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Old 11th October 2021, 03:35 PM   #81
jonesdave116
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Originally Posted by Mike Helland View Post
So we get more photons from the object that way.

At the very least, the sensor that we use to detect it should get warmer having 4 times as many photons hit it.
We detect gravitational lensing of the CMB. It is quite separate from the ISW effect. Or the S-Z effect. If these clever scientist chappies couldn't distinguish between them, they would say so.

Rotation of the cosmic microwave background polarization from weak gravitational lensing
Liang Dai
https://arxiv.org/pdf/1311.3662.pdf
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Old 11th October 2021, 04:47 PM   #82
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Originally Posted by Mike Helland View Post
"Overwhelming" is a subjective claim
Not to anyone who can count or understand the science !
What is the evidence for the Big Bang? lists nine lines of evidence that the Big Bang happened. As been pointed out to you many times, the physical properties of the CMB can only be explained by a Big Bang. The CMB alone is overwhelming evidence for the Big Bang.
  • The CMB has fluctuations matching predicted quantum fluctuations in the early universe.
  • The most perfect black body spectrum ever detected means it was emitted from a body in thermal equilibrium, i.e. the universe in a hot dense state.
    This also means that any claim that the CMB was emitted from galaxies is abysmally ignorant. Galaxies tend to have flattish spectra with spikes.
  • The CMB temperature matches it being emitted when the universe cooled enough for atoms to form.
  • We measure the temperature of the CMB increasing as predicted with increasing distance (a younger universe).
  • The normal matter, dark matter and dark energy predicted from CMB data matches predications from other measurements.
  • The integrated Sachs-Wolfe effect shows the evolution of gravitational potentials, i.e. large scale structures, in an expanding universe.
From the other thread:
30 April 2021: Mike Helland's idiotic tactic of asking irrelevant questions that he must know the answer to.
9 April 2021: Repeats fantasies about the Hubble constant, CMB anomalies and galaxy formation/evolution model
9 April 2021: You know that the CMB is only possible in an expanding universe (perfect black body spectrum).
That thread started on 1st December 2020 with gibberish about the CMB being reflected, ignorance about black body spectra, the typical crank ignorance the Eddington wrote about the CMB in his "temperature of space" calculation (Eddington's Temperature of Space).

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Old 11th October 2021, 09:20 PM   #83
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Paul LaViolette's arguments against the Big Bang are not the worst arguments that could possibly be imagined. As evidence for that evaluation, consider some of the arguments that have been put forward in this thread.

Originally Posted by Mike Helland View Post
I thought GR predicted the universe would collapse.
Originally Posted by Mike Helland View Post
From your source:

"This makes the CMBR look very slightly hotter in the direction of these potentials, which also contain the highest concentrations of galaxies"

Gee. There's no possible way the background radiation of the universe is hotter in the direction of the highest possible concentrations of galaxies without dark energy?

Couldn't those highest concentrations of galaxies be lensing light around it?

I dunno.
Originally Posted by Mike Helland View Post
Also, in the highest concentrations of galaxy, there's probably the most life.

Their radio/TV signals can contribute to the "CMB peaks" seen in their direction.
Originally Posted by Mike Helland View Post
I'm not suggesting photons gain energy through lensing.

I'm saying lensing gives you more photons.
Originally Posted by Mike Helland View Post
At the very least, the sensor that we use to detect it should get warmer having 4 times as many photons hit it.
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Old 12th October 2021, 10:24 AM   #84
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Originally Posted by W.D.Clinger View Post
Paul LaViolette's arguments against the Big Bang are not the worst arguments that could possibly be imagined. As evidence for that evaluation, consider some of the arguments that have been put forward in this thread.
Classy.

How it started:

https://ui.adsabs.harvard.edu/abs/19....735S/abstract

"Gravitational lensing of the CMB temperature and polarization patterns should be detectable by the Planck Surveyor satellite, leading to useful independent constraints on the cosmological constant and spatial curvature."


How it's going:

https://sci.esa.int/web/planck/-/516...ave-background

"One of the most intriguing is gravitational lensing, the deflection of light as it travels in the vicinity of massive objects such as galaxies and galaxy clusters. Gravitational lensing creates tiny, additional distortions to the mottled pattern of the CMB temperature fluctuations."
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Old 12th October 2021, 12:57 PM   #85
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Originally Posted by Mike Helland View Post
Classy...
Nothing to so with the craziness of Paul LaViolette. Or your lensing magically creates more photons fantasy.
A proposal that the Planck spaceacft should be able to detect gravitational lensing in 1999 and an ESA article from 2019 saying they were detected.
Gravitational lensing of cosmic microwave background anisotropies and cosmological parameter estimation (1999) by Stompor, R. and Efstathiou, G.
GRAVITATIONAL LENSING OF THE COSMIC MICROWAVE BACKGROUND
Quote:
This illustration shows how photons in the Cosmic Microwave Background (CMB) are deflected by the gravitational lensing effect of massive cosmic structures as they travel across the Universe. Using data from ESA's Planck satellite, cosmologists have been able to measure this gravitational lensing of the CMB over the whole sky for the first time.
This is a confirmed prediction of mainstream, Big Bang cosmology.

