Is it?

Nearly.

Some of it is.

The are models of an infinite universe that are compatible with the evidence, yes.

Bubblecar said:

The are models of an infinite universe that are compatible with the evidence, yes.

So the substance that took part in the big bang must have been infinite, yeah.

Peak Warming Man said:

So the substance that took part in the big bang must have been infinite, yeah.

It would seem so. If it’s infinite now, it’s always been infinite.

Peak Warming Man said:

Bubblecar said:

The are models of an infinite universe that are compatible with the evidence, yes.

So the substance that took part in the big bang must have been infinite, yeah.

Well for me that’s the confounding bit, as you probably know the pointy heads reckon it came from a singularity which to my mind is something very small, but I might be wrong in my understanding of a singularity.

Still, there is a shedload of stuff that came from a very small space. How did it all get crammed in there? Not just the stars but all the space in between the stars as well?

AwesomeO said:

Peak Warming Man said:

Bubblecar said:

The are models of an infinite universe that are compatible with the evidence, yes.

So the substance that took part in the big bang must have been infinite, yeah.

Well for me that’s the confounding bit, as you probably know the pointy heads reckon it came from a singularity which to my mind is something very small, but I might be wrong in my understanding of a singularity.

Still, there is a shedload of stuff that came from a very small space. How did it all get crammed in there? Not just the stars but all the space in between the stars as well?

It wasn’t an explosion into space, but an explosion that was also creating space.

Weird shit :)

There’s nothing wrong with an infinite universe being very much more dense in the past, while still being infinite in extent, and becoming less dense with time.

Can something be infinitesimally small?

the thing with singularities is that they are a mathematical artifact and can’t really be compared to anything physical.

Peak Warming Man said:

Can something be infinitesimally small?

Not if spacetime is quantized, as many physicists suspect.

What intrigues me is that Hydrogen can be compressed into other elements.

Maybe Hydrogen existed in another form before the big bang?

Bubblecar said:

Peak Warming Man said:

Can something be infinitesimally small?

Not if spacetime is quantized, as many physicists suspect.

Would quantizing preclude an infinite universe?

CrazyNeutrino said:

What intrigues me is that Hydrogen can be compressed into other elements.

Maybe Hydrogen existed in another form before the big bang?

hydrogen didn’t exist for quite a while after the BB.

Peak Warming Man said:

Would quantizing preclude an infinite universe?

No.

Bubblecar said:

Peak Warming Man said:

Would quantizing preclude an infinite universe?

No.

If a quantum is a bit, a something, does that preclude infinitely small, whatever the hell that means, but I have heard it said.

AwesomeO said:

Bubblecar said:

Peak Warming Man said:

Would quantizing preclude an infinite universe?

No.

If a quantum is a bit, a something, does that preclude infinitely small, whatever the hell that means, but I have heard it said.

Yes, but it doesn’t set any upper limit to the extent of the universe.

AwesomeO said:

Bubblecar said:

Peak Warming Man said:

Would quantizing preclude an infinite universe?

No.

If a quantum is a bit, a something, does that preclude infinitely small, whatever the hell that means, but I have heard it said.

Yes. Planck scale is theoretically the smallest measurements.

The Rev Dodgson said:

Some of it is.

If you mean “Is the universe infinite in positive time?” The answer is a definite “Yes”.

If you mean “Is the universe infinite in space?” The answer is “Probably, with a probability significantly exceeding 50%”.

If you mean “In an infinite universe is it true that everything that can be imagined exists?” Then the answer is “No”.

Bubblecar said:

Peak Warming Man said:

Can something be infinitesimally small?

Not if spacetime is quantized, as many physicists suspect.

That’s a slightly difficult one to answer.

The existence of the Planck length does not necessarily preclude the possibility of something being infinitesimally small.

Think of it in terms of the Heisenberg uncertainty principle. Position can be known to infinitely fine accuracy if the momentum is not known at all. Just because nothing is currently known that is infinitely small does not necessarily mean that something that is infinitely small won’t be found in the future.

But I could be wrong.

