"First detected by Arno Penzias and Robert Wilson in 1965, the CMB is one of the most conclusive pieces of evidence in favour of the Big Bang. In particular,
Big Bang theory predicts certain characteristics for the radiation left over from the birth of the Universe, all of
which are confirmed by the CMB:"
It might seem pedantic, to keep reiterating that the Big Bang theory predicts things, which are then found....
It is a fact that the COBE data are manipulated using Bayesian and Monte Carlo techniques which mostly belong to the data processing of political opinion polls, weather forecasting and gambling rather than hard observational science, and modifications to BB theory are made using these statistical methods:
"...They are often used in physical and mathematical problems and are most useful when it is
difficult or impossible to use other approaches.."
https://en.wikipedia.org/wiki/Monte_Carlo_method
https://en.wikipedia.org/wiki/Bayesian_inference
"However, the lack of power in the CMB temperature anisotropies at large angular scales (low-ℓ), as has been confirmed by the recent Planck data also (up to ℓ= 40), although statistically not very strong (less than 3σ), is still an open problem. One can avoid to seek an explanation for this problem by attributing the lack of power to cosmic variance or can look for explanations i.e., different inflationary potentials or initial conditions for inflation to begin with, non-trivial topology, ISW effect etc.
Features in the primordial power spectrum (PPS) motivated by the early universe physics has been the most common solution to address thisproblem. In the present work we also follow this approach and
consider a set of PPS which have features and constrain the parameters of those using WMAP 9 year and Planck data employing Markov-Chain Monte Carlo (MCMC) analysis..."
https://arxiv.org/pdf/1501.02647.pdf
"The multiple scattering of photons by a hot plasma in the early Universe should result in a blackbody spectrum for the photons once they have escaped at the epoch of reionisation. This is exactly what is observed for the CMB. The figure on the right plots a theoretical blackbody curve along with CMB data from the COsmic Background Explorer (COBE) satellite.
The agreement is so good that it is impossible to distinguish the data from the theoretical curve."
Saying it again: The data from COBE are not raw data, it's data that has been manipulated by highly sophisticated probability algorithms to fill in the holes left by the foreground 'contamination', the dust and 'noise' of our galaxy etc, which means large parts of the data are not visible or measurable, so are photoshopped. Then claimed to be a 'perfect blackbody curve'
(image of variation in measurements prior to COBE)
The facts are that Gamov predicted 50K, his students modified this to 5K, Penzias and Wilson measured the wavelength at 7.5cm not 2mm, and many others before COBE measured different values, WMAP didn't measure the CMB directly, measuring temperature differences only against a reference 4K, and Planck did the same, measured differences from a standard temp, still using probability functions to fill in the missing unobservable background which remains permanently behind foreground 'contamination'; dust and noise which hide forever the hidden parts of the sky behind this 'noise':
"The photons of the CMB were emitted at the epoch of recombination when the Universe had a temperature of about 3,000 Kelvin. However, they have been cosmological redshifted to longer wavelengths during their ~13 billion year journey through the expanding Universe, and are now detected in the microwave region of the electromagnetic spectrum at an average temperature of 2.725 Kelvin.
This agrees well with what Big Bang theory predicts."
Retrospectively predicted....
"Matter was instead distributed as a highly ionised plasma which was very efficient at scattering radiation. The result was that information (photons) from the early Universe were effectively trapped in an inpenetrable ‘fog’ which, to this day, hides these early times from astronomers."
"As the Universe expanded, however, its temperature and density dropped to a point where the atomic nuclei and electrons were able to combine to form atoms. This is known as the epoch of recombination, and it is at this time that photons were finally able to escape the fog of the early Universe and travel freely. The ‘Cosmic Microwave Background radiation’ (CMB) is the record of these photons at the moment of their escape."
More 'modern' theories modify this first scattering idea, various patches to the theory have the CMB changed later by some other theoretical effects...
"However, standard Big Bang theory does not account for all of the observed properties of the CMB. In particular, once we remove the dipole that arises due to our motion in the Universe, the CMB is incredibly uniform across the sky, varying by no more than one part in ten thousand. This suggests that regions of the Universe that are now widely separated, were once close enough to ‘communicate’ with each other in order to equalise their temperature.
However, this is not possible given standard Big Bang theory, the age of the Universe, and the finite speed of light."
"The red line in the figure on the left shows that according to Big Bang theory, the Universe had a radius of more than 10^-10 metres at 10^-45 seconds after the Big Bang. Since the speed of light travels at 3×10^8 m/s, information could only have travelled ~3×10^-37 metres during this time.
Big Bang theory therefore makes it impossible for the whole Universe to have equalised its temperature at these early times, as not all the Universe was in communication. In everyday life we cannot receive information beyond our horizon, so this is known as the horizon problem."
So here to 'fix' this Big Bang problem, an 'inflationary' period is introduced:
"
To resolve the horizon problem, astronomers introduced an inflationary period into the Big Bang model (blue region in figure). This sudden increase in the rate of expansion of the Universe soon after the Big Bang, resolves not only the horizon problem, but also the flatness problem. It has therefore been accepted as part of the current concordance model of cosmology."
(image of inflationary period)
Here is very bad science, IMHO
The logic is something like:
IF we have a fatal problem with the Big Bang idea...
AND we can't think of a better way to describe this microwave background noise,
THEN we'll just go with the Big Bang idea....
