Im not sure I agree with all of the statements made in the forbes article, the author/contributor is a Astrophysics PhD, who writes popular
science...It is very common that such authors put their ideas out there in public domain and don't really allow for any objective criticism.
I am a particle physics PhD. I am putting that out there on the table since the first obvious 'criticism' of my comment might be "Oh what do you know"
not that I am accusing anyone of doing that pre-emptively. The reasoning is mostly that the physics and processes occurring during the big bang is
closer to particle physics and so it gives an interesting cross over. The article is also an opinion piece, not a scientific article that has gone
through any scrutiny, so, lets do some right now.
I don't think that exactly what occurred is a done deal, but there are a few different interpretations. Let me address the points in that forbes
1) The Universe doesn't have different temperatures in different directions, even though an area billions of light-years away in one direction never
had time (since the Big Bang) to interact with or exchange information with an area billions of light-years in the opposite direction.
Not sure why this is a point of contention, this can be considered evidence that during the early universe all matter was causally connected as i
said. It means there was a time in which the universe was small and compact (in that space time was unexpanded) and even. If space time was to then
expand (and the space time expansion causing doppler shift of the relic radiation) you would completely expect the CMB to be flat. "Never had time" is
a confusing and quite honestly a weak argument since in a compact origin, you do expect exactly what we observe... that the CMB looks the same
everywhere, because it represents a time in which everything was connected by light transport.
Thus his evidence is an exact 180 degree shift compared to standard logical analysis... its like saying that left is in fact right.
2) The Universe doesn't have a measurable spatial curvature that's different from zero, even though a Universe that's perfectly spatially flat
requires a perfect balance between the initial expansion and the matter-and-radiation density.
This is an observation, I am not certain it is really classed as evidence against the big bang, it is like saying the odds of winning the lottery are
very small thus no one should win the lottery. Nature doesn't have to bend to our will. It could also be evidence that our measurements are not yet
accurate enough. Or that the properties of the universe at the scale we are at now is naturally flat, rather than a closed or open configuration.
Amazing yes, but I don't think that our observations are yet mature enough.
3)The Universe doesn't have any leftover ultra-high-energy relics from the earliest times, even though the temperatures that would create these relics
should have existed if the Universe were arbitrarily hot.
This is an unknown, firstly, if he means photons, then the CMB is basically relic ultra-high-energy photons from that era. Relics also have to be
reasonably stable should they be particle matter. We have, as yet, not observed anything like this in our particle accelerators. Does it mean that he
is wrong? well ultimately it is unknown. But if there are no ultra-high energy stable particles, you don't really expect a relic density either.
This point seems somewhat weak and dismisses the whole field of direct dark matter searches. This, if proven, could be those missing relics. There are
also other options for relics too.
Furthermore, his stipulation in regard to the physics that occurs at high density and high temperature is also somewhat economic with the truth. We
already know of how particle matter in extreme conditions behaves in weird and interesting ways. Like a compact fermi-gas can increase in pressure,
without increasing in temperature (or is it the other way around) The video also doesn't really explain that it is space-time itself that is
expanding, thus when you do compress the universe or make space-time smaller, so are the dimensional attributes of the objects contained within, or at
least, its a good assumption that it would be the case.
Expansion of spacetime and the concept of a closed - flat or open universe is also conceptually difficult to picture. It is the same difficulty people
have with representations of blackholes which pop-sci likes to show as a hole in a two dimensional plane. When really it is a 3 dimensional object.
In the same way, if you represent it in two dimensions, a closed universe is one that would remain looking like a sphere of 2d space... flat would
look like an infinite plane and open would look saddle shaped.