How does astronomy use the electromagnetic spectrum?

How does BB explain the origin of the electromagnetic spectrum? For example, why should there be optical light vs. nothing to see at all?

Consider some past discussions on issues like this in science.



 
Dec 27, 2022
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The underlying assumptions are that the universe is expanding and that the speed of light is constant. However the expanding-universe theory is too preposterous and will soon be abandoned. Then the only reason behind the cosmological (Hubble) redshift will turn out to be GRADUALLY DECREASING SPEED OF LIGHT. And cosmologists will have to start from the scratch.
 
"This uniformness is unseen in other wavelengths, which reveal the sky in dots and regions of varying brightness. In fact, cosmic microwave radiation is so odd that the researchers who first discovered it in the 1960s (completely by accident during experiments with echo balloons) originally thought it was produced by a telescope defect.

Subsequent research, however, confirmed that the microwave hum was coming from space and that it was nothing less than the residue of radiation released by the Big Bang, the enormous explosion which created the universe some 13.8 billion years ago."

According to cosmology calculators, depending upon the input value for H0, the universe radius when the CMBR became light was about 40-41 million light years radius. In the spectrum of the CMBR, where is the H-alpha line and He showing the universe then was filled with H and He gas? The same applies to the H1 21-cm line for H gas filling the universe during the cosmic dark ages and showing zero-metal gas?
 
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According to cosmology calculators, depending upon the input value for H0, the universe radius when the CMBR became light was about 40-41 million light years radius. In the spectrum of the CMBR, where is the H-alpha line and He showing the universe then was filled with H and He gas? The same applies to the H1 21-cm line for H gas filling the universe during the cosmic dark ages and showing zero-metal gas?
If I understand it, the photons were highly scattered during those 40 million years until the universe cooled, due to expansion, to about 3000K (2.73 x 1100). Suddenly, the electrons became bound to the protons, forming the first atoms. Thus, all those photons were released to go flying in every direction without all that scattering. So we’re not seeing emissions from h or he, hence no emission or absorption lines.
 
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If I understand it, the photons were highly scattered during those 40 million years until the universe cooled, due to expansion, to about 3000K (2.73 x 1100). Suddenly, the electrons became bound to the protons, forming the first atoms. Thus, all those photons were released to go flying in every direction without all that scattering. So we’re not seeing emissions from h or he, hence no emission or absorption lines.

However, Helio, others do not see this as you present.

Hydrogen absorption lines in the cosmic microwave background spectrum, https://www.researchgate.net/public...s_in_the_cosmic_microwave_background_spectrum, August 2004. "We have calculated the intensities of the subordinate hydrogen lines formed during the recombination epoch at redshifts 800≲z≲1600. We show that an allowance for the angular momentum splitting of hydrogen atomic energy levels and the dipole transition selection rules can reveal absorption features in the cosmic microwave background recombination spectrum in the submillimeter wavelength range."

Impact of inhomogeneous CMB heating of gas on the HI 21-cm signal during dark ages, https://arxiv.org/abs/1810.05908

What I see here, unlike the phases of Venus that can be clearly seen in astronomy, we do not see H and He gas filled the early universe, even during the postulated dark ages in BB cosmology. Apparently some are looking for this hard evidence.
 
However, Helio, others do not see this as you present.

Hydrogen absorption lines in the cosmic microwave background spectrum, https://www.researchgate.net/public...s_in_the_cosmic_microwave_background_spectrum, August 2004. "We have calculated the intensities of the subordinate hydrogen lines formed during the recombination epoch at redshifts 800≲z≲1600. We show that an allowance for the angular momentum splitting of hydrogen atomic energy levels and the dipole transition selection rules can reveal absorption features in the cosmic microwave background recombination spectrum in the submillimeter wavelength range."

Impact of inhomogeneous CMB heating of gas on the HI 21-cm signal during dark ages, https://arxiv.org/abs/1810.05908
Thanks. I will want to look at this closer. There must be both the huge release of photons, unaffected by the new atoms, but also a significant number that did interact by hydrogen and he. We had a thread on this that noted it’s H2 that allows transparency, not H.
 
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Frequencies of light invisible to the human eye reveal a vast amount of information about our universe. But it took decades for scientists to learn how

How does astronomy use the electromagnetic spectrum? : Read more
We’ve come a long way since Plato postulated the eyes emitted light to see things.