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Old 12th October 2021, 01:53 PM   #86
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Originally Posted by Mike Helland View Post
How it's going:

https://sci.esa.int/web/planck/-/516...ave-background

"One of the most intriguing is gravitational lensing, the deflection of light as it travels in the vicinity of massive objects such as galaxies and galaxy clusters. Gravitational lensing creates tiny, additional distortions to the mottled pattern of the CMB temperature fluctuations."
Where does it say they attribute those fluctuations to the aliens' "radio/TV signals"?

Where does it say they are able to detect those fluctuations by taking the temperature of their sensor?
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Old 12th October 2021, 02:23 PM   #87
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Originally Posted by Mike Helland View Post
Classy.

How it started:

https://ui.adsabs.harvard.edu/abs/19....735S/abstract

"Gravitational lensing of the CMB temperature and polarization patterns should be detectable by the Planck Surveyor satellite, leading to useful independent constraints on the cosmological constant and spatial curvature."


How it's going:

https://sci.esa.int/web/planck/-/516...ave-background

"One of the most intriguing is gravitational lensing, the deflection of light as it travels in the vicinity of massive objects such as galaxies and galaxy clusters. Gravitational lensing creates tiny, additional distortions to the mottled pattern of the CMB temperature fluctuations."
No.

How it started was someone pointing out that the integrated Sachs-Wolfe is strong evidence for Universe expansion, and then you claiming that the ISW could be explained by gravitational lensing.

How it has ended is you still being too ignorant to understand why your explanation is nonsense.
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Old 12th October 2021, 02:27 PM   #88
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Originally Posted by hecd2 View Post
No.

How it started was someone pointing out that the integrated Sachs-Wolfe is strong evidence for Universe expansion, and then you claiming that the ISW could be explained by gravitational lensing.

How it has ended is you still being too ignorant to understand why your explanation is nonsense.
Gravitational lensing causes fluctuations in CMB temperature.

So do late term ISW effects.

How much do these effects contribute temperature differences?

Is it something like g-lensing being 50% and late term ISW being the other 50%?

Or are they more subtle than that?
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Old 12th October 2021, 02:30 PM   #89
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Originally Posted by Mike Helland View Post
Gravitational lensing causes fluctuations in CMB temperature.
And there we have the core of your ignorance. It doesn’t.
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Old 12th October 2021, 02:33 PM   #90
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Originally Posted by hecd2 View Post
And there we have the core of your ignorance. It doesn’t.
"On their way to the Solar System, where they are eventually detected by the sensors on board Planck, photons from the CMB may cross many different massive systems as well as empty spaces. The photons encounter structures in different evolutionary stages, since the massive structures grow denser and the cosmic voids become less dense as time goes by. All of the structures from the different cosmic epochs contribute to bending the path of CMB photons. The total effect of these multiple deflections is a modification to the pattern of CMB temperature fluctuations, thus changing the typical 'shapes' of hot and cold spots in the CMB."

https://sci.esa.int/web/planck/-/516...ave-background
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Old 12th October 2021, 03:01 PM   #91
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Originally Posted by Mike Helland View Post
"On their way to the Solar System, where they are eventually detected by the sensors on board Planck, photons from the CMB may cross many different massive systems as well as empty spaces. The photons encounter structures in different evolutionary stages, since the massive structures grow denser and the cosmic voids become less dense as time goes by. All of the structures from the different cosmic epochs contribute to bending the path of CMB photons. The total effect of these multiple deflections is a modification to the pattern of CMB temperature fluctuations, thus changing the typical 'shapes' of hot and cold spots in the CMB."

https://sci.esa.int/web/planck/-/516...ave-background
No, I think you are getting confused about the distortion of existing temperature anisotropies by lensing, as opposed to lensing actually causing temperature anisotropies. Subtle difference.
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Old 12th October 2021, 03:13 PM   #92
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Originally Posted by jonesdave116 View Post
No, I think you are getting confused about the distortion of existing temperature anisotropies by lensing, as opposed to lensing actually causing temperature anisotropies. Subtle difference.
Right.

