Oh, and for the record: I’m an astronomy grad student. Just started, so unlike certain others here and in the wider community, I don’t have all my eggs in a basket woven of imaginary dark matter.

In fact, interesting spectra have been published,

So why can’t you leave references?

Name-calling aside,

Sorry, no – an identification of what you argue for, denial of verified phenomena like gas behavior.

your argument is that since astronomers refuse to discuss any detail of any alternative to Gravity-Only-Universe, every failure of GOU counts as positive evidence for the only models (GOU+epsilon, GOU+DM/DE) that they are willing to discuss.

I don’t know what you think the standard cosmology and standard particle physics is, but there are more forces than gravity. The remainder of your argument doesn’t describe any of my comments.

Scientists are interested in, you know, observations, particularly the ones that don’t match expectations.

Yes, I would know. And again, that doesn’t change that scientists aren’t interested in ‘answering’ them by question stoppers. The reason that scientists wants tests of theories is because they have predictive theories. Which, you should know, scientists are interested in.

And I note that you consistently refuse to describe your purported “observations, particularly the ones that don’t match expectations”. Instead you continue to describe purported ‘explanations’. It’s the cart before the horse, in typical denialist fashion.

Scientists are interested in, you know, observations, particularly the ones that don’t match expectations. They don’t assume as established fact the previous generation’s idle speculations. A healthy branch of science responds to uncertainty by entertaining multiple hypotheses, and by questioning untested assumptions. Maybe some future generation of astronomers will come around. In the meantime, the present observations are (more or less) safely archived for that future generation’s use.

At some point, if your model needs too many untestable (or, as I stated, circular reasoning) explanations, you might have to at least allow the possibility that you have to start over.

Standard cosmology has 6 free parameters, QM makes IIRC 5-10 assumptions (depending on formalization), standard particle physics has IIRC 26 free parameters. By your measure we could shove in a lot of extraneous baggage before we would consider cosmology a failure.

But in reality it predicts data when no other theory does. So you don’t present a reasonable alternative.

Btw, empirical formal systems are circular, first because they are based on irreducible axioms, second because theories predict their data, a fact that you seem to lament. Such circularities aren’t a problem because, famously, theories are tested before they are accepted.

I find it curious indeed that people tries to assign static truth values to facts, as they are a dynamical property of the process of knowledge gathering. Facts and hypotheses doesn’t have truth values; before observation respectively verification they are in degrees “not known, possible, impossible, likely, unlikely”, and after they are “accepted, rejected”. Formal logic comes up empty in describing this process.

I’m saying that to assume dark matter is not parsimonious.

Parsimony, or any other beauty measure on theories, is irrelevant as long as there isn’t any alternatives. The point with the observation of the Bullet cluster was that it rejected modified gravity theories up to a high significance. I assume the very similar observation of another cluster recently reported confirms this.

So given that only dark matter can explain observations, and that it has been directly tested, these observations give us more detail of the standard cosmology and dark matter itself.

As regards your unsubstantiated speculations on plasmas, it is ironic for three reasons.

First, astronomers like physicists in general likes to term their objects with the behavior exhibited. Thus interstellar plasmas are gases (as AFAIU they can be modeled thus in a first approximation), just as the electrons of a metal is often called a Fermi gas despite that it is actually a Fermi liquid (since it can be modeled as a gas in the first approximation, due to the idiosyncrasies of fermions). Similarly wrapped up branes are still called strings, because they can be modeled thusly – and the list goes on and on.

This is, you should know, what scientists do.

Second, if anything speculations in wide charge imbalances manifesting as currents are not parsimonious since space is (parsimoniously without broken symmetry at that) neutral on large scales.

Now, as DrFlimmer describes here, the ionization – recombination process renders plasmas mostly neutral, so we don’t even need parsimony, we know better. And, I assume, if there were large scale currents you would present observations of statistics of different doppler effects on characteristic spectra from different patches in plasma, but you do not.

Third, AFAIU Phil and other astronomers are a tad sensitive to proposals of magnetic fields. You see, it seems that it is easily used to whip up tentative explanations for anomalies. So it is both a question stopper and a bother to test. Ideal for crackpots btw, in their efforts to cherry pick data to shore up any odd denial of verified phenomena, say dark matter. [To be truthful, in this case: DM is verified, but possibly not universally accepted yet.]

Now seeing you are a denialist I assume you can’t accept what we know of nature. But it is IMO a worthwhile effort to show bystanders why denialism is wrong and why stopping asking questions is harmful to science.

Okay, so your knowledge on the topic comes from Encyclopedia Britannica? I suppose it suffices for a rudimentary understanding. It did help me learn a bit more about about what plasma is and how it behaves, though the article still lacked some of the more specific details that would pertain to this discussion. Still and all, from a basic, layman’s viewpoint, plasma, in an astronomical sense, seems somewhat gas-like: the particles are far apart, are in an agitated state, and expand in a volume, rather than all conforming to a container or droplet, like a liquid would. This may not be an accurate assessment, but, again, to the layperson, it looks like a gas in all those photos of celestial phenomena.