The serendipity along the way adds great color, so to speak, to the history behind understanding the spectrum. For instance, William Herschell placed a thermometer on each color of the spectrum he projected, likely using a prism. But he happen to notice that when he placed the thermometer off to the side (red side), the temperature was this highest. He discovered, as a result, the IR spectrum.
 
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However, Helio, others do not see this as you present.

Hydrogen absorption lines in the cosmic microwave background spectrum, https://www.researchgate.net/public...s_in_the_cosmic_microwave_background_spectrum,

In their short conclusion, they seem to confirm the spectral distribution that would exist for the Recombination event. Recombination, of course, is a major prediction of the BBT, giving us the CMBR. That they can see some Hβ and Hγ lines is interesting, and not contrary to BBT.
 
In their short conclusion, they seem to confirm the spectral distribution that would exist for the Recombination event. Recombination, of course, is a major prediction of the BBT, giving us the CMBR. That they can see some Hβ and Hγ lines is interesting, and not contrary to BBT.
Helio, that did not confirm or seem to confirm H or He in the CMBR spectrum. Note what was stated:

"CONCLUSIONS We have calculated the spectrum of hydrogen re-combination lines in the Wien region of the CMB radiation near its maximum. We showed that the correct analysis of the recombination kinetics can reveal the absorption features in the hydrogen recombination spectrum that correspond to the Hβ and Hγ lines. The presence of such features is an interesting fact of the conditions of almost complete thermodynamic equilibrium during the hydrogen recombination epoch. Observationally, this can increase significantly the detection probability of these spectral lines. A detailed analysis of the observing technique and the prospects for detecting these lines is beyond the scope of this study. Note only that the rapid in-crease in the number of submillimeter-wavelength telescopes and detectors and the emergence and development of new microbolometer arrays give hope that the predicted calculated distortions of the CMB radiation will be actually detected in the near future."

None have been reported as confirmed and detected and no H1 21-cm line for the cosmic dark ages. The abstract shows the redshift is in the range of 800 to 1600 compared to 1100 for the postulated redshift for the CMBR we see today. Showing the early universe whether the size of 41 million light years radius or larger during cosmic dark ages, lacks verification of H and He gas. It is a theoretical calculation that lacks verification like seeing the phases of Venus for example. BBT disciples should be very clear to the public about this I feel.
 
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Here is a bit more following my post #11.

The August 2004 reference I cited is on the NASA ADS Abstract too. Hydrogen Absorption Lines in the Cosmic Microwave Background Spectrum, https://ui.adsabs.harvard.edu/abs/2004AstL...30..509D/abstract

Another NASA ADS report, Lines in the cosmic microwave background spectrum from the epoch of cosmological hydrogen recombination, https://ui.adsabs.harvard.edu/abs/2006MNRAS.371.1939R/abstract, October 2006.

"We compute the spectral distortions of the cosmic microwave background (CMB) arising during the epoch of cosmological hydrogen recombination within the standard cosmological (concordance) model for frequencies in the range 1-3500 GHz. We follow the evolution of the populations of the hydrogen levels including states up to principle quantum number n = 30 in the redshift range 500 <= z <= 3500. All angular momentum substates are treated individually, resulting in a total number of 465 hydrogen levels. The evolution of the matter temperature and the fraction of electrons coming from HeII are also included. We present a detailed discussion of the distortions arising from the main dipolar transitions, for example Lyman and Balmer series, as well as the emission due to the two-photon decay of the hydrogen 2s level. Furthermore, we investigate the robusteness of the results against changes in the number of shells considered. The resulting spectral distortions have a characteristic oscillatory behaviour, which might allow experimentalists to separate them from other backgrounds. The relative distortion of the spectrum exceeds a value of 10^-7 at wavelengths longer than 21 cm. Our results also show the importance of detailed follow-up of the angular momentum substates, and their effect on the amplitude of the lines. The effect on the residual electron fraction is only moderate, and mainly occurs at low redshifts. The CMB angular power spectrum is changed by less than 1 per cent. Finally, our computations show that if the primordial radiation field is described by a pure blackbody, then there is no significant emission from any hydrogen transition at redshifts greater than z ~ 2000. This is in contrast to some earlier works, where the existence of a `pre-recombination' peak was claimed."

My main point is that H and He is not confirmed in the spectrum of the CMBR or in the period of the cosmic dark ages in BB cosmology. The claim of an original, hot primordial H and He gas that created the CMBR is theoretical, not something observed like H and He in the stars or H1 21-cm line gas in the Milky Way galaxy. BBT advocates should make this clear to the public.
 
