I don't currently believe in any cosmological theory and I don't even feel much need to believe in some theory. But it seems to me that there are lot of people who think that in all times there should be a theory that is considered as "truth".

For example, once in a while in some ATM-threads here this question is presented: "If you think that Big Bang theory is wrong, then what's your alternative?" Way I see it, the existance of alternative theory has nothing to do with correctness of the Big Bang theory. So it seems to me that this question is presented because there is a need for "true" theory, Big Bang theory can only be wrong, if there is another theory we can start considering as "truth".

I don't want to start a debate about Big Bang theory, but I'm interested to learn why there seems to be need for a theory of the universe. To me it seems that in the field of cosmology our knowledge is still so limited, that in my opinion the correct theory of the universe doesn't seem to be possible yet.

I understand that a theory might be needed to decide what kind of observations we should make next, but it seems to me that lighter version of theory, a hypothesis, would be enough for that.

Any thoughts on this?

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"Stupidity gets denser in a crowd" - Old Finnish saying. [My website and My BLOG] [Nimblebrain forums]

You can put some philosophy behind your question. All these theories where worked out by people, and al we know fore sure is that we gonna get born and when if your lucky when youre about 90 years old you die.

Everything we do in our lives is finite, people don't understand Infinitness. Whe symply can't handle this proces of Infinitness only our imagination helps. All these theories can't possibly handle Infinitness. The universe maybe will become more of a phylosophical methaphoor than a scientific subject when it is Infinite.

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"There are many ways of noing nothing"

If you have children, or still think like one , you'll always ask or be asked "Why, How, etc..."

Did you ever want to know how the magician did those neat tricks on stage?

Did the beauty of the sunrise lead you to research why it is red?

Or, the amazing complexity of life on earth to have you beg the question: where else?

All these things drive the imagination. All of them are goals for someone to reach.

The land was mastered by agriculture, the seas by the English , and apparently Space, in our lifetime, will only be conqured by the mind. It's for all of us left wishing that we were already travelling among the stars.

[edit]

Oh yeah, and those few who want to know everything, concpetually.

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Feynman
>~~~~<
Science is a way of trying not to fool yourself. The first principle is that you must not fool yourself, and you are the easiest person to fool.

Religion is a culture of faith; science is a culture of doubt.

When Sir Edmund Hilary was asked why he climbed Mount Everest, he replied simply, "because it is there".

Why do we need a theory of the universe: because it is there. And we need to keep looking, learning, refining, getting closer and closer.

Well said.

Exactly what I was thinking, you beat me to it! =D>

But it was George Mallory, not Sir Edmund Hilary, who said it.

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Microsoft is over if you want it.

The bar has been lowered for the promotion of ATM ideas; the bar for the acceptance of ATM ideas must remain high.

I believe Sir Edmund Hilary said it too:

"because it is there"

Because we might blast off in a spaceship only to crash into the crystal spheres surrounding the solar system (metaphorically, of course ).

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"Oh no no no I'm a rocket man Rocket man burning out his fuse up here alone." -- Sir Elton John

J Pax

I agree with all the comments made so far, but it seems that there is something wrong with my opening post, because everyone answered to some question I didn't think I was asking. So, it wasn't my intention to question theories in general, or to ask why we need knowledge. But thanks to all anyway for the effort!

I'll try again. It seems to me that in the field of cosmology, there is this tendency for people to accept theories surprisingly quickly (I don't mean just Big Bang theory, this applies to alternative theories as well). So I'm just looking for reason for this. Also, it seems that this tendency doesn't show up so much in other fields of science, is there something special in cosmology in this sense?

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"Stupidity gets denser in a crowd" - Old Finnish saying. [My website and My BLOG] [Nimblebrain forums]

I don't understand which theories you are talking about because I don't really see people too quickly accept new theories. If a theory is considered "mainstream", then it must have evidence backing it up.

