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Question How do we know that the universe started with a Big Bang?

ThePatriotBeast

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Apr 9, 2021
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"Astronomers have detected, throughout the universe, two chemical elements that could only have been created during the Big Bang: hydrogen and helium. Furthermore, these elements are observed in just the proportions (roughly 75% hydrogen, 25% helium) predicted to have been produced during the Big Bang. This prediction is based on our well-established understanding of nuclear reactions - independent of Einstein's theory of gravity.
Second, we can actually detect the light leftover from the era of the Big Bang. The blinding light that was present in our region of space has long since traveled off to the far reaches of the universe. But light from distant parts of the universe is just now arriving here at Earth, billions of years after the Big Bang. This light is observed to have all the characteristics expected from the Big Bang scenario and from our understanding of heat and light."

Got this answer from https://lweb.cfa.harvard.edu/seuforum/faq.htm
 
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rod

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The CMBR, H/He abundance, and redshifts are commonly held as the 3 chief pillars supporting the BB model. If you dig into the details of these 3 pillars, problems can be found, e.g. inflation needed to explain the smoothness of the CMBR vs. a lumpy and different temperature CMBR that should form based upon Special Relativity (the horizon problem), thus a light-travel-time problem in the standard BB model. BBN phase that creates the H/He abundance has free parameters in it, neutron lifetime. Example, Scientists carry out first space-based measurement of neutron lifetime, https://phys.org/news/2020-06-scientists-space-based-neutron-lifetime.html, June 2020. Big Bang Nucleosynthesis constraints and light element abundance estimates, https://ui.adsabs.harvard.edu/abs/1995PhLB..347..347K/abstract, Feb 1995. Alter some of these values can change the H/He abundance said to be created during BBN phase. The original temperature for the CMBR calculated by George Gamow and Ralph Alpher in late 1940s was about 51 K, not 3 K background.

Are the observations and measurements used to support the BB cosmology (this includes H0 or the Hubble constant and others used, e.g. Cosmological constant for the rate of expansion of space) as reliable and secure as measurements for stellar parallax, e.g. the star 61 Cygni?

Example. Resolving long-standing mysteries about the first parallaxes in astronomy, https://phys.org/news/2020-11-long-standing-mysteries-parallaxes-astronomy.html, November 2020.

My answer is no. Unless you can observe the BB event and formation of the CMBR directly, the stellar parallax measurements for 61 Cygni and Vega reported are more secure by the scientific method.
 
Apr 19, 2021
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Big bang in fact doesn't prove or answer anything even if it's called "theory without a rival"

Likely there was some explosion which is again "likely" the reason for "cosmic microwave background radiation" but the big bang itself explains very little and proves absolutely nothing, why?

IF for example we assume there indeed was big bang, this only explains expansion of our universe but opens a whole host of other questions even harder to explain such as:
1. How is it physically possible that all matter in observable universe was able to be put into a single athom?
2. What was there before big bang?
3. If there was something how it happen to exists, and if there was nothing then where did matter come from?

The biggest question is of course how did universe happen to exist and where it all began, to answer that question big bang may satisfy a tinny portion of the whole picture, but real problem with BB theory is this also makes the original question harder to answer.
 
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Asking the question of whether or not [this] universe had a beginning, leaves out the question of whether or not this is the only universe in existence. Some want to believe that this universe had no beginning, and likely will have no end. In order for [this] universe to have a beginning, it would be the only one to exist, and there for would have an end. If [this] universe had a beginning, what set off the birth of this universe, and did it have an umbilical cord? Did the BB (Big Bang) start with a massive Dark Star of super hot plasma that shrank to the point of the size of Earth, causing ripples in time and space? If the universe we know is not alone, and space is filled with an infinite number of universes, both big and small, did it begin with the mergers of different univeres? Do univeres exist in clusters, like that of Galactic clusters? The rapid expansion could be explained by the merger of two or more univeres. Can the acceleration of the universe be explained by the merger of our universe with a much larger universe?
 
