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  #21  
Old 05-08-2009, 06:09 PM
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Originally Posted by sally1jack View Post
& does it matter anyway
Finally nothing matters except where your next meal comes from but when well fed humans love to speculate upon such stuff ... we like to feel we above all others that came before us that we indeed know all the answers and we spend much time and effort to prove we do indeed know all the answers and if you spend all your life working upon the answers you will feel a failure if you do not believe you have found the correct answers.

I now know all the answers but I have forgot the original questions

alex
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  #22  
Old 05-08-2009, 06:25 PM
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Originally Posted by Shnoz View Post
Speaking of large expansions of space-time, is space-time able to move faster than the speed of light? Or is there a technicality that allows the universe to expand as it does without breaking the 'universal speed-limit'?
Yes, there's nothing in SR or GR (Special and General Relativity) which prevents it from doing so. SR only prevents objects within spacetime from moving at the speed of light. Only force carrying particles with no rest mass can move at the speed of light. That is photons, gluons and gravitons. W and Z bosons (the particles that mitigate the weak nuclear force) can't because they have rest masses greater than a proton.

Here's some stuff for you to read...

http://en.wikipedia.org/wiki/Gluon

http://en.wikipedia.org/wiki/Strong_interaction

http://en.wikipedia.org/wiki/W_and_Z_bosons

http://en.wikipedia.org/wiki/Graviton

http://en.wikipedia.org/wiki/Introdu...ial_relativity

I think you know enough to be able to understand these pages. If you have any trouble, just ask
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  #23  
Old 05-08-2009, 06:28 PM
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Originally Posted by xelasnave View Post
I had no idea that the idea was also considered by Alexei Starobinski at the same time as Alan Guth I mean what are the chances .... but that sort of thing happens so often it makes me wonder if ideas float in the aether available to those considering a particular matter... not really but the coincidence of like thought is rather common.

alex
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  #24  
Old 05-08-2009, 06:30 PM
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"160 billion ly would be a small fraction of that size"...
Is there any most widely accepted opinion on the size of the Universe... 160 is the largest guess I have read ..
The size depends on who you talk to....but 160billion l.y. is considered small.
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  #25  
Old 05-08-2009, 06:32 PM
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As it is all just theories, everything goes in my book
We know basically nothing.
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  #26  
Old 05-08-2009, 06:38 PM
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As it is all just theories, everything goes in my book
We know basically nothing.
I agree entirely with the maxim..."The more you learn, the less you actually know".
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  #27  
Old 05-08-2009, 07:01 PM
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I knew there would be more than mere coincidence at play... man the next time I say something that cries out for supporting authority well I will preface... Well according to the Akashic Records we know etc etc
Sounds so er so authoritive
alex
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  #28  
Old 05-08-2009, 07:06 PM
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More knowledge develops both ones humility and ones arrogance until both are so far apart it is hard for others to know exactly where you are coming from... The more you learn the more questions you should have not less.
alex
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  #29  
Old 05-08-2009, 07:16 PM
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More knowledge develops both ones humility and ones arrogance until both are so far apart it is hard for others to know exactly where you are coming from... The more you learn the more questions you should have not less.
alex
I don't know if you wrote this in response to my quote, but if so, I don't think you quite understood the meaning of the quote.....what it means is the more you learn, the more you discover that you really know even less than you think you do...so you have to ask more questions, learn even more and find out there's even more you don't know. It's a vicious cycle
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  #30  
Old 05-08-2009, 07:41 PM
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Originally Posted by renormalised View Post
I don't know if you wrote this in response to my quote, but if so, I don't think you quite understood the meaning of the quote.....what it means is the more you learn, the more you discover that you really know even less than you think you do...so you have to ask more questions, learn even more and find out there's even more you don't know. It's a vicious cycle
I was in my own little way completly agreeing with you...

Before I took up astronomy and the related interests I thought I had a fair idea but when I got into gravity etc I found I would find out something but that lead to more questions relating to the new subject matter and on following up whateven new thing I found out even more areas needed looking into... my reference to arrogance and humility was an observation of myself in so far that as ones ability to converse on various matters improves with time you ( I find..found) that so many mates seemed to be devoid of knowing anything if it were not beer babes or balls and in that regard I felt "better" or "more informed"...hence arrogant .. what else can you call it if you think you are "better" and I have been guilty of such a sin...never these days.. however as my knowledge grew more and more I also became more aware of the vast regions of specialisation in many many areas... once when I had the fleeting desire to learn some real math I went to a site and was horrified to find that just the index of the various areas of interest went for pages and pages... and any of those one line references to an area of math really openned the door to an area of math that one could devote a lifetime to... I like to learn as much as I can but it never amounts to much more than a general overview of a subject and one can see if one was to specialise then get ready to give your life to that one subject ... Music for example.. it has no end and an expert on one area may know little of other areas..science of course is the same... the stuff we discuss is a lot more complex than the casual chats we have here would suggest...I know that but chatting at an overview level is all I could ever achieve... I would be stupid to think otherwise.
Still the more you learn about the more one can develope humility and I hope one day I can be more humble than the other way..which I am not but probably sound that way... but those who know more know enough to understand and decent enough not to cut me up but rather offer help as everyone does here..which is so good.

