A dumb GR question.

[sjastro]

Originally Posted by Robh

Agreed. The forces are equal.
But the accelerations are not.

Regards, Rob.

GR is a field theory. Objects of different masses in a gravitational field experience the same acceleration (under free fall).

Regards

Steven

[xelasnave]

Originally Posted by CraigS

Who says "that there are other answers we will miss because simply accepting the premise of inflation means that other options will never be investigated" ?

Seems to me there is lots of investigation/query into it and all that surrounds it.

Also, it's not just math that gives rise to the principle of Inflation.

Whether Inflationary BBT is offensive to reason or not is no reason to discard it !

My 2 cents worth.

Cheers

Thank you Craig for your two cents worth but really I value your view as worth much more than a mere two cents.

AS to parra 1 ...I said it... and I said it because that is my view on the matter... I thought that was clear but sorry for any lack of expression that may have been confusing AND I do hope someone can offer a more reasonable and provable idea which will replace the notion of inflation.

If something is offensive to reason that is good enough for me to question it (and even throw it out without a new idea to replace it)..if it is lame it is lame ...I did not make it lame and only call it the way I see it...and not withstanding that everyone else may be happy to accept the view of Mr Guth I am sorry I simply do not.

I thought in this area math could be the only guide given that he speculates upon events some 13.5 billion years ago..I will be surprised if there can be more to the notion than what he has put forward...er sorry there was some Russian guy as well on this approach ....I find it difficult to accept that all we can imagine ...that is the entire universe came into existence in some thirty seconds (or less) and I wont accept such...there has to be a better way to make bbt work.

alex

[renormalised (Carl)]

Given what we know of the universe through observation, Alex, the only way that we know of at present which accounts for what we see is a brief period of inflation just after the BB. It was actually much, much less than 30 secs. The difference in time scale between the Inflationary epoch and 30 secs would seem more than an eternity, if you were an elementary particle!!!. In the time period between 10E-37 and 10E-32 secs was when inflation occurred.

Read this...Inflation Cosmology...If you can't understand it, then ask questions. You have to remember, Alex, what you're dealing with here is conditions so far out of the experience of the ordinary person in the street that it's no wonder people may think it's wacky. But I can assure you, if you do the science and play around with the maths, it begins to make sense. It's not perfect, but then again nothing is. Even Guth would be the first to say that.

[xelasnave]

Originally Posted by mbo

OK, I'll rephrase the question, if I get a marble and place it 200,000 K's from the earth, stationary with respect to the sun, i.e not in earths orbit, and time it till point of impact on the earth (Ignoring the atmosphere and friction), and I then repeat the experiment replacing the marble with Venus, will I get a smaller time to impact because of their mutual attraction?
If the Earth in the previous example were some how fixed (stapled to space) and therefore couldn't move toward venus, would the same time to impact be observed
And for a follow up, could you give me a mind picture of the warped spacetime involved :-)

I dont know the answer and submit anyone who presents an answer must rely upon the premise that all objects fall at the same rate.. My concern was simply that given the general premise of GR that it is mass that bends space maybe GR would/could or should entertain different fall rates for different masses...it seems GR does not ...but I suspect I still may be onto something as opposed to into something as folks suggest if one considers a view not in step with current accumulated knowledge

A mind picture of the warped space time eh?

I have no idea I am afraid...GR is a field theory that is sortta like a Pythagoras theorem with a negative time line..4 dimensions but I "see it" like a weather map showing barometric pressure (rightly or wrongly) except this weather map rather than showing air pressure differences scribes a gravity field using a grid like a weather map uses issobars...

