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Post by carnyx on Mar 20, 2011 21:11:57 GMT 1
We are told that the background radiation is the echo of the big bang. However, it is a poor analogy, because any explosions I have been involved in just make the single bang. You may hear a single echo if there is a reflecting surface a sufficient distance away, but the concept of a steadily fading 'big bang' is not tenable
So, are we to assume that the universe has an inside reflecting wall, travelling away from us, and against which radiation is bouncing? And won't this pose problems for the claim of a constant speed-of-light?
Bluntly if this is the best that the cosmologists can come up with, they are neither amusing or clever enough for the amount of state-funding (aka my effort) that they consume.
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Post by speakertoanimals on Mar 21, 2011 13:37:55 GMT 1
1) The explosion analogy for the Big Bang is in almost every instance, wrong. Hence basing any supposed problems of the Big Bang on this analogy is dommed before you even start.
2) The Big Bang actually says not the universe went bang, but that it was hot and dense, then expanded. Hence CMB is red-shifted remnant of the initial fireball is a better analogy.
It's not cosmologists, just idiots that have no idea of actual physics.
'Echo' can also be taken in the wider sense in which it is usually meant in cosmology. SO, the CMB itself was emitted about 400,000 years AFTER the Big Bang, but does contain information about earlier epochs. Hence not the 'Bang' directly, but as clsoe as we can get at the moment, hence 'echoes of the Big Bang' rather than hearing the Bang directly, in a fairly obvious sense without getting into daft discussions as to what it was bounced off of..................
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Post by carnyx on Mar 21, 2011 14:44:08 GMT 1
@sta
We are expected to believe that the background hiss is the redshifted remnant of the big bang.
Will this background hiss be the same for all observers? If an observer relays his hiss to another observer, won't it then have additional redshift?
Where is this background radiation emitting from? If it is diffuse, and from everywhere, then redshift must be a function of time and not distance, surely?
And again , if the earlier hotter denser universe is becoming less dense, it must be expanding, and there must be a sense of direction at any point not at the centre. And in the unlikely event we were actually at the centre of the expansion; given that microwaves travel at the speed of light, they would all have long gone by now, surely?
It would make sense if the radiation was somehow internally reflected, but not if the universe was open.
But what if the background hiss was spontaneous, i.e. it is magically emitted in space randomly all over the place. In that case we should see a redshifted gradient for the emissions further away.
But re your;
No, because in the really 'wider sense it is usually meant', it measn what it says in any dictionary.
..... so really, isn't it time that cosmologists started to 'purify the dialect of their tribe' as it were, and invented proper new words for their stuff, rather than overloading and subverting ordinary English?
And in doing so, do they realise they are perverting the language and effectively stealing from the dead what they have to leave the unborn? .... Or is this bending of the language all part of the thrill of being in 'the club' as it were ?
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Post by speakertoanimals on Mar 21, 2011 16:19:32 GMT 1
Wrong. Elementary mistake number one, you're still thinking of the Big Bang as some movement outward from a centre. It isn't. There IS and WAS no centre.
Yes. Relaying it doesn't count that is just sending a message about it, niot the thing itself. mo more puzzling than a photo of me being not the same as me..................
Everywhere. Of course it is a function of TIME, and I think you are now confusing the CMB with hubble redshift and distance. The CMB is from one time, and at one distance, just that that distance gets larger as the universe gets older. In effect, everything else we seeis CLOSER than the CMB, since it was emitted at later times.
Again, you're trying to reason as if the CMB started from somewhere, whereas it started from EVERYWHERE, just that everwhere was clsoer together back then!
Think of it this way -- we have lightbulbs spaced throughout the universe,. they all flash on at some time, and that's it. At one second after the flash, I see the light from bulbs a lightsecond away from me. At two second after the flash (assuming no expansion for the moment), I see light from bulbs two lightseconds away, and so on.
So, however long after the flash, I still see the light from the flash, just that the bulbs I am seeing doing the flashing get further and further away as time goes on. But WHENEVER I look, I still see the flash from all directions.