Peak Warming Man said:

Bubblecar said:

The are models of an infinite universe that are compatible with the evidence, yes.

So the substance that took part in the big bang must have been infinite, yeah.

Only if the bit of the Universe that started at the Big Bang was infinite.

The Universe may well be an infinite collection of finite parts, at least one of which appears to have started with a big bang.

Seems like a point of contention among the experts…

https://en.wikipedia.org/wiki/Multiverse

Proponents of one of the multiverse hypotheses include Stephen Hawking, Brian Greene, Max Tegmark, Alan Guth, Andrei Linde, Michio Kaku, David Deutsch, Leonard Susskind, Alexander Vilenkin, Yasunori Nomura, Raj Pathria, Laura Mersini-Houghton, Neil deGrasse Tyson, and Sean Carroll.

Scientists who are generally skeptical of the multiverse hypothesis include:
Nobel laureate Steven Weinberg,
Nobel laureate David Gross,
Paul Steinhardt,
Neil Turok,
Viatcheslav Mukhanov,
Michael S. Turner,
Roger Penrose,
George Ellis,
Joe Silk,
Carlo Rovelli,
Adam Frank,
Marcelo Gleiser,
Jim Baggott, and
Paul Davies.

I think infinity’s a quality, not so much a quantity, though can be dealt with as a quantity in math(?) no infinity (of the real world of things) having yet been apprehended.

I’m tempted also to think that an infinity, to exist, must be expanding.

mollwollfumble said:

The Rev Dodgson said:

Some of it is.

If you mean “Is the universe infinite in positive time?” The answer is a definite “Yes”.

I don’t see any reason to be positive about that.

mollwollfumble said:

If you mean “Is the universe infinite in space?” The answer is “Probably, with a probability significantly exceeding 50%”.

I don’t see any reason to assign a numerical probability to that. We have precisely zero information about how big the universe might be.

mollwollfumble said:

If you mean “In an infinite universe is it true that everything that can be imagined exists?” Then the answer is “No”.

Different question, but if we ask about everything that is possible, rather than everything that can be imagined, then the answer is yes (by definition of possible).

transition said:

I’m tempted also to think that an infinity, to exist, must be expanding.

—-

Now if is something is limitless, how can it go further?

tauto said:

transition said:

I’m tempted also to think that an infinity, to exist, must be expanding.

—-

Now if is something is limitless, how can it go further?

ahhhh my favourite question and one that i can give my favourite answer to, read about Hilbert’s Grand Hotel

AwesomeO said:

Peak Warming Man said:

Bubblecar said:

The are models of an infinite universe that are compatible with the evidence, yes.

So the substance that took part in the big bang must have been infinite, yeah.

Well for me that’s the confounding bit, as you probably know the pointy heads reckon it came from a singularity which to my mind is something very small, but I might be wrong in my understanding of a singularity.

Still, there is a shedload of stuff that came from a very small space. How did it all get crammed in there? Not just the stars but all the space in between the stars as well?

think of it this way…

Imagine a ruler with a series of 30 regularly spaced notches, now imagine that the spaces in between each notches increases.

The number of notches doesn’t change so as far as the ruler goes, it still measures 30 notches long

Peak Warming Man said:

Can something be infinitesimally small?

it’s a pleonasm

diddly-squat said:

AwesomeO said:

Peak Warming Man said:

So the substance that took part in the big bang must have been infinite, yeah.

Well for me that’s the confounding bit, as you probably know the pointy heads reckon it came from a singularity which to my mind is something very small, but I might be wrong in my understanding of a singularity.

Still, there is a shedload of stuff that came from a very small space. How did it all get crammed in there? Not just the stars but all the space in between the stars as well?

think of it this way…

Imagine a ruler with a series of 30 regularly spaced notches, now imagine that the spaces in between each notches increases.

The number of notches doesn’t change so as far as the ruler goes, it still measures 30 notches long

—-

Or think of it this way

When the big bang happened there was no matter only energy and fields of space-time.

CrazyNeutrino said:

What intrigues me is that Hydrogen can be compressed into other elements.

