As russT implies, reclassification is not the real issue: How do you delinieate between supernova types when the borderlines are so hazy? 2006gy has all the spectral earmarks of a type Ia, but some of the characteristics of a type II, and it is brighter than both. These categories, in the first small samples of supernova were much more distinctive than they are today. The difference between Ia and hypernova Ic involves even more hair splitting. Researchers work very hard to segregate the local sample, and events like 2006gy break all of the molds. It is no longer possible to confidently catalog very distant events, where spectral distributions are noisy and k-corrections iffy.

Look at the length of the light curve on 2006gy ( http://en.wikipedia.org/wiki/SN_2006gy ). If this supernova event occurred in deeply redshifted space, if you included the correction for time dilation, this curve would be much much longer than any we have ever observed. Remember, it is the long-length of the most distant light curves we could see that proved, in ~1994, the time dilation properties of redshifted events. But here in our own backyard we now have samples of very long light curves in extremely bright events. The rules that were used to prove redshifted expansion are broken by events like this. Is the redshifted sample of supernova events we are able to observe dominated by ultra-bright objects like this?

If we were to see an event like this in redshifted space, and the time dilation factor is correct, the length of the light curve should appear almost twice as long as this bright event we observed locally. There are no examples of light curves that long. We cannot conclude ultra-bright events are limited to local space. It is possible, even likely now, that the magnitude scaling factors are all wrong, including the correction for time dilation.

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jwj

It's a big universe out there...is it really unwinding, really burning out?

Jerry. Interesting thought, I'll wait for a few answers. Have a nice Fourth. Pete

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A third rate theory forbids.
A second rate theory explains after the fact.
A first rate theory predicts.
A. Lomonosov

Well, evidently the problem that I identified as starting in 1997, is not isolated to just 1a, 1c classifications.

Here is the original Chandra release.

http://chandra.harvard.edu/press/07_...ss_050707.html

Is this finding being correctly portrayed?

Do you and other 'mainstreamers' agree that this is a Monstrous Type II SN in galaxy NGC 1260?

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RussT
________________________________
Everything is, as it should be, otherwise, it wouldn't be!

Nice press release. Funny, but I see nothing in the release about reclassification.

This supernova was classified as a Type II event (core collapse within a star with a large hydrogen envelope) consistently. There was a suggestion that it might be an AGN, rather than a SN, due to its high luminosity and position very close to the center of galaxy and strong extinction, but continued spectral study has confirmed the initial Type II SN classification.

It's an unusual SN, due in large part to the very dense and massive circumstellar envelope surrounding it -- there's no doubt about that. But it was not misclassified, and not confused with a Type Ia SN.

Your strategy of jumping from one news item to another in search of any small disagreements or uncertainties is starting to remind me of the tactics followed by creationists. :-(

I see it more as evidence of how hard it is to classify supernova. There is a wide range of variance, even within the events that have always been classified as 'type Ia':

http://xxx.lanl.gov/PS_cache/astro-p.../0309665v2.pdf

Supernova 2002bo: Inadequacy of the single parameter description

It still amazes me how easy it is to create a tangled mess of a pile of rope or bungie cords. Likewise, the enterior of the earth is laced with unpredictable strata. An interior solar enviroment is likely just as complex, especially an aged star depleted in hydrogen. We shouldn't expect simple models to work very well.

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jwj

It's a big universe out there...is it really unwinding, really burning out?

Sorry if you got that impression SM, but you have totally misunderstood my intensions.

The first link I got on that was Wiki, which is why I linked the lower article. But I then realized that that was Universe Today, and so felt it important to link the original Chandra release, so everyone could see the 'Top in their field' direct remarks, without being edited by another science writer.

I also felt that it was important to give different sources so any 'uncertainties'
or in my estimation 'misinterpretations' could possibly be easier for others to see.

Any other "Pro's" want to add their quick evaluations?

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RussT
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Everything is, as it should be, otherwise, it wouldn't be!

RussT. A difference of opinion makes a horse race. Some people will never see things the way you do. Arp was once told..."there isn't any amount of evidence that you could present that could convince me of your point of view". Just hope you get mostly impartial jurors in life....you usually do.
I wish I had a photocopy of the article from the late sixties/early seventies.....when the best aerodynamic algorithms in the world, coupled with the fastest computers, proved to some MIT engineers that the bumblebee cannot fly. (they fit them special little running shoes ever since)....
We sell rain barrels to conserve water at the garden center. The other day, a guy who was a type 1a supernova-standard candle cosmologist took out a magic marker and changed the name to.....rain spheres. Everybody looked at him kind of funny. pete.