alex
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  #31  
Old 05-08-2009, 09:31 PM
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Your view is of no surprise as I take all that I read as having another view point ... some say we started with a seed and others say the big bang was all over..and perhaps both may be correct for even if the size of a grapefuit the Universe is indeed the universe and, as it is all that is, a comparrision to anything we can relate to will be difficult no doubt.
Clearly both cannot be correct. If the Universe expanded to a diameter of 160 billion light years in 30 seconds we wouldn't be having this conversation. The Universe would be big, have an open geometry, and very much dead as its' density would be far too low to allow matter to coalesce into planets, stars, galaxies and ultimately life.

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Still my defence is simply it was out there someplace and I will not take responsibility for inventing my current belief as to what is laid down by "inflation" or anything that would lend support for the notion of inflation..
Why this fixation on Inflation? Your beliefs fly in the face of Science in general so you might as well add SR, GR, QM, and Newtonian physics to the list to name a few.

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I simply dont buy it and I really feel that in doing so we may not pursue a more suitable and reasonable view...inflation has stopped questions asked that inflation sought to satisfy.
Sounds as if you are describing the Anthropic principle instead of Inflation.
Inflation arose to specifically tackle the flatness and horizon problems of Cosmology.

Quote:
Still an expansion from an atom to the size of a grapfruit is a rather huge jump in size..relatively..and perhaps it is even easier to cast doubt upon the theory and its reasonableness as we can comprehend something very small and how magical it would be therefore even if say an ant were to expand in size such that it now matches a grap fruit..in a mere fraction of a second... I mean how could such a thing happen.
There is nothing magical about it. It's an unfortunate situation that to understand physics (and not just Inflation) one needs to understand the mathematics behind it. Otherwise one is forced to accept a theory on "good faith" or throw one's hands up in the air and say it can't be right because it is misunderstood or found to be counter-intuitive.

Quote:
We talk of "space time" as if when such words are invoked we must accept mysterious notions as being reasonable but "space time" is not a mystery it is a geometric way of setting out what we observe in terms humans can work with....and I still suspect that the theory was grabed too eagerly in order to save the then dieing notion of the big bang...
Sorry Alex we live in a world where our technology confirms the existence of space time as reality from widely different perspectives such as the SR correction of time in GPS satellites to nucleur energy where E=mc2 is based on the conservation of energy in space time.

Quote:
Hope all is well in your Universe Steven
Likewise Alex.

Steven

Last edited by sjastro; 06-08-2009 at 09:03 AM. Reason: grammar
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  #32  
Old 05-08-2009, 10:51 PM
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Even if we could explain the big bang we will have find out were the thing that caused the big bang came from and what caused that and it would go on FOREVER.
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  #33  
Old 06-08-2009, 09:33 AM
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Steven good morning sorry I frustrate you it is not my intention.

You asked "Why this fixation on Inflation? Your beliefs fly in the face of Science in general so you might as well add SR, GR, QM, and Newtonian physics to the list to name a few".


I thought my fixation upon inflation was clear but I think you hit the nail on the head when you said "It's an unfortunate situation that to understand physics (and not just Inflation) one needs to understand the mathematics behind it". and certainly I am in the situation you cover when you said "Otherwise one is forced to accept a theory on "good faith" or throw one's hands up in the air and say it can't be right because it is misunderstood it or found to be counter-intuitive".

Maybe, almost certainly, there is much that I misunderstand.

Leaning all you know from the net means one follows no specific direction and ones knowledge becomes an accumulation of bits from here and there and certainly also one often has no way of knowing if the apparently reasonable site one has found is entirely correct.

AND yes for me it is a matter of reading all I can on a subject and either accepting it on good faith or rejecting it because "I dont buy it"... however I do try with my limited knowledge to think about the propostions I read about...which is certainly different to accepting the math and therefore the premise.

I find no difficulty in rejecting something even if that goes against the math ...

I have a non science background where one becomes sceptical and trained not to accept all things as they are presented.
Again this touches on belief and it is my belief that although math is infalible it may be that the premise that the math seeks to support could well be wrong.

