Some recent evidence against the Big Bang

The author appears to confuse "theory T is part of a larger theory U which has bits we don't understand and bits we haven't got quite right yet" with "theory T is probably wrong".

Here theory T is "several billion years ago the universe underwent a very rapid increase in size and decrease in temperature, from something extremely hot and dense to something much more like what we see now", a.k.a. "the big bang", and theory U is a detailed account of current best theories of inflation, star formation, galaxy formation, dark matter, dark energy, etc., etc., etc.

One can see exactly the same pattern with T being "over many generations, living things evolve both at random and to adapt to their environments, and this is how the biosphere got where it now is", U being a detailed account of current best theories of evolutionary biology, palaeontology, etc., etc., etc. The people making the argument in that case are creationists, they do not understand the relevant theories very well, and by pointing out areas of doubt and difficulty they are not in fact doing anyone any good.

I don't think MazeHatter is a creationist (though I think it's possible, and some of his/her past comments do seem like they lean in that direction) but I do think s/he's adopting their tactics, and the result isn't any more helpful here than it is there. Sure, it's possible that the whole "big bang" idea might turn out to be wrong, but the fact that you can find a scattering of things we don't understand about the early universe isn't much evidence for that and has to be weighed against all the things that current cosmological theories don't get wrong, which of course you don't hear about much because "current best scientific theory predicts roughly what is observed" usually isn't news.

[EDITED to remove gratuitous assumption that MazeHatter is male.]

In theory, light travels to infinity 
In observation, light comes from finite distances
So in theory space must expand  (v_galaxy = HD)
So in theory only a finite amount of time exists in physics
So in theory, no problem, we see finite light because of finite time

Observation 1. light doesn't travel to infinity
New Theory A. light doesn't travel to infinity (v_photon = c - HD)

Unrelated to my other comment: this is a decent sample of open problems related to the structure formation and element composition in the early universe. Cosmic inflation is an umbrella term for a number of models designed to solve the horizon and flatness problems by a rapid expansion many orders of magnitude shortly after the big bang. Several predictions of such models have been confirmed, while some others falsified, though with low confidence (e.g. the quadrupole moment in the CMB spectrum). Fine tuning of inflationary parameters is aesthetically the most unsatisfactory feature of inflation, but any known alternative is even worse. I am not qualified to judge the validity of the Steinhardt's claims, but other experts in the field don't seem as pessimistic.

As other posters have noted, this is not a case of overturning the 'big bang' in the sense that there was a time about 13 gigayears in the past when the universe was dense and hot and it has expanded since. Inflation (its veracity and the details thereof if it did indeed happen) and early galaxy formation are active areas of research.

Another is an asymmetry in the average temperatures on opposite hemispheres of the sky. This runs counter to the prediction made by the standard model that the Universe should be broadly similar in any direction we look.

I remember when that was discovered! It is very interesting. That and the 'dark flow', an apparent bias in the movement of galaxies across the visible universe. I have wondered if this apparent inhomogeneity in the early universe reduces the need for inflationary cosmology in the first place to explain what is observed? It was posited in the first place to explain extreme sameness in all directions of the CMB. That it runs counter to certain cosmological nuances does not go against the evidence that the universe is expanding and used to be dense and hot.

We are also getting a better look at galaxies at greater distances, thinking they would all be young galaxies, and finding they are not

They aren't noting their age, they are noting their star-forming status. And finding that many finished star formation much earlier than previous models suggested, suggesting models of galaxy and star formation are wrong. It should be noted that it does not take long after star formation stops for galaxies to lose their 'young' gleam - star brightness increases with the 3.5th power of mass and so star lifetime decreases with the 2.5th power of mass. A star 4x as massive as the sun will be 128x as bright and only live for a bit over 300 megayears. The thin scum of the largest stars (up to 100 solar masses) dominates the light produced by any given galaxy and goes away quite fast after star formation ceases, cosmologically speaking.