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A third rate theory forbids.
A second rate theory explains after the fact.
A first rate theory predicts.
A. Lomonosov

I know it's a while since these posts appeared in this thread, but I feel it is very important to address them.Here's my take: BAUT is an avowedly science-based internet discussion forum, focussed on astronomy and space science.

If a prolific poster, in BAUT's science sections (especially the Astronomy one), persistently posts material that can be shown to be seriously internally inconsistent, and further, inconsistent with the fundamental principles of astronomy as a science, I feel it is imperative that these inconsistencies be clearly and (if necessary) forcefully demonstrated.

This does not, and should not, involve any attacks on the person of the BAUT poster. If you, or any other reader of this thread, feel such personal attacks have, indeed, been made, please use the Report Post button.

Such a demonstration is also, IMHO, very much on-topic: if the basic premises of the material in the posts are deeply flawed, what value can the conclusions have?If more BAUT members examined more of the posts of a certain reluctant cosmologist BAUT member more critically, from a more consistently science-based foundation, applied even 1% of the scepticism so manifest in this member's posts to the posts themselves, .... and if the spur for such critical thinking were attributed to the posts of Nereid, then I would be delighted.

Back to the context. Here's an extract from an earlier post of mine (#49):To the main point of this post, which is the deeply flawed approach central to a great many of the posts of our resident 'reluctant cosmologist', both in this thread and others in the science sections of BAUT.

Let's look at just one example, in this thread.

- - - - - - -
Jerry: It is time to look for basic failures in our reasoning. Could anything be more exciting?
- - - - - - -
Nereid: What steps have you, yourself, taken to apply the Jerry radical scepticism to your own interpretations?

How would you go about estimating the possibility - in some quantitative fashion - that your own interpretations (etc) contain (fatal) basic failures (of reasoning)?
- - - - - - -
{Jerry did not answer these questions}
- - - - - - -
Nereid: Have you actually done any analysis yourself, Jerry?
- - - - - - -
Jerry:Yes I have, and just as importantly, I have discussed my observations with the cosmological community, [...]
There are A LOT of papers coming in nowadays, reporting possible bimodal distributions, and that the complete family of observations hint of binary episodes and other possible ranging errors for supernovae - including fundamental scaling:

http://xxx.lanl.gov/PS_cache/arxiv/p...706.2361v1.pdf
- - - - - - -

The approach which Ari Jokimaki suggests we should follow in situations like this ("if Jerry is so utterly wrong, it would be much simpler to show exactly what is wrong with things Jerry had said in this thread") would take quite a bit of effort, but the conclusion would be pretty straight-forward: the Sandstrom et al. paper can be shown to have little relevance to the robust distance ladder work, as it relates to distant supernovae. However, my guess is it would take dozens of pages of posts to make that conclusion clear ... and in the meantime, based on past posting behaviour, one could be highly confident that a certain BAUT member would have posted seemingly relevant, pertinent selective quotes from, and sweeping conclusions about, a dozen other papers.

Whatever this kind of asymmetry is, it is certainly not science.

How to address this tactic, this consistent pattern of posting behaviour?

I mentioned earlier that a highly pertinent way is to show the inconsistency in the approach.

The Sandstrom et al. paper's title is: "A parallactic distance ... from very long baseline observations". Now (trigonometric) parallax carries the implication of a direct, robust method of distance estimation. Presumably it appeals to our reluctant cosmologist because it is free of 'basic failures in our reasoning'.

But what if the method Sandstrom et al. used relies heavily on the very theories Jerry is on record, in dozens and dozens of posts, as saying is deeply flawed (GR)? If GR is as flawed as Jerry claims it to be, then surely any results, in astronomy, which include GR, directly or indirectly, in the observations or analyses, must be rejected (by Jerry)? Surely Jerry can only cite any such results as Sandstrom et al. (in support of some radical sceptical conclusion) if he has done a complete re-analysis of the work, to first identify, and then strip out, all GR-based aspects?

Has Jerry done this careful and detailed re-analysis, of the findings reported in papers he has quoted in all (or even any) of the posts in this (and other) threads? I don't think so.