Apr 19, 2021
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Asking the question of whether or not [this] universe had a beginning, leaves out the question of whether or not this is the only universe in existence. Some want to believe that this universe had no beginning, and likely will have no end. In order for [this] universe to have a beginning, it would be the only one to exist, and there for would have an end.
Good point there, however multiverse theory is not that much different from big bang except that it deals with multiple universes vs just [this] one.

Big question of the beginning and the future, that applies to [this] or single universe also applies to multiverse.
there is really no difference, even if each universe happen to exist as a chain product of previous universes, in which case sooner or later you're back to single universe and again to same problem as if there is was no multiverse involved at all.

I understand the question of this topic is scientific, however the answer can be only philosophical and will likely never be scientific, because even if there was some kind of a beginning the question remains the same right? :)

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Knowing that, is there philosophical answer to this?

Starting point for this big question that I'm sure may help to study this problem is called "Theory of nothing".

it does not solve the problem of existence of our universe because "nothing" simply means absence of everything; that is the matter and even space.

If there was absolute nothing, then something (the matter) could not happen to exist out of nothing because that's nonsense or at best logically impossible.

Therefore "something" must have existed, it does not matter much what this something was because without that initial something you're back at nothing therefore running out of possible solutions.

The real point with that something is not only what that something is but also when?
Of course this is another related question and the point is to look at problem not only as a matter and space but also time which leads us to space time and matter in that space and time!

Why?

If something (that is matter and space) existed at some point then whether it started to exist at some point or it existed since ever also depends on time (and possibly the evolution of time)

If there was no evolution of time, then from this observations so far it can only be time-infinite existence of something, because if it's not time-infinite then you're back at "nothing" at some point in time, (discussed earlier which simply does not give any results.)

On another side if there was some kind of evolution of time then we deal with "time theory".
The "A-theory of time" and "B-theory of time" may help to study this secondary possiblity.
 

IG2007

"Don't criticize what you can't understand..."
Apr 5, 2020
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1. How is it physically possible that all matter in observable universe was able to be put into a single athom?
2. What was there before big bang?
3. If there was something how it happen to exists, and if there was nothing then where did matter come from?
1. The same way it is possible to have a blackhole, but more logical perhaps.

2. That question itself is invalid, as the BBT states that everything, time, space, matter - everything, started to exist from the moment of Big Bang. Time didn't exist before the big bang, at least, the theory states so. And, in my opinion, (it's just my opinion, not of the theory's) it does not matter if time existed before the big bang, because it simply doesn't matter as all the matter was inside the yet-to-happen-less-than-one-atom-size universe.

3. Well, it is an extremely tricky question which has not yet been answered by anyone, though, if someone did, I didn't quite like it. I have a theory of mine though. There was nothing at first, 0, only 0. Then, it arose from the zero, two different types of matter, matter and antimatter, zeroing out the value. And, till now, I am going along the Mainstream in theory. But my theory adds another point, in matter and antimatter, only the energy is zeroed out, not the mass, and according to the energy-mass-equivalence-equation, e=mc^2. Mass has energy, thus it breaks the first law of thermodynamics when it does not zero out. Thus, my theory says that matter had positive mass and antimatter had negative mass. Now, that zeroes it out.

Now, you may ask, is negative mass only theoretical or does it have existence in reality? And, where is all the negative mass? Yes, negative mass has existence in reality, it has been observed in different experiments. A majority of antimatter has been wiped out by matter in the chaos of the big bang. The rest of the antimatter (remember, it contains negative mass now) drifted away due to their negative gravity or antigravity. Now, you may say, this is science fiction now. And I would say, no, I am supported by General Relativity. General Relativity states that anything that has mass curves the fabric of spacetime in a convex way, whereas anything that has negative mass curves the fabric of spacetime in a concave way. And thus, it creates a force opposite of gravity, so I guess it would be fair to call it antigravity. Now, as it has antigravity, it drifted away from the rest of the matter, perhaps they are in the edges of the observable universe.
 

Catastrophe

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How do we know that the universe started with a Big Bang?

For better or for worse, it is a fact of life that there will be some measure of duplication in the questions asked and, therefore, in the answers offered,

The fact is that we do not know anything about the Big Bang except, perhaps, that its very name was offered as derogatory.