Helio, that did not confirm or seem to confirm H or He in the CMBR spectrum. Note what was stated:
Correct. Somehow I misread their findings. Their work predicts future confirmation with better instruments/scopes.

None have been reported as confirmed and detected and no H1 21-cm line for the cosmic dark ages. The abstract shows the redshift is in the range of 800 to 1600 compared to 1100 for the postulated redshift for the CMBR we see today. Showing the early universe whether the size of 41 million light years radius or larger during cosmic dark ages, lacks verification of H and He gas. It is a theoretical calculation that lacks verification like seeing the phases of Venus for example.
Yes, but like Galileo favoring the Cop model, the model makes predictions that can be tested with future observations with improved telescopes. Time will tell.

But that the CMBR is like a giant ball oh hot H and He is not accurate since it, primarily, is the photon flood that was released as if from prison that was predicted and observed. Shortly after this instant blast, which varied slightly across the smaller universe, the light passed through the gas formed. This is the clouds they mention. Thus, we should see both the light from the CMBR plus some degree of absorption lines. Their computer modeling allows them to alter the redshift, so they offer this as well. Thus, if absorption lines are eventually found, say, for z=1500, then they will earn some credit in helping create a conundrum for BBT. It’s still the safe bet for something very close to z=1100.

BBT disciples should be very clear to the public about this I feel.
I think cosmologists are clear. Notice that this paper is only stating their findings, not taking sides. Or do you see it differently?

Given the plethora of ATM threads, including personal attacks on Einstein, it’s getting harder to justify one‘s efforts to have normal discussions of disagreement, though your the exception to this, thankfully.
 
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Correct. Somehow I misread their findings. Their work predicts future confirmation with better instruments/scopes.


Yes, but like Galileo favoring the Cop model, the model makes predictions that can be tested with future observations with improved telescopes. Time will tell.

But that the CMBR is like a giant ball oh hot H and He is not accurate since it, primarily, is the photon flood that was released as if from prison that was predicted and observed. Shortly after this instant blast, which varied slightly across the smaller universe, the light passed through the gas formed. This is the clouds they mention. Thus, we should see both the light from the CMBR plus some degree of absorption lines. Their computer modeling allows them to alter the redshift, so they offer this as well. Thus, if absorption lines are eventually found, say, for z=1500, then they will earn some credit in helping create a conundrum for BBT. It’s still the safe bet for something very close to z=1100.

I think cosmologists are clear. Notice that this paper is only stating their findings, not taking sides. Or do you see it differently?

Given the plethora of ATM threads, including personal attacks on Einstein, it’s getting harder to justify one‘s efforts to have normal discussions of disagreement, though your the exception to this, thankfully.
Helio, what I see is that some papers are clear, popular science reporting sites I find commonly do not call attention to what I pointed out about the CMBR, H, He, and cosmic dark ages. I agree, "Time will tell."
 
Helio, what I see is that some papers are clear, popular science reporting sites I find commonly do not call attention to what I pointed out about the CMBR, H, He, and cosmic dark ages. I agree, "Time will tell."
Yes, but the confluence of all those independent lines of evidence — as enumerated in the Big Bang Bullets thread — greatly favors the general BBT, with tweaking still needed.

When Galileo allowed others to see for themselves the phases of Venus, which falsified the Ptolemy model, a few simply claimed the telescope could not be trusted. The main body of scientists (i.e. Jesuits) made carefull observations and quickly agreed with Galileo. The empirical weight of evidence crushed the 2000 year-old model, which had very little weight in its favor over the other two models.

Perhaps new observations will debunk the BBT, but the current weight of evidence favoring BBT has grown to a very high level to earn the respect given it by cosmologists since the tiny start in 1927.

iPad
 
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FYI, my understanding about H in the CMBR spectrum came from an earlier post by Unclear Engineer in another thread and article on the forums.

Unclear Engineer in post #33 said, "I doubt that we will be able to measure isotope distributions out to
"20 billion light years", at least during my lifetime, since that requires using electromagnetic radiation,
and we are having trouble seeing much in the CMBR, specifically no alpha lines for hydrogen."

