Expansion

[Stormcloud]

Agreed.

[Obvious Leo]

Mechsmith. I think you've got a few concepts a bit mixed up. I won't digress into the cyclical universe in this thread except to say that a universe with a beginning is metaphysically unsustainable without the existence of an external causal agent, which I regard as a cop-out because an untestable explanation which explains everything is actually an explanation which explains nothing.

Your age of the universe is a theory, not a fact. It is mostly substanciated by the optical illusion of the "Red Shift" and the resulting Hubble Constant.

You've got to be careful not to chuck out the baby with the bathwater because the word "theory" has a different meaning in science than it does in common usage. The evidence for the age of the universe is not contingent on the spacetime paradigm because age is not a spatial construct. Although it makes no sense to speak of how far away an event is occurring , it makes perfect sense to speak of how long ago an event has occurred. . The current estimate of 13.8 billion years since the big bang is extremely well supported by empirical evidence and I would be most surprised if it was too far wide of the mark. However many people have a funny idea about what the big bang actually was and think of it as an explosion from a zero-volume point. In fact it was a gradual emergence from a zero-volume point which I can illustrate with quite a charming thought experiment.

The furthest that astronomers can see with their gee-whiz telescopes is the cosmic microwave background at a "distance" of about 13.7996 billion years. Don't regard these numbers as cast in stone because it makes no difference to the point I'm making. This is when the proto-galaxies were forming and steadily moving away from each other. Prior to this time the universe was a place of Stygian darkness because the energy of its radiation was too high to be resolvable into a wavelength which any of our current technologies could detect. Thus I call on Superman, who conveniently makes himself available whenever I need him for my thought experiments. Superman can see through the last 400,000 years of "space" all the way back to the big bang itself. What do you reckon he would see? Will he see the universe suddenly bursting into existence? Not a chance, my friend. Superman would see the universe sucking itself back into a zero-volume point and vanishing from existence.

By focusing our telescopes further and further away from the present moment we're simply watching the history of our cosmos being played out in reverse.

Hasn't ennybody figured out that a big bang-expanding universe would have been a bit smaller thirteen or fifteen billion years ago

This is where you've got yourself seriously confuddled. All this is very well understood by cosmologists and has been very accurately modelled. When I said that spacetime was a metaphysically unsustainable paradigm I certainly didn't mean to imply that it wasn't a useful tool. It is a remarkable piece of mathematical ingenuity which models the holographic world of the observer to an astonishing level of precision. It predicts what the observer will observe and so far the observer has rarely failed to observe what the spacetime model has predicted. On the rare occasions that it has failed this has always been satisfactorily explained as a misinterpretation of the paradigm rather than a flaw in its construction. Other than the fact that it models the world of the observer rather than the world which is continuously coming into existence the spacetime model appears to have no flaws. Likewise I regard the quantum wave function as the most significant human invention since the wheel and the Standard Model of Particle Physics as a masterpiece of mathematical virtuosity. All these models are extraordinarily successful at doing what they have been designed to do and the technological revolution which was the 20th century is sufficient testimony to the fact that the predictions yielded must be a very close approximation to reality. Despite all this it is metaphysical nonsense to assume that any epistemological paradigm can reveal anything about the ontological truths which underpin it.

Therefore, although near enough might be good enough for physics, which only needs to invent your iPad, near enough is not good enough for metaphysics, which needs to explain the nature of physical reality to you. There's no shortage of hubris within the community of physics but the tide is slowly but surely turning at long last. Their hundred year impasse is not in fact a physical question but a metaphysical question which means they need to re-examine their foundational assumptions. They've tried getting rid of time by spatialising it out of existence and it clearly hasn't worked. What I've done is get rid of space by putting it into the consciousness of the observer, which leaves me with just time and gravity to contend with. This leaves me with John Wheeler's universe of sublime austerity, which he remained committed to until his dying day, and this is the same universe which Albert can explain to his barmaid. This is a cosmos that a child could understand and in my opinion that means it should be taken very seriously indeed.

Regards Leo

P.S. Stormcloud. You have no authority to preach at me and clearly have no point to make. I'll offer you a piece of wisdom at a never-to-be-repeated discount, courtesy of one of my least favourite philosophers, Ludwig Wittgenstein

"Whereof one cannot speak, thereof one must be silent"

[Steve3007]

Stormcloud:

Leo, professionalism at best, is but glorified ignorance - in disguise. All your academic claptrap will not one wit wisdom make. When you see through the eyes of a child you will SEE.

Another interesting example of the way in which ignorance can push apart people who might otherwise actually agree on something. (I've just been noting the same thing on a different thread).

Stormcloud, if you'd actually read some of Leo's words instead of just weighing them and concluding from their mass that they are "academic claptrap" you'd find that Leo actually agrees on this general principle of simplicity that you're advocating. It should be possible to explain the workings of the universe to a child. Or, as Einstein put it in his early 20th Century sexist way, a barmaid.

[Obvious Leo]

To be honest, Steve, I was rather amused by the "academic claptrap" slur because I have a rather low opinion of academia myself. I am not, nor have I ever been an academic, and if I were to advance my philosophy in academic circles I would be shown the door without ceremony. I am a hermit scholar beholden to no doctrine except the Aristotelian doctrine of causation and I worship only at the shrine of human reason. However I am by temperament a contrarian rogue who dares to believe that the comprehension of our universe is not a unique privilege only granted to a handful of supergeeks who speak through machines with their eyelashes. Being good at arithmetic doesn't make you wise.

