Lambda-CDM theory - Woo or not?

[Tubbythin]

No, in fact your collective actions in this thread as it relates to "dark matter" conclusively demonstrate a preference for protecting your dark sky religion, over a preference for empirical physics.

I don't have a sky religion. So you are plainly talking utter rubbish.

It's quite clear from your subjective choices that you have no desire to "fix" your metaphysical kludge,

I don't have a metaphysical kludge. Once again you are talking utter crap.

instead you consistently and collectively select a path that A) protects your sky religion, and B) attacks the individual rather than dealing the the issues.

I don't have a sky religion. Stop making stuff up. It is a sign of someone who cannot make a reasoned argument.

You have NEVER shown any physical cause/effect connection between "acceleration" and your mythical dark sky energy entities. You have mathematical fallacies that defy the laws of physics, that's it.

What are you talking about? I don't have any mythical dark sky energy entities. What we have is the Einstein Field equations which are very very good at describing experimental data. It just so happens they describe the experimental data the best if one of the constants in the equations is non-zero. Since there is no reason (other than aesthetics I suppose) to suppose that this cosmological constant should be 0, I really cannot comprehend your stance.

Show me ANY experiment where "space" did any expanding in the lab?

No. Do you believe that the Universe was designed so that all aspects of it should be measurable on a scale of human convenience? I sure as hell do not. And if this is not the case then there is no reason whatsoever that space expansion should be demonstrable on a lab scale. I can only conclude that either you think the universe was designed for human convenience (in which case your babbling about others alleged sky entities is utterly hypocritical) or you are demanding something totally irrelevant due either as a distraction tactic or due to a complete inability to comprehend really basic things like scale.

Yes, you are correct. Yes, as a skeptic of your religion, I subjectively and consciously chose a "solution" that minimized the need for "dark sky gods". You folks consistently chose a path to protect you dark sky religion.

Nope. You introduced religion to the debate. Nobody else. You're the one that seems to be demanding that science can only be observed on scales practical to humans, lifting humans from inconsequential observers of the Universe to privaleged beings. And you have the temerity to suggest it is others that are invoking religion! Staggering.

 

[Tubbythin]

Michael, the cosmological constant has been around since the very beginning of GR - 1920 or so (I forget the exact date). For most of the period since then cosmological data was imprecise enough that it was consistent with CC=0. As of about 12 years ago (did you see the Nobel prize in physics announcement today?) the data was no longer consistent with CC=0. Therefore, in the standard cosmological model, the CC is not zero.

Can you please explain to me what it is that bothers you about that? I really cannot understand your viewpoint. The story with the CC is exactly the same as with any other parameter in any model in physics - you fit it to data, and then you have a theory, and then you can make pre- or post-dictions that might or might not be consistent with other pieces of data. And as I've told you many times, this has basically nothing to do with Guth or inflation - that's a whole different story.

I'd like to add that it is no more magical than G or e or any other constant you choose to measure other than it's a bit more difficult to measure.

 

[W.D.Clinger]

By applying Michael Mozina's extraordinarily versatile technique for proving that things don't exist, I conclude that Michael Mozina doesn't exist and can safely be ignored.

FYI, the empirical difference is that I actually show up in the lab, whereas your invisible and/or dead sky entities do not.

Sorry, but I just went through the lab and you weren't there.

Seriously: When did you ever show up in a lab? Can you give us a citation or other evidence?

 

[edd]

Sorry, but I just went through the lab and you weren't there.

Seriously: When did you ever show up in a lab? Can you give us a citation or other evidence?

Pretty unlikely. I mean, have you ever met an ethics committee?

 

[Michael Mozina]

And yet I've written a number of posts trying to explain to you (in hopefully fairly basic terms) aspects of, for example, neutrino physics, nuclear physics and basic details of the standard model.

Sorry. You've been gone awhile. Out of sight, out of mind you know. I gave ben a pass, and I'll happily give you one too, if you would be so kind as to set RC straight over the electrical discharges in plasma issue.

 

[Michael Mozina]

Michael, the cosmological constant has been around since the very beginning of GR - 1920 or so (I forget the exact date).

Ya, but that doesn't give me the right to stuff magic energy into that constant does it? Having a "constant" that you believe somehow relates to expansion (as opposed to redshift) is one thing. Claiming that "dark energy did it" is quite another.

For most of the period since then cosmological data was imprecise enough that it was consistent with CC=0. As of about 12 years ago (did you see the Nobel prize in physics announcement today?) the data was no longer consistent with CC=0. Therefore, in the standard cosmological model, the CC is not zero.

Can you please explain to me what it is that bothers you about that? I really cannot understand your viewpoint. The story with the CC is exactly the same as with any other parameter in any model in physics - you fit it to data, and then you have a theory, and then you can make pre- or post-dictions that might or might not be consistent with other pieces of data.

