Did the Big Bang happen?

[HappySkeptic]

So in essence everything is nothing and nothing is everything. Is this at all related to the whole matter/anti-matter thing?

In his undergraduate textbook, Modern Physics (4th edition), Professor Kenneth S. Krane discusses cosmology in his last chapter.  In it, he states that the Universe is either finite or infinite in spatial extent.  Do you agree?  He also states that General Relativity can handle both scenarios, a finite Universe or an infinite one.  In either scenario, our Universe is expanding.  Of course, if our Universe is infinite, then, it is certainly conceivable that there are events that occurred in our infinite past or will occur in our infinite future, given that the speed of light, the rate of information transfer, is finite.

Now, if our Universe is finite, it is expanding, not only into its future, but in all three spatial directions, hence, its overall volume is increasing over time.  What, exactly, do you think, in this scenario, the Universe is expanding "into"?

I find it easier to conceptualize a finite universe.  An infinite universe is usually discussed in terms of some multiverse scenario (like branching universes).  While the universe appears flat, it may be so big we can't tell the difference between it and one with curvature (finite).

The universe isn't necessarily expanding into anything.  Spacetime is defined by relationships within itself.  We have no idea of anything external.  If the universe, as far as we are concerned is "all that there is", then there literally isn't anything to expand into.

Think of it this way -- imagine space as a fisherman's net, where the crossing ropes are nodes of spacetime.  Imagine that information takes T time to travel between any two nodes.  The distance doesn't matter (Only the number of nodes separating two points can be thought of as distance).

Then, add double the amount of ropes, so that the nodes quadruple.  If the time for information transfer between adjacent nodes is still T, we have effectively expanded the dimension of space by two, without "expanding" the size of the net.  The size of the net is meaningless - only the number of nodes between two points defines distance (as measured by the speed of information transfer).

So, does the expansion of space really mean anything is expanding, or are we just creating more "nodes" of spacetime (and spacetime is quantum?)?  We couldn't tell the difference, since there is no difference to us.

[Jehanne]

JairCrawford's logic appears to me to be Aristotelian.

[Brian37]

Others have said here that QP or QM do not argue for either a finite universe or infinite universe. The real question isn't to focus on that. The real issue is either way, a God is not required. 

Hurricanes for example, are a very organized form of storm. But climate scientists and weather scientists would still not be able to tell you the exact molecule or cloud that lead to it's formation, or the exact first raindrop to hit the ground from the storm. But no sane climatologist is going to claim Poseidon cause it. Weather scientists can however, talk about conditions that determine that lead to a hurricane.

The background radiation is as far back as scientists can measure, but they can work out the formulas that give us a good idea as to the conditions that lead up to that famous picture.

[Anomalocaris]

……..what I’m wondering is… Is it possible that there was no Big Bang and that the universe simply always existed?…….

Anything is possible.   Given the evidence we have, just how possible is it that there was no Big Bang depends entirely on what precisely you mean by Big Bang.     Also, what do you mean by “always” when you say universe always existed?

[JairCrawford]

I’m gonna try to reply to everyone who asked me stuff while I was out lol. I’m tired so I apologize if I miss anything.

1. On the whole whether finite or infinite, the universe does not “require God” to explain the science: I agree. I see God less and less as the ‘thing’ that fills in the gaps these days and take a much more purely fideistic approach to faith. So my asking these questions is, legitimately, not faith-driven. I am curious about the science.

2. Do I think the universe is finite or infinite? Um… I have no idea. I like the idea of the universe possibly being curved and therefore being a four-dimensional sphere. But even with such a model where if you keep going in one direction theoretically you could end up back in the same place, that doesn’t mean the universe is finite from a time perspective.

3. I like the theory of quantum eliminating the singularity causing an infinite state of time before the Big Bang. It is much simpler to my mind than trying to figure out what “happened” “before time”.

4. When I said always I was speculating a universe that has existed forever. Infinite time.

[Brian37]

……..what I’m wondering is… Is it possible that there was no Big Bang and that the universe simply always existed?…….

Anything is possible.   Given the evidence we have, just how possible is it that there was no Big Bang depends entirely on what precisely you mean by Big Bang.     Also, what do you mean by “always” when you say universe always existed?

Theists never can give your question a solid answer. And actually "Big Bang", if I am remembering correctly, simply was popular nomenclature when the cosmic microwave background radiation was discovered. If I am remembering correctly, it is better described as rapid increasing inflation, or rapid expansion. 


