PhysBang

Before there were any reports of SNe Ia observations, there were published frameworks about just how to measure the effects of dark energy. A quick glance over any of these papers should reveal the fundamentals of ow to not only measure the effect of the energy, but also how to look for finer measurements on its behaviour, either in the paper itself or in the references of the paper.

In what units? Why don't you repeat your argument in some statistical detail. What is the estimated effect of these local space velocities? What is their estimated impact on the measurements of these events? What is the estimated effect of this lateral motion? What is its estimated impact on the measurements of these events?

It is not unknown to me; indeed, I have it right here. Ellis soon abandoned the paper because there were observable features of the universe that he was not able to reproduce. Take a look at his later work around the same time. Additionally, if you take the time to read Ellis' work, you will find that his model is radically different from your own model. In his model, the cosmological redshift is caused by the gravitational potential between one centre of the universe and the other centre of the universe that our galaxy is located near. I have no idea what analogy you could be drawing. If you are talking about the redshift, the redshift is entirely gravitational. I don't really want to address whether or not Ellis was right on this point (I'm going to be writing on that in a month or two, if I'm lucky), but he isn't right on this point today. There are numerous sky surveys out there to build actual evidence for general, first-approximation, homogeneity of the kind required for the standard cosmological models.

I also like the claim on page 86 that de Sitter wrote that "there cannot be the slightest doubt that Lemaitre's theory is essentially true," Lemaitre's theory, in this context, being the relativistic model (with the cosmological constant/dark energy) used in the standard cosmological model today.

Sorry, which de Sitter universe is this? Is this the one in which de Sitter used the cosmological constant and incorrectly thought was static. The one published in De Sitter, W. (1917) “On the Curvature of Space,” Proceedings of the Section of Sciences, Koninklijke Akademie van Wetenschappen te Amsterdam 20: 229–242? The one that Felix Klein's extension of the metric showed that the model wasn't static? The one with a matter-free universe? The one that has the same dark energy as the current standard cosmological model?

Wheeler was discussing a general, approximate way to describe general rel That is a statement on the nature of the cosmological constant, something known prior to its verification through measurement. This is not the argument that you, and no scientist, presented. Really? You really directly observe gravity? What does it look like? You must have what it takes to be a cosmologist.

Why do you continually make the mistake of identifying the relationship of the SNe Ia redshift with the general geometry of spacetime? One can have a flat spacetime with the observed redshifts; indeed, this is the general conclusion. The supernova results are consistent with a generally flat spacetime, but not a generally flat spacetime based only on the energy density of matter. In the past, cosmologists got sloppy in discussing general curvature and mass energy density, but we muct make this distinction today. This law is not part of contemporary cosmology, except that it is an approximation of the general behaviour of the scale factor. Only in very strange circumstances would there be no deviation from this Hubble law for the high-z supernovae. This doesn't seem to make any sense, if only since there is ample evidence of the third derivative of the scale factor that rules out such a model. You are assuming that the contruction would be like this without any evidence. This is not an argument given for dark energy by the supernova observation teams. To determine more exact properties requires more evidence and the means to gather this evidence are known (which you will learn some details of if you bother to read the paper you provided a link to earlier). There are many different hypotheses to explain this energy density in more detail, but the lack of a detailed mechanism for the energy density is not required for us to believe that it's a real physical entity. We do not know the mechanism for gravity, but we do acknowledge its existence.

What about the extent to which the model fits the data? Indeed, the WMAP year three report you provided a link to reports better data and better parameter constraints from the data. What about the fit to the data of models that do not make those assumptions, as reported in the document you linked to? Did you read that paper? That paper is about distinguishing between an unchanginc cosmological contant and a dark energy with a differnt equation of state such that the energy density that varies over time. This is a paper about distinguishing between types of dark energy, not about dark energy in general. The SNe Ia results support a closed model far more than they support an open model. If you look only at the 1999 paper of the Supernova Cosmology Porject, you will see that the total energy density skews above the critical density. Because of the mathematics of the cosmological constant (or another kind of dark energy), it contributes to the overall geometry of the universe. In a purely Friedmann model, the mass-erergy density of matter is about the only thing to consider for closure, so it is used interchangably for referring to closure. However, it is important to include all energy densities when considering the overall curvature of the universe, because they all play a role. Luckily, the big bang theory had a built in way to tweak its parameters through measurement.

Do you have a source for this claim? Every WMAP publication indicates a determination for the energy density of the cosmological constant. Later publications give a determination for the possible range of the equation of state for a variable energy field that acts as a cosmological constant. Here's some: http://www.sdss.org/news/releases/20031028.powerspectrum.html I can't recall that discrepancy in value, since I don't accept the derivation. Perhaps you'd like to review the original source for that prediction? The standard derivation uses an arbitrary high-frequency cut-off point for the vacuum energy in order to return a finite result. This is fine for a calculation of the Casimir effect, which depends only on the low-frequency modes of the vacuum energy, but needs to be justified for the calculation of vacuum energy density. A convincing model has yet to show why mass density or baryon density is so small. Should we not believe in these energy densities? All we have is measurements of these densities. Why should the demand for a law-like explanation trump actual measurements? This division is accurate if dark energy is actually an energy density and not simply a constant of the Einstein Field Equation. It may be that the vacuum energy of quantum mechanics has not gravitational effect. The cosmological constant still acts as an effective energy density, but that is because of the algebra of the Einstein Field Equation. Given the strength of the effect as measured, we could not expect to detect the impact of dark energy in a lab. Given that the expansion of the universe dilutes other energy densities, we can only expect that the dark energy density was not always the dominant energy density of the universe.