Quote
The big bang got its name from a man who thought the theory ...
https://www.popsci.com › big-bang-term-origin-fred-h...


28 Mar 2018 — Hoyle, who died in 2001, did more than just name the big bang (and argue against its existence). He also worked with Willy Fowler to show that .
Quote

We cannot make any scientific experiment on this theory. It does have some mathematics which "suit" it but, then, mathematics is only a language which describes some facts or fantasies.
Remember, the map is not the territory.
Map–territory relation - Wikipedia
https://en.wikipedia.org › wiki › Map–territory_relation


"A map is not the territory" — Polish-American scientist and philosopher Alfred Korzybski remarked that "the map is not the territory" and ...
"A map is not the territory" · ‎Relationship · ‎

There are other possibilities, such as that the Universe (by definition, there is only one - if you want more, call them something else) is cyclic. The so-called Big Bang could simply be a transition point between states. Just because tadpoles have a beginning and an end, it does not mean that the Universe has to be equally limited.

So, the truthful answer to your question is "we don't".

Cat :)
 

Catastrophe

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It's like saying "you don't know what's inside my shoebox--- so my claim that I have a real magical Leprecon inside is plausible."
No, not good reasoning at all.

Theories and ideas in Astronomy are regularly revised/destroyed/re-written.
In large part because astronomy deals with vast quantities and matters that can't be put into test tube and repeatably experimented on in a lab......
So yes we should keep humility and qualify often "the most current theory/explanation of......"
rather than saying "the Solar system has 9 planets......."
Funny it just took one vote of the IAO to invalidate that "fact."
Quote

I found this elsewhere, posted by a t_image. (My emphasis).

Also: "Thus the real test of science is whether the result is reproduceable or not. In order to complete a "scientific transaction" the independent third party test is required."

Here is another quote attributable to a Mister T:
Quote
IMO this is an example of how sometimes math doesn't work well for complex interactions.
or at least current mathematical models don't.
when applying math to natural phenomena I don't believe Occam's razor applies.
a concise mathematical formula is usually just an approximation and there are countless terms in any model that have not been discovered yet.
Take pi (mmmm...pie!) you use pie in any formula and you introduce an approximation.
even the smallest approximations, when applied to very small or very large phenomena get out of control after a few trillion calculations.
Quote

OK Last addition:
the "statement that the universe is temporally finite only applies to the Big Bang model and we KNOW that that model is incomplete because it has a singularity in the math. My emphasis.
Source https://www.physicsforums.com/threads/intro-to-big-bang-and-infinity-concepts-comments.938138/ "


Cat :)
 
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There was nothing at first, 0, only 0. Then, it arose from the zero, two different types of matter, matter and antimatter, zeroing out the value. And, till now, I am going along the Mainstream in theory. But my theory adds another point, in matter and antimatter, only the energy is zeroed out, not the mass, and according to the energy-mass-equivalence-equation, e=mc^2. Mass has energy, thus it breaks the first law of thermodynamics when it does not zero out. Thus, my theory says that matter had positive mass and antimatter had negative mass. Now, that zeroes it out.
Nothing wrong with your calculation, mathematically you can zero out gravity\anti-gravity, matter\anti-matter etc.
but problem with that is the result is not really zero as you seem to depict it, because matter\antimatter, zero mass etc. is something rather than nothing.

Which again touches the "Theory of nothing" I tried to breakdown in my earlier post.

This is not strictly my own opinion or theory, for example Stephen Hawking also similarly said that there likely never was "nothing" but rather something exited since ever, however according to his interpretation that something
was infinitely approaching close to nothing but was never really absolute nothing or zero, (such that this zero could imply nothing or some starting point in time (it would be theoretically wrong)).

2. That question itself is invalid, as the BBT states that everything, time, space, matter - everything, started to exist from the moment of Big Bang. Time didn't exist before the big bang, at least, the theory states so.
True, from the point of a big bang as you said, because BB theory also states following: (copied from wikipedia)
However, the Big Bang model does not describe how energy, time, and space were caused, but rather it describes the emergence of the present universe from an ultra-dense and high-temperature initial state
So if we govern our self this way then the question in the title "How do we know that the universe started with a Big Bang?" contradicts the true meaning of the big bang, because the big bang theory by it's definition cannot answer this question.