I have been trying to understand GR for so long I cant remember when I started but I dont see it as much more than a geometric representation (a grid I suppose) of how we can describe space and that action across the universe is not immediate or instant...but it does suggest mass makes the squares of our grid smaller on all 4 dimensions... I am not fond of math and the suggestion is that without math one can not understand GR ..happily there are others here who are so in tune and knowledgeable on GR (and lots of other stuff) and each time they comment folks like me crawl a little further forward with not much hope of ever really getting there...but gravity is such a wonderful subject I cant stop asking questions on GR.

alex

[xelasnave]

Originally Posted by renormalised

Given what we know of the universe through observation, Alex, the only way that we know of at present which accounts for what we see is a brief period of inflation just after the BB. It was actually much, much less than 30 secs. The difference in time scale between the Inflationary epoch and 30 secs would seem more than an eternity, if you were an elementary particle!!!. In the time period between 10E-37 and 10E-32 secs was when inflation occurred.

Read this...Inflation Cosmology...If you can't understand it, then ask questions. You have to remember, Alex, what you're dealing with here is conditions so far out of the experience of the ordinary person in the street that it's no wonder people may think it's wacky. But I can assure you, if you do the science and play around with the maths, it begins to make sense. It's not perfect, but then again nothing is. Even Guth would be the first to say that.

Carl I was not even game to suggest that I had read it was less than 30 seconds ... I have no doubt that the math will be convincing..it should not be anything less..and given the notion has been around for a while if the math was flawed someone would have pointed the math error out by now one would assume... but I will accept the math adds up but sorry I still will not buy it. If a religion offered such a time frame for creation would we not all scoff at what we are asked to accept as a matter of faith let alone to accept such a time frame as the result of doing credible science. I played with simple math all my career...via spread sheets..started with super calc ..something I doubt most folk would have heard about..anyways I learnt that spread sheet manipulation can produce a projected profit or loss depending on how you adjusted various inputs... and all that was fun but leaves me thinking others probably could do similar..maybe even a Government...oh horrors.

I also refuse to keep something until something better comes along simply on the basis that I have no replacement...as in life I would rather do without rather than accept something I find uncomfortable...hardly science but that is my view ..no more.

AND as I said we deal with an event that is 13.5 billion of years ago so really who knows ... now if we did not throw out the steady state model we could move on without inflation... my point here is simply that at a point in time steady state was acceptable (I think Dr A was in that camp at one point as he found he needed his CC) and yet we moved on past that model to something completely different... who is to say the future will not see a new universe model that finds favour and math in support... I do have one on offer

I do read a bit on this stuff but I cant offer a question other than (for those looking on) why did we need inflation again?
alex

[renormalised (Carl)]

The problem I see here is that you find the notion of something happening on such a large scale in so short a time a little hard to swallow. Things is, Alex, we are not dealing with ordinary states of existence here. We are dealing with time frames, energies and phases of state that are beyond normal, ever day experience. What you need is a way of "tossing" normality aside and seeing into those conditions that were present at that stage in the universe's evolution. That's what physics provides us. That's what the maths provides us, even if we don't fully understand what we're looking at or trying to work out. Honestly, I don't think anyone truly does, or otherwise they wouldn't be studying it!!. All the physics and maths are tools. Our best tools for understanding what happened. Because something appears unacceptable to our common sense or sense of reality doesn't mean it can't have happened. It just means we don't have the necessary tools or the insight to see past the mental road block.

I'll have to answer the rest of this for you tomorrow. It's late and I'm tired, so I'm going to head for zzzz land right now

[mbo (Pat and Kirk)]

Originally Posted by xelasnave

I do read a bit on this stuff but I cant offer a question other than (for those looking on) why did we need inflation again?
alex

I'm looking forward to the corrections / deeper explanations, but I believe it's just that red shifts (velocities, and also the necessary accelerations since the big bang) don't add up with decelerations that should have occurred due to gravity (between every thing with mass, including Galaxies), so they're is a net inflation in the universe that seems to need some other force / matter / energy to explain itself, i.e, to make the sums add up.
???

[sjastro]

Originally Posted by mbo

I'm looking forward to the corrections / deeper explanations, but I believe it's just that red shifts (velocities, and also the necessary accelerations since the big bang) don't add up with decelerations that should have occurred due to gravity (between every thing with mass, including Galaxies), so they're is a net inflation in the universe that seems to need some other force / matter / energy to explain itself, i.e, to make the sums add up.
???