But let's see: Jerry, in what ways - direct or indirect - did Sandstrom et al. use GR (in their VLBI-based parallax research)?

(to be continued)

Neried, lets take these one step at a time:

Perhaps we have a language barrier. From Wikipedia (or any of a few dozen papers

In my book, saying something is 'unknown or mysterious' is equivalent to saying "there is no local analog".

What is there in this definition that you disagree with so strongly?

If the best the 'best and the brightest' can come up with is that 'most of universe is mysterious and unknown', shouldn't we be looking for possible errors in their discovery process? Isn't it possible that the lack of a good textbook explanation for lightning illustrates an ignorance of nature at a primal level?

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jwj

It's a big universe out there...is it really unwinding, really burning out?

Indeed, it seems that you do not speak the same language as cosmologists, despite the 'reluctant cosmologist' moniker.

'local', to a cosmologist, means something like 'within the Milky Way galaxy', or 'within a local region of space sufficiently small that significant deviations from the Hubble flow can be observed' (i.e. within the reach of the Great Attractor).

In this respect, dark matter most certainly has a local analog, but dark energy does not.
And if this had been written by almost any BAUT member but you Jerry, it might, nay would, be entirely acceptable.

However, as hundreds (possibly thousands) of BAUT posts attest, you yourself are quite clear about your strong interest in, and self-proclaimed familiarity with, modern papers on cosmology.

Yet, as this one simple post of yours makes clear, you quite cheerfully adopt your own, somewhat idiosyncratic, definitions ... and why? To make a point that you could make equally well without shooting your own credibility in the foot?

Oh, and here's the icing on the cake* (my bold): "There are no examples of light curves that long. We cannot conclude ultra-bright events are limited to local space."

Who wrote that? When? In which BAUT thread?

*I'll leave it up to the reader to work out just how consistent this use of 'local' is, between the two posts.

You mean besides floating theoretical concepts upon the the BA and other BBs?

I've hauled a pile of papers from university to university, I've had email dialogs with principle supernova researchers and cosmologiest, and I constantly bounce whatever I am proposing against new and published research.

It is nearly 100% certain that I am wrong about many things. I am of the opinion that when we are told nobody knows anything about 96% of the universe, it is time to float some radical ideas. Most of them will be wrong.

For example, CREIL as the primary source of cosmic redshifting. It took several months of posting on UT threads before a good argument was raised against CREIL (by Antioseb), and I was able to discard the concept.

We worked the 'local CMB' together, and clearly concluded there is not enough optical depth of known local sources to account for the 'CMB'. There is nothing wrong with not having all the answers, there is everything wrong with having answers for everything and insisting that they cannot be wrong.

On the other hand, I have hypothesized Newtonian calculations, using orbital mechanics, do not properly establish the masses of planets. This silly idea should have been easy to disprove - but when I started digging through the papers, I could see a trend that is very consistent with this outragous idea. It lead to the 'gravity behaving badly' thread, and it is a fact: Every successful Martian landing probe has had to dissipate more energy than expected.

Taking this one step further, I reasoned that the differential in altitude at which the gravity of Mars is calculated should lead to degeneracies in the harmonics that are a function of altitude. These degeneracies exist.

Likewise, the orbital solutions of the moment of inertia of Mars favor a differentiated core, whereas the measurements from the surface favor a massive center. Hard numbers: Conflicting results.

Read the Viking papers: They burned ~20% more energy during retro-rocket firing; the surface gravity is 1-3% greater than expected. Spirit and Opportunity were barely within three sigma on landing velocity and range. As you know, I can go on and on, the only real question is whether or not there is a consistent trend. Let's see what happens with the Phoenix probe.

Again, I do not understand our communication problem: I answered the question, and provided a reference to my paper on the subject...or did I leave out the reference?

http://xxx.lanl.gov/ftp/astro-ph/pap...04/0404207.pdf

Science at the fringe is the hardest kind: Sorting through papers that are 99.9% garbage, looking for a glimpse of truth. But once you have established that the current consensus theory is going nowhere, that is about the only choice. (You can throw Ideas out on a BB and watch them get chewed up, but that is somewhat counterproductive and destroys your credibility.)

You seem to think I should have a good idea of the way things should be, and that is not true, nor is it easy to establish.

