Hi Dr Joe,
I have repeated questions and answers for clarity. Don’t worry, I have summarised it below. New in BOLD:
A multi-part question, if I may, about singularities.
1. My understanding is that, at t = 0, physical laws break down, due to division by zero. I also understand that beyond this zero point, by a minute interval, big bang theory is pretty solid, and this is reassuring. Am I OK so far?
Yes. But the division by zero is because the physical dimension, r, is zero (the universe is a singularity at time = 0).
1a. I am sorry, I should have cleared that my use of t = 0 here included an alternative scenario – namely the mid-point of a nexus (in that hypothetical scenario). Since I am open to thinking about (not necessarily supporting) such, I was making the point that the ‘OK part’ (BBT) can (according to this hypothesis) be considered irrespective of the precedent ‘singularity’, viz, separating the unknown beginning from the supported sequitur.
2. What is current official standpoint on such a (BB) singularity
? Coming from (1), there are suggestions of infinite density, temperature et cetera. Am I correct in thinking that these infinite
conditions are the result of singularity theory, and not essential prerequisites
of the following BBT?
2. Well, I guess it’s not a requirement to have a singularity for a big bang event, but if you run the movie backwards, as it were, you end up with a singularity. (The same thing you have in a black hole, just with more mass.) We only have one universe, so the big bang model only operates in one place. And so, because of this, I would say that, yes, a singularity is a prerequisite. But to me, by calling it a prerequisite seems to indicate the model is operating somewhere else (another universe, for example), and, of course, we don’t know anything about other universes (or even if they exist). (By the way, the big bang theory is the vernacular name for the favored theory/model of the universe. It should be called the inflationary model/theory, for reasons we get to in your other post, below.)
2a. This starts by following from (1). I do not understand (mea culpa) how ‘running the movie backwards is a valid scientific process. The fact that you use a euphemism alerts me. When you have a jump like inflation, followed by a gradual curve, followed by increasing expansion, what sort of a backward projection do you make, and how do you justify it? Do you have enough data to make any such projection? If (not a straight line but) a ‘flattish’ parabola (or such) were fitted to the data, might not those incredibly small intervals like 10^-35 (10-35) become more ‘believable’ intervals? When we do not understand >95% of the observable universe, how can we begin to even think of laying down what the Universe was close to t = 0, whichever version we choose? What sort of scales do you use when you make the projection? Is this published somewhere I can access?
Please pardon my queries. I am a great fan of Korzybski (General Semantics) = “the map is not the territory”, et cetera. Probing is my second nature.
BTW I believe (if we are to uphold the viability of language) we have to ban words like universes, except in such a context as “Observable universes depend on the location of the observer” There is one ‘Universe’ in my book. Either we urgently need some new definitions or cosmology discussions are going to fail in short order.
Finally, my use of the word ‘prerequisites’, I believe, is quite justified. Suggesting ‘other universes’ is abhorrent in my book. I was merely asking whether the well attested BBT was inseparable from the (in my humble view) questionable (metaphysics, not science) model.
My question was “Coming from (1), there are suggestions of infinite density, temperature et cetera. Am I correct in thinking that these infinite conditions are the result of the singularity model, and not essential prerequisites of the following BBT?” In other words, Can we not (hypothetically) have BBT without some sort of (imho) fictional singularity?
3. I preface this question by stating that I am not looking for support of any particular outcome. I have serious reservations about some possible outcomes.
Is there any scientific reason why a singularity might not be replaced by a nexus,
as in the cyclic scenario 'big crunch' or super black hole -> nexus -> big bang, omitting the singularity? I do accept that there are serious questions with cyclic models, particularly in relation to entropy and the 2ndLoTs.
3. I don’t know enough to know whether the singularity could be replaced by something else. I also don’t know why you might want to or need to replace it. Speaking of big crunches: Problems with these models aside, it is highly unlikely our universe will cycle like this: big bang, recollapse, big bang. There’s just not enough mass/density to allow that. Up to 20 years ago, it was thought to be highly unlikely (because of the lack of mass), but now with dark energy (which is accelerating the universal expansion), it is even more unlikely to recollapse.
3a. In view of the adoption of ‘useful fudge factors’ are we really in any position to categorically rule out the word “cyclic”. Coming back to Korzybski, verbal plasters may only cover over the chasms in understanding, Maybe ‘cyclic’ evokes unhelpful connotations. Maybe we should be thinking of a Universe where mere words like ‘beginning’ and ‘end’ have no cosmic meaning. I think it is sometimes a failing, as well as a blessing, that homo sapiens insists on ‘knowing all about everything’. His quest for truth may result in his ignorance. Is the Universe, whatever it is, a closed system? And are we addressing only the <5%?
4. Are we limiting our thinking on possible
to recycling the 'same old' Universe phases/components in total negation of the fact that we really know nothing about >95% of the observable u
4. Apart from the unlikelihood of a cyclic nature of our universe, I don’t think so. Everything in our universe exists (whether or not we know what it is and understand it), so if we did have a cyclical universe, I don’t see why there would be problems with recycling matter/energy. Presumably the universe at the quantum level (and the forces/energy therein associated) would be the same from cycle to cycle. I suppose with each big bang event there could be minor fluctuations in forces and constants (mass of electron, for example). I hadn’t thought about this from the perspective of what differences (if any) might interfere with the cycle, and that is interesting. We could certainly end up with universes where the constants are tweaked such that atoms can’t form, or fusion can’t take place. Again, though, a cyclical nature of the universe is not on the cards for us.
4a. Much of this was dealt with in 3a. I would like to reconsider the word ‘cyclic’. Maybe we should be thinking of a Universe where mere words like ‘beginning’ and ‘end’ have no cosmic meaning. They are just words we invented, and have no underlying reality. Mere ‘grunts of a partially evolved ape’, one might think.
So let me replace all of the foregoing with a somewhat shorter version.
We have a very adequate Big Bang Theory (more correctly, as you point out, Inflationary Model/Theory) which, however, is based on an insubstantial base where the division by zero (r) invalidates using the laws of physics.
I believe that the layman, looking at the suggested beginning – an infinitely small concept at infinite density and temperature, might find ‘bursting out of nothing rather less palatable than an honest admission that we do not know, and probably have no means of knowing, the ultimate precedent of inflation. On this occasion, might he not be correct?
Thank you for the most interesting responses, which I value highly, and for your time in considering what are, in fact, metaphysical questions.