away - this was from what was known as the Doppler Effect. Subsequently this was developped as the Big Bang Theory.

In my blog, I show that by taking Einstein Equivalent Principle, one gets that Doppler Effect = Gravitational Shift, and from there, I derived Hubble Law. Now if you can show where my derivation is wrong, then fine, I will appreciate, but so far, you haven't. The only argument that can destroy my claim is my assumption that the universe is infinite. If the universe is finite, then my claim doesn't hold any longer.

[Surgenator]

At the large r limit (when the source is very very far away from the observer) the gravitational redshift are identical for identical stars. It doesn't matter that one of the one of the stars is 100 billion lightyears further away. Read the link I provided and look at the 2nd equation in the article.

I have read your link and nothing in there contradicts my blog. Secondly, there is no reference to two identical stars, so I have no clue where you get that. Simply put, galaxies at different distances will have different redshifts. It doesn't matter what their masses are. What matters is the mass of the source of gravity. In the first figure, the source is the earth, but in the appendix, it's an infinite number of galaxies.

What is known about gravitational redshift.
1) There is a maximum redshift, z(r->inf) ~ GM/(c^2*R) that gravity can accomplish.
2) We can take the large r limit for stars light years away.

Consider the thought experiment
- Take two identical stars where one is 1 million light years away, and the other is 1 billion light years away.
- Their redshift due to gravity will be the GM/(c^2*R) because their masses and radii would be same and they are so far away.
- If the universe is not expanding, their redshifts should be the same.
- If the universe is expanding, their redshifts should be different because the expansion of the universe will also redshift the star's light.

First, did you follow my logic? Second, what do you think the observations actually are?

Two words: statelite galaxies. If the masses of each galaxies would be the same, then you shouldn't have any satellites. A satellite requires a central mass that is much heavier than itself to orbit around.

I'm not talking about satellites. Your point is irrelevant.

I was addressing this point

[...] mass and the size of the source. And so my argument is that this will be the same for every galaxy.

Galaxies cannot all have the same mass if you have one galaxiy orbiting another. So I was rebuting your rebutal to my 2nd argument which makes it relevant.

You haven't shown that so far how my claim doesn't hold up. I believe you did not understand my blog. Let me give a short synopsis. Historically Hubble discovered his eponymous law through observation, not theory. He concluded that all galaxies were moving away - this was from what was known as the Doppler Effect. Subsequently this was developped as the Big Bang Theory.

In my blog, I show that by taking Einstein Equivalent Principle, one gets that Doppler Effect = Gravitational Shift, and from there, I derived Hubble Law. Now if you can show where my derivation is wrong, then fine, I will appreciate, but so far, you haven't. The only argument that can destroy my claim is my assumption that the universe is infinite. If the universe is finite, then my claim doesn't hold any longer.

I did understand the overall picture in your blog. However, I'm not going to go in detail through your math or logic to determine where specifically you made a mistake. That is too much work on my end. My two arguments address your claim that "Doppler Effect = Gravitational Shift" through thought experiments. The first one takes the case of the same gravitational potential but at different distances away. The second is different gravitational potentials but at the same distance away. In either of the cases, the observations would not match to what you claim.

[little_monkey]

[quote='little_monkey' pid='788993' dateline='1415045970']

I have read your link and nothing in there contradicts my blog. Secondly, there is no reference to two identical stars, so I have no clue where you get that. Simply put, galaxies at different distances will have different redshifts. It doesn't matter what their masses are. What matters is the mass of the source of gravity. In the first figure, the source is the earth, but in the appendix, it's an infinite number of galaxies.

What is known about gravitational redshift.
1) There is a maximum redshift, z(r->inf) ~ GM/(c^2*R) that gravity can accomplish.

You're using this formula wrongly. In that link, they are talking about a light emanating from inside a star with a radius less than a Schwarzchild radius, which is the radius of a black hole. The point the author is making is in that case, light won't be able to escape. My thought experiment is not about light emanating from the inside of the earth, but from an emitter standing at a distance d above the ground. Different experiments require that you use the math properly.

You haven't shown that so far how my claim doesn't hold up. I believe you did not understand my blog. Let me give a short synopsis. Historically Hubble discovered his eponymous law through observation, not theory. He concluded that all galaxies were moving away - this was from what was known as the Doppler Effect. Subsequently this was developped as the Big Bang Theory.

In my blog, I show that by taking Einstein Equivalent Principle, one gets that Doppler Effect = Gravitational Shift, and from there, I derived Hubble Law. Now if you can show where my derivation is wrong, then fine, I will appreciate, but so far, you haven't. The only argument that can destroy my claim is my assumption that the universe is infinite. If the universe is finite, then my claim doesn't hold any longer.

I did understand the overall picture in your blog. However, I'm not going to go in detail through your math or logic to determine where specifically you made a mistake. That is too much work on my end.

Sorry but if you can't do the math, you're not in a position to criticize.

My two arguments address your claim that "Doppler Effect = Gravitational Shift" through thought experiments. The first one takes the case of the same gravitational potential but at different distances away.

That's why I put 3 different emitters at 3 different distances. But I show that for all these cases, you get one general equation.

The second is different gravitational potentials but at the same distance away.

That is not possible for a gravitational potential. It's inversely proportional with distance. So at equal distance, the gravitational potential has to be the same.