My point here is not to disapprove any ones opinions or real theories (we are only discussing), but rather highlight that the answer to this question cannot be empirical due to the nature of infinity and a hard line between nothing and something.
 
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There are other possibilities, such as that the Universe (by definition, there is only one - if you want more, call them something else) is cyclic. The so-called Big Bang could simply be a transition point between states. Just because tadpoles have a beginning and an end, it does not mean that the Universe has to be equally limited.
Good one, multiverse should probably not be called a "theory" at all, but rather "human imagination" in an attempt to blur out or calm down our inability to comprehend non "limited" universe or the nature of infinity.

So, the truthful answer to your question is "we don't".
"we don't know" is chaotic, I think the OP wants some reasonable answers here o_O
 
BB yes, but how we got a BB in the first place is a topic for unique thought.

Microwave dents seem to show that time and space existed before the BB so I think a few solutions exist.

1. The BB is just 1 of an infinite number that interact to halt and start BB,s

2. Fluctuation is the universe with the BB as just an event of energy overdose in one region of forever.

3. Our BB is everything but expansion runs out of the ability to create new /time/space at some extreme distant time.
Self gravity takes over and returns the energy to one zone that is to much energy for that zone, BB.

Probably that list could continue many many more ideas.
 

Catastrophe

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Good one, multiverse should probably not be called a "theory" at all, but rather "human imagination" in an attempt to blur out or calm down our inability to comprehend non "limited" universe or the nature of infinity.


"we don't know" is chaotic, I think the OP wants some reasonable answers here o_O
""we don't know" is chaotic, I think the OP wants some reasonable answers here"
Hard luck. There are none. :)
As you said above, due to: "our inability to comprehend non "limited" universe or the nature of infinity." No point in saying there are fairies at the bottom of the garden. Cat :)
 
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Atlan0101

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"Astronomers have detected, throughout the universe, two chemical elements that could only have been created during the Big Bang: hydrogen and helium. Furthermore, these elements are observed in just the proportions (roughly 75% hydrogen, 25% helium) predicted to have been produced during the Big Bang. This prediction is based on our well-established understanding of nuclear reactions - independent of Einstein's theory of gravity.
Second, we can actually detect the light leftover from the era of the Big Bang. The blinding light that was present in our region of space has long since traveled off to the far reaches of the universe. But light from distant parts of the universe is just now arriving here at Earth, billions of years after the Big Bang. This light is observed to have all the characteristics expected from the Big Bang scenario and from our understanding of heat and light."

Got this answer from https://lweb.cfa.harvard.edu/seuforum/faq.htm
"The blinding light that was present in our region of space has long since traveled off to the far reaches of the universe...." What far reaches of the universe? Outside of the event horizons and singularities of blackholes, Planck level blue-white holes, us here, now, and every other real space, real time, 0-point position of our universe, any universe, every universe, there is no such thing as the far reaches of the universe. To mean, no light from that region of the observable universe has ever, or will ever, pass us by to some non-existent far reaches of the universe. Altogether, we are the dead center of infinity [and] the far reaches of the universe. That distant so-called BB horizon is not only distant but right here, right now, inside us as the collapsed horizon of Planck level blue-white holes. We, and all points of the universe broad and deep, other than the singularities of blackholes, are in -- within -- that collapsed horizon. Again, no light from that region of the universe has ever, or will ever, pass us by.