The article in EB mentions that plasma is often considered the fourth state of matter. My questionm then, what are the ionization temperatures for transforming something into plasma? There are specific temperatures at which all elements turn into the various states (e.g., water is solid below 0C and gas above 100C). There is a clearly ordered transition from solid to liquid to gas. Is it only possible, then to turn a gas into plasma? Are there any occasions in which a solid can be turned into a plasma without going through liquid or gas stages, even if for a very small fraction of a second?

Out of curiosity, I also looked up dark matter in the EB, and found this quote:

There is evidence, however, for nonluminous matter—so-called dark matter (see cosmos: Dark matter)—extending out nearly twice this distance. The entire system is rotating such that, at the position of the Sun, the orbital speed is about 220 km per second (almost 500,000 miles per hour) and a complete circuit takes roughly 240 million years. Application of Kepler’s third law leads to an estimate for the galactic mass of about 100 billion solar masses. The rotational velocity can be measured from the Doppler shifts (see Doppler effect) observed in the 21-cm emission line of neutral hydrogen and the lines of millimetre wavelengths from various molecules, especially carbon monoxide. At great distances from the galactic centre, the rotational velocity does not drop off as expected but rather increases slightly. This behaviour appears to require a much larger galactic mass than can be accounted for by the known (luminous) matter. Additional evidence for the presence of dark matter comes from a variety of other observations. The nature and extent of the dark matter (or missing mass) constitutes one of today’s major astronomical puzzles.

So, according to the same source you provided saying that plasma is not a gas, evidence for dark matter does exist. If EB is a solid resource for the “commonplace fact” that plasma is not a gas, then by the same logic, it is also a solid resource for the current evidence for or against dark matter.

http://www.britannica.com/EBchecked/topic/463509/plasma

I’m assuming that your lack of providing any sort of resources with a scientific basis that I can learn from means that you are merely spouting opinion, rather than concepts that have any valid scientific basis whatsoever. What is so difficult about providing links to sources? Where did you come by your ideas, if not by scientific study? What education have you actually had in any field related to your claims?

I ask you for serious information because I have no background in astronomy or any related field, and I’m met with “the sky is blue”? Mr. Myers, whether you believe it or not, I really am interested in learning. You can either provide some links to some scientific literature supporting your claims, or you can continue to act like a troll.

Umm…Wikipedia is not exactly a scientific, scholarly work. So, again, please point me to the scientific studies which prove your points. Thank you.

You are claiming several things:

1) That it is plasma and not gas (and that pkasma is not gas).
2) That this plasma is suffused with E-M energy
3) That it is this plasma that accounts for all of the mass of the universe outside of planet(oid)s.
4) That E-M energy is the major force at work in the universe, rather than gravity (implied in your arguments).

Now, I am not an astronomer, so your statement that the idea of dark matter is absurd really is not “ordinary textbook stuff” for me. What I am asking from you is:

a) Proof that plasma is not a gas. I want studies showing this, not just your word.
b) Proof that the plasma in the universe is suffused with E-M energy, as you describe. Again, studies rather than only your word.
c) Proof that the plasma in the universe accounts for all of the mass of the universe outside of planet(oid)s. Yet again, studies to support your claims.
d) Proof that E-M energy is the dominant force at work in the universe, rather than gravity. If my supposition here is wrong, please correct me, but if not, then show me to the studies that support your contention.

As I was trying to say in my first post to you and the BA, while you may be convinced of all this and it may seem perfectly clear to you that you are right, it isn’t clear at all to me. I have no background in cosmology, so all of these topics are new to me. Show me the evidence. Let me evaluate it as best I can. I expect the same kind of information from the BA, as well.

If a former scientist turned blogger-clown started promoting perpetual motion, and I called him out, what sort of proof would you demand of me?

I’m not really asking you about dark matter. I’m asking you to support your claims regarding the plasma/E-M bit. Rather than continuing to cry out “He’s wrong, he’s wrong,” show us that you are right.

@shane: Wikipedia has “Plasma therefore has properties quite unlike those of solids, liquids or gases and is considered to be a distinct state of matter.” To say, as it also does, that plasma is “an ionized gas” tells you how to get it, but not what it really is. Try it: do “liquid is melted solid” and “liquid is solid” mean the same thing, or is one true and the other false?

I did. A number of dictionaries I looked up say it is gas. So does the wiki for whatever that is worth. BTW Phil didn’t say it was just a gas as Nathan misquotes he said “calling a plasma a gas — which it is”. Subtle difference.

Also, I wouldn’t use a dictionary as the last word for a scientific definition anyway.