http://arxiv.org/PS_cache/arxiv/pdf/...705.4467v1.pdf

SN 2005hj: Evidence for Two Classes of Normal-Bright SNe Ia and Implications for Cosmology

In addition, Middleditch recently restated his merger arguments:

http://arxiv.org/PS_cache/arxiv/pdf/...705.3846v1.pdf

'Dark Energy' cosmology is based upon the the assumption that all supernovae 'type Ia' are the result of a white dwarf detonation at a critical mass. The variations in polarity of light during supernova expansions; and the variations in the light curve decay rates as characterized in Quimby, throw significant doubt upon this optomistic assumption.

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jwj

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

Dark energy cosmology is based on the phenomenology of the supernovae, not the mechanism of their origin. Just like with quasars, their usefulness is not limited by the lack of a physical model for the production of the phenomena associated with the observations.

The introuction of multiple classes of supernovae may just bolster the dark energy cosmology, as there has been recently been suspicion of an unknown systematic error in the data. (Authored by Reiss et al., I can't remember the details of citation right now.)

No, the characterization of supernova type Ia as rigid standard candles is based upon the assumption that this is a special type of explosion, a white dwarf star that has increased to a specific mass and detonated. We are accumulating more and more evidence that this may not be a valid assumption.

This is only true as long as the classes of supernova can be carefully discriminated at high redshift, and placed in the same magnitude range as their low redshift analogs.

All of the conclusions about dark energy (and even time dilation) are based upon these assumptions. The Quimby paper provides good evidence that using the lightcurve/width relationship to calibrate the magnitude range of type Ia supernova is problematic.

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jwj

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

More evidence for LCDM here:

http://xxx.adelaide.edu.au/abs/0706.0033

Note the results are independent of the Sn Ia data.

Well, you can make the claim all you want, but the white dwarf explosion is only a candidate to explain the regularity. Perhaps you could point us to a SNIa paper that makes the strong claim you are suggesting?
Great. If this leads to better ability to discriminate at distance, this may eliminate some of the discrepancies that are seen in the SNIa observations. This could be the beginning of great days for the LCDM model.

There they go using that word "Detection".

No Dark Energy was "Detected"!!!

Next they will be coming up with a pretty Blue (Oh wait, blue is CDM...they better use another color) Picture of it and its 'detected', 'observed' distribution, so more people can be confused, because only the experts can really know what's really going on.

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

No, this is obviously your own mis-interpretation of the abstract where they clearly say they "detect the effects" of dark energy, not that they detect dark energy.

Well, actually they said, "[We] detect the effects of dark energy on the distances to the clusters at ~99.99% confidence." That's a fairly confident detection.

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

Matt.o: "Note the results are independent of the Sn Ia data." Thanks Matt.o.

Indeed, LCDM is a coherent (many lines of evidence point to it; e.g. Matt.o's independence point), relatively simple (6 parameters as opposed to the dozens in some cosmologies), and elegant description of the Universe that has been arrived at through painstakingly careful analyses AFTER the rejection of numerous other theories. It is probably "correct" in the sense that a thousand years from now scientists will still be using a refined version of it to write a biography of our Universe just as today we use a refined version of Eratosthenes determination of the size and shape of the Earth when we study the planet.

On the other hand, if in the small chance that Jerry is correct that LCDM is flat out (no pun intended) wrong, then the cosmology community will eventually concur with him at least on this much. Still, I think Jerry's accusation that most cosmologists just ignore alternative theories and suppress evidence is misleading. Jerry reveals that he is a poor historian when he makes such an accusation. For example, Ned Wright, a cosmologist Jerry has vociferously attacked before, was reluctant to give up the idea of a matter dominated flat Universe during the late 1990s. Neil Cornish, a finite Universe supporter, upon not finding evidence for a finite Universe, gave up the idea and said: "We're disappointed because we favoured the small-Universe idea," says Cornish. "But I guess you've just got to take the Universe you're given." Countless other examples exist, but since Jerry's game is doubting, let's play it: I seriously doubt Jerry would make such an admission if his own cosmology ideas turn out to be wrong or, more likely, if his ideas about other people being wrong end up being, well, wrong. So, ironically, one of his central criticisms is actually most applicable to himself.