One of the misconceptions about Inflation as expounded by Alex is that it is some hocus pocus event designed to get the numbers to add up.

It's no coincidence that Inflation commenced with the separation of the electromagnetic/weak and nuclear forces shortly after the BB. This is an example of spontaneous symmetry breaking.
http://en.wikipedia.org/wiki/Spontan...metry_breaking

Spontaneous symmetry breaking is well understood in particle physics and we can observe examples of it in accelerator experiments such as the creation of W and Z bosons.
The search of the Higgs boson is based on similiar principles.

Perhaps one day in the future with a 10^16 GeV particle accelerator we might be able to recreate Inflation in the laboratory. (Provided we don't annihilate ourselves and the Universe by creating a vacuum metastability event ).

The LHC on the other hand can only deliver a paltry 1.4 X 10^4 GeV.

Inflation is a Quantum Field Theory explanation for a cosmological issue.

Regards

Steven

[xelasnave]

Thanks Carl for the link to Wiki and sorry I nodded off myself last night.

Carl and Steven I would like to thank you both for your help.

Steven I am sorry I upset you that I wont swallow the medicine but say this again ... maybe there is another explanation rather than inflation... at the risk of selective cherry picking of facts here is a slice from Wiki which although a very simple explanation gives us an understanding of the problem inflation seeks to fix... and all I am suggesting is that there may not be a problem or that there is another way to get around it.
...
from wiki.

Inflation answers the classic conundrum of the Big Bang cosmology: why does the universe appear flat, homogeneous and isotropic in accordance with the cosmological principle when one would expect, on the basis of the physics of the Big Bang, a highly curved, heterogeneous universe? Inflation also explains the origin of the large-scale structure of the cosmos. Quantum fluctuations in the microscopic inflationary region, magnified to cosmic size, become the seeds for the growth of structure in the universe (see galaxy formation and evolution and structure formation).[3]

I innocently ask this ...is it unreasonable to entertain the possibility that the universe is flat etc simply because it may be older than we calculated? or could there have been another mechanism? or for the other alex did electricity have something to do with it I more than ever think it is an important area and my impression is because the problem is fixed all says lets move on..we have a fix lets look at some other problem...maybe.... but irrespective of what was expanding the increase in volume is hard to accept if it were not for the math is my point and I think all will reluctantly agree.

But is so much fun trying to grasp the ungraspable and comprehend all these matters and wonderful that such a forum exists.

Some members may like this

http://www.youtube.com/watch?v=HwCCMHH378Q

I found it easy so it will be a snap for younger more capable minds.

alex

[bojan]

Originally Posted by xelasnave

I also refuse to keep something until something better comes along simply on the basis that I have no replacement...as in life I would rather do without rather than accept something I find uncomfortable...hardly science but that is my view ..no more.

The problem with you Alex is, you are not placing the questions to get answers.. you are rejecting the answer even before you read it.

It was explained many times, that in order to reject something, one has to have the good understanding of what he/she is rejecting, and why. At least, this is how the science works.
Gut feeling is simply not enough here, those things are way out of our everyday experience (as put by Carl), and our brains, evolved to deal with other people and cave bears and everyday food and such petty matters, are not equipped with necessary "firmware" to comprehend things like inflation on intuitive basis.

What we have, luckily, is our ability for abstract thinking (is this a bug in our software/firmware?) , that can use formalised math structures (mind you, your visicalc or Supercalc or excel spreadsheet joggling is totally inadequate and un-fair comparison to what we have to deal with here).
But it takes a lot of time to develop those abilities in individuals. Some of us can't do it at all (which of course doesn't mean we are less worthy .. we might be better in some other things, that those geeks can't do at all).

[CraigS]

Originally Posted by bojan

The problem with you Alex is, you are not placing the questions to get answers.. you are rejecting the answer even before you read it.