Add in expansion, and we still keep seeing the flash, just that as time goes on, the flash comes from further and further away, and has traversed more stretching space as it travelled to me, hence gets more and more redshifted as time goes on. When I saw the flash one second after the flash, it was hrdaly redshifted at all, but when Is ee light that has been travelling through expanding space for billions of years, it has got redshifted all the way from ludicrously high temps to a few degrees above absolute zero.
Go buy another dictionary! WHY do you try and insist that people are only allowed to use words in the way you see fit, rather than using them in a more general way to try and make clear to the non-specialist what is going on...................
They have, just then people like you accuse them of hiding nonsense behind impenetrable jargon!
Stop wasting my time, we've had this whole big bang nonsens ething before, you didn't pay attention then, and you've given me no reason since for believeing you will pay attention now. You just don't understand cosmology, even the basics, so why try and DEBATE it as if you did?
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Post by carnyx on Mar 21, 2011 17:51:28 GMT 1
@sta, your analogy assumes that the radiation emanates from an ever-widening band, which is itself travelling away from us at some velocity. But if it is travelling at or near the speed of light, why should we be able to see any back-radiation?
And, if we are only receiving radiation from far far away, effectively from the edges of the known universe then we should expect a difference in shift proportional to our distance from the centre of the universe. That we do not, means we must be at the centre. And ether way, it should descripe a nice smooth regular shape. But does it?
And then, re your point about subverting the simple word 'echo' ;
.. is simply that it does not. But it mangles a perfectly good word in trying to do so. It is culturally lazy; the equivalent of wrecking a pair of pliers in order to open a can of beans.
And if you were to look, the more creative and fertile scientific enterprises coin new terms (jargon if you like) all the time, whereas the moribund ones, don't.
But we all know that Cosmology is not really science at all, it is a typical piece of speculative parascience, like Freudianism in that, were any of its prognostications to become remotely real, they would become part of real science, which leaves cosmology forever speculatively floundering 'out there'..
But tell me, is cosmology really a fit occupation for an adult, or should it remain a recreational amusement? A Genre? Sci Fi without the human interest?
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Post by speakertoanimals on Mar 22, 2011 3:40:00 GMT 1
No. WE define OUR centre for what we see. No more mysterious than the fact that if we had lightbulbs all switched on at one instant, for an instant, everywhere, that after a time t, we should see the light from all bulbs a distance ct from us. Doesn't mean we are at the centre, just because what we see describes a sphere about us.
Since you can't seem to handle simple geometry, let alone cosmology, who are you to judge? Like a tone-deaf chimp trying to say that Beethoven is a waste of time.
And if you REALLY think that, what a sad individual, because the immensity of what we know about the universe and where we came from has passede you by. You'd be better off believing in the great green arkleseizure, it is at least slightly entertaining................
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Post by carnyx on Mar 22, 2011 15:49:26 GMT 1
@sta
I have already pointed out the hole in this analogy, because it means that the light is merely taking longer and longer to get to us, at the rate of the speed of light itself .... rather than that the universe is expanding. We should expect to see no redshift either, because according to this analogy the emitters are not moving!
So, using this analogy merely confirms that the reason for redshift is a function of time and distance, rather than ever-faster velocity with distance. It also confirms that the Universe may not be expanding at all.
Then, we have the problem of where exactly this background radiation is coming from.
So, STA, could you oblige with a critique? ( and if you need to emit, please make it witty)
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Post by speakertoanimals on Mar 23, 2011 14:10:19 GMT 1
Except you've missed the point again, which is to show that we can have light at an instant being received from a sphere of objects surrounding us, without us being at the centre of anything!
Letting space expand uniformly just adds a little extra distance to be travelled and redshift into the basic picture. But the we are not at the centre, and nothing is at the centre argument still stands.
If you can't understand the simple static example, how do you ever hope to understand the full expanding case.....................
From matter when it decoupled from radiation 400,000 years after the bang. It comes from ALL matter, just that what we can see of it depends on where and when we are, just as what flashing lightbulbs we see depend on where and when we are.
There isn't a PROBLEM as to where it is coming from, it comes from everywhere, that is kind of the point. Every speck of matter in the universe emitted radiation that became the CMB, the universe is full of it, and always was, just that since things have stretched a bit since then, it has got red-shifted. It is really very simple.