(0 + 1 = 1)
"The presence of a background radiation which has a temperature, spectrum and uniformity consistent with Big Bang cosmology and inflation,
is extremely difficult to produce by any other means. Therefore, astronomers believe that by studying the properties of the CMB, they are in fact studying the conditions of the early Universe."
http://astronomy.swin.edu.au/cosmos/C/C ... Background
Using Monte Carlo strings or Bayesian probability techniques, when you look backwards to look forwards to come up with new maths, once you start messing with probabilities in never-ending cycles of theory->falsification->patch theory=modified new theory etc you are firmly in Emperor's clothes territory....
the result is increasingly improbable... dark matter dark energy dark new physics, dark ages....
The basics of physics should always have some connection to observable reality IMHO
This is a taste of unbridled what-ifs:
If it is not integrated then:
"The non-integrated Sachs–Wolfe effect is caused by gravitational redshift occurring at the surface of last scattering. The effect is not constant across the sky due to differences in the matter/energy density at the time of last scattering."
or if it is integrated:
Integrated Sachs–Wolfe effect
"The integrated Sachs–Wolfe (ISW) effect is also caused by gravitational redshift, but it occurs between the surface of last scattering and the Earth, so it is not part of the primordial CMB. It occurs when the Universe is dominated in its energy density by something other than matter. If the Universe is dominated by matter, then large-scale gravitational potential energy wells and hills do not evolve significantly. If the Universe is dominated by radiation, or by dark energy, though, those potentials do evolve, subtly changing the energy of photons passing through them."
"There are two contributions to the ISW effect. The "early-time" ISW occurs immediately after the (non-integrated) Sachs–Wolfe effect produces the primordial CMB, as photons course through density fluctuations while there is still enough radiation around to affect the Universe's expansion. Although it is physically the same as the late-time ISW, for observational purposes it is usually lumped in with the primordial CMB, since the matter fluctuations that cause it are in practice undetectable."
undetectable
or if it is something else: 'Late-time' integrated Sachs–Wolfe effect:
"The "late-time" ISW effect arises quite recently in cosmic history, as dark energy, or the cosmological constant, starts to govern the Universe's expansion. Unfortunately, the nomenclature is a bit confusing. Often, "late-time ISW" implicitly refers to the late-time ISW effect to linear/first order in density perturbations. This linear part of the effect ***entirely vanishes in a flat universe with only matter, but dominates over the higher-order part of the effect in a universe with dark energy. The full nonlinear (linear + higher-order) late-time ISW effect, especially in the case of individual voids and clusters, is sometimes known as the Rees–Sciama effect, since Martin Rees and Dennis Sciama elucidated the following physical picture."
"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."
https://en.wikipedia.org/wiki/Sachs%E2% ... lfe_effect
Planck results 2015:
"The 2015 release upholds that of 2013,
with only slight tweaks to various cosmological parameters. It still overwhelmingly favors an early universe defined entirely by six parameters, no matter how many ways
the team pushed and prodded the data. These parameters are
1. The density of baryonic matter (a.k.a. normal, like you and me) in the first few minutes of the universe
2. The density of cold dark matter at that same time
3. How far sound waves had traveled when the CMB photons were released — also known as the “sound horizon” or the size of baryon acoustic oscillations
4. The fraction of CMB photons over the universe’s history that have scattered off particles set free by radiation from stars/quasars ionizing the neutral hydrogen filling the cosmos
5. The strength of the initial density fluctuations on a physical scale of about 65 million light-years (20 megaparsecs) at the end of inflation*
6. How the strength of the density fluctuations on various scales at the end of inflation changes with scale
"
There’s still the strange problem of the missing galaxy clusters. The Planck team finds a certain lumpiness in the CMB, which should match up with the lumps in the distribution of matter in the universe (a.k.a. cosmic structure, which is made up of galaxy clusters). But Planck predicts about 2.5 times more clusters than are actually observed.
This could be due to error in the estimates from either side,
or due to new physics."
Could be due to error? Or is it 'new physics' .... wow!
"One neat result is that the era of reionization — basically, when the universe’s galaxies really started lighting up with stars —
is later than estimated using data from Planck’s predecessor, WMAP. WMAP had favored reionization at a redshift of 10 (470 million years after the Big Bang), but Planck pegs it at 8.8 (560 million years after the Big Bang)."
WMAP caused a problem, no worries, Planck fixes it:
“For many cosmologists,
I would say that it is a relief,” says David Spergel (Princeton), who worked on the WMAP team. Scientists studying early star formation
had a hard time explaining the earlier start time from WMAP, so a slightly later start is a good thing."
"These involve an inflation spawned by the decay of a single energy field, a field that decreased slowly compared to the universe’s expansion rate. (Given that the observable universe expanded at least 5 billion trillion times in 10 nano-nano-nano-nanoseconds, that’s not that slow.) The energy scale implied for inflation is less than 2 x 1016 gigaelectron volts, on par with the level expected for the merger of the strong, weak, and electromagnetic forces into one (called the Grand Unified Theory). Physicists think these forces were united in the first mini-moment of the universe, then broke apart. Their breakup
might somehow be connected to inflation."
"(Given that the observable universe expanded at least 5 billion trillion times in 10 nano-nano-nano-nanoseconds, that’s not that slow.)"
Whoops, might have to change another couple of parameters:
"*Updated: In the original version of this blog, the descriptions of
cosmological parameter #5 and #6 described the same parameter. Parameter #5 is now updated to be the amplitude of the initial density fluctuations, and the scalar spectral index is now #6, to match the order given in the Planck literature. Fun fact: Planck's value of parameter #5 says that, after inflation, the density of matter varied only 0.000000002 on a scale of 20 megaparsecs. "
mmm
... might somehow...
Notice the pushing, prodding, and tweaking that goes on and on and on to make the Big Bang plausible!
Haha, to my mind this is more like squashed credibility
Come on! The Emperor has no clothes!