It was explained many times, that in order to reject something, one has to have the good understanding of what he/she is rejecting, and why.
Gut feeling is simply not enough here, those things are way out of our everyday experience (as put by Carl), and our brains, evolved to deal with other people and cave bears and everyday food and such petty matters, are not equipped with necessary "firmware" to comprehend things like inflation on intuitive basis.

What we have, luckily, is our ability for abstract thinking (is this a bug in our software?) , that can use formalised math structures (mind you, your visicalc or Supercalc or excel spreadsheet joggling is totally inadequate and un-fair comparison to what we have to deal with here).
But it takes a lot of time to develop those abilities in individuals. Some of us can't do it at all (which of course doesn't mean we are less worthy .. we might be better in some other things, that those geeks can't do at all)

Whilst I don't think Alex is "broken" and in need of fixing I loved your above post Bojan (Can I call you that ?). You reiterated my thinking to a tee !

Y'know, as an example for Alex, I just followed on reading Carl's suggested material (from my other thread about Supernova data) and suddenly I got that issue which Steven pointed out (about Hubble's Law violation) which I couldn't see a couple of nights ago. (Remember how I said I had more reading to do ? Well it suddenly hit me last night with a lot of clarity, too.

OK so there ya go Alex, if you hang in there and follow the thinking, even if its unpalatable, sometimes it all falls into place and clarity results.
I think mainstream Science Cosmology is full of this type of stuff because of the high degree of rigor and consistency applied to the creation of theory. I feel privileged to be able to experience this feeling.

Alternative thinking is fine by me, too. I do frequently find that the result is not not clarity though. I did read the other Alex's pages on Plasma/Electromag material. Sorry, that didn't work for me but that's Ok, as are (this) Alex's viewpoints.

Cheers

[bojan]

Originally Posted by CraigS

Whilst I don't think Alex is "broken" and in need of fixing I loved your above post Bojan (Can I call you that ?). You reiterated my thinking to a tee !

Oh, I don't think that either
He only needs some more education in the matter (and who doesn't... ) and a bit more support to discipline his thinking process (and I am not much different here..).
Plenty of which is offered here on this forum

[renormalised (Carl)]

Originally Posted by sjastro

Perhaps one day in the future with a 10^16 GeV particle accelerator we might be able to recreate Inflation in the laboratory. (Provided we don't annihilate ourselves and the Universe by creating a vacuum metastability event ).

The LHC on the other hand can only deliver a paltry 1.4 X 10^4 GeV.

Inflation is a Quantum Field Theory explanation for a cosmological issue.

Regards

Steven

This only goes to prove that God was a particle physicist...someone, on some planet in the dim darkest past was playing around with just such energies in a particle accelerator, when....Oops....another BB was created. Instant false vacuum followed by inflation and hey presto, new universe

Now, all we have to do is find the guy's name tag and we'll know God's name

I just hope this time it's someone cool like Brian Cox, or super eminent like Ed Witten, that presses the little red "go" button

[xelasnave]

Hi Bojan
thank you for trying to help me get there
Please do not think I miss the point of what you suggest. You will be happy to know I attend my lectures by Suskin, I am trying to grasp the 11 field equations and at present reading all I find on the higgs bosen and in particular trying to understand the implications of the higgs field (which explains why gravity is a pushing force sorry but the general concept is great and I can use most of it

I have no difficulty in abstract thinking I would like to think or any difficulty in grasping anything.

I enjoy a confidence bordering on arrogance yet remain humble

I have a decent aptitude for science and topped fifth year with 98.5% in general science ..the reason I dislike math is math cost me the 1.5 % denying me 100%.. added 2 and 2 and wrote 5 and 5 was the answer to the next question..ahead of myself you see...which is what you suggest is my problem I guess

Perhaps I present as too casual and project an impression such as you grasp and if I do that is entirely my fault.

Maybe my background firstly in law then in selling has built me into a different item than others.