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"We live in a society where it's considered okay for intelligent people to be scientifically illiterate." -- Lawrence M. Krauss

Everybody is a little bit philosopher. Most of them want to know why and where we exist. It is connected with knowledge and cosmology is a kind of knowledge which have to answer where we are.
- are we alone in the Universe ?
- Is our Universe just an accidental phenomenon ?
- Is anywhere higher civilization ?
- Is there higher dimensional Universe with other laws?
Everybody believes something is truth. Many people believe in different truth. Cosmology is a base of religions and atheism. Searching cosmology people are shaking a religion.

It's good to know that, because it's possible that I'm only imagining this situation, or perhaps I'm just overly sceptical and wondering why others are not. So I'm not claiming that this situation is necessarily real, it might be only in my head.

Yes, but to me it looks like that in case of Big Bang theory there is not so much evidence that it should gain so wide acceptance as it has. But I quess this is at least partly a matter of opinion.

I do believe that something is the truth, but I believe that we don't know what that something is yet, I think that we are not even close to knowing that.

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"Stupidity gets denser in a crowd" - Old Finnish saying. [My website and My BLOG] [Nimblebrain forums]

I'm just happy to be here...

I think to properly answer your question we need to understand the very basic nature of humans. We don't like to live under uncertainty. Uncertainty invokes fear upon us that's why we need to get rid of it. I agree with the rest that we are naturally a philosopher and want to know where we come from, and how we got here, but people sometimes forgot we do it not usually just out of curiosity.

Imagine a case when a person experiencing partial amnesia. He was placed on an island with nothing else. He was surrounded by the wild animals and he need to combat every situation to survive. For the unusual moment when he was safe and alone, he would wonder where he came from, how he got here and why he got here. Out of curiosity, yes, but more importantly, he felt anxious and unsecured because if he didn't know how and why he got here, there was no guarantee he would still be here the next minute.

However people denied it, I think deep in our mind we believe we come here with a purpose. I hate to get up in the morning only to know my life is nothing more than some biochemical arrangement. We want to feel important and cosmology is one way to answer our questions. That we seem to be too quick on the theories is the same as a person going to drown - he would try to hold onto anything that could possibly safe him.

I'm not saying this is the only reason why we believe in these theories but merely it is part of the reason. There could be different incentives for different people. Money, fame, pure scientific goal, just to name a few.

Hope that answer your question.

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"We live in a society where it's considered okay for intelligent people to be scientifically illiterate." -- Lawrence M. Krauss

I actually think the opposite, that the evidence for the Big Bang is pretty impressive. Of course, we may not have all the details worked out, but what we've put together so far fits the observations pretty darn well.

Ummm.., Ari, you sure can open a can of wormy possibilities. If i understand your (?) question/chalenge, it goes something like, "What is the need of an absolute truth for the orgin of our shared reality, anyway!?!" Or are you making a case for, "We dunno, is good enough." By the very nature of its inquiry, cosmology treads the same ground as religions plow for their own source of the absolute "Truth." Only a process called 'the scienitific method' separates their efforts, as well as their claims. And as for the "Big Bang," it is only our current 'best guess,' because in the scienitific search for the very source of our shared reality/universe, it is not claimed to be complete as yet.
Evolution is another "theory," that has had its share of emotional reactions and counter claims, although it is much more tested, and solid, when compared to the big bang. Both 'fields' spring from our most fundamental questions, asked and shared to some degree within humanity from its very start. So if not along these lines of inquiry, then where else might scienitific focus be restricted? Drifting off topic, sorry, but think you can begin to see those 'special' qualities in these "theories," that can bring forth such strong emotional agitation.

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In the beginning, the universe was created. This made a lot of people very angry, and has been widely regarded as a bad idea. -- Hitchiker's Guide to the Galaxy

Good points, pretty much what I was asking for.

Well, these examples don't actually generate honest belief, but from the outside it would still appear that way, and perhaps the person who would be into it because of money for example, wouldn't even know it (as it might be a subconscious thing), so that person might think that his/her belief is honest. So yes, I agree.

