Distant Galaxies. How far, How big?

[BlameTheEx]

This is a reworking of a post that I have published before. I am posting it, in its own thread, in hope of sparking discussion.

 

I have found this rather interesting article:

http://hubblesite.org/newscenter/newsdesk/archive/releases/2004/07/text/

 

There is a lot to ponder here.

 

"The final ACS image, assembled by Anton Koekemoer of the Space Telescope Science Institute, is studded with a wide range of galaxies of various sizes, shapes, and colors. In vibrant contrast to the image's rich harvest of classic spiral and elliptical galaxies, there is a zoo of oddball galaxies littering the field. Some look like toothpicks; others like links on a bracelet. A few appear to be interacting. Their strange shapes are a far cry from the majestic spiral and elliptical galaxies we see today. These oddball galaxies chronicle a period when the universe was more chaotic. Order and structure were just beginning to emerge."

 

This must be a fairly conclusive refutation of any purely "Steady State" theory of the universe. Clearly it was very different then.

 

"The NICMOS sees even farther than the ACS. The NICMOS reveals the farthest galaxies ever seen, because the expanding universe has stretched their light into the near-infrared portion of the spectrum. "The NICMOS provides important additional scientific content to cosmological studies in the HUDF," says Rodger Thompson of the University of Arizona and the NICMOS Principal Investigator. The ACS uncovered galaxies that existed 800 million years after the big bang (at a redshift of 7). But the NICMOS may have spotted galaxies that lived just 400 million years after the birth of the cosmos (at a redshift of 12). Thompson must confirm the NICMOS discovery with follow-up research."

 

There is a simple way of calculating the age of a galaxy, as it is observed, using redshift. (Age of galaxy) = (Age of universe) / (Redshift+1). This assumes the following:

 

1) The red shift is entirely due to velocity, or at least some other time dilating effect, such as gravity. That makes: (Redshift+1) = (Time Dilation).

2) There was indeed a Big Bang, and at that point the galaxy, and the point from which we are observing were of negligible distance from one another (nether galaxy nor observer were formed at the time, of course, but we could assume that their constituents were).

3) The relative velocity of observer and galaxy has remained constant.

 

 

Assuming the age of the universe as 13 to 14 billion years that would make a galaxy with a redshift of 7 about 1700 million years old. NASA makes it only 800 million years old, so clearly they are assuming that the universe was expanding much faster in it's early years. or there is some other flaw in my reasoning.

 

Few now believe that the universe's expansion was constant. Perhaps the most accepted theory claims that the universe's expansion dropped fast early on due to gravitational force, and then speeded up due to "dark energy". Given that nobody seems to know what "dark energy" is, I can't hold this theory as conclusive. If, as many suppose, the BB was an explosion, or expansion, of space the matter is even less clear cut. The mechanics of an expanding universe need not follow that of a firecracker. The expansion could be non-linear in unexpected ways. We just don't have any way of directly testing the expansion characteristics of space.

 

Sadly direct comparison of redshift against distance (as measured by absolute magnitude of supernovae) leaves a rather confusing mess that eliminates few possibilities. On the evidence, I wouldn't bet against expansion being truly fixed to the hubble constant right up to the time of the BB, or at the other extreme, following an exponential curve! Details may be found here:

<a target=_blank class=ftalternatingbarlinklarge href="http://www.astro.ucla.edu/~wright/sne_cosmology.html

">http

[Tormod]

Kudos to you for trying to bring some fresh air into your topic. I was about to reply but got put off by your final list of points (especially 4, which is quite unneccessary, and 7, which made me realise that your post itself is a novel so I won't bother - where is the limit before your interest drops?).

 

Point 6 is a good one.

 

For example, where is the explanation, or evidence, for this assertion:

Perhaps the most accepted theory claims that the universe's expansion dropped fast early on due to gravitational force, and then speeded up due to "dark energy".

 

Since the list of points is directed at FreeThinker you are violating our FAQ.

 

There. I brought your discussion off topic. See, the entire essence of your post is an attack at one of my moderators and I do not tolerate that. If you feel that the other threads you are participating in are veering off track because you are being continually misinterpreted, that is of course not very good but maybe there is more than one side to that story?

 

Here is my own list:

 

1) Do not add rules to these forums without checking with me first.

 

Tormod

[Bo]

Well there is indeed a lot to be said (i'll try to give as much references as possible )

 

There is a simple way of calculating the age of a galaxy, as it is observed, using redshift. (Age of galaxy) = (Age of universe) / (Redshift+1). This assumes the following:

This also assumes that the age of the universe is equal to the inverse of the hubble constant. (calculated myself, so no ref ) This is one of the most crudest ways to estimate the time of the universe (it gives the age of the universe as approx 10 billion yrs) (A.Liddle; "an intorduction to modern Cosmology"). So your miscalculation is to be expected. The main reason is as you pointed out that the expension of space isn't constant.