Nobel or not, the association of "dark energy" to that constant is highly dubious IMO. It's one thing to see a pattern of acceleration in the data. It's another thing to make the claim that "dark energy did it". Again, from my perspective at least they are TWO different issues. Even if I grant you that expansion and acceleration are valid interpretations of the redshift data (as I believe they are), "dark energy did it" is still a metaphysical kludge. When did you ever see "space" do any expanding in an empirical test of concept? Where do I get some "dark energy" to be sure it has the "properties" it would need to explain that acceleration?

And as I've told you many times, this has basically nothing to do with Guth or inflation - that's a whole different story.

I realize it's a whole different story, but it's another "whole different metaphysical negative pressure in a vacuum story" that I have to buy into, hook line and sinker, to even start to buy into your concepts about the age of the universe.

 

[Tubbythin]

Ya, but that doesn't give me the right to stuff magic energy into that constant does it?

Nobody has.

Having a "constant" that you believe somehow relates to expansion (as opposed to redshift) is one thing. Claiming that "dark energy did it" is quite another.

I'm not meaning to be insulting here, but I think you have this exactly backwards. I'll try to explain...
The accelerating expansion of the Universe has been observed. This is perfectly consistent (so far) with the idea of a non-zero cosmological constant. So the interests of parsimony, this is the most popular view. But it is not definitively known to be correct. Therefore, to avoid unnecessary backtracking in the future, a more generic term is proposed: "dark energy". Nobody is stuffing any magical properties into dark energy. All they are doing is suggesting possible properties of it that are consistent with the data. So saying dark energy did it is a LESS strong claim than claiming the cosmological constant did it! Thus rejection of all dark energy solutions is a clear rejection of a none zero cosmological constant. In other words, rejection of dark energy means rejection of the simplest solution consistent with the data. The non-zero cc solutions are a subset of the dark energy solutions, not the other way round.

Nobel or not, the association of "dark energy" to that constant is highly dubious IMO. It's one thing to see a pattern of acceleration in the data. It's another thing to make the claim that "dark energy did it". Again, from my perspective at least they are TWO different issues. Even if I grant you that expansion and acceleration are valid interpretations of the redshift data (as I believe they are), "dark energy did it" is still a metaphysical kludge. When did you ever see "space" do any expanding in an empirical test of concept? Where do I get some "dark energy" to be sure it has the "properties" it would need to explain that acceleration?

A cosmological constant of the right sign and magnitude does exactly that. That's what Einstein's equations tell us. By definition a non-zero cosmological constant implies dark energy.

I realize it's a whole different story, but it's another "whole different metaphysical negative pressure in a vacuum story" that I have to buy into, hook line and sinker, to even start to buy into your concepts about the age of the universe.

No it isn't. It's a "a constant we thought had one value actually has a different value when we measure it more precisely" story. I bet that if we measured G more precisely you wouldn't reject that result?

 

[sol invictus]

Ya, but that doesn't give me the right to stuff magic energy into that constant does it? Having a "constant" that you believe somehow relates to expansion (as opposed to redshift) is one thing. Claiming that "dark energy did it" is quite another.

I literally have no idea what you're talking about.

"Dark energy" is just a term for whatever is leading to the acceleration. A cosmological constant is one form of dark energy.

Nobel or not, the association of "dark energy" to that constant is highly dubious IMO. It's one thing to see a pattern of acceleration in the data. It's another thing to make the claim that "dark energy did it".

You're not getting it. It's like this. Observations indicate that the universe's expansion is accelerating. That is consistent with a positive CC. It is not consistent with zero CC (at least not in GR with only ordinary matter around). Therefore, the best-fit GR model include a positive CC plus matter plus radiation plus neutrinos. That theory makes many predictions for other measurements, quite a few of which were later confirmed.

That's it. End of story. No magic, no gods, no Guth, no mysterious dark energy other than the same old CC that's been part of the theory since 1920 or so.

I realize it's a whole different story, but it's another "whole different metaphysical negative pressure in a vacuum story" that I have to buy into, hook line and sinker, to even start to buy into your concepts about the age of the universe.

Inflation lasted a tiny fraction of a second. The age of the universe doesn't in any way depend on whether or not it happened.

 

[Michael Mozina]

I literally have no idea what you're talking about.

"Dark energy" is just a term for whatever is leading to the acceleration. A cosmological constant is one form of dark energy.

Let's try a little role reversal here to see if you can put yourself in my shoes. Image me telling you that "magic/God energy" is a term for whatever is leading to the acceleration. Further I claim that a cosmological constant is one form of "magic/God energy".

Do you accept that premise?

 

[sol invictus]

Let's try a little role reversal here to see if you can put yourself in my shoes. Image me telling you that "magic/God energy" is a term for whatever is leading to the acceleration. Further I claim that a cosmological constant is one form of "magic/God energy".

Do you accept that premise?

I think it's a stupid and misleading term, but it's just a term. So, OK.

Is your point simply that you don't like the term "dark energy"?

 

[Michael Mozina]

I think it's a stupid and misleading term, but it's just a term. So, OK.