As I understand the history (and my understanding may be absolutely wrong and I have no difficulty in accepting that may well be the way of it) the big bang notion arose from an observation that space was expanding... by Mr Hubble (an ex lawyer and potential contender for the boxing heavy weight world championship) and that from that observation the math went into play reasoning and supporting the notion that if it is expanding it must mean that at somepoint it expanded from a "point"... In my view such an observation does not entitle the extrapolation in support of a point where the Universe "started" . AND I realise there was much much more work before the big bang idea fully evolved.

AND my fixation upon the big bang generally comes down to the grabbing of any observation and fitting it into the big bang picture... and I am not the only person who thinks that way ...and clearly the big bang has well earned support... and I do similar..every new fact I fit neatly into the Push Universe and although I get labled as morosophic I consider that condition may well exist in the big bang camp... and I dont want to frustrate you or cause you to point out where I am wrong as I am outlining mere beliefs which is bad because this is a science thread..

No one needs to be reminded that the "big bang theory" is a "theory" and I guess my concern is that those who support it simply now exclude any alternative ... prior to the background radiation discovery we also had a steady state model so if the interpretation of the background radiation is flawed I see no reason why steady state should not be on the table.

Yet big bang is treated as fact until now it is proved incorrect... given the difficulty in absolutely proving anything how could one prove its "incorrectness"...

AND Steven I am not presenting this to argue any point with you. I find all you say covers whatever we discuss and like to think you are someone who knows their stuff.. your input has always been helpful and informative and I thank you for the time you take when I know I must frustrate you .... as I said I do not seek to argue when I raise these matters that has all pulling their hair but to merely express my concerns and lack of preparedness to surrender to the math if the premise seems wrong... to me.


You also said..."Sorry Alex we live in a world where our technology confirms the existence of space time as reality from widely different perspectives such as the SR correction of time in GPS satellites to nucleur energy where E=mc2 is based on the conservation of energy in space time". I have no problem with E=MC^2 or our science other than ...well you know my beliefs about "attraction", dark matter etc.

I see myself as others see me... a fool that has tried to learn too much about too little having a teacher who has to look it up on the net (me in both cases) and deprived of knowing everything as others do.

You will be happy (or alarmed) that I have been trying to relate my push thing to a math base.

I would like to post my ideas and run it by you and the other wonderful folk here but in truth I feel very uncomfortable as I have had little meaningful feed back from my mates at the site Ron set up... but if I can I will post something if I can if for no other reason to show those who encourage me to use math see I do listen.

Have a great day I really enjoyed reading your reply
alex


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  #34  
Old 06-08-2009, 06:36 PM
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I think some fair points have been made here. We cannot trust any theory (eg inflation or the Big Bang) to the point where we can say we are 100% certain they are true. Who knows, we could just be dream of some weird alien creature! But I wouldn't chuck those theories out for just any alternative unless it had some pretty good evidence.

P.S. Thanks for the info Renormalised!
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  #35  
Old 06-08-2009, 06:44 PM
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I hope it helped...as I hope did this thread. What do you make of our discussion here??. If it's a bit over your head, let me know
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  #36  
Old 06-08-2009, 06:47 PM
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...Who knows, we could just be dream of some weird alien creature! ...
It might be the other way around...the Universe maybe the dream and we are the dreamers
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  #37  
Old 06-08-2009, 06:56 PM
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I hope it helped...as I hope did this thread. What do you make of our discussion here??. If it's a bit over your head, let me know
well for me it is both Yes and no...
I can see the points of opportunity for problems and needless to say I will work around them...
As to KE it may be an "average" thing maybe ... in other words, and as it must be, there will be many contributers to the pressure or particle or energy flows speculated to make up space but that may be at a single level as it were but the combinations general smooth out.
thanks for being so kind and helpful.
Thinking about this stuff keeps my mind off serious personal issues I am sick of having to bear ...and I think it must be good at my age to still be having a go as one would think the brain is like everything else ..give it regular exercise...or lose it.
Anyways I know folk will flock around me at the pub the hear about all this because as you know gravity is a very interesting subject. I still dont know what they see in football and TV

alex
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  #38  
Old 06-08-2009, 07:14 PM
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Of course they'd flock around....gravity sucks

You can avail them of the physical laws governing the motions of a football.... air pressure, air resistance,velocity, gravitational acceleration, ballistic trajectories etc etc. Even apply them to a TV, although TV's don't work so well when kicked or thrown
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  #39  
Old 06-08-2009, 07:20 PM
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I hope it helped...as I hope did this thread. What do you make of our discussion here??. If it's a bit over your head, let me know:D
Of course I'm only in yr 11, but I did understand everything here once peoples had explained it. There are lots of people my age who know heaps of things!
There's certainly some very cool topics in this thread, that's why I'm so interested in astronomy and the like! Maybe one day we will be able to find more information as to what was 'before'.
Thanks to everyone for answering my questions!
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  #40  
Old 06-08-2009, 07:36 PM
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Glad we could help
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