There are many effects, categorized as 1st order and 2nd order.

https://cosmologist.info/notes/Lense...ICTPSchool.pdf

Check out page 20
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Old 12th October 2021, 03:22 PM   #93
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Originally Posted by Mike Helland View Post
You need to read the posts you write and what you quote. The temperature fluctuations in the CMB were caused when the CMB was emitted. The temperature fluctuations in the CMB are not caused by gravitational lensing - their shapes are modified. Thus what you wrote was wrong.
https://sci.esa.int/web/planck/-/516...ave-background
Quote:
On their way to the Solar System, where they are eventually detected by the sensors on board Planck, photons from the CMB may cross many different massive systems as well as empty spaces. The photons encounter structures in different evolutionary stages, since the massive structures grow denser and the cosmic voids become less dense as time goes by. All of the structures from the different cosmic epochs contribute to bending the path of CMB photons. The total effect of these multiple deflections is a modification to the pattern of CMB temperature fluctuations, thus changing the typical 'shapes' of hot and cold spots in the CMB.
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Old 12th October 2021, 03:36 PM   #94
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Originally Posted by Mike Helland View Post
"On their way to the Solar System, where they are eventually detected by the sensors on board Planck, photons from the CMB may cross many different massive systems as well as empty spaces. The photons encounter structures in different evolutionary stages, since the massive structures grow denser and the cosmic voids become less dense as time goes by. All of the structures from the different cosmic epochs contribute to bending the path of CMB photons. The total effect of these multiple deflections is a modification to the pattern of CMB temperature fluctuations, thus changing the typical 'shapes' of hot and cold spots in the CMB."

https://sci.esa.int/web/planck/-/516...ave-background
This is proof that you are incapable of understanding what you read. You are confusing transverse displacement of photons with changes in photon energy. And you have been doing it for days in spite of being corrected by several people. That’s just par for the course.

I repeat that your claim that gravitational lensing causes fluctuations in CMB temperature is profoundly wrong.

Last edited by hecd2; 12th October 2021 at 03:37 PM. Reason: Word omitted
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Old 12th October 2021, 03:50 PM   #95
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Originally Posted by hecd2 View Post
This is proof that you are incapable of understanding what you read. You are confusing transverse displacement of photons with changes in photon energy. And you have been doing it for days in spite of being corrected by several people. That’s just par for the course.

I repeat that your claim that gravitational lensing causes fluctuations in CMB temperature is profoundly wrong.
I never said the photons change energy.

If lensing focuses multiple CMB photons toward a radio telescope, what happens?
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Old 12th October 2021, 04:10 PM   #96
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Originally Posted by Mike Helland View Post
I never said the photons change energy.
Yes you did.

You said:
Quote:
Gravitational lensing causes fluctuations in CMB temperature.
And that is the same as photons change energy.

So yes, that’s what you’ve been claiming for days and it’s wrong.
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Old 12th October 2021, 04:11 PM   #97
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Originally Posted by Mike Helland View Post
Right.

There are many effects, categorized as 1st order and 2nd order.

https://cosmologist.info/notes/Lense...ICTPSchool.pdf

Check out page 20
Uh huh. And your point is?

Let's take;

Gravitational lensing effect on the fluctuations of the cosmic background radiation
Blanchard, A. & Schneider. J. (1987)
http://adsabs.harvard.edu/pdf/1987A%26A...184....1B

This is a scanned paper, so I cannot cut and paste, unfortunately. So, I'll screenshot and paste

Blanchard & Schneider.jpg

So, the lensing is just distorting the already present temperature fluctuations, not causing them. Indeed, it is quite possible to distinguish, and correlate, between the effects of lensing and thermal effects from the SZE, for example;

Cross-correlation of the thermal Sunyaev–Zel’dovich effect and weak gravitational lensing: Planck and Subaru Hyper Suprime-Cam first-year data
Osato, K. et al (2019)
https://arxiv.org/pdf/1910.07526.pdf

And also between lensing and the ISW effect;

Planck 2013 results. XIX. The integrated Sachs-Wolfe effect
Planck Collaboration (2014)
https://www.aanda.org/articles/aa/pd...aa21526-13.pdf

Quote:
We investigated three separate approaches, which essentially cover all previous studies, and also break new ground. (i) We correlated the CMB with the Planck reconstructed gravitational lensing potential (for the first time). This detection was made using the lensing-induced bispectrum between the low-`l and high-`l temperature anisotropies; the correlation between lensing and the ISW effect has a significance close to 2.5σ
Of course, 2.5σ isn't the particle physicists' holy grail of 5σ, but it is 99.38% confidence level!