It does, thank you!

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"Stupidity gets denser in a crowd" - Old Finnish saying. [My website and My BLOG] [Nimblebrain forums]

As I see it, there is mostly indirect evidence, and the whole thing relies too heavily on one thing, the cause of the redshift. But I think that it's very subjective thing how much we put weight on the evidence. Also, the fact that I don't believe in Big Bang theory might cloud my judgement in this matter.

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"Stupidity gets denser in a crowd" - Old Finnish saying. [My website and My BLOG] [Nimblebrain forums]

No, it's not that. I'm as curious about this matter as anybody.

Not exactly this one either, but this one's closer. It's more like We don't know yet, so let's not get overly excited by our theories.

Yes, but perhaps some think that it's already in it's polishing phase. :wink:

I agree.

Well, I think that we should proceed with observations leading the way, rather than theory driving the observations method. I'm just thinking about a hypothetical situation that someone would show beyond reasonable doubt that space doesn't expand, and that would mean that Big Bang theory is wrong. How much of our research would be valid after that? For example, everything done on the inflation theory would be more or less worthless.

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"Stupidity gets denser in a crowd" - Old Finnish saying. [My website and My BLOG] [Nimblebrain forums]

I think the question Ari is asking is why - given the large gaps in our knowledge - is the exploration of alternatives treated with such contempt? Why is it that astronomers must adopt one theory (BBT) or face being classified as "fringe" (or even worse)?

Its a philosophical question with a sociological component to the answer.

It is not only the redshift pointing towards the Big Bang. There is also the Cosmic Background Radiation.

There's lots of evidence that is consistent with the current BBT theoretical construction. But underlying that entire model is the requirement that the universe is expanding. What Ari is saying - and its a good point - is that expansion is an interpretation, not an observation. Hubble did not prove the universe expands as is often written. Hubble found that there is a general increase in redshift as distance increases. That has been interpreted as the result of expansion.

Whatever other evidence may be consistent with the BBT, the whole model is wrong if there is no expansion.

Its healthy for science to have a multitude of options. Look at Dark Matter. You have the favored non-baryonic CDM, but you also have alternative exotic DM proposals (such as warm DM), then there is Baryonic DM, MOND ...

But what is interesting is that the BBT has directed most research toward CDM at the expense of more carefully exploring other options. This is well explained in the introduction of this important paper. The authors specifically state that it is time to explore DM independent of theoretical considerations - and that the emphasis on CDM has taken research away from understanding the DM phenomenon.

That speaks directly to this point made by Ari:

It's not a general increase in redshift as distance increases. It's a very specific and directly proportional increase, and this has been verified for objects well beyond those observed by Hubble.

As you say, it is "often written" that Hubble proved, or rather he demonstrated that the universe expands. Why do you suppose this is "often written" and so widely accepted? Are 99% of all scientists in the world rushing to judgement simply because they would like to have some theory of the cosmos? To think so is much too conspiratorial, methinks.

No, the reason it is "often written" that Hubble showed that the universe expands is because this redshift explanation is simple and natural, and especially because there is no coherent, viable alternative explanation that fits and explains these observations. Oh, sure, we see a variety of tired-light proponents on this Against the Mainstream board, but really, these are inconsequential dumpster divers just rummaging around in the trashbin of history.

As Grey says, the evidence supporting this theory is "pretty impressive", and I might add, as more and more observations are made, the evidence just continues to mount.

And of course dgruss will point out that not all evidence falls into the support group, particularly evidence collected by Halton Arp. And there have been many discussions on this board about the veracity of such evidence and Arp's interpretation of it.

Nevertheless, Hubble's theory remains solid, with no competitors.

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Everyone is entitled to his own opinion, but not his own facts.