Nor has it ever been "late" in reaching us (that region is frozen in time, a fixed horizon such as any frame of time at the speed of light). I, for one, call it time reversal. To mean space and time are mass and energy (mass (space) - energy (time)). Mass and space one physicality. Energy and time, another. Positive time (+) is [to] us from every direction of the universe we observe, including from down and in, the micro-universe. Negative time (-) goes away from us in every direction toward that distant BB / Planck horizon, up and out, and down and in. 14 billion light years is negative (-) 14 billion years. negative (-)14 billion years plus positive (+) 14 billion years equals 0-point, both here and now in the light and there and now in a dark universe (to us) we can never observe from our position regarding all other real space, real time, 0-points. Of course to those observers away in the distance, it is we, not them, who are in the distant horizon of the BB. It is we who are observed to be behind the times by 14 billion years. Rather it is our position, as well as our velocity (position and velocity; as in the principle of uncertainty (the principle of [increasing] or [accelerating] uncertainty)), that is observed to be permanently behind the times.

The way we are decelerating in the universe (thus the universe itself [apparently] accelerating in expansion to infinity) you'd think we, this plane of universe we are on, or generation of universe we are in, were advancing toward some kind of infinite Big Crunch Vortex / Big Hole Vacuum / Big Mirror ('naked singularity') state. The final disappearance -- by absorption -- of our very local, very finite, universe ((u) ('1')) into the non-local of the infinite Universe ((U) ('1')).
 
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there is no such thing as the far reaches of the universe. To mean, no light from that region of the observable universe has ever, or will ever, pass us by to some non-existent far reaches of the universe. Altogether, we are the dead center of infinity [and] the far reaches of the universe.
You seem to be thinking about space in the sense of "presentism" which states that neither the past nor future time exists, instead the time is here and now, what happens now is *now* and it does not "travel" from the future passing us and then going into the past.

Other 2 theories are "eternalism" and "growing block universe"
All 3 have their own supporters...

The "eternalism" may sound like some religious-only concept of time (in fact it is religious), BUT it is AFAIK currently used theory in science as well (however by scientists it is called "block universe"), eternalism or block universe is our reality of time, and it makes a lot of sense for the problem that you're trying to wrongly classify as dead point within infinite time or present-only.

Again, no light from that region of the universe has ever, or will ever, pass us by.

Nor has it ever been "late" in reaching us (that region is frozen in time, a fixed horizon such as any frame of time at the speed of light)
If you're referring to those parts of the space which expand faster than light then you're correct, however it applies only from the point in time when expansion reached FTL speed but not before.

Also we don't know whether space will stop expanding at some point so saying that light will never reach isn't certain.

In any case that doesn't mean the time is fixed or frozen on some imaginary infinite or expansive line, such that it's present-only.
 
I don't see any substantive replies to my posts #13 and #14.

Cat :)
I think because the answer is blowing in the wind.
They had a song like that about how many trees etc.
Proving the BB was real isn't to difficult, proving how it got energy to be a BB that one is blowing in the wind :)

One thing for sure is no free energy ride for us or the universe so solving the what was before the BB i think would answer the rest.
 
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I think because the answer is blowing in the wind.
I really hope you're not referring to my comments because I don't consider them as answers.

Proving the BB was real isn't to difficult, proving how it got energy to be a BB that one is blowing in the wind :)
No offense but, this sounds like "accept it or not, that's how it is now and you better don't challenge that"

But then, why disapproving or defending something that was not proved in the first place? :)

There are few candidate theories you surely know about that could evolve to answer the missing "creational" portion of the BB or even give a complete new theory at some point, candidates listed for:
Theory of everything - Wikipedia
 

Atlan0101

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You seem to be thinking about space in the sense of "presentism" which states that neither the past nor future time exists, instead the time is here and now, what happens now is *now* and it does not "travel" from the future passing us and then going into the past.

Other 2 theories are "eternalism" and "growing block universe"
All 3 have their own supporters...

The "eternalism" may sound like some religious-only concept of time (in fact it is religious), BUT it is AFAIK currently used theory in science as well (however by scientists it is called "block universe"), eternalism or block universe is our reality of time, and it makes a lot of sense for the problem that you're trying to wrongly classify as dead point within infinite time or present-only.


If you're referring to those parts of the space which expand faster than light then you're correct, however it applies only from the point in time when expansion reached FTL speed but not before.

Also we don't know whether space will stop expanding at some point so saying that light will never reach isn't certain.