See Arny - Explorations in Stars, Galaxies and Planets, McGraw-Hill, 2002; or any contemporary text on basic astronomy

http://en.wikipedia.org/wiki/Supernova
http://arxiv.org/PS_cache/astro-ph/p.../9512171v1.pdf

http://arxiv.org/PS_cache/astro-ph/p.../9806396v1.pdf

http://arxiv.org/PS_cache/astro-ph/p.../9805201v1.pdf

http://arxiv.org/PS_cache/astro-ph/p.../0303428v1.pdf

Like many branches in astronomy, there is far less certainty today than there was ten years ago.

The 1.4mass(solar) criteria for a white dwarf explosion is the primary justification for the assumption that the expected range of supernova type Ia magnitudes is extremely tight at cosmic distances. Any colliding binary scenario, (rather than mass accretion to a fixed mass), cannot possibly produce the tight range of magnitudes that are now assigned to the supernova Ia class.

Supernova data reduction algorythms used today assume that there is no magnitude bias in the distant sample. We should know by now this is an invalid assumption if the range of magnitudes observed locally is greater than the range of magnitudes assigned to the most distant events. This is exactly the current situation: None of the most distant events are considered to be as bright as the brightest of the local sample.

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jwj

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

Let's look at those sources. Clearly wikipedia is right out, and I can't accept introductory texts and popular accounts as sources on this matter. Reiss et al. and Permutter et al. seem to go out of their way to mention the hypothetical nature of the white dwarf explanation. The Garnavich et al. exception may never have made it to print and the paper does not rely on the mechanism of the supernovae.

Your quote from Wheeler is entirely disengenuous, as it is the beginning of a passage pointing out exactly my point earlier. I'll quote the passage more completely, with the author's original emphasis.
Wheeler, with his emphasis on the word, "know," is clearly chastizing those in the community who accept the identification of SNIa with binary explosions invovling white dwarfs, even though he is probably a member of this group.

We might be able to advance the science of these observations with a better science of white dwarfs. However, I am sure that Huygens and Leibniz thought that they could improve upon Newtonian mechanics with a better theory of the vortex of particles. If one wants to attack the science of the SNIa observations, one should do it on the basis of the evidence actually used. Hypotheses on the nature of SNIa play little actual role in the science.

Just how much variation in SN Ia intensity could be achieved by variations in spin rate (rotation rate) of the w dwarf? And if it can't, what would the presumed mechanism be for the variation in Ia intensities?

If I may offer some observations, based on a significant number of months of reading, carefully, Jerry's posts in BAUT and its predecessors.

"Disingenuous" implies that we have access to Jerry's own motivations; I feel that, since the public records of his posts is the only thing we have to use as evidence, we cannot reliably make conclusions about his motives.

What we can do, however, is look at how well a more thorough, more careful read of the sources Jerry cites aligns with the conclusions, or implications, Jerry makes from such sources.

In this regard, my impression is that what you found wrt Wheeler is, sadly, rather common.

Putting this another way: based solely on his track record, here in BAUT, of the accuracy and pertinence of citations to the (nearly always ATM) point he is making, you are very likely to find that the cases Jerry makes are weak, inconsistent, wrong, flawed, ...

While I've not done a formal statistical analysis, I shouldn't be at all surprised to learn, if such an analysis were done, that you have a better than even chance of being able to show pretty much the opposite of the case Jerry makes, by doing nothing other than carefully and thoroughly reading the papers he cites (and directly related references).

Is my post too convoluted? Would anyone care to try to pithily summarise it in plain English?

This quote is directly from the abstract

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

Granted, although I think it is a bit silly to dismiss the paper based on that since the previous sentence in the abstract clearly states they detect the effects of DE, no? They are very careful throughout the paper in their wording (I assume you have read the paper?) and the paper is very thorough. Perhaps you could come up with something better than a semantics argument?

Fair point, but it is also the point I was trying to make - The explosion of a white dwarf is the textbook explanation for a type Ia supernova. On the one hand Perlmutter and Reiss mention the exact nature of the beast is not known, on the other hand, they procede with data reduction that assumes that they do understand exactly what is happening, including using a single parametric for scaling the light curve width and magnitude relationship. There are other parameters to play with: velocity, polarity, light curve shapes (sometimes one hump, and sometimes two). It is the assumption that they are operating on a single star with a predictable mass and a single explosive mechanism that allows them to ignore these other parametrics while determining cosmic parameters. I don't think it is good science to ignore the humps.

