Raymond Tallis: Time Travel and Other Myths about Time

There is an excellent and informative recent updated article on this controversy over the Big Bang and new JWST data, by astronomer Guillermo Gonzalez, at https://evolutionnews.org/2023/11/the-bi...two-tests/. It is entitled The Big Bang Survives Two Tests, dated November 2, 2023.

In summary, the article shows that now some time after the first observations from JWST, the Big Bang theory has passed both a strong test and a weak one. That’s not to say there are now absolutely no tensions between theory and observation.

"As Stephen Meyer pointed out in September 2022, even if the initial JWST observations were taken at face value and showed that galaxy formation did not agree with predictions, it would not disprove the Big Bang theory. It would just show that theories of galaxy formation need revision. This is because the Big Bang theory rests on three observational pillars: the cosmic microwave background radiation, the abundances of the light element (H, He, Li) isotopes, and the Hubble-Lemaître redshift-distance law.
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Well, it looks like some astronomers have done the needed (investigation of this matter). One study compared a suite of cosmological simulations to the JWST observations of distant galaxies. They found that standard early galaxy growth models can explain the JWST observations without invoking nonstandard cosmology or ad hoc fine-tuning of models. In particular, their simulations show that bursty star formation needs to be taken into account in these early times, rather than a smoothly varying one. Neglecting it can lead to biases in estimating the number of bright galaxies in early times.

Another recent study (not yet peer reviewed) concluded that early JWST observations of distant seemingly massive and mature galaxies were misinterpreted. The galaxies they studied were selected according to a certain spectral feature called a double-break (highly redshifted Lyman and Balmer breaks). For five of the galaxies, the colors were due to emission lines in star-forming galaxies which caused them to be misclassified as massive double break galaxies. They observed more galaxies and over multiple fields than the early studies, giving them a much better handle on the statistics. The field-to-field cosmic variations can cause the maximum mass to be vastly overestimated. They conclude that the double-break galaxies they surveyed do not contradict standard cosmology.
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While they haven’t received much attention, a couple other recent studies provide a clean and simple test of the Big Bang theory. One of them determined the age of an ancient star cluster, M92. Clearly, to be consistent with the Big Bang theory the ages of the oldest stars cannot exceed the cosmological age. To date, observations of the cosmic microwave background radiation have yielded the most accurate and precise cosmological age (13.80 ± 0.06 billion years).

M92 is one of about 160 known globular star clusters in the Milky Way galaxy and is estimated to contain about 330,000 stars. Given its proximity, astronomers have been studying it for over a century, each decade bringing to bear better observation tools and/or better models. This latest study yielded an age of 13.80 ± 0.75 billion years and determined that the observations are consistent with the stars in the cluster having formed nearly simultaneously. To date, this is the most accurate and precise determination of age for a group of coeval stars. Within the quoted error, M92 formed up to 0.75 billion years after the Big Bang, which is enough time for M92 to have formed according to standard cosmology. If M92 were found to be, say, 16.5 ± 0.75 billion years, then that would pose a major challenge to the Big Bang theory."

There's more.

While the parameters in virtually every mathematical model can be adjusted to yield desired results, explaining away the existence of the ambient cosmic microwave background is incredibly hard. The uniformly redshifted radiation, no matter which direction we look, strongly suggests an universe that is expanding everywhere.

While the parameters in virtually every mathematical model can be adjusted to yield desired results, explaining away the existence of the ambient cosmic microwave background is incredibly hard. The uniformly redshifted radiation, no matter which direction we look, strongly suggests an universe that is expanding everywhere.

Doesn't anyone feel uneasy that the CMB consists of isotropic black body radiation! I mean suppose the CMB did not exist, I'd have thought there would be some radiation coming from dust of various sorts etc.

David

Doesn't anyone feel uneasy that the CMB consists of isotropic black body radiation! I mean suppose the CMB did not exist, I'd have thought there would be some radiation coming from dust of various sorts etc. 

David

Interstellar dust emits radiation across a broad frequency range, primarily in the infrared. Unlike the isotropic CMB, dust is not evenly distributed in the universe, leading to non-isotropic radiation.

Interstellar dust emits radiation across a broad frequency range, primarily in the infrared. Unlike the isotropic CMB, dust is not evenly distributed in the universe, leading to non-isotropic radiation.

Surely this is dust which is re-radiating starlight, but if thermal energy is repeatedly re-radiated, doesn't it settle into the black body spectrum?

I mean the idea that the universe has some black body spectrum radiation - possibly with scattered radiation superimposed on it - seems intuitive to me.

David

Surely this is dust which is re-radiating starlight, but if thermal energy is repeatedly re-radiated, doesn't it settle into the black body spectrum?

I mean the idea that the universe has some black body spectrum radiation - possibly with scattered radiation superimposed on it - seems intuitive to me.

David

Yes, dust also emits blackbody radiation, which is characterized by the shape of its spectrum rather than specific wavelength intervals. The spectrum's peak and distribution depend on the dust's temperature. Telescopes like the Herschel Space Telescope are designed to detect this radiation, especially in the infrared range, (Herschel was designed for studying star formation and the properties of interstellar dust). Maybe also Spitzer , but I didn’t doublecheck on this telescope.