In short, these people are not stupid, and would not be claiming detection of three different effects, if those effects were too vague to measure.
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Old 12th October 2021, 05:50 PM   #98
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Originally Posted by hecd2 View Post
Yes you did.

You said:

And that is the same as photons change energy.

So yes, that’s what you’ve been claiming for days and it’s wrong.
I very specifically did not claim that.

I said gravitationally lensing may divert additional CMB photons to the radio telescopes.

What happens when a radio telescope gets additional photons?
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Old 12th October 2021, 06:07 PM   #99
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Originally Posted by jonesdave116 View Post
Uh huh. And your point is?

Let's take;

Gravitational lensing effect on the fluctuations of the cosmic background radiation
Blanchard, A. & Schneider. J. (1987)
http://adsabs.harvard.edu/pdf/1987A%26A...184....1B

This is a scanned paper, so I cannot cut and paste, unfortunately. So, I'll screenshot and paste

Attachment 45491

So, the lensing is just distorting the already present temperature fluctuations, not causing them. Indeed, it is quite possible to distinguish, and correlate, between the effects of lensing and thermal effects from the SZE, for example;

Cross-correlation of the thermal Sunyaev–Zel’dovich effect and weak gravitational lensing: Planck and Subaru Hyper Suprime-Cam first-year data
Osato, K. et al (2019)
https://arxiv.org/pdf/1910.07526.pdf

And also between lensing and the ISW effect;

Planck 2013 results. XIX. The integrated Sachs-Wolfe effect
Planck Collaboration (2014)
https://www.aanda.org/articles/aa/pd...aa21526-13.pdf



Of course, 2.5σ isn't the particle physicists' holy grail of 5σ, but it is 99.38% confidence level!

In short, these people are not stupid, and would not be claiming detection of three different effects, if those effects were too vague to measure.
So what's a good example of this?

For instance, is there a super cluster that you know of that causes late term ISW? What's the temperature increase in Kelvin?

*edit* this seems close: https://arxiv.org/abs/0805.2974

Last edited by Mike Helland; 12th October 2021 at 06:26 PM.
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Old 13th October 2021, 05:18 AM   #100
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Originally Posted by W.D.Clinger View Post
Paul LaViolette's arguments against the Big Bang are not the worst arguments that could possibly be imagined. As evidence for that evaluation, consider some of the arguments that have been put forward in this thread.
This is true. LaViolette's nonsense is cretinously stupid but there are worse
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Old 13th October 2021, 05:20 AM   #101
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Originally Posted by Mike Helland View Post
<drivel snip>

Originally Posted by Mike Helland View Post
Gravitational lensing causes fluctuations in CMB temperature.
No, not in the Real World.

Originally Posted by Mike Helland View Post
I never said the photons change energy.
And now you're lying again.
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Old 13th October 2021, 12:48 PM   #102
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Originally Posted by Mike Helland View Post
I very specifically did not claim that.

I said gravitationally lensing may divert additional CMB photons to the radio telescopes.

What happens when a radio telescope gets additional photons?
You need to read your own posts!
You started with an ignorant Couldn't those highest concentrations of galaxies be lensing light around it? question on 9 October 2021 about the ISW effect. Obviously ignorant because lensing does not affect photon energy and maybe not mentioned yet the ISW effect also exists for supervoids!
Late-time integrated Sachs–Wolfe effect
Quote:
Accelerated expansion due to dark energy causes even strong large-scale potential wells (superclusters) and hills (voids) to decay over the time it takes a photon to travel through them. A photon gets a kick of energy going into a potential well (a supercluster), and it keeps some of that energy after it exits, after the well has been stretched out and shallowed. Similarly, a photon has to expend energy entering a supervoid, but will not get all of it back upon exiting the slightly squashed potential hill.

A signature of the late-time ISW is a non-zero cross-correlation function between the galaxy density (the number of galaxies per square degree) and the temperature of the CMB,[3] because superclusters gently heat photons, while supervoids gently cool them. This correlation has been detected at moderate to high significance.[4][5][6][7][8]
You specifically wrote "So we get more photons from the object that way." about the Einstein Cross and have been going on about that ignorance since. All the lensing galaxy does is bend light (photons) from the background galaxy.
Gravitational lensing does not create more photons.
Gravitational lensing does not know about our telescopes and magically "divert additional CMB photons" to them.
Photon intensity (counts) is not photon energy (temperature). The ISW is a variation in CMB temperature.