I disagree with you completely on this. Reiss & Company have always operated upon the premise that the family of events that produce a type Ia are tightly constrained. They have assumed (or rather demonstrated locally) that the magnitude (in blue) produces the most consistent magnitude estimates when comparing local supernova events. They are also assuming these are NOT binary explosion events, which would require an evaluation of the viewing angle prospective in order to nail down the light curve width and magnitude relationship.

The difficulty is, and always will be, direct comparison between redshifted events and local events. Locally we know that the supernova lightcurve length is proportional to the magnitude. We also know there are a very few oddball supernova that are much brighter and have very similar spectra (Ic). We know that the magnitude/light curve relationship does not hold for these very powerful events - they may have very long to short light curves.

All supernova cosmology is based upon the hypothesis that the most distant events we are recording are more like the narrowly defined local sample, and none of them fit in the Ic hypernova category, as observed locally. If instead, the distant sample is dominated by brighter events, the whole Hubble magnitude relationship is completely chard.

Look at the alternative case: Assuming the distant events are more like hypernova. The single observation of a true hypernova at cosmic distances would be much brighter, nullifying the hypothesis. I am waiting to see this event, but until we do, I am of the opinion that an assumption that the most distant events we do observe represent the brightest of the local sample represents the most objective science; while the assumption that the most distant events are representative of the average magnitude found in the local supernova sample is seriously flawed: Current supernova cosmology is based upon the exploding white dwarf hypothesis, and a curious notion that we have not seen ANY very distant, very bright explosions.

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jwj

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

Like everyone, my world-view distorts the way I look at the facts, or in Ned Wright’s words I have “deep rooted misconceptions”. I work hard to nullify my own positions, and my ‘best position’ has changed many times: I am not satisfied that anyone has good answers.

Cosmologies are based upon optimistic assumptions. What I see is a scientific community that has eliminated too many options, boxing itself into an endless corner. I interpret the evidence in a way that indicates to me that it is going to take more than baby steps to find a way out. I hope I am having a positive effect in this regard: Convincing others that they should take many steps backward and look for fundamental flaws. But if it sounds like I am screaming conspiracy, I’m making too much noise. Scientist may have deep rooted misconceptions, but IMO astrophysicists are rarely motivated by something other than a search for fundamental truths.

Since this is already off topic, may I refer everyone to Pamala Gay's impassion plea to creationist to quit vilifying scientists who defend evolution? The long and worthless challenge by fundamentalists puts all scientific inquiries on the defensive and retards the legitimate search for good answers, answers that are consistent with the observational data.

http://www.starstryder.com/2007/06/0...nce-and-tears/

Thank you, Pamala...and Fraser.

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jwj

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

Cougar. I agree. I know you're a professional reviewer. 99.99% confidence levels are high enough to bet the homestead on. But, when Larry Sulak published that identical confidence level with regards to supernova 1987a, and the neutrino /gravitational wave coincidences....it was dismissed out of hand as an aberration. I guess that must come under the ...(Some are more equal than others...)... clause in physics.

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

Non-radiative hydrodynamical "simulations"...and

"Numerical Simulations"

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

As far as I know, Cougar is not a professional reviewer, and this would disagree with that 99%, or any other % for that matter.

http://scholar.google.com/scholar?nu...ronero+fractal

And just for clarity, if you read these, you will see there is a huge difference between 'statistical analysis' and Numerical "SIMS" or any other kind of "SIMS"!

And Pietronero identifies and thoroughly analysizes a 'built in' homogeneity in most of the 'statistical anylasis' that have been done.

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

Nope, not good enough. Care to elaborate?

Love it!

99+% is meaningless in any cosmological scenario. All cosmologies are based upon fundamental, unqualified assumptions. Detection of 'dark energy' at any level of convidence always means the oberservations to not agree with expected results, based upon underlying assumptions about how we should observe matter at the fringe of the observable universe. Bad initial assumptions will lead to misplaced confidence in statisitically quantified solutions.

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jwj

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

Yet again Jerry is making more "all" and "always" generalizations about cosmology and cosmologists. Clearly, Jerry's world-view is one of radical skepticism and a lack of confidence that, as he puts it, "anyone has good answers." However, "all" and "always" statements are bold and non-trivial and are rarely ever found in the cosmology papers that the "reluctant cosmologist" so often criticizes. In fact, the majority of astrophysics papers mention that there could be some unaccounted for possibility which deserves further investigation using better data and/or f/u analyses. Jerry says he is not convinced that anyone has good explanations, but he offers criticisms (which are explanations in their own right--that is, explanations of why others are wrong), which make use of not assumption free scientific data, which he assumes are valid in post after post. As usual, he wants to have it both ways!