Yes, dust also emits blackbody radiation, which is characterized by the shape of its spectrum rather than specific wavelength intervals. The spectrum's peak and distribution depend on the dust's temperature. Telescopes like the Herschel Space Telescope are designed to detect this radiation, especially in the infrared range, (Herschel was designed for studying star formation and the properties of interstellar dust). Maybe also Spitzer , but I didn’t doublecheck on this telescope.

Exactly - and how do we know how much intergalactic dust there is? I wonder if the CMB signal is actually the signal from interstellar dust - dust that is far enough away from anything that it only radiates black body radiation!

David

Exactly - and how do we know how much intergalactic dust there is? I wonder if the CMB signal is actually the signal from interstellar dust - dust that is far enough away from anything that it only radiates black body radiation!

David

Is it the redshift of radiation due to the expansion of the universe that you wish to disprove? (disproving redshifting is equivalent to disproving that the universe is expanding). Let's assume that this expansion does not occur. Then your hypothesis would require an almost perfectly dense and uniform distribution of interstellar dust throughout the universe, emitting in the microwave spectrum. However, as you yourself pointed out earlier, most emission from dust is due to heating from starlight. This heating cannot be as uniform as required to replace the CMB theory. There’s also the problem that gravity wouldn’t leave dust uniformly distributed.

There’s also the redshift in the spectral line emission from distant stars, providing critical evidence that the universe is expanding. (Discovered by Edwin Hubble)

Interstellar dust is one of the least likely alternative possibilities for the CMB; so far it has apparently been seriously implicated only in causing certain extremely slight irregularities in the CMB, not all the observed small variations. The graph below shows how very closely the observation data actually follows the theoretical black body curve. The error bars are too small to be seen even in an enlarged image, and it is impossible to visually distinguish the observed data from the theoretical curve.

From https://en.wikipedia.org/wiki/Cosmic_mic...background:

"The CMB is not completely smooth and uniform, showing a faint anisotropy that can be mapped by sensitive detectors. Ground and space-based experiments such as COBE and WMAP have been used to measure these temperature inhomogeneities.
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Precise measurements of the CMB are critical to cosmology, since any proposed model of the universe must explain this radiation. The CMB has a thermal black body spectrum at a temperature of 2.72548±0.00057 K.[6] The spectral radiance dEν/dν peaks at 160.23 GHz, in the microwave range of frequencies, corresponding to a photon energy of about 6.626×10−4 eV. Alternatively, if spectral radiance is defined as dEλ/dλ, then the peak wavelength is 1.063 mm (282 GHz, 1.168×10−3 eV photons). The glow is very nearly uniform in all directions, but the tiny residual variations show a very specific pattern, the same as that expected of a fairly uniformly distributed hot gas that has expanded to the current size of the universe. In particular, the spectral radiance at different angles of observation in the sky contains small anisotropies, or irregularities, which vary with the size of the region examined. They have been measured in detail, and match what would be expected if small thermal variations, generated by quantum fluctuations of matter in a very tiny space, had expanded to the size of the observable universe we see today. This is a very active field of study, with scientists seeking both better data (for example, the Planck spacecraft) and better interpretations of the initial conditions of expansion. Although many different processes might produce the general form of a black body spectrum, no model other than the Big Bang has yet explained the fluctuations. As a result, most cosmologists consider the Big Bang model of the universe to be the best explanation for the CMB.

The high degree of uniformity throughout the observable universe and its faint but measured anisotropy lend strong support for the Big Bang model in general and the ΛCDM ("Lambda Cold Dark Matter") model in particular. Moreover, the fluctuations are coherent on angular scales that are larger than the apparent cosmological horizon at recombination. Either such coherence is acausally fine-tuned, or cosmic inflation occurred.
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Two of the greatest successes of the Big Bang theory are its prediction of the almost perfect black body spectrum and its detailed prediction of the anisotropies in the cosmic microwave background. The CMB spectrum has become the most precisely measured black body spectrum in nature."

Interstellar dust is one of the least likely alternative possibilities for the CMB; so far it has apparently been seriously implicated only in causing certain extremely slight irregularities in the CMB, not all the observed small variations. The graph below shows how very closely the observation data actually follows the theoretical black body curve. The error bars are too small to be seen even in an enlarged image, and it is impossible to visually distinguish the observed data from the theoretical curve.

Well just imagine how intergalactic dust would look to us - it would look like black body radiation - exactly what your graph shows!

I mean, do we have any reason to assume that intergalactic space does not contain dust? The only way it will show itself will be as BB-radiation - which is exactly what the CMB is!

The simple explanation of the CMB is that it comes from intergalactic dust, the more complicated explanation (preferred by physicists) is that it is light from the Big Bang stretched out over 14 billion years of expansion.

When it comes to those supposed minute fluctuations in the CMB, well if they are real, we will never know what they might represent if we don't look at alternatives to the idea that the CMB comes from a Big Bang. It is possible to use computer models to 'explain' anything - now if the BB enthusiasts had actually predicted the CMB, before it was discovered, that would be more suggestive.

David