However, although it does indeed seem to be the case that the universe is in fact expanding, the inflation explanation has plenty of detractors, several of whom are giants in the field. -ETL
In physical cosmology, cosmic inflation, cosmological inflation, or just inflation, is a theory of exponential expansion of space in the early universe.
The inflationary epoch lasted from 10^−36 [10 to the minus 36!] seconds after the conjectured Big Bang singularity to some time between 10^−33 and 10^−32 seconds after the singularity.
Following the inflationary period, the universe continues to expand, but at a [far] less rapid rate.[1]
Inflation theory was developed in the late 70's and early 80's, with notable contributions by several theoretical physicists, including Alexei Starobinsky at Landau Institute for Theoretical Physics, Alan Guth at Cornell University, and Andrei Linde at Lebedev Physical Institute. Alexei Starobinsky, Alan Guth, and Andrei Linde won the 2014 Kavli Prize “for pioneering the theory of cosmic inflation.”[2].
It was developed further in the early 1980s.
It explains the origin of the large-scale structure of the cosmos.
Quantum fluctuations in the microscopic inflationary region, magnified to cosmic size, become the seeds for the growth of structure in the Universe (see galaxy formation and evolution and structure formation).[3]
Many physicists also believe that inflation explains why the universe appears to be the same in all directions (isotropic), why the cosmic microwave background radiation is distributed evenly, why the universe is flat, and why no magnetic monopoles have been observed.
The detailed particle physics mechanism responsible for inflation is unknown.
The basic inflationary paradigm is accepted by most physicists, as a number of inflation model predictions have been confirmed by observation;[4] however, a substantial minority of scientists dissent from this position.[5][6][7]
The hypothetical field thought to be responsible for inflation is called the inflaton.[8]
In 2002, three of the original architects of the theory were recognized for their major contributions; physicists Alan Guth of M.I.T., Andrei Linde of Stanford, and Paul Steinhardt of Princeton shared the prestigious Dirac Prize "for development of the concept of inflation in cosmology".[9]
In 2012, Alan Guth and Andrei Linde were awarded the Breakthrough Prize in Fundamental Physics for their invention and development of inflationary cosmology.[10]
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Criticisms
Since its introduction by Alan Guth in 1980, the inflationary paradigm has become widely accepted.
Nevertheless, many physicists, mathematicians, and philosophers of science have voiced criticisms, claiming untestable predictions and a lack of serious empirical support.[5]
In 1999, John Earman and Jesus Mosterin published a thorough critical review of inflationary cosmology, concluding, "we do not think that there are, as yet, good grounds for admitting any of the models of inflation into the standard core of cosmology."[6]
In order to work, and as pointed out by [Stephen Hawking mentor] Roger Penrose from 1986 on, inflation requires extremely specific initial conditions of its own, so that the problem (or pseudo-problem) of initial conditions is not solved: "There is something fundamentally misconceived about trying to explain the uniformity of the early universe as resulting from a thermalization process. [...]
For, if the thermalization is actually doing anything [...] then it represents a definite increasing of the entropy.
Thus, the universe would have been even more special before the thermalization than after."[143]
The problem of specific or "fine-tuned" initial conditions would not have been solved; it would have gotten worse.
At a conference in 2015, Penrose said that "inflation isn't falsifiable, it's falsified. [...]
BICEP did a wonderful service by bringing all the Inflation-ists out of their shell, and giving them a black eye."[7]
A recurrent criticism of inflation is that the invoked inflaton field does not correspond to any known physical field, and that its potential energy curve seems to be an ad hoc contrivance to accommodate almost any data obtainable.
Paul Steinhardt, one of the founding fathers of inflationary cosmology, has recently become one of its sharpest critics.
He calls 'bad inflation' a period of accelerated expansion whose outcome conflicts with observations, and 'good inflation' one compatible with them: "Not only is bad inflation more likely than good inflation, but no inflation is more likely than either [...]
Roger Penrose considered all the possible configurations of the inflaton and gravitational fields.
Some of these configurations lead to inflation [...]
Other configurations lead to a uniform, flat universe directly – without inflation.
Obtaining a flat universe is unlikely overall.
Penrose's shocking conclusion, though, was that obtaining a flat universe without inflation is much more likely than with inflation – by a factor of 10 to the googol (10 to the 100th) power!"[5][116]
Together with Anna Ijjas and Abraham Loeb, he wrote articles claiming that the inflationary paradigm is in trouble in view of the data from the Planck satellite.[144][145]
Counter-arguments were presented by Alan Guth, David Kaiser, and Yasunori Nomura[146] and by Andrei Linde,[147] saying that "cosmic inflation is on a stronger footing than ever before".[146]
https://en.wikipedia.org/wiki/Inflation_(cosmology)#Criticisms
But no matter what theory is proposed; where did the thing that went >blooie< come from? What was it? Compressed gasses, a magic cube? What?
Wouldn’t the universe at the end of the inflationary period still be only very small? Surely, the inflationary theory doesn’t posit that the universe grew to billions of light years across in 10^32 seconds?
So the universe grew a lot slower after Jimmy Carter was gone. ;-)
Could be that the guess about the age of the Earth is the one that is way the crap off.
I always start out sure that I can sort this whole thing out
and then a little ways into it I start getting a headache.
I don’t suppose anybody would accept “it is what it is?” :)
Why do you go out of your way to post comments like this? Who here actually understands what the heck you just posted????
Progress in fundamental cosmology usually requires advances in other fields of physics. My guess is that the Large Hadron Collider or some later and better version of such a device will eventually resolve the argument over cosmic inflation. For now, the concept is too useful and too dug in to be repudiated. Like the old joke about the tourist in Mexico who persists in playing an obviously rigged roulette wheel, it is the only such game in town.
It was much smaller back then..................