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Post by carnyx on Mar 23, 2011 16:50:30 GMT 1
@sta
"Every speck emitted", then stopped emitting? And are we now hearing a succession of emissions from static specks that are progressively further and further away?
And WRT the claimed redshift, we know it as a frequency drop. But changes in the speed of propagation (for example via 'inflation') does not affect the frequency as you have pointed out in the past.
So I question whether the supposed redshift is in the background radiation at all, and whether is is a surmise. I.e. ..how can they tell that this background hiss has redshifted characteristics?
Also could it be that the background radiation is being continuously emitted by every speck right now, and so is basically the Universe just humming.
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Post by speakertoanimals on Mar 23, 2011 17:17:54 GMT 1
Not so much emission, and stopping absorption. Before, all was very hot, so stuff emitted radiation and absorbed it, making the universe opaque. When temperature fell, then radiation decoupled. Rather than matter emitting that radiation, it was just that the radiation that already filled the universe stopped being absorbed.
Why?
Facts: it is THE BEST blackbody spectrum we have, and it is astoundingly uniform across the entire sky. That alone tells us it is something different to the ordinary light-emitting processes we see now (stars and galaxies). The fact that it is so uniform, plus observed redshift and hubble law for other stuff, tells us that only sensible answer is that it predates all this clumpiness and shiny stuff, and is the relic of the earliest, hot dense and featureless days of the universe. Indeed, given that observed hubble law predicts and earlier, hotter universe, we'd be in trouble if the CMB wasn't there!
Except expansion ISN'T changes in the speed of propagation! Hence why expansion is allowed to cause a frequency shidft, whereas changing refractive index isn't, because they are DIFFERENT processes. Really, if you don't know the BASICS, how can you hope to present anything other than a repeated version of argument from incredulity?
No, because stuff NOW is at a wide range of temperatures, and that is what we see, the cool gas that doesn't shine, and the nice toasty stars that do! IF the CMB was recent, then we'd expect the distrbution to be as clumpy as we see the night sky to be -- except it isn't, it is ridiculously smooth! Hence we have to refer back to a time when the universe was equally smooth, before gravity started to collapse stuff into galaxies and clusters of galaxies.
And that is the problem ANY other supposed explanation has to account for -- how come it is so uniform, even at opposite sides of the sky, and how come it is such a good blackbody spectrum. Because any recent process, given clumpy and unevenly illuminated state of the present universe, isn't going to produce anything like that.
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Post by carnyx on Mar 23, 2011 17:48:51 GMT 1
@sta,
Whoa!
"Hence why expansion is allowed to cause a frequency shift, whereas changing refractive index isn't, because they are DIFFERENT processes...."
We all know by now that refractive index ( aka density) changes merely change the rate of propagation and not the frequency, as I pointed out. But here we are talking about frequency changes per-se.
And, I have a feeling that this 'expansion' you refer to is an example of the 'special ' use of words to protect a void ...
Imagine a small troop of photons paddling away in a fixed rhythm (aka frequency), over an ocean with huge hidden currents ( aka 'inflation') But, at every island they pass, and whatever speed they are doing, the locals observe them paddling with the same rhythm.
What is their 'red-shift'? And can we tell anything else about them apart from this fixed frequency .. for example where they started from, or the direction they originally came from, or how long they have actually been travelling?
And the idea that background radiation will still be whizzing by after all this time is frankly strange, as we are told that it is travelling at the speed of light which is constant, and in straight lines near enough. How sure are you that it is not being spontaneously created by radiation emitting from matter on a continuous basis? (Like the directionless uniform hum of a great city?)
Or, could it be the same-o same-o radiation whirling around in great circuits in a closed Universe? Could this surmise be the next paradigm to be revealed as the new orthodoxy?
BTW; my problem is apparently that I can accept that explanations can be partial, and provisional, and competing stuff exists. Whereas I suspect your problem is that any current ex-cathedra explanation is the 'right true and only one' and must be believed and defended competely until the next one comes along. Such loyalty may be a virtue when it is tempered by a tolerance of ambiguity, but otherwise it seems a bit too, well, religious, and not free.