The expansion could be non-linear in unexpected ways.

indeed most cosmological models use something called inflation. inflation basicly says that in the first milliseconds after the big bang space expended at an incredible fast rate. The reason we need this model is the following: The universe looks at the very large scale everywhere the same (homogenity), but the current size of the universe and the finitedness of the speed of light means that many galaxies only 'see' each other for the first time now; but the homogenity implies that in earlier times they should have been in contact. So the idea is that at the big bang everything was in contact; then space expended very fast and all matter and radiation lost track of each other; and now it begins to see each other again.

Apart from this inlation, a few years ago it was also measured that the present day universe is also accelarating. this is caused by the dark energy (or maybe the same mechanism that caused the big bang?). The problem with dark energy is basicly the following: General relativity permits something called the 'cosmological constant' This is basicly some sort of vacuum energy that acts like the dark energy. QM also predicts a vacuum energy; The measured cosmological constant and QM calculations are a complete mismatch; so a better understanding of the vacuum is necessary. Right now many people (including myself ) are working on the consequences of string theory on the vacuum. Indeed it turns out that in string theory there are universe possible where inflation is a natural consequence; One of the problems is that there are about a million possible vacua... (a nice reference for all the above is e.g. http://superstringtheory.com/cosmo/ Also any google search for inflation will work)

 

We just don't have any way of directly testing the expansion characteristics of space

This is not completely true; By looking at the irregularities in the cosmic microwave background it is possible to extract many information on the beginning of the universe. (see e.g http://map.gsfc.nasa.gov/m_mm.html )

 

I still maintain that there is some possibility that the red shift is a property of space and the universe is not expanding.

Of course you should never rule out possibilities. But you must realize that the expension of hte universe means (in this contect) an expension of space itself (also: A. Liddle "ïntroduction to modern cosmology"); so the red shift is a property of space itself (if this isn't what you meant; please say so)

 

The analogy of comparing the universe to the surface of a 4 (or maybe 5) dimensional balloon that is being pumped up leads to an apparent paradox. In this version, whatever directi

[BlameTheEx]

Tormod

 

My sorrow that you were put off by my list of points. I knew that it was bound to be off-putting, but considered it the lesser of evils. I considered that the debates in previous threads were even more off-putting, and hoped to avoid a repeat.

 

As to my post being in itself somewhat of a novel, what can I say but guilty? I guess It is up to others to decide whether it is a novel worth reading! I do the same with other posts. The point intended is that I will probably answer a short reply for politeness sake alone. A long reply would have to engage my interest too.

 

Regarding your considering of point 4 to be unnecessary, I am uncertain as to why. could you explain?

 

My apologies for not having read the F.A.Q. I was unaware that they carried such force, or I would have read them. Be assured that when I repeat those points (as I will, although with modifications) Freethinker will not be mentioned. If you wish I will edit that comment out.

 

I was also unaware that Freethinker was still a moderator. His title has changed to "Hypopathic". I had assumed that you had stripped him of his rank due to, what appears to me, abusive posts. I am still a little surprised to find out that you have not!

 

I don't pretend to have the right to add rules to this forum. The list was to give warning as to my intentions for my own replies. In this case I admit, that this was not well expressed, and I apologise. I had, rather naively assumed that others would know that I only had power over my own replies. Would you like me to repeat them with the following prefix?:

 

"The following points express how I intend to handle replies. They are in no way rules of conduct for anybody else."

 

However if you consider these intentions unacceptable, please tell me, and I will leave.

 

Regarding Point 6. please note the word "may". Naturally if I suspected that the point made did have an explanation or backing, I would ask what it was, and of course as, in the case you mentioned, we both know what the backing is, I would not be so obnoxious as to apply point 6. Still I take you point. It was badly written.

[BlameTheEx]

Bo

 

Once again my thanks for your well thought out reply.

 

Regarding the possibility of the red shift being a property of space:

 

The "tired light" theory in its normal form is well discredited, because it's now clear that distant objects are not only red shifted but time dilated. However there is still an option, even if you exclude the rather unlikely "variable time" theory, and a closely related one that would hold that everything is expanding, right down to the size of atoms!