ETA: There is actual idiocy that the 4 images in the Einstein Cross multiply the intensity in that optical image 4 times. That can only happen if gravitational lensing somehow created more photons than are emitted from the lensed galaxy. That does not happen.

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Old 13th October 2021, 12:58 PM   #103
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Originally Posted by Reality Check View Post
You specifically wrote "So we get more photons from the object that way." about the Einstein Cross and have been going on about that ignorance since. All the lensing galaxy does is bend light (photons) from the background galaxy.
Correct.

Quote:
Gravitational lensing does not create more photons.
Gravitational lensing does not know about our telescopes and magically "divert additional CMB photons" to them.
Correct.

I never said those things.


Quote:
Photon intensity (counts) is not photon energy (temperature). The ISW is a variation in CMB temperature.
Ok.

So the question remains, how does a radio telescope know the difference?

This isn't optical astronomy.

Radio telescopes measure something called "Brightness temperature".

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

"Brightness temperature or radiance temperature is the temperature at which a black body in thermal equilibrium with its surroundings would have to be in order to duplicate the observed intensity of a grey body object at a frequency ν. This concept is used in radio astronomy, planetary science and materials science. "

http://physics.wku.edu/~gibson/radio/brightness.html

"Brightness Temperature is a proxy for specific intensity and is measured in kelvins, which are like degrees Celsius but are counted up from absolute zero. The brightness temperature is the temperature needed for a blackbody (thermal) radiator to produce the same specific intensity as the observed source."
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Old 13th October 2021, 01:23 PM   #104
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Originally Posted by Mike Helland View Post
So what's a good example of this?
An Imprint of Super-Structures on the Microwave Background due to the Integrated Sachs-Wolfe Effect
Quote:
We measure hot and cold spots on the microwave background associated with supercluster and supervoid structures identified in the Sloan Digital Sky Survey Luminous Red Galaxy catalog. The structures give a compelling visual imprint, with a mean temperature deviation of 9.6 +/- 2.2 microK, i.e. above 4 sigma. We interpret this as a detection of the late-time Integrated Sachs-Wolfe (ISW) effect, in which cosmic acceleration from dark energy causes gravitational potentials to decay, heating or cooling photons passing through density crests or troughs. In a flat universe, the linear ISW effect is a direct signal of dark energy.
Highlighted supervoid to emphasize that anyone who knows what the ISW effect is knows that it is not gravitation lensing. Aside from the ISW beg changes in photon temperature! and lensing not changing photon temperature!
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Old 13th October 2021, 01:30 PM   #105
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Originally Posted by Mike Helland View Post
...I never said those things.
A couple of "Corrects" and a lie that he never wrote these posts. Persists with idiotic questions.
Any telescope measures photon intensity by how bright the image becomes.
Any telescope measures photon temperature by the color (spectra) of the photons.
Brightness temperature is a brightness (intensity) measurement used to measure surface temperature of objects such as stars and galaxies ("This concept is used in radio astronomy, planetary science and materials science.").
The idiocy includes that radio telescopes are not used for the ISW effect measurements! They use galaxy catalogs from optical sky surveys and the CMB from Planck. The ISW effect is a correlation with the galaxy distribution in superclusters and supervoids with the variations in the temperature fluctuations of the CMB.

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Old 13th October 2021, 01:33 PM   #106
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Originally Posted by Reality Check View Post
A couple of "Corrects" and a lie that he never wrote these posts.
You added the words "create", "knows about", and "magically", as if a g-lens had intention, or created photons out of thin air.

You said those things. Not me.

Then called me a liar.

This will be my last response to messages like that.

Quote:
Persists with idiotic questions.
Any telescope measures photon intensity by how bright the image becomes.
Any telescope measures photon temperature by the color (spectra) of the photons.
How does a radio antenna know how bright something is?
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Old 13th October 2021, 01:49 PM   #107
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Originally Posted by Mike Helland View Post
You added ...
The words are in what I wrote abut the obvious ignorance in his posts. Repeats his irrelevant obsession with radio telescopes.
14 October 2021: A doubly ignorant fantasy that the ISW effect is gravitational lensing on 9 October.
14 October 2021: His very specific "So we get more photons from the object that way" nonsense.

Last edited by Reality Check; 13th October 2021 at 01:51 PM.
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Old 13th October 2021, 01:56 PM   #108
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Originally Posted by Mike Helland View Post
How does a radio antenna know how bright something is?
Same way any telescope does.
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Old 13th October 2021, 03:39 PM   #109
W.D.Clinger
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Originally Posted by Mike Helland View Post
How does a radio antenna know how bright something is?
I asked the radio antenna downstairs, and it said it doesn't know anything about brightness. It is, after all, just a length of wire.