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Post by speakertoanimals on Mar 23, 2011 18:00:26 GMT 1
Your picture of expansion is dodgy. There is no sea and no currents. Everyone who observed the paddlers says they are moving at lightspeed, no matter how the observers are moving!
Plus you shouldn;t mix up inflation (early, very, VERY fast incxrease in size, that then stopped), with everyday and still-continuing expansion, they're not the same thing.
no they don't -- the frequency depends on the observer and their state of motion, as well has hiow much expanding space the photon has passed through before we observe it!
Commonsense analogies are usually totally worthless, because they'll get the constancy of lightspeed wrong for starters, hence the rest is useless.
D'uh! I LOOK at where it came from, no more mysterious than the fact that I can see the image of a star, and infer that that was the direction the light appears to be coming from, and is coming from!
WHy? most space is empty, not everything has to bang into something else and be stopped. The universe is not full of lead. Nor does the light get tired, so what else could it be doing other than still travelling after all these years....................................
I think your problem is that you don't know enough of the basics to get more than kiddie-level explanation, which is frankly fairly useless -- you certainly can't REASON from it! Hence all these arguments from incredulity, because that is all you have, and all based on descriptions of the actual physics that are umpteen levels below the actual, detailed explanation.
If you think it ODD that light should still be travelling after so long, then there isn't much I can do to help you!
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Post by speakertoanimals on Mar 23, 2011 18:24:46 GMT 1
No it isn't -- but you can only really understand it if you can get away from the mental picture of objects expanding, or expansion as some sort of sea, because they all will lead you wrong.
Expansion, in simple terms, means that two objects who consider themselves to be stationary relative to each other at the start, will later find that they are now further apart, yet neither one of them has experienced ANY acceleration, and they aren't in a gravitational field (which of course could cause objects to move further apart whilst they are both in freefall hence fell no acceleration). The explanation is that they are both stationary, which is what they consider themselves to be, yet the space between them has got bigger.
We can only analogise this in terms of dots on a piece of elastic, or something similar, yet these pictures are misleading. There is a consistent, mathematical picture of such expanding spaces, but unless you can do that maths, you'll just have to take that on trust, because there is NO suitable analogy you can construct based on everyday experience. And if you keep doing so, you'll just come up against seemingly problem after problem.
The fault is not in the physics or the maths, but how far everyday analogies can be used to understand the universe -- not very far is the answer to that!
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Post by carnyx on Mar 24, 2011 14:01:22 GMT 1
@sta
The background hiss has all the attributes of a very faint fog, and so the simplest explanation is that, like fog, it is being somehow emanated from interstellar particles. And, like fog, you can't readily measure or capture it at anything other that a macro scale. Even having widely dispersed and interlinked observation points cannot tell you much more about it other than you can glean form a single POV.,
Trying to connect it to other phenomenon to provide a cross-explanation is still only speculative speculative, which in the hands ot 'true believers' is a sure safeguard against any real progress towards understanding more about either phemomenon.
Expanslion, inflation.. Hubble, BB & co .. is not really needed IF a simpler explanation of background hiss is to hand, ...even if it is as unprovable as the contraption currently on offer ... as Ockham taught us.
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Post by speakertoanimals on Mar 24, 2011 15:53:27 GMT 1
Rubbish I'm afraid. The key thing we know about interstellar or intergalactic stuff is that it is PATCHY. SO how come, from that patchiness, we get the SAMe temperature form different parts of the sky, AND the best blackbody spectrum we have ever found? We have to look for a process that will give us that, and the initial hot dense state and decoupling via the usual hot big bang is the only process that will. These local explanations just don't work when it comes to the fine detail.
Plus don't forget the important link between the very scale small anisotropies in the CMB, and structure in the universe! The predictions are amazing, and it is only the big bang model that explains this and many other things all in one neat package.
Why do people continually pretend that alternative explanations have never been tried? They have, and they failed, which is why the big bang is the best and simplest explanations for a whole range of phenomena, from the CMB, to the hubble shift, to current structure, to the primordial abundance of helium, lithium etc. It explains a whole load of stuff BETTER than any other explanation that has been offered. It's called the scientific method................
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