It should also be noted that there IS a very distinct arrow-of-time in star formation rates that points at the early universe being very different than the late universe: ARXIV, PDF Popular press

To quote myself from a previous post I made:

To make a long story short, a survery was made looking into deep space, and back in time up to 11 billion years, of a pretty good proxy of star formation (the emission lines produced by emission nebulae that are lit up like neon lights by the ultraviolet light of freshly-born huge stars). After doing some fancy math to correct for the expansion of space and the like the conclusions are striking - the modern average rate of star formation in the universe is less than 1/30 the peak rate of 11 billion years ago, and half of the stars in the universe are over 9 billion years old. To make matters even more interesting, the empirically-derived relationship between time and star formation actually converges to a finite number of stars when you project it into the future, and at infinity reaches a total number of stars born only 5% more than currently exist today.

95% of stars that will ever exist already exist.

This is a very strong tendency through time for star formation rates to be high early and tail off. (NOTE: if space weren't expanding, that star formation rate difference would be even higher than the above figure given the observations made.) Combined with the fact that there don't seem to be any stars older than the age of the cosmic microwave background radiation... yeah, something big happened 13 gigayears ago.

To my mind the cosmic microwave background radiation, the observation of the slow reionization of the universe from neutral hydrogen to hydrogen plasma over the course of hundreds of megayears after the first quasars, and the fact that if you fit models of space expansion and run them back to t=0 and calculate the densities and temperatures thereof and simulate nuclear reactions of the first few minutes after t=0 you can get out the primordial hydrogen and helium and isotope ratios that are observed (lithium 7 showing difficulties with the models with several possible implications which are being explored, including possibly relaxing the assumption of homogeneity) are the best pieces of evidence that about 13 gigayears ago there was a major event where a dense hot universe began expanding into a cool empty one. That and the redshift. Basically, something banged, and theyre still trying to figure out what did and why, and lots of details of the early universe are still being worked out. As is the apparent fact that the expansion is accelerating, and the fact that the best model so far for predicting the motions and spins of galaxies requires nonbaryonic mass.

Additionally, to my mind, any speculation as to if the big bang was truly the 'beginning of time', or one among many, or symmetrical about t=0, or all manner of other things is premature as there is insufficient data as to the nature of the event in the first place. The fact that an event happened seems clear though.

Another is an asymmetry in the average temperatures on opposite hemispheres of the sky. This runs counter to the prediction made by the standard model that the Universe should be broadly similar in any direction we look.

Why doesn't this just mean that we are moving w.r.t. the rest frame of the CMB? The signal is redshifted in the hemisphere we're moving away from, and blueshifted in the hemisphere we're moving towards, so it would look hotter in the hemisphere we're moving towards.

Astronomy is extremely difficult. We don't know the relevant fundamental physics, and we can't perform direct experiments on our subjects. We should expect numerous problems with any cosmological model that we propose at this point. The only people who are certain of their cosmologies are the religious.

You need to do a lot more work for this sort of post to be useful. Cherry-picking weak arguments spread across the entire field of astronomy isn't enough.

What makes this a rationality post?

It seems that in the 1980's, when I was first introduced to the Big Bang as a child, the experts in the field knew then there were problems with it, and devised inflation as a solution. And today, the validity of that solution is being called into question by those same experts:

The dominant Big Bang theory (the Lambda CDM model of inflationary cosmology) today has evolved significantly from the Big Bang theory of the 80s. For example, the realization in the late 90s that the expansion of the universe was accelerating rather than decelerating required significant changes.

And yes, we know that we do not yet have a perfect understanding of it yet, and that more tweaks and modifications are needed. But I think it is inaccurate to talk as if the big bang model needs to be thrown away. The situation is more like a jigsaw puzzle where we have a good idea in general what is going on, but there are still missing pieces.

Downvoted for circumventing minimum karma requirements. Don't do it.

"The most merciful thing in the world, I think, is the inability of the human mind to correlate all its contents. We live on a placid island of ignorance in the midst of black seas of infinity, and it was not meant that we should voyage far. The sciences, each straining in its own direction, have hitherto harmed us little; but some day the piecing together of dissociated knowledge will open up such terrifying vistas of reality, and of our frightful position therein, that we shall either go mad from the revelation or flee from the light into the peace and safety of a new dark age."