Bang or No Bang?

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Wade Hampton III
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Joined: Fri Oct 18, 2013 10:40 pm
Location: Pontiac, SC

Bang or No Bang?

Post by Wade Hampton III » Wed Aug 01, 2018 3:13 am

From the Web...

Almost everyone has heard the story of the Big Bang. But if you
ask anyone, from a layperson to a cosmologist, to finish the
following sentence, "In the beginning, there was..." you'll
get a slew of different answers. One of the most common ones is
"a singularity," which refers to an instant where all the matter
and energy in the Universe was concentrated into a single point.
The temperatures, densities, and energies of the Universe would
be arbitrarily, infinitely large, and could even coincide with
the birth of time and space itself.
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Pop Or Fizz?
Pop Or Fizz?
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But this picture isn't just wrong, it's nearly 40 years out of
date! We are absolutely certain there was no singularity associated
with the hot Big Bang, and there may not have even been a birth
to space and time at all. Here's what we know and how we know it:

https://www.forbes.com/sites/startswith ... 45baec7d81

User avatar
Wade Hampton III
Posts: 2339
Joined: Fri Oct 18, 2013 10:40 pm
Location: Pontiac, SC

Re: Bang or No Bang?

Post by Wade Hampton III » Mon Oct 01, 2018 1:14 am

Danilo Angelo, Graduate Computer Engineering & Electrical Engineering, University
of Campinas (2000), wants to know...

Did anything exist 10 Billion years before that Big Bang happened?

Ok, I will take an unorthodox route here. There are a lot of answers to the question
saying things like“No. Time started at the ‘Big Bang’”. It is a rather understandable
and secure position, but it is somewhat misleading.

I want to get a little deeper.

The Big Bang is the process of expansion of the universe, which appears to have started
in a singularity, 13.8 billion years ago. The Big Bang is still happening. We are still
in this expansion process.

There is a thing called the Big Bang Theory. It is a scientific Theory that describes
this process of expansion. Scientific Theories are hypothesis which developed a great
level or merit by accumulating a a great deal of empirical evidence and corroboration.
That applies to the Big Bang Theory as well. We do have a great set of empirical evidence
for the expansion. Nevertheless, there are two things that are commonly believed to be
covered by the Big Bang Theory, which are not:

The singularity itself (time = zero);
The inexistence of a time prior to the singularity.

The mathematical model used to describe the process of expansion of the universe in fact
points to a singularity at time=zero and is undefined for time < 0. This may be interpreted
as the inexistence of time before the singularity (which may actually be the case), but also
may be interpreted as a time irrelevant to the development of our universe (which also makes
sense, since causality breaks at the singularity). The fact is that we cannot currently assess
any empirical information that corroborates the idea of the singularity at time = zero or the
nature (or inexistence) of time < zero. Any statement about these conditions are, at least
currently, unfalsifiable, therefore unscientific. Thus, such claims cannot be part of any
Scientific Theory, including the Big Bang Theory. The bottom line is that, for all that we
know, we are not justified to say that there definetely was no time before Big Bang’s
singularity. We can say at best that, according to the model, no time prior to the
singularity has causal relationship with our universe, which may mean “no time at all”
or a “time with no relevance to the dynamics of our universe”.

Let’s see what Stephen Hawking says on the matter:

—————————

“A Brief Story Of Time” - Chapter 3:

This means that even if there were events before the big bang, one could not use them to
determine what would happen afterward, because predictability would break down at the
big bang. Correspondingly, if, as is the case, we know only what has happened since the
big bang, we could not determine what happened beforehand. As far as we are concerned,
events before the big bang can have no consequences, so they should not form part of a
scientific model of the universe. We should therefore cut them out of the model and say
that time had a beginning at the big bang.”

—————————

“A Brief Story Of Time” - Chapter 8:

At the singularity, general relativity and all other physical laws would break down:
one couldn’t predict what would come out of the singularity. As explained before, this
means that one might as well cut the big bang*, and any events before it, out of the
theory, because they can have no effect on what we observe. Space-time would have a
boundary – a beginning at the big bang.

—————————

These excerpts clearly mean that there is nothing we know (or at least that Hawking
knew at the time of the writing) that excluded the existence of time before the singularity,
but we choose to “cut them out of the model” because “events before the big bang can have
no consequences”, since causality breaks at time=0. They also clearly mean that the Big
Bang Theory states nothing about the non-existence of time before the singularity.

Note: Stephen Hawking uses “Big Bang” and “singularity” interchangeably in the book,
althought he recognizes that the singularity is a mathematical model and that the
singularity is not part of the Big Bang model or the Big Bang Theory (“one might as
well cut the big bang*, and any events before it, out of the theory”).

* That means, the singularity.

So, long story short, the answer to the question is:
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We don’t know if something existed 10 billion years before Big Bang’s singularity, and
possibly we will never know, since causality seems to break at the singularity, what
makes possible events before it both non-assessable and irrelevant to the dynamics of
our universe.

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