Jerry attempts to have it both ways in that he holds two mutually incompatible world-views, radical skepticism and a belief in the scientific method. He occasionally makes use of the scientific method to attack Big Bang cosmology and buttress his own views (albeit more often the former). Therefore, he must belief, at least to some extent, in the scientific method-- the very method the people he spends so much time criticizing use.

Since Jerry is bold, here is a test for Jerry. Some South African politicians and their bought scientists have denied the link between HIV and AIDS using the same radical ATM skepticism that Jerry uses when it comes to cosmology. But I seriously doubt they would agree to put there money where their mouth is which in my test case would mean agreeing to receive a blood-transfusion from an infected individual. I doubt most of these HIV skeptics would agree to such a transfusion even given their radical rhetoric. So, I tried to think of a cosmology version of this test case for Jerry. Here it is: Jerry is a big CMB basher/skeptic-- he does not believe that differences in the density of matter early in the Universe's history gave rise to the voids and galaxy superclusters we observe in the more recent Universe. Jerry, since you and believe this, would you be willing to take you and your family back in time in an unprotected wooden structure (you should be okay with time travel because you are such an ATM aficionado) to the time when the CMB was generated? Correct me if I am wrong, and maybe you are also skeptical of this (since skepticism is your gig), but wood burns at a temperature well below 3000K.

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.

Supernova researchers make many assumptions: The most important is that the most distant sample of supernova have the same magnitude distrubution as local supernova type Ia. 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 Goldhabers curves and see zero magnitude bias with increasing distance, I am forced to conclude [because I believe Goldhaber is not misrepresenting his data], that one or more of the parametric assumptions Goldhaber 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 sand.

So I will state it again: Given the broad range of supernova magnitudes and light curves we observe locally, it is not scientifically acceptable to assign all of the most distant supernova magnitude estimates to a subluminous subset of the local population.

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jwj

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

The assumption is that there is a small intrinsic dispersion among these events and that some of that dispersion can be accounted for by the light-curve shape. Some of the evidence about differences in dispersion has effectively reduced the dispersion because it has made the light-curve correction more efficient.

Do any of these new results increase the dispersion of absolute magnitudes more than the 10% that was originally documented? Do any of them have any effect on the determination of a cosmological constant term?
I'm not sure what you mean by this. Having looked at the Goldhaber et al. 2001 ApJ paper, there seems to be no basis for your claim here. Is there some other paper to which you are referring?
Where are you getting this from? The intrinsic dispersion available to these events is pretty small. How "subluminous" do you think these distant events are?

While I don't necessarily disagree with anything here, I would like to point to one rather annoying, or amusing, foible quite obvious in many of Jerry's posts, and to raise an implication of the apparent approach Jerry takes that has piqued my curiosity for some time.

The foible: bald, black&white statements supposedly based on reliable sources (published papers in relevant, peer-reviewed journals) that turn out, on investigation* to be outrageously, riotously, hilariously, infuriatingly, ... wrong. And does Jerry change his behaviour, based on having so many of his diatribes shown to be so disconnected with the actual research findings/approaches/whatever? No! ... that's part of the charm.

The implication: intense scepticism of mainstream theories, and the extent to which observations provide support for them, or not ... yep, that's our Jerry.

But how even-handed is this radical scepticism? Do we see Jerry posting at length in ATM threads (other than those promoting his own ideas), with choice quotes from papers by Arp (for example), skewering published Arpian theories? Or outpourings of incredulity concerning the methods, analyses, conclusions, etc of papers which find the CMB to be, maybe, local?

It gets worse.

If mainstream astrophysics must be questioned, and challenged, from its very foundations, then pray tell Jerry, where are your broadsides against modern telescopes, instruments, and space probes? After all, as you well know, no modern astronomer actually looks through the eyepiece of a telescope! Everything in all the papers is the result of the application of a vast range of applied physics (and computer science, and statistics, and ...), all built on the very same foundations that you are strident in insisting must not be accepted.

If you can't swallow the *conclusions* of papers by the high-z supernova search team (to take just one example), why aren't you choking on the unwarranted assumptions buried deep in the bones of the telescopes, detectors, data pipelines, etc the team used to make their so-called observations in the first place?