If you're asking how radio astronomers know how bright something is, maybe they use an EMF meter.

To be infinitesimally more serious, I suppose they could use something analogous to an S-meter.

Seriously, Mike: Take some courses in some scientific or technical discipline such as physics, where the courses would have a laboratory component.

Failing that, you might consider taking up a hobby that involves electronic instruments. Photography, perhaps. If you can't afford a light meter, you could just study the relevant scenes in Love Actually.
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Old 13th October 2021, 03:47 PM   #110
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Originally Posted by W.D.Clinger View Post
To be infinitesimally more serious, I suppose they could use something analogous to an S-meter.
Right. The antenna will create a voltage from radio signals of whatever wavelength the antenna is tuned to.

From what I gather, in optical astronomy:

"Specific Intensity - intensity per unit wavelength or frequency, e.g., in watts per square meter per hertz per steradian [W m-2 Hz-1 sr-1]. "

And in radio astronomy:

"Brightness Temperature is a proxy for specific intensity and is measured in kelvins.... The brightness temperature is the temperature needed for a blackbody (thermal) radiator to produce the same specific intensity as the observed source."

http://physics.wku.edu/~gibson/radio/brightness.html

So, since we're just an S meter, and presumably a single wavelength antenna, then what we're really doing is measuring the intensity of photons coming in at that one wavelength (*edit* well, there's more than one wavelength in the band).

That can tell us the brightness temperature of the light.

Which is a strange name, because it doesn't really tell us the whole story about brightness or temperature.

Do I have that right?

Last edited by Mike Helland; 13th October 2021 at 04:28 PM.
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Old 13th October 2021, 04:46 PM   #111
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Originally Posted by Mike Helland View Post
I very specifically did not claim that.
You very specifically did in post #88 of this thread there in black and white for everyone to see. Mike Helland said:
Quote:
Gravitational lensing causes fluctuations in CMB temperature.
Why deny it, when everyone can see your erroneous claim.


Quote:
I said gravitationally lensing may divert additional CMB photons to the radio telescopes.
Radio telescopes? What radio telescopes?

Quote:
What happens when a radio telescope gets additional photons?
Additional with respect to what? And how is this relevant in the slightest to the case we are discussing?



The fact is that the ISW effect and the weak lensing effect are different and are detected using different methods (secondary temperature fluctuations in one case correlated with sources of gravitational potential; and correlations between multipoles in the primary anisotropies in the second case).


When you have read and understood everything in these two papers, then you will be qualified to comment on the late ISW as strong evidence for Universe expansion. Until then, you'll just be displaying ignorance as ever:
Planck 2013 release Paper XIX: https://www.aanda.org/articles/aa/pd...aa21526-13.pdf
Planck 2015 release Paper XXI: https://www.aanda.org/articles/aa/pd...aa25831-15.pdf
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Old 13th October 2021, 04:52 PM   #112
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Originally Posted by Mike Helland View Post

And in radio astronomy:

"Brightness Temperature is a proxy for specific intensity and is measured in kelvins.... The brightness temperature is the temperature needed for a blackbody (thermal) radiator to produce the same specific intensity as the observed source."

http://physics.wku.edu/~gibson/radio/brightness.html
a) This is not radio astronomy and b) the concept of brightness temperature is irrelevant where the object you are detecting (the CMB) is the most perfect blackbody ever measured. There is no point in comparing the object being measured with a blackbody in this case, because the object being measured IS a blackbody.


Honestly Mike, your attempts to pick holes in physics that is way, way over your head by means of fundamental misunderstanding is what gets under people's skin. That, and your inability or refusal to learn anything ever. Read the two papers I linked above, understand them fully, and then we can talk.

Last edited by hecd2; 13th October 2021 at 04:54 PM.
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Old 13th October 2021, 04:56 PM   #113
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Originally Posted by hecd2 View Post
Why deny it, when everyone can see your erroneous claim.
My claim was, gravitational lensing could, as in the case with an Einstein cross or Einstein ring, bend CMB photons towards us that would have otherwise went off in some other direction.

That would increase the intensity, and therefore brightness temperature.

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


Quote:
Radio telescopes? What radio telescopes?
What do we use to measure the CMB?

It's not in the optical range.

*edit*

https://en.wikipedia.org/wiki/Planck...29#Instruments

"Both instruments can detect both the total intensity and polarization of photons, and together cover a frequency range of nearly 830 GHz (from 30 to 857 GHz)."