 

In this version we could view the universe as some sort of singularity. It is shaped like the surface of a 4th (or is it a 5th?) dimensional balloon. It assumes that raw space can have the property of velocity. This is not in itself remarkable. Unless we went for an expanding universe theory that counted on a pure explosion of matter into a pre-existing universe (now considered unlikely) then we would have to assume space can have a velocity.

 

The difference here is that we give space velocity without it actual moving, like the escape velocity created by gravity. Gravity indeed would be one possible cause.

 

Think of each point in space having a unique direction in the 4 dimensions which is zero velocity. In fact that point in space is DEFINED by this direction. This direction could be said to be the (local) direction of time.

 

While expansion free, this would be far from a steady state universe. There is, in effect, a tax on movement. Where would the energy lost to red shift go? Also I wonder if, as fundamental particles can be considered as standing waves (moving at light speed, although only in circles), would they be loosing energy too? Finally it doesn't answer the big questions: where did all the matter come from, and why did everything appear to start about 14 billion years ago?

 

Clearly this model has serious problems to overcome, but perhaps they are not much worse than expanding universe models (why did the BB not create equal quantities of antimatter, what is the dark energy, how did it create the dark matter?).

 

Regarding the paradox:

 

A quibble, but I did say "apparent".

 

Regarding distant galaxies being smaller than they appear:

 

I am excited that you agree on this point. I must say that I still expect someone to find a flaw it that argument, but I now feel a lot more hopeful. Naturally Nasa must have worked it out, but I do wish they had published it where I could find it. This test of the expanding universe theory deserves more prominence. A test that conclusive HAS to be exciting!

 

My thanks for drawing my attention to that link on cosmic microwave background. I had not realised how much could be made from the data. In particular I was surprised to read that the reduction of frequency from the originally emitted gamma rays was by redshift alone! I had wrongly thought of this reduction as being most likely due to the gamma rays being absorbed by matter that then re-radiated the energy as heat.

 

The conclusions were so impressive that I tried reading one of the papers involved:

http://arxiv.org/PS_cache/astro-ph/pdf/0302/0302207.pdf

 

Sigh. It's rather more technical than I can handle. If you, or anybody can explain the reasoning behind these conclusions in a "for dummies" format, it would be of great help.

[Tormod]

Blame, I'll let the matter drop right here but will respond to your questions. I may have been in a particularly bad mood that morning but I did mean what I wrote, even if it was somewhat blunt.

 

Originally posted by: BlameTheEx

Regarding your considering of point 4 to be unnecessary, I am uncertain as to why. could you explain?

 

Point 4 is unneccessary, because it is (or should be) plain that this is how every thinking person in this forum likes to see themselves. If everyone followed rule 4 it would be a perfect forum. Maybe we should put in the FAQ.

 

My apologies for not having read the F.A.Q. I was unaware that they carried such force, or I would have read them. Be assured that when I repeat those points (as I will, although with modifications) Freethinker will not be mentioned.

 

I don't think you should ever repeat those points, Blame. They should be self-evident. If you feel a need to express them I am sorry.

 

If you wish I will edit that comment out.

 

No need for that now.

 

I was also unaware that Freethinker was still a moderator. His title has changed to "Hypopathic". I had assumed that you had stripped him of his rank due to, what appears to me, abusive posts. I am still a little surprised to find out that you have not!

 

Again, read the FAQ. The user titles are automatically created from the number of posts any member has made. A bug in the software makes it impossible for me to put "Moderator" there for the mods. All the moderators have been told to put "Forum moderator" in their sig and I'll point my wiggly finger at them all for not doing so (apart from Unc, who actually mentions it).

 

Freethinker is an invaluable member of Hypography and without him and the other mods I would not be able to maintain this forum. Yes, he may appear to be an obnoxious cheesehead but he is our obnoxious cheesehead. Okay? (Now he'll start bashing me instead).

 

However if you consider these intentions unacceptable, please tell me, and I will leave.

 

If anything is unacceptable, I'll send you a Private Message. I was just warning you, and you are taking it well. Please understand that I really value your participation in our forums and I may as well apologize for being so blatantly arrogant in my reply to you. Please, do not leave.

 

Regarding Point 6.

 

Blame, it was just a case in point. Apart from your list of rules your post was excellent and just what I want to see more of around here. I just don't want people to start posting lists of how they want people to behave when they reply to *their* threads (it would very soon turn into a horrible mess). We are all equals here, although we behave differently. If we can accept each other's differences, especially in posting style and forum behaviour, it will be much easier to start talking and stop flaming.

 

Thank you for taking me up on my criticism. Now let's get back on topic.

[Bo]

The difference here is that we give space velocity without it actual moving, like the escape velocity created by gravity. Gravity indeed would be one possible cause.