Let's look at the Gravity-B probe authentification of GR. First, they demonstrated once again that there is a measurable effect of 'GR' on the timing of a probe in Earth's orbit. They also found possible evidence of frame dragging. I expect these 'GR' effects to be real: They should be observable in any theory where gravity is treated as having a time-dependent vector attribute. What I am also looking for is a deviation from GR, especially in terms of a drift factor that is a function of the Earth's distance from the Sun.

The G-Probe B scientists have identified a time dependent drift and/or dampening, but they have assigned it to a combination of a shifting attenuation in the Polhode moment of the gyroscopes and 'patch effects' in the gyro housing. Even after the data is released, it is highly unlikely I could disentangle this paired relationship and establish whether or not the solar factor I think should exist, exists. In any case, it would not be worth the time: No one would accept my interpretation, no matter how mathematically rigorously my I approach to the problem.

Look at Huygens: They threw out their own radar and radial accelerometer data, relying instead upon analysis of electrical noise, prior predictions, wind speed assumptions; and the absurd notion that the probe rotated backwards, (opposite the direction of the carefully engineered vanes), in order to establish a descent profile consistent with their expectations. There is nothing scientific about that.

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jwj

It's a big universe out there...is it really unwinding, really burning out?

It seems that I am not making my point very clearly; let me try again.

Suppose Jerry cites a paper (call it "A") to support a claim that estimates of the distance to certain high-z SNe (including the uncertainty of those estimates) is flawed*.

Suppose that paper's conclusions depend, directly or indirectly (or both), on certain assumptions concerning the 'behaviour of gravity'; specifically, that gravity behaves as GR says it should.

We know, from dozens and dozens of posts, that Jerry has a very deep issue (or several sets of issues) with GR; specifically, that it does not describe the behaviour of gravity at all accurately, even within our own solar system.

What can one say, then, about the (logical) consistency of Jerry's use of A to support claims about the distance to certain high-z SNe?

If Jerry presented a detailed, quantitative analysis showing the extent to which A's conclusions depend upon GR (or something similar), then one could at least, in principle, check the consistency of Jerry's claims (but probably not the claims themselves).

If Jerry has presented no such analysis, in what way - scientifically speaking - can his claims be said to differ from gibberish?

Turning up the contrast: Jerry, if you don't, or won't, or can't at least show how - quantitatively - the results presented in astronomy/cosmology/astrophysics papers depend upon the direct or indirect use of GR, what scientific legitimacy does any claim (or even comment) you make using those results have?

How could any such claim, or comment, have any scientific legitimacy at all?

(to be continued)

*Let's assume, for now, that the paper does, in fact, have even a remote connection to distance estimates in astronomy.

Hey, N, how you been? Too quiet of late.

Sorry I know its off topic but I have to ask...
Jerry.. if there exists gravitational anomalies such that Martian bound spacecraft are affected on landing, then wouldn't all Earth launches be similarly or more affected? Wouldn't we see a consistent pattern in the failure of our satellites to orbit at the predicted height?

Feel free to ignore or answer offline... its just been bugging me.

You're opening the door to a discussion of an ATM idea ... this particular ATM idea has been discussed in quite a few (ATM) threads (just use the BAUT search facilities, to find ATM section threads started by Jerry).

If you can't find the answer to your question in those hundreds (thousands?) of posts, please PM Jerry*.

*or some other BAUT member who is very familiar with Jerry's ATM ideas ...

I'm having difficulty digesting this, so please help me out ...

You have one preprint in ADS, in your own name, and another with JMB ... and that's the extent of your published works (on cosmology)?

These two preprints represent an application* of the Jerry version of radical scepticism, applied to your own (and JMB's) ideas?

Let me see now ... ah yes, here we are ... (I've done some editing) ....

Belief in the scientific methodology does not mean blindly accepting a series of assumptions that lead to a set of solutions. And it most certainly does not mean accepting what might be called fundamental as canon: Any postulate may be proven wrong by new evidence. We should be seeing much of this today, but the descrepancies are not being recognized.

[Jerry, the s]upernova researcher[] make[s] many assumptions: The most important is that [the direct and indirect use of GR in obtaining astronomical data, and analysing it, is not even recognised, much less acknowledged or identified]. We have been seeing an increasing amount of evidence over the last decade that this is not the case.