So the idea is, a black body should be emitting equal energy on all wavelengths. Which, fits in the error bars:



http://www.astro.ucla.edu/~wright/CMB.html

Last edited by Mike Helland; 13th October 2021 at 06:07 PM.
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Old 13th October 2021, 06:52 PM   #114
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Originally Posted by Mike Helland View Post
My claim was, gravitational lensing could, as in the case with an Einstein cross or Einstein ring, bend CMB photons towards us that would have otherwise went off in some other direction.

That would increase the intensity, and therefore brightness temperature.
Repeats his abysmally ignorant claim and a obviously lying question/answer ("What do we use to measure the CMB?/It's not in the optical range.").
Everyone who reads the other thread can see he knows about the CMB and that it not detected with radio telescopes. Everyone who can read knows that CMB stands for cosmic microwave background. The CMB is detected with microwave telescopes such as WMAP and Planck. It is a lie to persist with radio telescopes that do not detect the CMB.

Brightness temperature is not a actual temperature as anyone who reads the Wikipedia article knows.

14 October 2021: A doubly ignorant fantasy that the ISW effect is gravitational lensing on 9 October.
14 October 2021: His very specific "So we get more photons from the object that way" nonsense.
Intensity of photons is not temperature of photons.
The CMB is not emitted by a radiating body with a brightness temperature.
The CMB is not a gray body- it is the most perfect black body we have detected.
The CMB temperature fluctuations were caused when it was emitted, not your gravitational lensing fantasy.
The CMB temperature fluctuations are modified by travelling through superclusters and supervoids. The ISW effect changes the temperature through gravitational redshift and blue shift becoming asymmetrical because we live in a universe with accelerating expansion. Gravitational lensing changes the shapes of the fluctuations (hot and cold spots), not the temperature.

He borrows figure from Ned Wright's Cosmic Microwave Background page where the FIRAS data from 1993 has error bars multiplied by 50 to make them visible. We know that he CMB has so perfect a black body spectrum to such an accuracy that the error bars are an order of magnitude thinner than the theoretical line! The next figure on the page emphasizes this.

Last edited by Reality Check; 13th October 2021 at 07:23 PM.
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Old 13th October 2021, 06:56 PM   #115
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I am not a radio astronomer, and the general topic of radio astronomy is not the subject of this thread. I doubt, however, whether anything I could write here could diminish Mike Helland's understanding of radio astronomy or physics.

Originally Posted by Mike Helland View Post
Right. The antenna will create a voltage from radio signals of whatever wavelength the antenna is tuned to.
Selectivity is a relevant concept. Selectivity is what allows you to listen to sports talk radio without having to listen, all at the same time, to religious programming, soft rock, hard rock, hip hop, jazz, blues, classical, local news, national news, international news, or Gilligan's Island.

Radio antennas can have directional selectivity, and can also be selective with respect to frequency. (They can also be selective with respect to polarization, but we needn't talk about that here.) Compared to optics, antennas have poor directional selectivity. Although antennas are often tuned to a specific range of wavelengths, an antenna is usually less selective (with respect to frequency/wavelength) than the receiver fed by the antenna.

Originally Posted by Mike Helland View Post
So, since we're just an S meter, and presumably a single wavelength antenna, then what we're really doing is measuring the intensity of photons coming in at that one wavelength (*edit* well, there's more than one wavelength in the band).
Yes, a frequency band, by definition, includes a range of wavelengths.

Antennas aren't selective enough to pick out a single wavelength. As you move away from the resonant frequency of an antenna, its sensitivity diminishes. A highly selective receiver is going to be more selective than the antenna.

Originally Posted by Mike Helland View Post
Do I have that right?
For the most part, no.

Originally Posted by hecd2 View Post
a) This is not radio astronomy and b) the concept of brightness temperature is irrelevant where the object you are detecting (the CMB) is the most perfect blackbody ever measured. There is no point in comparing the object being measured with a blackbody in this case, because the object being measured IS a blackbody.


Honestly Mike, your attempts to pick holes in physics that is way, way over your head by means of fundamental misunderstanding is what gets under people's skin. That, and your inability or refusal to learn anything ever. Read the two papers I linked above, understand them fully, and then we can talk.
Good advice.

Originally Posted by Mike Helland View Post
What do we use to measure the CMB?

It's not in the optical range.
Discovery of the cosmic microwave background is generally credited to Penzias and Wilson, who detected and measured the CMB using an extremely sensitive and quiet directional antenna combined with a receiver cooled by liquid helium. (It seems the CMB had been detected and measured earlier via spectroscopy, but that earlier detection was not recognized as the CMB until after the Penzias and Wilson detection.)