Regards Leo

[Stormcloud]

Cheers Steve, point taken. I over stepped the mark. My apologies Leo

[Steve3007]

Wow! I actually changed somebody's mind! Thanks Stormcloud. That's the first, and possibly the last, time I've ever knowingly managed to do that.

[Xris]

Steve, Leo. What would either of you say to the idea that if our understanding of how light alters over distance and time is seriously questionable? Are you really forming a picture of the universe simply because of your belief in the red shift observations?

[Obvious Leo]

Stormcloud. Your apology is graciously offered and humbly received. At no stage has it been my intention to persuade anybody to my own world-view. All I ask is that I be accorded the respect due to a legitimate scholar and that those who are troubled by the foundational questions in physics might examine my words rationally and weigh them according to the parameters of simple human logic.

Regards Leo

[Stormcloud]

No worries Leo. I will stick to the simple and leave the complex to you. Good evening to you both.

[Xris]

No worries Leo. I will stick to the simple and leave the complex to you. Good evening to you both.

Once you reduce the reasoning to its fundamental question you dont have to be a scholar in cosmology to tell someone they might just be wrong. The BBT has changed but it has only changed because the unbeliever has questioned the logical consequences. The BBT is no longer a singularity but a concept that relies on expansion from every point of observation. It relies now on empty space, nothing, becoming more nothing. It informs us that expansion only operates on the galatic scale but then refuses to accept galaxies collide long after the space between them should have increased. So please carry on questioning it won't hurt anyone.

[Mechsmith]

Leo, I suspect that I have a few concepts mixed up. If I didn't I probably wouldn't be here Since light will red or blue shift with no other stimuli than gravity then a simple mechanical universe would cause the Hubble Constant without any relative motion. This gravitational red shift would also increase with distance in this universe.

The "apparent" speed of recession as shown by the red shift will happen to some degree simply due to the effects of gravity. Without correcting for the gravitational "red shift" it is not fair to say that the galaxies are receeding. That seems to mean that the "Doppler Effect" is the only cause of the shift. We know that there are other influences. This is what I meant by "optical illusion". A rainbow remains an optical illusion until you correct for the refraction of light then it's simply fog. The Hubble Constant remains an optical illusion until you correct for the various gravitational and mechanical influences. Then I suspect it will become static on a sufficiently large scale.

But if the red shift is primarily due to gravity then the Cosmic Microwave Background Radiation simply becomes light from more distant stars that has been red shifted to the microwave spectrum and then one arguement against an infinite, eternal, and evolving universe becomes the resolution of "Olbers Paradox".

Trying to figure out the change in wave lengths due to these influences has proved beyond my abilities although it has been shown take place.

Ah well, Possibly won't be the only thing I can't figure out today Happy thinkin, M.

[Obvious Leo]

Mechsmith. Red-shifts and blue-shifts don't require the assumption of an intervening empty space. Light travelling through time alone will produce exactly the same observed effect.

You're exactly right that it is gravity that drives the galaxies apart, just as it is gravity that holds the bound galaxies together. This is one of the biggest problems that the spacetime model encounters because expanding space has no mechanics to underpin it. Does it expand simply by spreading itself out a bit, thus making thinner space, or does it expand by creating new bits of space to fill in the gaps? I'm sure you can appreciate the absurdity of this question. Why should gravity cause space to expand between galaxies and yet gravity stops space from expanding within galaxies? Why should some galaxies be bound in clusters that draw them towards each other, thus contracting space and blue-shifting light, and others not? Gravity is the answer to all such questions but GR clearly shows us that gravity is only physically bound with time and not with space, with which it is only bound in a geometric sense. It is SR that confounds the GR model by using two different co-ordinate systems for time and conflating them with a wholly artificial 3D co-ordinate system for space.

If we chuck SR in the wastepaper basket where it belongs all these confusions vanish. Space isn't real.

Regards Leo

[Logic_ill]

Is anyone suggesting movement, rather than space or its expansion? Speeds are all there is, and we compare them?

[Mechsmith]

Leo, I am afraid that I have not communicated adequetly. Later hopefully we could discuss the probable fallacy of the expanding universe . On this side of the blue marble it got past my bedtime. Maybe I'll get a good dream. M.

P.S. the Hubble Deep Field website is now using fifteen billion years as an age for the universe. I still can't make it square with the pictures. Later

[Atreyu]

If the universe is finite then beyond the universe there must be nothing, ABSOLUTELY NOTHING. Can you imagine absolute nothing? Yes by not imagining at all. Imagine nothing = not imagining. Now if there is absolute nothing outside universe, then how can the universe expand? Where is it getting the free space to expand?

Well, I'd first have to say that IMO the Universe is infinite, not finite. And I take that view in part precisely because of the issues you have brought up.

As far as how the Universe can 'expand' into 'free space' or 'nothing', it does not. There is no 'free space', no vacuums, and no 'nothing'. There is nothing outside of the Universe. The Universe *is* 'All'. The only way to resolve this is to say that *everything* is growing, not just apparent space or apparent volume. Mass, energy, force, space, awareness, intelligence --- they are *all* growing in tandem. 'Expansion' *implies* a growth of space.