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CMBR data it doesn't carry any redshift.
BBT calculation/Theory?
"Mark asked how we know the redshift of the CMBR if it has no emission or absorption lines, which is the usual way to determine redshifts of e.g. stars and galaxies."
Hence, the expected CMBR redshift value based on the BBT calculation should be 1100.However, we know by now that based on the observed CMBR data it doesn't carry any redshift.
Is it correct that the redshift of the CMBR has no emission or absorption lines?
Quote from: Dave Lev on 31/01/2023 08:47:02Is it correct that the redshift of the CMBR has no emission or absorption lines?No, that's a category error.A red shift is a number, it is 1100 in this case.How can a number have lines?
The most accurate way to measure redshift is by using spectroscopy.
If the absorption or emission lines they see in the star's spectra are shifted, they know the object is moving either towards us or away from us."
Therefore, the emission & absorption lines are critical for the redshift measurements.
Do you agree by now that as there is no emission or absorption lines in the CMBR then there is no redshift in the CMBR data?
QuoteQuote from: Dave Lev on Today at 09:53:26If the absorption or emission lines they see in the star's spectra are shifted, they know the object is moving either towards us or away from us."You seem not to have appreciated the importance of the word "if" at the start of that quote or you have failed to recognise that the whole emission spectrum is a very broad "line".
Quote from: Dave Lev on Today at 09:53:26If the absorption or emission lines they see in the star's spectra are shifted, they know the object is moving either towards us or away from us."
QuoteQuote from: Dave Lev on Today at 09:53:26Therefore, the emission & absorption lines are critical for the redshift measurements.NoAll you need to do is look at the peak of the blackbody spectrum.Indeed, that's all you can look at. It's essentially the only number you get which refers to the wavelength.
Quote from: Dave Lev on Today at 09:53:26Therefore, the emission & absorption lines are critical for the redshift measurements.
You can easily measure the red shift.We know what the effective temperature is when hydrogen recombines.And we know what the temperature of the CMBR is.And the ratio of those gives us the red shift- about 1100. (It's a bit more complicated than that- not every atom has to be ionised; but since you don't even understand the basics, we can leave the complicated bits aside for now).
We know what the effective temperature is when hydrogen recombines.
z \text{ (redshift)} = \frac{3000}{2.725} = 1100
"The redshift of the Cosmic Microwave Background (CMB) is not measured, it is calculated."
We know what the effective temperature is when hydrogen recombines.And we know what the temperature of the CMBR is.And the ratio of those gives us the red shift- about 1100. (It's a bit more complicated than that- not every atom has to be ionised; but since you don't even understand the basics, we can leave the complicated bits aside for now).
Now you claim that there is no need for emission & absorption lines.
you have failed to recognise that the whole emission spectrum is a very broad "line".
There is no spectroscopy in this explanation.
So, why do you claim: "You can easily measure the red shift."
Therefore, do you confirm that we do not measure the redshift value from the CMB radiation data by spectroscopy?
You assume that the hydrogen recombines temp is 3000K.
Can you please prove it?
Even if that value is correct, do you agree that we have calculated the CMBR redshift by the following formula?
Hence, why do you insist that we measure CMB redshift (by using spectroscopy)
while you fully confirm that the redshift is calculated based on the hydrogen recombines idea (without any spectroscopy)
The only plausible source for radiation with no structure (no lines or bands etc) is the recombination of hydrogen nuclei and electrons.
What is the redshift of the Cosmic Microwave Background (CMB)?https://thecuriousastronomer.wordpress.com/2015/07/30/what-is-the-redshift-of-the-cosmic-microwave-background-cmb/"Mark asked how we know the redshift of the CMBR if it has no emission or absorption lines, which is the usual way to determine redshifts of e.g. stars and galaxies."So, do we all agree that there is no emission or absorption lines in the CMBR and therefore there is no way to extract the redshift value from the CMBR data?
QuoteQuote from: Dave Lev on 31/01/2023 15:54:26You assume that the hydrogen recombines temp is 3000K.We have measured it.Even thishttps://en.wikipedia.org/wiki/Atomic_hydrogen_welding#:~:text=The%20process%20was%20invented%20by,3400%20to%204000%20%C2%B0C.Gives you a pretty good estimate.It's not an assumption.You just assume that nobody understands it- because you don't understand it.
Quote from: Dave Lev on 31/01/2023 15:54:26You assume that the hydrogen recombines temp is 3000K.