Edited to respond to Mike Helland's edit, which added this gem:
Originally Posted by Mike Helland View Post
So the idea is, a black body should be emitting equal energy on all wavelengths.
False.

Last edited by W.D.Clinger; 13th October 2021 at 07:05 PM.
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Old 13th October 2021, 07:33 PM   #116
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Originally Posted by Mike Helland View Post
So the idea is, a black body should be emitting equal energy on all wavelengths.
Another very ignorant statement.
Anyone who has ever learned about black bodies knows about Planck's law with its peak in spectral radiance (radiance is the energy emitted per unit time).
He camot even understand Ned Wright's Cosmic Microwave Background page which has a (not quoted!) description for the figure he borrowed. That figure has TB values for various wavelengths and instruments.
The FIRIS results are in the next figure and has wavelengths from about 2.5 cm to 20 cm. Each of the dots on the line is at a different frequency and so energy. The dots fit Planck's law.

Last edited by Reality Check; 13th October 2021 at 07:35 PM.
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Old 14th October 2021, 12:52 AM   #117
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Originally Posted by W.D.Clinger View Post
Selectivity is what allows you to listen to sports talk radio without having to listen, all at the same time, to religious programming, soft rock, hard rock, hip hop, jazz, blues, classical, local news, national news, international news, or Gilligan's Island.
Indeed. The antenna centers on a wavelength, but picks up much more.


Quote:
False.
Indeed. For all the fuss I made about brightness temperature, I should have said that instead of energy.
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Old 14th October 2021, 10:11 AM   #118
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Originally Posted by Mike Helland View Post
My claim was, gravitational lensing could, as in the case with an Einstein cross or Einstein ring, bend CMB photons towards us that would have otherwise went off in some other direction.
No.

First of all the Einstein ring or cross is strong gravitational lensing and is the result of imaging a bright source against a dark background. Nevertheless, the temperature of the source is not modified by the process - in other words, all elements of the imaged source appear to be the same temperature as the source would appear in the absence of the foreground massive object.

Similarly, gravitational lensing of the CMB is weak lensing of an almost (but not quite) uniform all-sky source, by which the anisotropies are distorted geometrically (ie their position and shape are modified, by a very small amount, from what they would be in the absence of the gravitational potential) but no temperature fluctuations are "caused". No additional hot spots or cold spots are created by gravitational lensing.
Quote:
That would increase the intensity, and therefore brightness temperature.

https://en.wikipedia.org/wiki/Brightness_temperature
No it wouldn't. You misunderstand the concept (as ever). The brightness temperature of the imaged Einstein ring or cross will be exactly the same as the brightness temperature of the source in the absence of the foreground mass.

Similarly, the brightness temperature of the CMB equals exactly the temperature of the CMB (since the CMB is a perfect blackbody within experimental error) and the temperature of any part of it is not modified in any way by gravitational lensing.

How are you getting on with reading and understanding those papers I linked to?
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Old 14th October 2021, 10:18 AM   #119
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Originally Posted by Mike Helland View Post
What do we use to measure the CMB?

It's not in the optical range.
Generally resonant microwave horns for directionality and frequency discrimination and either solid state detectors or bolometers for detection. These are not radio telescopes with reflectors and anttenae.

Last edited by hecd2; 14th October 2021 at 10:18 AM. Reason: Missing: not
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Old 14th October 2021, 10:28 AM   #120
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Originally Posted by hecd2 View Post
No.
First of all the Einstein ring or cross is strong gravitational lensing and is the result of imaging a bright source against a dark background. Nevertheless, the temperature of the source is not modified by the process - in other words, all elements of the imaged source appear to be the same temperature as the source would appear in the absence of the foreground massive object.
Right.

If you see double vision while looking at an ice cube, the ice cube doesn't get colder.

Quote:
Similarly, gravitational lensing of the CMB is weak lensing of an almost (but not quite) uniform all-sky source
Right.

It can only be weak gravitational lensing, because strong lensing requires the background to be close to the foreground.

Since you believe the CMB light is 14 billion years old, no strong lensing can occur.

Unless... the CMB photons aren't the oldest ones around.



Quote:
Similarly, the brightness temperature of the CMB equals exactly the temperature of the CMB (since the CMB is a perfect blackbody within experimental error)
Everyone is perfect... within experimental error.

IF the universe is expanding, the redshift-distance data alone is overwhelming evidence the expansion rate is faster now than before.

IF the universe is expanding, dark energy is clearly needed. I agree with that.

I don't think +/- 10 micro Kelvin is as strong as evidence where there are super clusters/voids, but you're entitled to your opinion.
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