The thing about QP/QM theist like to throw at us is "Well, if anything goes, then why can't a God be the cause of it?" That begs the question, if everything has a cause, then what caused God. That causes the problem of infinite regress. The theist has to insert something even more powerful than the "all powerful" they claim exists and is the cause of everything. If that God doesn't need a cause, then why would the universe need a God to cause it?

There is the issue of probability in terms of likelihood too. QP/ QM does postulate some really freaky stuff, but that is not license to plop in a gap answer just because one likes the idea. QP/QM postulates parallel universes, multiverses, bubble universes. Some quantum physicists have postulated up to 12 dimensions.  In terms of relativity, my understanding is we(or the "now") we perceive is a locked in forward arrow we cannot escape from because we are stuck in our dimension. Whereas from a different perspective elsewhere in the universe, we could look like to them, as going backwards or in reverse, and neither perspective would be wrong. 

Just like there perspective of a semi in the opposite lane of traffic way off in the distance in front of you coming towards you, looks small off in the distance, but the closer it gets the bigger it gets. To you your perspective is forward in front of you, to that semi driver, they also perceive you as being small until the distance closes. Then once you pass each other, you get smaller and smaller. In the case of QP/QM this is where "relativity" flies out the window and macro physics cannot accurately suffice in describing the sub atomic level.

But back to the issue of likelihood. Stephen Hawking "A God is not required". He was not leaving the door open as a possibility in saying that. There are things scientists have discarded and left behind as possibilities once better data became the consensus in science. Is it, for example possible that I am dating Angelina Jolie? She exists, I exist, so it must be true we are dating because I claimed it. No sane person would or should buy that claim. 

So as far as possibilities. 

1. An "All Powerful" God does exist?

Or

2. Humans in antiquity anthropomorphized the world around them, and gave their gods human like qualities as a reflection of their own nature and desires. And humanity in that time has passed down the religions of their society/parents, long before the child can formulate adult critical thinking skills. 

QP/QM isn't out to uphold zombie gods or magic babies. It is freaky enough without people trying to plop in old mythology as a gap answer.

[Jehanne]

I’m gonna try to reply to everyone who asked me stuff while I was out lol. I’m tired so I apologize if I miss anything.

1. On the whole whether finite or infinite, the universe does not “require God” to explain the science: I agree. I see God less and less as the ‘thing’ that fills in the gaps these days and take a much more purely fideistic approach to faith. So my asking these questions is, legitimately, not faith-driven. I am curious about the science.

2. Do I think the universe is finite or infinite? Um… I have no idea. I like the idea of the universe possibly being curved and therefore being a four-dimensional sphere. But even with such a model where if you keep going in one direction theoretically you could end up back in the same place, that doesn’t mean the universe is finite from a time perspective.

3. I like the theory of quantum eliminating the singularity causing an infinite state of time before the Big Bang. It is much simpler to my mind than trying to figure out what “happened” “before time”.

4. When I said always I was speculating a universe that has existed forever. Infinite time.

The term "Big Bang" originated with Professor Fred Hoyle, a critic of what cosmologists often refer to today as The "Standard Model" or Lambda-CDM model or FLRW, with some variation on the last one (such as FRW). In any case, the term "Big Bang" stuck in popular culture, and so, it persists also within the Academy.

In my opinion, the Cosmos is infinite, in both time and space, without a beginning and without an end. The late Professor Carl Sagan, in the opening scene of his Cosmos program, gives a neat and dramatic expression of this position, available on YouTube.

[Brian37]

I’m gonna try to reply to everyone who asked me stuff while I was out lol. I’m tired so I apologize if I miss anything.

1. On the whole whether finite or infinite, the universe does not “require God” to explain the science: I agree. I see God less and less as the ‘thing’ that fills in the gaps these days and take a much more purely fideistic approach to faith. So my asking these questions is, legitimately, not faith-driven. I am curious about the science.

2. Do I think the universe is finite or infinite? Um… I have no idea. I like the idea of the universe possibly being curved and therefore being a four-dimensional sphere. But even with such a model where if you keep going in one direction theoretically you could end up back in the same place, that doesn’t mean the universe is finite from a time perspective.

3. I like the theory of quantum eliminating the singularity causing an infinite state of time before the Big Bang. It is much simpler to my mind than trying to figure out what “happened” “before time”.

4. When I said always I was speculating a universe that has existed forever. Infinite time.

The term "Big Bang" originated with Professor Fred Hoyle, a critic of what cosmologists often refer to today as The "Standard Model" or Lambda-CDM model or FLRW, with some variation on the last one (such as FRW).  In any case, the term "Big Bang" stuck in popular culture, and so, it persists also within the Academy.