That was the first I encountered thinking like this about the CMBR, the foundation for modern BB cosmology. All lines of *independent evidence* come from the model to explain the origin of the CMBR that presently, lacks confirmation of H gas or He gas in the spectrum as well as during the postulated cosmic dark ages.
 
FYI, my understanding about H in the CMBR spectrum came from an earlier post by Unclear Engineer in another thread and article on the forums.

Unclear Engineer in post #33 said, "I doubt that we will be able to measure isotope distributions out to
"20 billion light years", at least during my lifetime, since that requires using electromagnetic radiation,
and we are having trouble seeing much in the CMBR, specifically no alpha lines for hydrogen."

That was the first I encountered thinking like this about the CMBR, the foundation for modern BB cosmology. All lines of *independent evidence* come from the model to explain the origin of the CMBR that presently, lacks confirmation of H gas or He gas in the spectrum as well as during the postulated cosmic dark ages.
There are three related areas that I would like to better understand:
1) The ocean of photons were released from captivity (scattering). These are independent of the H that had just formed, hence no lines in the spectrum. This is what was predicted in BBT and is now the CMBR.
2) But some photons did interact with H in that epoch, hence the search for the lines.
3) Much of the H soon became H2, which makes H transparent, but not all.

Over time, the more distant light from Recombination had to pass through clouds of gas, thus necessitating that we see absorption lines in these clouds. But these lines would vary in redshift with their distance. This was a prediction, and guess what they found? This is known as the Lyman Alpha Forest.

The BBT predicted that the sea of photons at Recombination would present an almost perfect BB. I think this was assuming homogeneity. But there are other aspects to the spectrum that were also predicted, such as the power spectrum, and others. Among all the dozen or so predictions, the CMBR includes the strongest arguments favoring BBT. It easily bumped BBT to mainstream for the hold-out cosmologists, with few exceptions (Hoyle).
 
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Here is a short summary of areas in BB cosmology that I feel lack verification at present.

My plan to spot neutrinos from the big bang would transform cosmology, https://www.newscientist.com/articl...-from-the-big-bang-would-transform-cosmology/

space.com mentioned this too in the past. https://forums.space.com/threads/a-...ock-a-key-mystery-of-ghostly-neutrinos.29431/

My observation. The Big Bang is missing some critical components. Primordial neutrinos created are still missing, there is no spectrum confirming the presence of H, He gas in the CMBR, there is no H1 21-cm line observed for the cosmic dark ages, there are no Population III stars observed, and we do not have any gas clouds showing zero-metals documented.
 
"This is known as the Lyman Alpha Forest."

Helio, nice list in your post #18, however, the Lyman alpha forest seen in quasar light still shows metals in the gas, no matter what the redshift. The original, pristine gas created during BBN has not been observed. This does not overthrow BBT but is another component predicted that remains unseen as I show in post #19, some of the other items predicted but still not confirmed.
 
My post #20, where is the complete list of all the predictions that BBT failed and later modified, including predictions that remain unverified? I would enjoy reading that list :)
 
Here is a short summary of areas in BB cosmology that I feel lack verification at present.

My plan to spot neutrinos from the big bang would transform cosmology, https://www.newscientist.com/articl...-from-the-big-bang-would-transform-cosmology/

space.com mentioned this too in the past. https://forums.space.com/threads/a-...ock-a-key-mystery-of-ghostly-neutrinos.29431/
Yes, detecting these primordial neutrinos would push our observation way past the CMBR, so it is very important that we try to find them, which would allow greater BBT tweaking.

My observation. The Big Bang is missing some critical components.
Newton's gravity theory did not state the gravity on Jupiter, nor could they determine it at that time, so was Newton's theory in jeopardy. The use of "critical" implies some sort of existential threat to BBT, but it's not, or am I wrong? Supposing neutrino discoveries will debunk BBT is highly unlikely. But every theory must be falsifiable, so maybe it could happen, but we certainly aren't at any critical point, IMO.

Primordial neutrinos created are still missing, there is no spectrum confirming the presence of H, He gas in the CMBR, there is no H1 21-cm line observed for the cosmic dark ages, there are no Population III stars observed, and we do not have any gas clouds showing zero-metals documented.
But BBT argues that there are no observable Pop III stars, not because they aren't there in the model, but because telescopes of extreme powers don't exist, including the JWST. The fact that we don't see Pop III stars today is a requirement of BBT. It's unfair to degrade a theory for observations that aren't currently possible, when there are tons and tons and tons of evidence that already support the theory.