You’re incorrect Cougar – “general” is the proper word. It might be helpful to go back to the beginning on this. Here is a link to Hubble’s original paper discussing the redshift distance relation. It is instructive to compare then with now.

1.Hubble Stated: “Distances of extra-galactic nebulae ultimately depend upon application of absolute-luminosity criteria …”

In other words, in order to examine the redshift-distance relation you must have distances to galaxies. Then it was limited to cepheids, variables, and blue giant stars to determine the distances to galaxies. Today we also have Fundamental plane, surface brightness fluctuation, Tully-Fisher, Supernova, Planetary Nebula and globular cluster luminosity functions as methods of determining galaxy distances.

But in principle this has not changed in 75 years. To evaluate the redshift distance relation you must have distances to galaxies.

2.On the redshift distance relation Hubble concluded: “The results establish a roughly linear relation between velocities and distances among nebulae for which velocities have been previously published, and the relation appears to dominate the distribution of velocities.”

Note Hubble’s use of the word “roughly” in defining the relation. “Roughly” is synonymous with the word “general” – which I used. Why did he use the word “roughly”? Look at Figure 1 of his paper. There is plenty of scatter around the mean relation. That situation has not changed today. New data has not resulted in galaxy or galaxy cluster distances that universally fall tightly to the mean redshift distance relation. There can be sizeable scatter - which cannot simply be attributed to distance errors.

3. Hubble made the following statement regarding the scatter of the “rough” redshift distance relation: “The residuals for the two solutions given above average 150 and 110 km/sec and should represent the average peculiar motions of the individual nebulae and of the groups, respectively.”

In other words at the very outset it was assumed that deviations from the Hubble relation could be attributed to peculiar motions. This remains the standard interpretation today.

4. Hubble then addressed the scatter of absolute magnitude relations: “Secondly, the scatter of individual nebulae can be examined by assuming the relation between distances and velocities as previously determined. Distances can then be calculated from the velocities …”

This has not changed either. Numerous papers come out where distances to galaxies are needed and they assume Hubble distances. But this procedure assumes that Hubble distances are accurate and contain no effects from intrinsic redshifts.

To put some numbers to this question about the “general” or rough nature of the Hubble relation it helps if you look at the published distances. Assuming H0=72, here are the redshift deviations of the fundamental plane clusters of the HKP final report:

Dorado: +137 km s-1
GRM 15: +1117 km s-1
Hydra: +526 km s-1
Abell S753: +773
Abell 3574: +902
Abell 194: +1075
Abell S639: +2242
Coma: +965
Abell 539: +1448
DC 2345-28: +1149
Abell 3381: +2190

Here for Tully-Fisher distances from my paper:

Centaurus: +1264
Pisces: +811
Antlia: + 913
Coma: +1215
Abell2197/99: +987

And since these numbers are cluster averages, you will find individual galaxies within these clusters with much larger values. For example, the Surface brightness fluctuation method (SBF) indicates the following redshift differences in Centaurus:

NGC 4709: + 2362, ESO 323-34: + 2086, NGC 4616: +1960.

What is interesting about Centaurus is that the original analysis of the cluster in the1980’s indicated a bimodal redshift distribution with peaks around 3000 km s-1 and 4500 km s-1. According to the Hubble relation that would suggest two clusters superimposed with one at about 43 Mpc (Cen30) and the background group at about 64 Mpc (Cen45). But Cepheid, Tully-Fisher, and SBF studies all put the core of the cluster at ~33 Mpc including both Cen30 and Cen45 galaxies. Thus today the Cen45 galaxies must be explained by presuming a merging of two clusters. Given the redshifts the merger velocity is ~ 2000 km s-1 and we happen to be catching the merging when the two clusters overlap.

No he didn’t Cougar. Hubble demonstrated that redshift roughly increases with distance. One possible interpretation of that observational result is that the universe is expanding. You’ve insisted expansion is observed before – and you’re wrong.

Appeals to consensus do not constitute evidence in a scientific debate.