In any case that doesn't mean the time is fixed or frozen on some imaginary infinite or expansive line, such that it's present-only.
If I've read you right then you seem wrong on a few counts of what I said (What I've said in several threads and posts).

First off, I've made clear I see no faster than light existing. The traveler can be at a velocity that might be considered infinite with regard to an observer sitting here on Earth and still not be traveling at any faster than light velocity. Both the traveler and observer would measure their local speed of light to be 'c'. Non-locally (non-local to both) things would be different as both would be on their own planes of velocity graduating even to different universes the greater the difference becomes. The traveler, if capable of a constant of self-propulsion (a constant of acceleration and/or deceleration), will have the ability to contract space and time [compact] 4-dimensionality (contracting a local tractable bubble of space and time) and, of course, will also have the ability to expand space and time [compact] 4-dimensionality (expanding the local tractable bubble of space and time): Mass (space). Energy (time).

The total of all Planck level blue-white holes (quantum fluctuations) throughout all of an infinity of spaces and an eternity of all times is summed up in a single, centralized, mainframe of Big Bang. Being physically finite (even if not in consciousness, possibly), and residing in a finite local, relative, universe ((u) ('1')), it is impossible to observe, much less deal in, the infinite of Universe ((U) ('1')). The infinite, regarding the finite, collapses in horizon, literally,, but all its infinity is still useful, the collapsed horizon then also manifesting itself as a physicality, exactly as Planck realized must be the case. The mainframe sum of Big Bang is no infinite of energy, though, just as no Planck level blue-white hole (no quantum fluctuation) is an infinite of energy.

The 'naked singularity' of the infinite mainframe of Big Crunch Vortex / Big hole Vacuum / Big Mirror of all blackhole singularities of all spaces and times is a very different story. It is the infinite Universe ((U) ('1')), timeless, therefore there is no energy (no time) to it. All energy (time) being stripped away. It, too, is centralization of a decentralization. In its case mass, massing, infinite density of massing to some dark primordial state. But there is the integral dimension of Big Mirror mirroring the infinite itself to an infinity of infinites (1:1:1:1.... to infinity): To an infinity of point infinitesimal / finite local, relative, bubble universes. An infinite Multiverse (M) multi-dimensionality at once mirrored to an infinity of multiverses (m) (the infinite Universe ((U) ('1') at once mirrored to an infinity of universes ((u) ('1:1:1:1...')). Those Planck level blue-white holes so hot they are here one instant, gone the next, nothing actually but quantum fluctuations, quantum sparks, in a constant stream, an infinity of streaming, renewing the material existence of "finite" universes the disposals of blackholes have reduced and removed over times throughout all spaces.

Thus you're both wrong and right. Yes, there is a cosmological constancy. A constant of "merry-go-round." A constant of conduit, hyper-conductivity and streaming. A constant of Vortex. A relentless continuity of real time universal clock moment. That is the only constant of "present." "The irresistible force of an immovable object (both a truly irresistible force and a truly immovable object in one and the same entity). A constant balance of natures. Not the horror of a 1-dimensional string imbalance -- a titanic disorder end to end -- in creationism past (yes "creationism", no matter what the disclaimer) to deep freeze future we are presented with and, essentially, ordered to accept all too often. A decades old display of 1-dimensional thinking and mediocrity even in our most brilliant thinkers and theorists in the professions. Just one utterly lonesome [finite] universe within an infinite nothingness; a nothing at all when there should be no void, including no void of infinite(s), point infinitesimal(s), and infinities of.... There should be no void.
 
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First off, I've made clear I see no faster than light existing.
I did not say speed faster than light exists.

What I meant is that 2 "distant" points in space move from each other FTL, that's why light may not reach.

However since space doesn't expand at constant rate saying light will never reach is moot point, because it applies only from the point in time when 2 points reached 50% of light speed and onward.

For example, given 2 distant points A and B, and central point C:
A - C - B

If points A and B each happens to move away from point C at 60% of the speed of light then point B moves away from point A at 120% the speed of light which is faster than light, so light from point A may never reach point B.

For all time until points A and B were expanding up to (but not including) 50% speed of light, the light will eventually reach both points.
 
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