Firstly from law I realize everyone has an axe to grind and am skeptical enough to question the unquestionable and demand reason from the unreasonable...
AND from sales I picked up an ability to be suspicious when someone is trying to sell me a pup.

I do feel you are under a misapprehension as to what I do know and how wide I read on the matters we discuss and I suggest why I am critical is that I take a great deal of time with my hobby...and a hobby it is... I have not received classic training in physics or math but really to suggest it is beyond me I do not accept....although I am feeling the years my mind is in fair condition.

As to what we are talking about ..er one thing..inflation..as an example... who knows if it is fact or nonsense and irrespective of how one "sees" a field..as energy or particle virtual or real..whatever.. the concept certain is indeed abstract... but just because I reject abstract does not mean I can not entertain what is being said... it is plain English after all...and many good and different folk out there explaining any aspect of the current model you care to focus upon.... and the net how good is it..and utube has good stuff these days...

Remember we are talking about a field expansion ..and the exponential expansion a doubling by a doubling etc some 100 times to what some call infinity..and we both know we cant double finite to ever ever get infinite...... the bb field (where the opportunity that gravity was repulsive is entertained).inflated we are asked to consider...what is a field..well I do know what it is as hard as you find that to accept..it is the way we describe space when something is there...guess who said that? his name starts with F or a field is points of varying values of magnitude ..a field is seen as energy but via the uncertainty principle we can have virtual particles ... well it is not easy to describe in a manner that lay people can understand and to try and describe it to lay folk one will use metaphor and example that really distorts the concept as entertained by scientists...and I probably am neither lay man or scientist so my style fits neither ... as to the adequacy of spread sheet rearrangement or the comparison I bet maybe at least some folk use spread sheets in physics and if they dont still rely upon a similar approach via dedicated programs my comparrison was not met to offend by making out any of this stuff is simple...but rather that it comes down to premise and input.

Still as I said I appreciate the opportunity to talk about this stuff with professionals and lay folk ...with or without beer.

Thank you for taking an interest and sharing your views I find your input over the years most helpful.

alex

[CraigS]

Originally Posted by bojan

Oh, I don't think that either
He only needs some more education in the matter (and who doesn't... ) and a bit more support to discipline his thinking process (and I am not much different here..).
Plenty of which is offered here on this forum

Ahh .. the word finally popped out "discipline".
Requires a lot of that to wrangle in this field.

Cheers & Rgds.

[xelasnave]

I have to laugh about being classed as undisciplined in my thinking not because of what goes on here but these days the only way I get to use the net is when I stay at a mates place..
I am there now...
anyways he is a tarot card reader, he is off doing such now and I get to use his net ...great for me...but he is convinced that crop circles are not man made, that 2012 is the end of the planet and planet x is a reality and that emotion comes from the chest area etc etc...... and so all day all night we argue er discuss stuff... and still stay friends...
I try to teach him the disciple I gained in law..look at the evidence and facts etc etc question everything for there be fools and liars happy to push their wagon...always follow the money for real answers ..never rely on hearsay, ..and as to the law to find out what the law says not what you would like it to say..(and I get that message here addressed to me) . and most of all to remember that if we get to a point where there seems no explanation not to introduce a god or aliens to explain the unexplainable but simple conclude there is no reasonable answer so lets not introduce magic to fix all the things we cant answer or explain...

anyways I will yield to higher opinion here (this forum) and try to be better ...but me to him is probably like you guys to me..if you see my point...anyways around here (this town) I am probably in the minority where it comes to 2012, planet x and all that crap... but folk believe it and to change their view is not easy if thats what you wish to do...

You can tell them that bright star above the pub is planet x (pick any one as they want to believe so they do) ...We (astronomers with a portable scope) could all make a fortune if we set up our scopes in a public place selling viewing time so folk can look at or find planet x... but offer views of Saturn or Jupiter probably no takers

All I can do is respect that they have ideas different to mine and leave it at that... I mean planet x for example...they say it has an orbit of thousands of years etc...mmm bit far out I ask..yes. they say...mmm. how do they grow their food?... like us is the answer ...mmmm at their apparent orbit maybe it is too cold to grow anything bit far from the Sun maybe.... but no one sees the point dam it... hey planetxers find out how cold Mars is and ask how many degrees above absolute zero will planet x be... but my point is missed.