*which may be nothing more than reading the paragraph the quote is from, or may require much more work.

A lot of use realized that back on January 14, 2005, when the Huygens probe ignominiously crashed into Titan due to the variable G problems Jerry had written about.

What a shame that such a wonderful science mission came to such an disastrous end!

BTW, IIRC, there were also predictions from the same source that the Cassini probe itself would meet with catastrophe due to variable G. I know that, as someone who worked on Cassini's RTGs, such a catastrophe was almost unbearable.

Oh well.

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A person's name, or a mark representing it, as signed personally or by deputy, as in subscribing a letter or other document.

Just checking some of the seminal papers on SN Ia use. In Hamuy et al. 1996, AJ 112, 2391, the results of the study of SN Ia at lower redshift indicate that galxies with younger stellar populations have brighter events. This would seem to indicate that we would expect to find brighter SN Ia the further back that we looked.

Thank you - this is what I have been saying.

I don’t think the most distant of supernovae is subluminal. I think it is contaminated with, and in fact dominated by, the more luminous family of supernova observed locally and classified as type Ic hypernovae in the local sample. There is some very fine hair splitting in separating type Ic hypernovae and ‘textbook type Ia’ locally. (Very often the Ic are first identified as being Ia, but as the light curve develops more slowly, they are moved into the Ic class.) I think that the distant sample of supernova classified as type Ia are dominated by these much brighter events with very long light curves.

Goldhaber 2001 is considered a seminal paper: It establishes that the light curve width / magnitude relationship over a wide redshift interval. Goldhaber demonstrated this by using a single parameter, the stretch factor, to directly correlate magnitude with light curve width. They then tested the sanity of the method by plotting the variation in the stretch factor across all redshifts, and concluded the small residuals and random distribution found in the residuals validated the single parametric assumption – the stretch factor.

This methodology is not sound, because they normalize the sample about the mid point- a redshift of =0.48. Normalizing about the mid point will get you into trouble if the distribution has unexpected biases. In this case, that would be true if and only if the distribution of supernova at high redshift that we happen to observe are naturally more brilliant than the local sample…which they should be, because at great distances we are more likely to sort out the most brilliant events.

Brilliant scientist sometimes make brillant mistakes.

As far as the Huygens probe goes, it was two years before the mission scientist released the fact that the most significant radar bytes are 'randomly corrupted', and they have not been able to reconciliate the calculated descent profile with the radar data. I cannot find any papers or raw data from the sonar. They also, for the first time, to my knowledge, recently stated that the radial accelometers only capture a few moments of the descent, and the rotational rate was calculated using very iffy radio polarization data that was not characterized before the mission. Add to this, again, to my knowledge, they have never released the results of the VLA triangulation. So all of the data that might have supported my argument - including the A channel doppler wind data, is non-existant. I said the Huygens probe would likely fail, but if the probe did succeed, then the data returned from the descent would be very different from what was expected.

There is only a fraction of the video expected, and mission scientists concluded that the probe rotated backwards during most of the descent - opposite the aerodynamic design (hence the failure of the rotary accelerometers). If flying backward is not unusual, if utter failure of two radar systems is not unusual, if bi-directional shifts in wind speed that are proportional to altitude, and a surface with the consistancy of sand are not different from what was expected, then what could possibly be considered abnormal?

There is much about the Saturn system that is making little if any sense. especially not the surface of Titan. It is time to look for basic failures in our reasoning. Could anything be more exciting?

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jwj

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

No, you have been saying that there is some special class of supernovae that aren't actually type Ia. The actual paper shows that among the sample observed in the Calan/Tololo group, the SNe Ia, nicely behaving according to the light-curve width to peak magnitude relationship, were found amongst younger populations.

This doesn't mean that this is what was actually found later or that there is some separate class of SNe further out. I'm still waiting for you to establish either claim.

If the bright novae from the Hamuy et al. (1995/1996) studies are your basis for identifying these bright SNe, then it appears that they follwo the same relationship between light-curve and peak brightness that allows these events to be used as candles.
So, you are saying that the distant supernova are different enough, in just the right way, that the differences in their their light-curves exactly cancel out the time-delay and the brightness differences when normalized at a redshift of 0.48. In addition we have the unlucky circumstance that Goldhaber et al. happened to pick this magic redshift number.