Cougar, you’ve just illustrated the contempt for alternatives I was referring to before:

I guess rather than be offended by the obnoxious phrase - or perhaps more properly classified as an insult - “inconsequential dumpster divers just rummaging around in the trashbin of history.” I should be thanking you for re-inforcing my point than many mainstream supporters treat serious discussion of alternatives with contempt. Granted that goes both ways, but it’s not my record to do so, so I fail to see why you would lower yourself to that level in response to something I’ve written.

Of course your phrase “no coherent, viable alternative explanation that fits and explains these observations.” in addition to being wrong also seems to illustrate Ari’s original point at the start of this thread:

Both for and against Cougar. You actually think there is no contradictory evidence?

You really don’t need to speak for me. My point about the Hubble relation being “general” does not involve the bulk of Arp’s work. Most of his work involves quasars for which the cosmological component is insignificant compared with the intrinsic component.

This sounds like overcompensation.

Helpful to ignore the last 80 years of observations related to this question? I don't think so.
Are you claiming the standard deviation is the same for recent measurements and Hubble's original, rudimentary measurements?
Oh, excuse me. Expansion is just one possible interpretation. And what are the other viable possible interpretations that have not been shot down? Why, there aren't any! Expansion is a simple explanation for the observations. Other explanations have been tried, but they have failed. If it's not expansion, what is it?
I'm not appealing to consensus. I'm asking a question. And the simple answer that you don't want to allow is, expansion is widely accepted because it makes sense.
No, I've illustrated a bit of intolerance at the raising of decades-old theories that were shown to be fatally flawed almost as soon as they were originally brought up. I quickly lose respect for those who simply ignore evidence that kills their pet theory. When a theory has been shown not to work, one must move on.
Your characterization is an insult. I thought that was one of the best phrases I've come up with yet on this board. And perfectly accurate and expressive. I'm talking about long-dead theories that people who haven't done their homework keep bringing up - as if they haven't already been shown to be untenable. What are you talking about?
I'm not hearing any viable alternative....

And of course Ari's right: that fact doesn't validate the big bang theory. But I point out, the theory has plenty of support to stand on its own.
Seek and ye shall find.
What "intrinsic component"? Is this something that is observed or interpreted from "interesting proximities" or statistical manipulations?
Characterize it any way you like. You're free to attempt to show where the statement is wrong, but please don't present any theories that have already been shown to be flawed.

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Everyone is entitled to his own opinion, but not his own facts.

That's one part of it, but I was also interested of the psychological side of this, to which kanon14 gave very good answer.

CMBR in itself doesn't point towards the Big Bang. If we would only be aware of CMBR and not redshift, we wouldn't conclude that universe expands. So CMBR is interpreted to support Big Bang theory only if redshift is interpreted to support Big Bang theory.

Hubble himself didn't think he demonstrated that the universe expands. In fact, he was very sceptical about it, couple of examples:

Hubble, 1947 - The 200-Inch Telescope and Some Problems It May Solve.

Hubble, 1937 - Red-shifts and the distribution of nebulae

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"Stupidity gets denser in a crowd" - Old Finnish saying. [My website and My BLOG] [Nimblebrain forums]

How do you know this? I question this conclusion.
Interesting historical anecdotes. Nevertheless....

From some little university called Cambridge….
Gee, they're saying expansion is a fact. But that's just Cambridge University.

Here's an interesting Islamic view of this question.
Here's something from some other little university… Berkeley?
The PBS science editor must be in on the conspiracy.
A little logical blurb from South Carolina State University:
I could go on, particularly since a quick google search of "expansion of the universe" yields 139,000 hits. (This seems to be a pretty prevalent idea.) Of course prevalence is not proof. Then again, it seems imprudent to casually discount the studied conclusions of 99% of the scientific community.

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Everyone is entitled to his own opinion, but not his own facts.