In my opinion, the Cosmos is infinite, in both time and space, without a beginning and without an end.  The late Professor Carl Sagan, in the opening scene of his Cosmos program, gives a neat and dramatic expression of this position, available on YouTube.

I don't see the Cosmos as infinite in the context you buy. I do see it as a fluctuating cycle between off and on. The on stage is what we are riding in, but the universe will suffer a heat death and go back to off. We may be the result of the decay of a prior universe, but again, QP/QM in either case, something out of nothing, or something prior, is not postulating a super cognition as cause. But ultimately science has yet to figure that out.

[polymath257]

So in essence everything is nothing and nothing is everything. Is this at all related to the whole matter/anti-matter thing?

In his undergraduate textbook, Modern Physics (4th edition), Professor Kenneth S. Krane discusses cosmology in his last chapter.  In it, he states that the Universe is either finite or infinite in spatial extent.  Do you agree?  He also states that General Relativity can handle both scenarios, a finite Universe or an infinite one.  In either scenario, our Universe is expanding.  Of course, if our Universe is infinite, then, it is certainly conceivable that there are events that occurred in our infinite past or will occur in our infinite future, given that the speed of light, the rate of information transfer, is finite.

Now, if our Universe is finite, it is expanding, not only into its future, but in all three spatial directions, hence, its overall volume is increasing over time.  What, exactly, do you think, in this scenario, the Universe is expanding "into"?

When cosmologists speak of the universe being finite or infinite, they usually mean in spatial extent using a comoving frame.

In the classical version of general relativity, there were three options: either space is positively curved (like a sphere) and time is finite in both directions, space is flat (like a plane) and time is infinite into the future but not the past, or space is negatively curved (like a saddle) and time is infinite into the future and not into the past.

Which of the three possibilities actually occurs depends on the density of matter and energy: a higher density leads to more gravity and an eventual collapse associated with the positive curvature. Less density leads to negative curvature and expansion forever. A critical density leads to flatness (and, yes, expansion forever).

This whole description became more complicated with the discovery of dark energy (also known as the cosmological constant). Einstein had originally introduced this notion as a way of having a static universe but it was discarded (except for graduate student exercises) after the expansion of the universe was discovered.

I won't go into specifics, but the nice trichotomy above is shifted and it is possible to have expansion forever even if the universe is positively curved.

Anyway, in anything based on general relativity and NO quantum mechanics, the universe is finite into the past.

The question of what the universe is expanding into is a subtle one and requires a bit different perspective.

In modern cosmology, we discuss the geometry of spacetime, not just of space itself or time itself. The two together form the basic geometry of the universe. So when a cosmologists models the universe, they model it throughout both space and time as a single object. All dynamics occur within this object at different time slices.

So, as an analogy, I'm going to describe a 'universe' that is one dimensional in space and one dimensional in time and that is also curved in spacetime.

Imagine a globe. Imagine the latitude of a point describes the time and the longitude describes the spatial location. The two together will characterize the point. We imagine points further south are previous to those further north.

Space is then the collection of points at a particular time: this corresponds to a latitude line.

Now, starting at the 'beginning' of the south pole (more about this later), the latitude lines get larger as we approach the equator: in other words, space is expanding as we move forward in time. At the equator, we have maximum expansion, and then space begins to contract until we get to the end (the north pole).

So, looking at this analogy: what does space expand into?

The answer, literally and geometrically, is *the future*. And that is the answer to what space expands into.

Finally, notice that it is impossible to go south of the south pole: there is no 'before the south pole'. This is analogous to there being no 'before the Big Bang'. This is a geometrical aspect of this particular universe of spacetime.

I have other analogies along this line, but his one handles many questions many people have. I hope it helps.

[Mister Agenda]

So, what I’m wondering is… Is it possible that there was no Big Bang and that the universe simply always existed?

We seem to have a lot of evidence of the universe expanding. We also have evidence of cosmic background radiation from when the universe was hot. But do we have evidence that these things started from a singularity? Is that part of all of it truly known fact? How can this even happen since in order for such an event to happen it would have to be “outside” time, because it would be before the expansion of the space time fabric?

The evidence for the Big Bang/Initial Expansion is very robust, but strictly speaking, what happened before the expansion isn't really part of the theory, which describes what happened when the hot dense universe began to expand. How long the hot dense version of the universe was there, 'where' it came from, whether some version of the universe has always existed...these are mysteries. The Initial Expansion theory does a pretty good job at what it's supposed to do: explain how our universe came to be the way it is.

So it's possible there was a Big Bang AND the universe simply always existed.