I apologize for my zeal. It is just that science is too often misrepresented as merely the success of the predicted as if theories spring from the mind like Athena. Coldcreation couples this presentation with the false claim that the cosmological constant was entirely unprecedented (though this also contradicts his claims that it was discussed and rejected). His cutting and pasting of that article together is very dishonest, as there are phrases in his quote that do not appear anywhere in the document.

Yes, what you wrote is delusional. I'm not surprised. Scientific American is often a good resource for bad physics. OK, there is no FLRW metric. There is the Robertson-Walker metric. This is used in the Friedmann models. And it is used in the Lemaitre models. (The "F" and the "L".) The Lemaitre models have accelerated expansion. They were developed in the 1920s and studied since then. Some scientists did seriously consider the possibility. The current value for the cosmological constant is very, very low compared to what it could be, so it was not measured in many tests. That it wasn't measured in so many tests (being below the threshold of measurement) could be the reason many scientists though that it was zero. Fantasy that is actually measured in many different ways, yes. You are welcome to your opinion. I'm sure you would rather have an ad hoc explanation that doesn't fit the facts. What are your readers supposed to do when you simply outright lie? You write this crap like the only way to do science is to come up with any crazy idea as long as it has nothing to do with any measurement and then wait until there is a lucky observation. Cosmologists came up with a framework of actually measuring the properties of the universe and then actually measured these properties. WTF is a "linear regime"? The universe may simply be more than you can imagine and comprehend. This was a favoured result, but not one that was predicted. Cosmologists were committed to measuring, not dictating. Not just matched none of the above, but showed systematic results that provided a measurement of cosmological parameters. The predictions made were how to make cosmological measurements. One could also consider the measurements made by one technique to be a prediction. Then one can look at the measurements made by another technique as another prediction. I would be interested to find out just what issue of Scientific American that original quote came from, since it is not the one that modest posted.

If by "mild" you mean "delusional", then yes. Unfortunately, the Scientific American author (if that is really the origin of the quote--there seems to be some typos involved) also makes some basic mistakes in his or her description. The positive value of the cosmological constant was not taken seriously because there was no measurement of it. Now there is a measurement of it, so it is taken seriously.

Except that this description of the history of cosmology is pure fantasy. Lemaitre came up with the mathematics to describe the current model in the 1920s. People had been analyzing the models involved for decades. The change to cosmology did not overturn the majority of previous work in the field and meshed with other empirical tests.

Why don't you read up here: Supernova Cosmology Project I have no idea what units you are talking about, nor what values you are talking about.

The one big reason would be that we don't really know whether or not SNe Ia are white dwarf novas. The basis for the calibration is empirical evidence, not the theory of white dwarf stars. Actually, that's exactly what is given in every paper discussing the cosmological results of SNe Ia observations. That's the point of the observations. They get a measurement of just how much dark energy has influenced the expansion. And, nicely, this amount matches what they get from the details of the CMB!

And so this makes the Big Bang more acceptable?

The problem with the iron whiskers is whether or not they can be fine tuned enough to both produce a homogeneous and blackbody radiation while at the same time preserving the optical depth of the universe.

Ummm.... no.... "CMBR", unless you are using it in some truly bizarre context, stands for cosmic background microwave radiation. This means that it is radiation; in this case the radiation is in the form of photons. Plasma is not radiation. The CMB is in the form of a black-body spectrum, that is, it is a collection of photons that have the same spectral characteristics as if it was emitted from a perfect absorber and re-emitter. Not simple any collection of noise signals can produce such a spectrum unless the noise is very highly (and strangely) correlated.

I'm not sure what you think this has to do with the CMB. The CMB hasn't really interacted with anything, except gravitationally, since it was generated.

If it's got Tatu, I'm in!

I'm not sure what difference this makes, as the change in temperature is entirely due to the same factor that gives rise to redshift.

I'm not sure how much of this story is "untold". The story of the disaster is part of at least one business ethics textbooks.

There is definitely an actual timescale for cosmological events. Physical systems do deviate from this timescale, but as far as the influence of the background radiation and general universal expansion is concerned, there is an identifiable timescale. Now this is a psychological construct just like anything in physics is a psychological construct: if we want to accurately describe the universe, we have to use this timescale.

I'm guessing you mean the singularities in the Big Bang models and the singularities that are supposed to be in black holes. I'm not sure what you mean here. There is a singularity at the "beginning" of almost all Big Bang models. However, most Big Bang theorists don't believe in the singularity. That is, they know that the energies near this singularity are so high that it makes accurate descriptions of this period difficult if not impossible. The real Big Bang theory is a theory about the history of the universe, but not a complete history. But the singularity of the Big Bang theory is a singularity with everything. There is no outside space without mass. All space takes part in the singularity and the era immedieately after the singularity. The black holes themselves don't have all the mass of the universe within them. I don't understand black hole theory very well, but according to the claims of the theory, black holes do not have more mass than they formed with and that they gain over time. In a black hole, there is an increase in density within the universe. The singularity of the Big Bang is a singularity of the entire universe. It may have no beginning as we know it. Singularities are not descriptions of phenomena. They are, by definitions, places in the mathematical framework of a theory where description of physical phenomena is impossible.

I see. So your answer is: you don't like the theory, so you aren't going to learn anything about it, or the currently available data, and you're going to continue to find things that you find confusing and try to confuse other people with these examples. Is this right? This is doubtful, given the mathematics involved. Hunh? The Big Bang theory says that the universe is general to a great deal of approximation, but not entirely. Mike C