Maybe Hydrogen existed in another form before the big bang?

“compressed” is a very poor choice of words

there is no meaningful definition for “before the big bang” and even if there were we are causally disconnected from it, so it’s again, meaningless

diddly-squat said:

CrazyNeutrino said:

What intrigues me is that Hydrogen can be compressed into other elements.

Maybe Hydrogen existed in another form before the big bang?

“compressed” is a very poor choice of words

there is no meaningful definition for “before the big bang” and even if there were we are causally disconnected from it, so it’s again, meaningless

That’s just an assumption. There is zero evidence for it.

The Rev Dodgson said:

mollwollfumble said:

If you mean “Is the universe infinite in space?” The answer is “Probably, with a probability significantly exceeding 50%”.

I don’t see any reason to assign a numerical probability to that. We have precisely zero information about how big the universe might be.

that’s not entirely true, we know it’s at least as big as the visible universe.

diddly-squat said:

The Rev Dodgson said:

mollwollfumble said:

If you mean “Is the universe infinite in space?” The answer is “Probably, with a probability significantly exceeding 50%”.

I don’t see any reason to assign a numerical probability to that. We have precisely zero information about how big the universe might be.

that’s not entirely true, we know it’s at least as big as the visible universe.

That’s information about how small it might be.

We have no information about what maximum size it could be.

I think infinities are probably really nasty if not expanding, i’m glad there’s only the one, being the expansion of this universe. I’d guess it excludes all other infinities.

The Rev Dodgson said:

diddly-squat said:

CrazyNeutrino said:

What intrigues me is that Hydrogen can be compressed into other elements.

Maybe Hydrogen existed in another form before the big bang?

“compressed” is a very poor choice of words

there is no meaningful definition for “before the big bang” and even if there were we are causally disconnected from it, so it’s again, meaningless

That’s just an assumption. There is zero evidence for it.

ummm no, we are causally disconnected, that much is certain… our past light cones extend backward to the big bang and no further.

diddly-squat said:

The Rev Dodgson said:

diddly-squat said:

“compressed” is a very poor choice of words

there is no meaningful definition for “before the big bang” and even if there were we are causally disconnected from it, so it’s again, meaningless

That’s just an assumption. There is zero evidence for it.

ummm no, we are causally disconnected, that much is certain… our past light cones extend backward to the big bang and no further.

Of course it isn’t bleeding certain.

It’s an assumption that causal connectedness can only occur within light cones.

As far as their is any evidence about that, the evidence suggests it isn’t true.

The Rev Dodgson said:

diddly-squat said:

The Rev Dodgson said:

That’s just an assumption. There is zero evidence for it.

ummm no, we are causally disconnected, that much is certain… our past light cones extend backward to the big bang and no further.

It’s an assumption that causal connectedness can only occur within light cones.

do have a reference that backs your claim?

ChrispenEvan said:

The Rev Dodgson said:

diddly-squat said:

ummm no, we are causally disconnected, that much is certain… our past light cones extend backward to the big bang and no further.

It’s an assumption that causal connectedness can only occur within light cones.

do have a reference that backs your claim?

Surely the request for a reference should be for evidence that supports d-s’s claim?

The Rev Dodgson said:

ChrispenEvan said:

The Rev Dodgson said:

It’s an assumption that causal connectedness can only occur within light cones.

do have a reference that backs your claim?

Surely the request for a reference should be for evidence that supports d-s’s claim?

you have made a counter claim though by implying it isn’t true. therefore you are beholden to the same requirements of proof.

you should have just asked for the proof rather than make a judgement.

To reverse the question: Is the finite universe still a goer?

tauto said:

To reverse the question: Is the finite universe still a goer?

the evidence so far backs a flat universe, within a couple of %, being such it fits with the theories that say therefore it is infinite.

the theory being GR.

tauto said:

To reverse the question: Is the finite universe still a goer?

Yes, it may be finite (although most of the recent work favours an infinite model as being a simpler fit with the evidence). But if it is finite, the results from analysis of the cosmic microwave background radiation show us that it is still many times bigger than our observable universe.