The irony here, is what happens when the observational data is believed to be accurate, but not the data reduction methodology. When I look at [Jerry's preprint], I am forced to conclude [...], that one or more of the [...] assumptions [Jerry] uses to determine the magnitude distribution are false. That means at least one facet of GR is false, and it snowballs from there: Alternatives are needed, and Titan is covered with [ice].

Oh, and yes, you did include a link to that preprint ... but not in the post where you replied to my question.

*The only such application?

The claims about gravity, actually the hypothesis, are driven by supernova observations, not the other way around. Specifically the energy distribution in UHEGRs, some of which have been tied to specific supernova events and all of which are difficult to impossible to model using GR constraints upon the kinetic energy molecules relative to the absolute speed of light.

The latest round of gamma ray evidence makes one of the few 'possible' mechanisms for gamma ray generation virtually impossible: gamma ray beaming. The irony is that I think there are many more direct and important evidences of unusual gravity than unexplainable gamma ray events.

But that just begs the question: I have been wrong about many things. So what? Newton died believing in spontanious generation and transmutation.

Look at the evidence: We see much more luminous supernova today that were thought to exist just ten years ago. This has cosmological implications. It does not matter who says so. The interpretations need to be revisited.

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jwj

It's a big universe out there...is it really unwinding, really burning out?

We all know any deviation of the laws of physics from what has been established has to be either extremely small, or have such wide implications that the puzzle we are looking at is very distorted. This is true of all the solutions that require more than three + time dimensions; but is is even more true of any three dimensional solution.

If someone has a hypothesis that requires fundamental flaws in well- established laws, it is reasonable to assume specific tests must be performed to expose these flaws. However, a nullifying test of a prediction of an established theory should also count as evidence of a fundamental flaw, whether there is or is not a competing theories on the table. Also, any test that appeared to rule-out alternatives, which has proven to be less definitive as more evidence emerges should be highlighted as an area for rigorous investigation. The recent increase in both the range of absolute magnitudes of supernova and supernova light curves requires a reexamination of 'proven' concepts: Such as the Wilson hypothesis.

As an asside, your are correct, if there is a formal definition of 'local space' in the cosmic world. I was using the term, in one case, as a loose reference of space we have explored, and in another as space limited to just beyond where the Hubble flow becomes significant in terms of magnitude(z~0.06).

Getting back to my main point: New theories often require new tests, not just examination of old ones that were not specifically designed to test an alternative theory. No amount of mathematical manipulation involving existing data may justify a new theory if all of the degrees of freedom have not been properly controlled.

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jwj

It's a big universe out there...is it really unwinding, really burning out?

Locally, GR effects are rarely an issue (they are small, relative to other errors); but the GR effects were very important in determining the location of the Hipparcos satellite in a Lagrange orbit.

At that time, Hipparcos gave us the best absolute references for the distance and proper motion of stars within our galaxy. However there have been several papers published since then that indicate the originally published error-estimates in the Hippocratus catalogue were too tight.

Astrometrics are extremely difficult. There was difficulty with the guidance system for Hipparcos, so it is not too alarming that the errors bands are wider than expected. Once again, it is not possible to ascertain whether local space is different from what is expected using GR calculations.

Sandstrom's corrections are important, because any time you shorten the local frame of reference - reduce the distance to nearby galaxies, you have to assume that either the local galaxies are less luminous, or the attenuating effects of intervening matter are greater than previously calculated.

Extrapolating to a cosmic sample, if the measured attentuation is greater locally than prior estimates, attenuation may be greater on a cosmic scale as well. This would in turn imply that the most distant supernova we are seeing are also more attenuated and therefore (possibly) much brighter than current estimates.

Supernova researchers looking at these issues argue that, if this is in-fact true, the 'Dark Energy' acceleration is actually much greater than that which has already been measured; so they sometimes dismiss this argument as being moot. However, if the most distant supernova are super-bright events, there is no agreement between dark energy estimates when WMAP, supernova and other techiques are compared with each other. If attenuation (due to gases and dust) is greater locally, it is more likely the attenuation is also greater on a cosmic scale, so the most distant events could be brighter than currently calculated.

If the most distant supernova are as luminous, or greater, than the brightest of the local sample, there is no agreement in the different methods used to calculate the dark energy content of the universe. This either indicates a systemic failure in the data reduction algorythms or a flaw in the theory. Or both.