Today we have very sensitive and advanced observation tools.Therefore, we should have the technology to detect/observe the CMBR around those far away galaxies. Do we really observe that the CMBR λobserved over there is as high as expected (based on the age of the early universe)?
So why the 3000K had been selected?
(It's a bit more complicated than that- not every atom has to be ionised; but since you don't even understand the basics, we can leave the complicated bits aside for now).
However, how do we know for sure that the CMBR λobserved is exactly the same as the "Atomic hydrogen welding"?
So why we do not use the peak in the "Atomic hydrogen welding" to set the λobserved?At the maximal level of 6000 °C (or 6273K) the redshift should be about:Z = (6275 – 2.75) / 2.75 = 2,281
How can we claim that the real redshift of the CMBR is exactly 1100?
Therefore, do you finely confirm that we have never measured the CMBR λobserved?
Z= (λobserved -λrest) / λrestZ = (6275 – 2.75) / 2.75 = 2,281
We have observed the temperature we observed.2.72548±0.00057 K.We have observed the wavelength we observed 1.063 mm
QuoteQuote from: Dave Lev on Today at 05:36:48So why the 3000K had been selected?(It's a bit more complicated than that- not every atom has to be ionised; but since you don't even understand the basics, we can leave the complicated bits aside for now)
Quote from: Dave Lev on Today at 05:36:48So why the 3000K had been selected?
Quote from: Dave Lev on 04/02/2023 05:36:48Z= (λobserved -λrest) / λrestZ = (6275 – 2.75) / 2.75 = 2,281Why did you suddenly shift from using wavelengths to temperatures?Don't you see the problem there?
Quote from: Dave Lev on 04/02/2023 05:36:48Today we have very sensitive and advanced observation tools.Therefore, we should have the technology to detect/observe the CMBR around those far away galaxies. Do we really observe that the CMBR λobserved over there is as high as expected (based on the age of the early universe)?I'm not sure what you are trying to say. It seems like you are saying the CMBR wavelength we detect around those galaxies should be different than the CMBR wavelength we detect on earth, but that doesn't make any sense.
We see that based on the BBT, 12 B years ago, the expected CMBR temp is 15K.So, in less than 2 billion years the expected CMBR (based on the BBT) had been cooled down from 3000K to 15K.I couldn't find the expected CMBR temp at 13 B Years ago, but I assume that is should be higher than this 15K.We clearly see galaxies at a distance of more than 13BLY away.Those galaxies had been formed more than 13 B years ago.So, as we see those galaxies, why can't we monitor the ambient-temperature-of-the-universe around those ultra-far away galaxies?
The simple answer is that the photons we see from the galaxy itself are 12 billion years old and the photons we see from the CMBR that were in the vicinity of that galaxy are 13.6 billion years old.
form neutral atoms of mostly hydrogen. Unlike the plasma, these atoms could not scatter thermal radiation by Thomson scattering, and so the universe became transparent
we should have the technology to detect/observe the CMBR around those far away galaxies.
There are several expected temp levels in that "Atomic hydrogen welding" process
we only use the measured peak temperature as the λrest in the redshift formula
As long as this value is based on the BBT, then we all must agree that it doesn't reflect the real CMBR redshift!
The Big Bang theory suggests that as the universe expanded, it cooled and became less dense- So the peak of the Black Body radiation spectrum shifted to longer wavelengths/lower frequencies- When the temperature of the universe dropped low enough for the last of the hydrogen protons & electrons to combine into neutral hydrogen atoms, the universe became transparent to all wavelengths up to UV (photons <13 eV)- So what we now see in the CMBR is the plasma black-body radiation, red-shifted from a temperature of around 3000K to 2.7K
This means that HD1 is far from the "surface of last scattering", which is the source of CMBR at z=1100
The CMBR exhibits a dipole, suggesting a motion of our star in our galaxy of about 600km/sec, relative to the CMBR. https://astronomy.swin.edu.au/cosmos/c/Cosmic+Microwave+Background+Dipole
Hydrogen welding is conducted in hydrogen gas, which has several additional degrees of freedom than the atomic hydrogen which is believed to be the source of the CMBR.
- So what we now see in the CMBR is the plasma black-body radiation, red-shifted from a temperature of around 3000K to 2.7K- The formation of atomic hydrogen was not the source of the radiation, but more the "camera shutter" through which we can now see the plasma of the universe's early fireball.