If i understand you correctly you say: Let's give space it's velocity (inflation); but then reshape our coordinates to make the actual velocity zero. This coordinate transformation defines our properties of spacetime. (if i'm not correct please say so )

Well i have the feeling that this gives no new properties to inflation, nor is it fundamentally different. A coordinate transformation doesn't change the physics, only the way we look at it.

 

The conclusions were so impressive that I tried reading one of the papers involved:

http://arxiv.org/PS_cache/astro-ph/pdf/0302/0302207.pdf

 

Sigh. It's rather more technical than I can handle. If you, or anybody can explain the reasoning behind these conclusions in a "for dummies" format, it would be of great help.

 

Well the best dummy-format is probably on the site of WMAP itself; but if you have some specific questions, i can try to answer them... (not on the first 5 chapters that are all about measurement systems, data acquisition etc; i know very little on that... )

Bo

[BlameTheEx]

Bo

 

Here goes my best shot for explaining that universe model. No promises that it works of course.

 

Heres the lorentz transform in its most simple form:

 

t squared + v squared = 1

 

t is the velocity in time, that is the reciprocal of time dilation. This gives a stationary object as travelling through time at a velocity of 1.

v is the velocity in space, measured against the speed of light. That is giving (speed of light)=1.

 

From this point of view ALL objects travel at the speed of light. If you are standing still, you are travelling at the speed of light through time.

 

Now this works out fine if the direction of time is constant, but what if it were not? Change the direction of time and you change the velocity of an object in space.

 

Now comes this model of the universe:

 

Try to imagine the universe as the surface of a 4 dimensional balloon. As this is a 4th dimensional balloon its surface has 3 dimensions, which gives you the local directions for the 3 dimensions of space. That leaves one dimension to find, that of time. It can only be perpendicular to the surface. The effect would be, that no matter which direction you travelled in, the direction of time would be turning towards your direction of travel. You would slow down.

 

Ok, that was probably a little difficult to visualise. Lets try to make it easier by looking at a 2 dimensional balloon. That is a simple circle. Now we have one dimension of space, and one of time. Time is again perpendicular to surface of the circle at any one point. Suppose you are sitting on the circle, and fire off a bullet at the speed of light. your bullet is travelling totally in a vector of space, and not at all in the local direction of time. The bullet can't leave the surface of the circle, because that's all the space there is. It can only travel round it. Once the bullet has travelled a quarter way round the circle, the old vector of space is now the new vector of time. The bullet stops.

[Freethinker]

Originally posted by: BlameTheEx

(Yes, all this is for you FreeThinker).

Nice to hear you are so easily intimidated by me!

 

Rather than cram pages of disclaimers in your posts, if you just actually answered direct question with factual proof in the first place the need would not be there.

 

If you want to just speculate, Fine. That can be very interesting.

 

But then admit it when an assertion is challenged. Don't invent a dogmatic defense.

[BlameTheEx]

FeebleThinker

 

Intimidated? Go Get stuffed. Bored more like.

[Uncle Martin]

C'mon Blame'..... nobody likes FT's posting style,... That is a poor excuse for denying those of us that are truly interested in your views. Answer his question and be done with it. Then we can continue to read what you have in mind.

[BlameTheEx]

Uncle

 

Anybody truly interested in my views will get an answer. FreeThinker is not, only his Ego.

 

I have already tried answering his questions in the hope of "being done with it". You only have to check previous threads to see how well that works.

 

If you feel that he has made a valid question here, and you want my answer then all you have to do is ask. I am more than happy to reply to you. However best as I can figure it there was no question in his statement, only criticism. What exactly would you have me answer?

[Freethinker]

Originally posted by: BlameTheEx

FeebleThinker

 

Intimidated? Go Get stuffed. Bored more like.

Which is it? Stuffed or Bored? They are close to being Synonyms in this context.

[Freethinker]

Originally posted by: BlameTheEx

Uncle

 

If you feel that he has made a valid question here, and you want my answer then all you have to do is ask. I am more than happy to reply to you. However best as I can figure it there was no question in his statement, only criticism. What exactly would you have me answer?

Unc, next time you talk to BeLame, suggest that he can find the accumulation of unaswered questions on other threads.

[BlameTheEx]

Bo

 

I tried the WMAP site.

It goes this far:

 

Apparently it has measured, with considerable accuracy, the average size of lumps in the cosmic microwave background.

 

The size of these lumps are intimately linked to some theory of galaxy formation. The Problem is I can't find any reference to the theory. The conclusions based on the theory and these lumps are there. It is a list of answers a cosmologist would sell his soul for, but where is the theory?