There is another snag:

Cosmic estimates of dusts and gas extinction are based upon both the local experience, and the differential spectra of supernova (comparing wavelengths that are attenuated by dust with wavelengths that are not).

General relativistic corrections are thought to mimick dust extinction on a cosmic scale. If the extinction factor for dust-and-such is greater locally, it may also be greater on a cosmic scale. If extinction levels are greater than current estimates, there is not enough 'dust budget' left in the measured differential spectra of redshifted supernova to allow for general relativistic extinction.

The 'dust extinction problem' is perhaps the greatest dilemma facing supernova researchers at this time. In surveys looking for supernova in redshifted space, a much smaller sample of distant supernova are being found than expected, using local estimates of the number of supernovae that should be found. This is evidence of greater extinction than expected, based upon analysis of supernova spectra, after corrections for relativistic effects. You will hear more about this in the future.

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jwj

It's a big universe out there...is it really unwinding, really burning out?

I'll reply at greater length later; this is just to record my astonishment ...

Jerry, if gravity behaves so badly within just a few thousand, to a few hundred million km, of the Earth (according to you*), surely every astronomical observation is, potentially, off by -2 to >2 OOMs (1% to a factor of hundreds)?

If so, then surely the only consistent comment you, Jerry, can make about any astronomical observation, is that no scientific analysis (or interpretation) can be done (or made) ... at all?

... unless and until the extent to which GR is incorporated (directly or indirectly) in the observations is fully identified (first), characterised (second), and quantified (last).

Put this another way ... 'gravity behaving badly' introduces a systematic uncertainty into all astronomical observations ... without a handle on the nature of the systematic, all of astronomy is reduced to pure empiricism (or worse) ...

(to be continued)

*At least, that's what I think you have been saying, in at least hundreds, if not thousands, of posts here in BAUT.

It is only within the last 10 years that the Hubble Constant has been narrowed down to a few percent - there was a raging debate for decades, with the 'Hubble constant' calculated to be anywhere from 58 - 100 kms/MPs...a constant that we are now told is likely variable. It is not unreasonable to suspect that systemic errors in data reduction still exist.

Even if one assumes Dark Matter does not exist, the gravimetric force is so small relative to other electromagnetic forces that many of the other observational tools we are using would only be marginally impacted. This includes supernova events.

Likewise, even if the luminosities determined in the evaluation of distant supernovae are off by two orders of magnitude, the spectral information we gleam is still valid, and supernovae remain valuable standard candles. I am arguing that when we quantify supernovae luminosities, we should be seeing the same range of magnitudes in distant events that we are observing locally. Isn't this exactly consistent with the cosmological principle that you are accusing me of eschewing?

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jwj

It's a big universe out there...is it really unwinding, really burning out?

Why must you distort the views of the science? The Hubble constant was always the current value of a function. No matter what, every cosmologist who believed in the Big Bang theory believed that we would see a deviation from the standard Hubble behaviour as we looked at more distant stars.
What is the evidence for this claim again? Looking just at the Permutter et al. 1999 ApJ paper, they actually demonstrate that they were seeing the same range of magnitudes in distant events. They actually run their numbers without any stretch factor correction at all and still get roughly the same results.

Virtually every cosmologist who believed in the big bang also expected the supernova magnitude data to show evidence of slowing expansion: The issue was was whether-or-not the Hubble expansion rate was slowing enough to lead to an eventual contraction of the universe; or slowing so slow that the universe would always continue to expand: Would gravity overtake the big bang or not? It is not a 'distorted view' to imply that the results were opposite of what was anticipated.

In 1999, I didn't have any issues with Perlmutter's analysis. Now, we have observational evidence of at least a half dozen 'nearly local' supernova events that are brighter than the brightest estimates in Perlmutter's sample. This strange half-dozen 'supernova' have very long light curves, longer than any lightcurves we have observed in redshifted space.

It is no longer safe to assume that the most distant events are not more like these brightest events the we have observed locally. It does not matter how they are classified, or if you call them supernova or bossanova: Correct application of the Wilson hypothesis requires that if we cannot find REDSHIFTED events with very long light curves, as long as the light curves of these very bright events that we observe locally; the length corrections, applied due to time dilation, may be artificially shrinking the length of redshifted light curves.

Viewed from this prospective, Perlmutter's 1999 paper doesn't contain any evidence of observational bias, but it should: The most distant events discovered in Perlmutter should be brighter, on average, than the local sample, and they should also have longer light curves.