>It’s an assumption that causal connectedness can only occur within light cones.

dumb thought from a dysmathtic…

if I conceptualize some geometry involving lines, those lines traverse and then extend out of the universe to some point beyond the existing universe, is that theoretical point a possibility originated from the existing universe, or does it exist anyway?

and of mass and the various forces acting on things in this expanding universe much has a destination in a space that does not exist yet.

As the universe becomes less dense, more empty space is being created. But it’s being created within the universe. Anywhere that exists is always within the universe.

Bubblecar said:

As the universe becomes less dense, more empty space is being created. But it’s being created within the universe. Anywhere that exists is always within the universe.

—-

Less dense in matter implies more dense in energy.

>> If you mean “Is the universe infinite in positive time?” The answer is a definite “Yes”.

> I don’t see any reason to be positive about that.

Even in the absence of dark energy, there is nowhere enough matter in the universe to shop the expansion. With dark energy this becomes even more certain unless a “big rip” occurs at some future time. All observational evidence says that the “big rip” can’t exist. Taking this further, considering the metastability of the universe, instability generates more expansion.

>> If you mean “Is the universe infinite in space?” The answer is “Probably, with a probability significantly exceeding 50%”.

> I don’t see any reason to assign a numerical probability to that. We have precisely zero information about how big the universe might be.

The curvature of the universe is either -ve, positive or zero. For both negative and zero curvature the universe is infinite in space. All current evidence points to the curvature being very close to zero, so the probabilities of positive curvature and negative curvature are equal, so the probability that space is not infinite is 50% minus half the probability that the curvature is exactly zero. The likelihood that the curvature is exactly zero is looking good right now.

> if we ask about everything that is possible then the answer is yes (by definition of possible).

I was hoping to avoid this one. It’s a subtle point. Given finite knowledge of an infinite system, what appears to be possible will never be the same as what is really possible. So rephrasing it as “In an infinite universe is it true that everything that appears to be possible exists?” Then the answer becomes more difficult, the answer relies on the possibility that the same circumstances may occur and infinite number of times, which can hog state space in the infinite continuum to such an extent as to crowd out states that appear to be possible.

> Less dense in matter implies more dense in energy.

No.

> if I conceptualize some geometry involving lines, those lines traverse and then extend out of the universe

They never leave the universe.

> causal connectedness only occurs within light cones

Yes, but be aware that if the light cones pass through a singularity such as the Big Bang or the throat of a Kerr wormhole then causal connectedness is broken even within the light cone.

> I think infinities are probably really nasty if not expanding, i’m glad there’s only the one, being the expansion of this universe. I’d guess it excludes all other infinities.

Um, not really. But think of it in reverse, finite is even nastier than infinite. With “infinities”, you don’t have to worry about what the edge is like and what is outside.

> What intrigues me is that Hydrogen can be compressed into other elements. Maybe Hydrogen existed in another form before the big bang?

Even a single hydrogen atom can’t be compressed enough to pass through the Big Bang. Light can, though. Light can be compressed to higher energies and shorter wavelengths without limit.

> https://en.wikipedia.org/wiki/Multiverse

There are a multitude of multiverse hypotheses. I tend to like the eternal inflation multiverse (because the universe is metastable) and dislike both the topological multiverse (no sign of it in the Planck data) and quantum multiverse.

>> Can something be infinitesimally small?
> Not if spacetime is quantized, as many physicists suspect.

In theory (perhaps not in practice) then even in quantum theory it can be infinitely small if its momentum is completely unknown.

>> Can something be infinitesimally small?
> Not if spacetime is quantized, as many physicists suspect.

In theory (perhaps not in practice) then even in quantum theory it can be infinitely small if its momentum is completely unknown.

To expand on that idea some more, the Planck length is simply the length scale of the unification of gravity and quantum mechanics, it doesn’t preclude the existence of entities smaller than that. It just means that our present understanding of quantum theory is incomplete at smaller scales than that.

ChrispenEvan said:

The Rev Dodgson said:

ChrispenEvan said:

do have a reference that backs your claim?