For goodness sakes Cougar that’s not what I did at all. You said this:

That statement was wrong. Even Hubble recognized it is a “rough” relation. By no means did I ignore the last 80 years. I specifically compared Hubble’s initial results and assumptions with the situation today. That was the point of the four points – which you seem to be ignoring.

It depend upon which measurements you’re referring to. The raw data for calculating distances has much smaller scatter. But despite the more accurate data, the observed scatter of the redshift-distance relation remains large. In fact that’s the important point – despite the improved data the Hubble relation remains rough. I provided you a list of cluster redshift deviations.

Illustrating Ari’s point again. Cougar, a number of alternatives have been discussed here such as Narlikar&amp;Arp and CREIL. Not to mention the possibility of expansion with superimposed intrinsic redshifts. Since you’ve seen those discussions, why don’t you point to the evidence that shows those alternatives are disproven.


I’m not going to keep defending my statements against your careless reading of what I’m saying. If you have specifics make your point. All I said is that expansion is not an observation – it is an interpretation. If you care to pay attention to the discussions you’ve had with me you would know that I’ve said on numerous occasions that it is possible that the universe is expanding and intrinsic redshifts are superimposed upon that. I don’t rule that option out and I NEVER SAID EXPANSION DOESN’T MAKE SENSE. Yet another example of you mischaracterizing my points.


My characterization is an insult??? Cougar, people that post on this board support tired light theories. YOU characterized them as “dumpster divers”. That is an insult. I stand by my opinion that in calling tired light supporters “dumpster divers” you have demonstrated contempt for alternatives. But it hardly surprises me given the various insults you’ve made regarding Arp.

No, you refuse to admit that there are viable alternatives. You won’t admit that expansion is an interpretation not an observation. You will not even admit that your statement that the Hubble relation is not “general” is incorrect – despite being provided a comparison of Hubble’s and modern data that demonstrates the point. Any comment on the published cluster distances and their resultant implied peculiar motions?

I said that in my original post you responded to:

This is what I meant above about you being careless reading (or at least in responding) to my posts. We’ve come full circle and you’re claiming to be offering a counter point to what I’ve been saying which is actually another way of stating the very first sentence of my post you had a disagreement with!

Only if its there. But put on blinders and ye shall not find.

Cougar, this is not the first time you’ve claimed not to know what I mean by intrinsic component despite the numerous discussions we’ve had about it. I recall quite well that when Jerry linked to my paper, you wanted the right of rebuttal. I’m still waiting. And if you want I’ll even provide you with two more papers that were recently accepted for publication.

Examples of what you think is shown to be wrong?

Every one of those examples is an incorrect statement Cougar. I don't care if Cambridge, Berkeley, and every other university on this planet says expansion is an observed fact. Its an overstatement.

What is observed is spectral redshifting that generally increases with distance. Expansion is an interpretation. What you've pointed out is the very reason why people are confused about this issue. Many of these universities are incorrectly classifying expansion as an observation.

And perhaps you could point out where Ari or myself has called this a "conspiracy" or implied the same?

And has it not also been directly observed that spectral shifting is caused by relative velocity? This effect cannot be turned off, and it is a direct association. So why is it that the further an object is from us, the faster it appears to be moving away from us? (And this Hubble relation is a direct proportion, not some "general", "rough", wishy-washy relation. Something three times further away appears to be moving away three times as fast. The fact that these measurements don't always match exactly is hardly surprising. Objects have their own peculiar velocities, and astronomers are not yet real good at establishing an accurate distance (independent of redshift) for generic objects billions of lightyears away.)
Please. You're taking my artful turn of phrase out of context. I said that tired light proponents are "inconsequential dumpster divers just rummaging around in the trashbin of history." You've heard of the "dustbin of history", haven't you? Quite a few attempted scientific theories end up there because they are found not to work. And what would you call someone rummaging around these long dead theories? Your personal assertion that my descriptive phrasing is an insult doesn't make it so.

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Everyone is entitled to his own opinion, but not his own facts.