Now that the magnitude and lightcurve range has expanded locally, Perlmutter has unwittingly demonstrated that the observational bias that should exist but doesn't, might be offset by the time dilation correction. Without this correction factor, the more distant supernova light curves are longer, and therefore dominated by brighter events, as they should be.

You can argue that there is not a large enough sample of overly-bright supernova events observed locally to reach this conclusion, but unless we start observing 'hypernovae' events in redshifted space, with very long light curves, the observational data are turning in this direction.

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jwj

It's a big universe out there...is it really unwinding, really burning out?

This is definitely true. I remember attending a talk by Adam Riess in which he explicitly stated that their intention was to measure the deceleration of the universe. In his title he had the word "deceleration" crossed-out and "acceleration" written over it.

But that is not what you wrote. You wrote, "a constant that we are now told is likely variable." To me, this seems like a smear.

'A constant' was inaccurate, just as 'local' was used ambiguously. This is not a simple topic, and trying to keep it as simple as possible can lead to confusion.

It is not a smear to state that the astrophycal community has reversed itself in the past - it happens. Neither is it a personal attack to argue the community is generally wrong in the way some data is being handled, based upon failing assumptions. You can look at the results of the supernova magnitude studies many ways. One way is to conclude there must be 'dark energy'. Another way is to look very closely at the way the data is being reduced and argue "there may be systemic errors here, the fundamental assumptions do not seem to be consistent with our observations".

We shouldn't be seeing 'local' supernova-like events that are brighter by more than two orders of magnitude than we initially thought could occur; and not also concluding that the most distant events we observe are highly populated/contaminated with these extremely luminous events. (A few local events that are extremely bright should translate to many observations at great distance.) Adam Riess and Saul Perlmutter could not have known that in 1996, but they do now. The data reduction methods they are using, that seem to indicate the most distant events are of rather ordinary magnitudes, are flawed.

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jwj

It's a big universe out there...is it really unwinding, really burning out?

Every book I've read on the topic states that they DID look very closely at the data and tried to imagine how there could be systemic errors.

Why not? The brightness of Type II events depends largely on the mass of the star. There is a very wide range of masses for stars.

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

Yes they were. Which is why I think unexpected physics are needed to explain why there were no selection effects. (It is quite unusual to agree that a researcher has been very thorough, but disagree strongly with the conclusion.)

Because with a hydrogen envelope still present, the mass should be sufficient to re-establish gravametric constraint upon the central engine. In this case, even though there was a hydrogen envelope, the central event was powerful enough to blow everything apart. I have seen conflicted reports on whether the spectral distribution inside the hydrogen envelope is 'Ia' like, but in any case, it was not thought larger central masses than the canon 1.4 solar mass would result in a super-brilliant supernova event. Since one did, many could. What is not known is what range of magnitudes and SEDs these 'total explosions' are limited to. Could it happen at a 1.6 solar mass with no hydrogen envelope? if it could, the absolute supernova type Ia magnitude scale is suspect.

Perhaps a more likely scenario is that binary stars are involved, or the alignment of the explosive charge within the star is less than spherical. In any case, once the potential for a wide range of detonation scenarios to exists is proven to exist, it is no longer reasonable to assume we have a good handle on the absolute magnitudes of these events. Selection bias is inevitable if it is assumed otherwise. This is precisely what happened when the magnitude of distant Cephieds was grossly underestimated. (The original Hubble distance scale was way to small.)

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jwj

It's a big universe out there...is it really unwinding, really burning out?

http://arxiv.org/PS_cache/arxiv/pdf/...707.1024v1.pdf

A THREE-DIMENSIONAL DEFLAGRATION MODEL FOR TYPE IA SUPERNOVAE CONFRONTED WITH OBSERVATIONS

RÖPKE, HILLEBRANDT, SCHMIDT, NIEMEYER, BLINNIKOV, MAZZALI

I am impressed with the amount of effort that goes into trying to create these simulations, and especially impressed by how close the results agrees with the early spectra. Does this mean that if you start with the theoretically driven mass for a type Ia (1.4 Solar); you can't get what we have been assuming are Chandrasahkar mass-limited explosions? Would it help to start with a pair of white dwarfs? Or an asymmetric event?

__________________
jwj

It's a big universe out there...is it really unwinding, really burning out?