Surely the request for a reference should be for evidence that supports d-s’s claim?

you have made a counter claim though by implying it isn’t true. therefore you are beholden to the same requirements of proof.

No, saying we don’t know is not a counter claim, it is the default position in the absence of evidence.

ChrispenEvan said:

you should have just asked for the proof rather than make a judgement.

Feel free to do that if it is your preferred manner of debate.

ChrispenEvan said:

tauto said:

To reverse the question: Is the finite universe still a goer?

the evidence so far backs a flat universe, within a couple of %, being such it fits with the theories that say therefore it is infinite.

It fits even better the theories that say it is at least as large as x, where x is the minimum size that fits the observations.

It says nothing at all about whether it is infinite or not, other than that remains a possibility (with unknown probability).

Bubblecar said:

tauto said:

To reverse the question: Is the finite universe still a goer?

Yes, it may be finite (although most of the recent work favours an infinite model as being a simpler fit with the evidence).

Eh?

In what way simpler?

The Rev Dodgson said:

ChrispenEvan said:

The Rev Dodgson said:

Surely the request for a reference should be for evidence that supports d-s’s claim?

you have made a counter claim though by implying it isn’t true. therefore you are beholden to the same requirements of proof.

No, saying we don’t know is not a counter claim, it is the default position in the absence of evidence.

you didn’t say we don’t know you said it was an assumption that it was true. that implies that you don’t think it true. so please provide evidence of this claim. otherwise i will take it that you can’t back it and are just talking out your arse. as usual in these debates. oh and take offense if you like too. or even say you don’t.

ChrispenEvan said:

The Rev Dodgson said:

ChrispenEvan said:

you have made a counter claim though by implying it isn’t true. therefore you are beholden to the same requirements of proof.

No, saying we don’t know is not a counter claim, it is the default position in the absence of evidence.

you didn’t say we don’t know you said it was an assumption that it was true. that implies that you don’t think it true. so please provide evidence of this claim. otherwise i will take it that you can’t back it and are just talking out your arse. as usual in these debates. oh and take offense if you like too. or even say you don’t.

No, if I say something is an assumption it means that I think it is an assumption. That means we don’t know whether it is true or not.

What I say if I think something is not true is that I think it is not true.

I hope that clarifies the situation for you.

As for talking out of arses, I bow to your practical expertise on that topic.

The Rev Dodgson said:

Bubblecar said:

tauto said:

To reverse the question: Is the finite universe still a goer?

Yes, it may be finite (although most of the recent work favours an infinite model as being a simpler fit with the evidence).

Eh?

In what way simpler?

I’d imagine that averaging the results of CMBR observations gives a flat universe, and that cosmologists would regard that as a much simpler approach than assuming that the limits of resolution achieved so far represent a “real” divergence from flatness.

Bubblecar said:

As the universe becomes less dense, more empty space is being created. But it’s being created within the universe. Anywhere that exists is always within the universe.

yeah get that, but what i’m saying is math (including geometry) represents a where of sorts, maybe computational dimensions.

i’m not averse to (the idea of) some physics that involves emergence of something that obliterates the connection with its past(annihilation).

https://en.wikipedia.org/wiki/Light_cone

ChrispenEvan said:

https://en.wikipedia.org/wiki/Light_cone

Is there some part of that you would like us to take note of, or are you just doing an observer?

ChrispenEvan said:

AwesomeO said:

Bubblecar said:

No.

If a quantum is a bit, a something, does that preclude infinitely small, whatever the hell that means, but I have heard it said.

Yes. Planck scale is theoretically the smallest measurements.

Didn’t pirates make people walk the plank?

>…….. I bow to your practical expertise on that topic

reminds me of that joke, superman is flying around and sees wonder woman down on the ground laying in an inviting position, so superman flies down and obliges then asks how was that, to which the invisible man responds i’ve got a really sore arse.

Perhaps the entire universe in the singularity existed as a computer simulation and could fit into something so tiny and when it broke/burst/whatever matter/energy/spacetime was created

Sure