But if they finally grasped my point that problem will go away because on planet x they are all gods or so advanced they have energy other than solar...

I am using my time here looking at some great clips on utube higgs bosen, etc...and enjoying my big trip to town.

alex

[sjastro]

Originally Posted by renormalised

This only goes to prove that God was a particle physicist...someone, on some planet in the dim darkest past was playing around with just such energies in a particle accelerator, when....Oops....another BB was created. Instant false vacuum followed by inflation and hey presto, new universe

Now, all we have to do is find the guy's name tag and we'll know God's name

I just hope this time it's someone cool like Brian Cox, or super eminent like Ed Witten, that presses the little red "go" button

God has been referred to as a mathematician.

I don't think destroying old Universes is particularly Godlike.
Anyone pressing the button and destroying the Universe would certainly earn a Darwin award that will never be topped.

Steven

[sjastro]

Originally Posted by xelasnave

Thanks Carl for the link to Wiki and sorry I nodded off myself last night.

Carl and Steven I would like to thank you both for your help.

Steven I am sorry I upset you that I wont swallow the medicine but say this again ... maybe there is another explanation rather than inflation... at the risk of selective cherry picking of facts here is a slice from Wiki which although a very simple explanation gives us an understanding of the problem inflation seeks to fix... and all I am suggesting is that there may not be a problem or that there is another way to get around it.
...
from wiki.

Inflation answers the classic conundrum of the Big Bang cosmology: why does the universe appear flat, homogeneous and isotropic in accordance with the cosmological principle when one would expect, on the basis of the physics of the Big Bang, a highly curved, heterogeneous universe? Inflation also explains the origin of the large-scale structure of the cosmos. Quantum fluctuations in the microscopic inflationary region, magnified to cosmic size, become the seeds for the growth of structure in the universe (see galaxy formation and evolution and structure formation).[3]

I innocently ask this ...is it unreasonable to entertain the possibility that the universe is flat etc simply because it may be older than we calculated? or could there have been another mechanism? or for the other alex did electricity have something to do with it I more than ever think it is an important area and my impression is because the problem is fixed all says lets move on..we have a fix lets look at some other problem...maybe.... but irrespective of what was expanding the increase in volume is hard to accept if it were not for the math is my point and I think all will reluctantly agree.

But is so much fun trying to grasp the ungraspable and comprehend all these matters and wonderful that such a forum exists.

Some members may like this

http://www.youtube.com/watch?v=HwCCMHH378Q

I found it easy so it will be a snap for younger more capable minds.

alex

No offense taken Alex.

In regards to your question if an older Universe would eliminate the requirement for Inflation, the answer is no.

The density of the early Universe would be too high. A curved (closed) geometry Universe would result. In fact if the density is too high, expansion may have ceased early, the Universe collapses onto itself and we wouldn't be having this conversation.

Steven

[renormalised (Carl)]

Originally Posted by sjastro

God has been referred to as a mathematician.

I don't think destroying old Universes is particularly Godlike.
Anyone pressing the button and destroying the Universe would certainly earn a Darwin award that will never be topped.

Steven

Not only that, they'd never be able to collect on it

Unless you believe in an afterlife, in which case, they'd have metaphysical egg thrown at them, for sure

Or, is that rotten metaphysical tomatoes

[CraigS]

Originally Posted by renormalised

Not only that, they'd never be able to collect on it

Unless you believe in an afterlife, in which case, they'd have metaphysical egg thrown at them, for sure

Or, is that rotten metaphysical tomatoes

I'll have to take a break from my textbooks and consult my tarot cards on that one .. I'll get back to you.