Is your point simply that you don't like the term "dark energy"?

So if I tell you that "God energy" and "God matter" makes up 96 percent of the universe, that's ok by you too?

 

[Michael Mozina]

I think it's a stupid and misleading term,

FYI, that's my beef in a nutshell. If you called it "acceleration", that implies no "cause". It's the moment you associate "cause" and objectify that "cause" with a stupid name that I cry fowl. I see nothing useful in adding the term "dark energy' to the observation of acceleration anymore than you see logic in my associating that same observation with magic or with God.

 

[sol invictus]

So if I tell you that "God energy" and "God matter" makes up 96 percent of the universe, that's ok by you too?

As I said above:

"I think it's a stupid and misleading term, but it's just a term."

FYI, that's my beef in a nutshell. If you called it "acceleration", that implies no "cause". It's the moment you associate "cause" and objectify that "cause" with a stupid name that I cry fowl. I see nothing useful in adding the term "dark energy' to the observation of acceleration anymore than you see logic in my associating that same observation with magic or with God.

It does have a cause, Michael - in GR, the cause is the cosmological constant. If the CC is zero, no acceleration. If it's non-zero, there's an acceleration with magnitude set by the value of the CC (plus the density of matter and radiation).

That was the whole point of my last five posts.

 

[temporalillusion]

Sean Carroll likes the term "smooth tension" rather than dark energy.

He posted a Q and A today that is relevant I think:

http://blogs.discovermagazine.com/cosmicvariance/2011/10/04/dark-energy-faq/

 

[Michael Mozina]

As I said above:

"I think it's a stupid and misleading term, but it's just a term."

It's only a term until you start claiming that 71 percent of the universe is made of "God energy" or "magic energy". Now you've taken a simple observation of acceleration and turned it into a "religion".

It does have a cause, Michael. In GR, the cause is the cosmological constant.

That constant isn't a "cause" anymore than any constant in any formula is a PHYSICAL CAUSE sol. There is a physical cause, I'm sure we both agree, but whatever the empirical physical cause of acceleration might be, it's not caused by a constant in a math formula! It's not caused by "magic energy" either. It's not caused by anything that cannot otherwise be shown to exist and have an empirical material effect on objects with mass.

If the CC is zero, no acceleration. If it's non-zero, there's an acceleration with magnitude set by the value of the CC (plus the density of matter and radiation).

I'm not debating how it works, I'm debating WHY it works, and HOW it works and the CAUSE of what we observe, not the math formulas themselves. Nobody doubts that the constant exists in the math formula. Nobody doubts we can set it to a variety of values. Nobody has shown that "dark energy" has any right being stuffed into those formulas anymore than I have shown that God energy or magic energy deserves to be stuffed in there.

 

[sol invictus]

It's only a term until you start claiming that 71 percent of the universe is made of "God energy" or "magic energy". Now you've taken a simple observation of acceleration and turned it into a "religion".

Huh?

That constant isn't a "cause" anymore than any constant in any formula is a PHYSICAL CAUSE sol. There is a physical cause, I'm sure we both agree, but whatever the empirical physical cause of acceleration might be, it's not caused by a constant in a math formula! It's not cause by "magic energy" either. It's not cause by anything that cannot otherwise be shown to exist and have an material effect on objects with mass.

What?

Did you understand anything I said in my last six posts or so?

I'm not debating how it works, I'm debating WHY it works, and HOW it works and the CAUSE of what we observe, not the math formulas themselves. Nobody doubts that the constant exists in the math formula. Nobody doubts we can set it to a variety of values. Nobody has shown that "dark energy" has any right being stuffed into those formulas anymore than I have shown that God energy or magic energy deserves to be stuffed in there.

That quite literally makes no sense whatsoever. It contradicts itself. The constant you refer to is dark energy.

As far as I can tell, Michael, you're so ideologically opposed to this that you're incapable of maintaining any kind of coherent conversation about it, let alone thinking about it rationally. So I don't think there's any point in continuing.

 

[ben m]

Let's try a little role reversal here to see if you can put yourself in my shoes. Image me telling you that "magic/God energy" is a term for whatever is leading to the acceleration. Further I claim that a cosmological constant is one form of "magic/God energy".

Is that what you're doing? That would be a great improvement over what you've been doing in the past.

a) You'd be agreeing that the cosmological data are well-explained by some sort of acceleration.

b) You'd be agreeing that something other than baryons, attractive gravity, and normal baryonic physics was needed to explain the observations.

c) You'd be agreeing that it was possible to learn new physics---even at as vague a level as "there's some sort of extra acceleration out there"---using precision cosmology data, without being able to isolate this phenomenon in a late-20th century Earth lab experiment.

None of which you have been willing to do elsewhere.

So: sure, call it whatever idiotic thing you want. Science is about the hypothesis/data comparisons, not about the names you attach to the hypotheses. If you get to the point that you're willing to write down the "God energy" hypothesis, state that the God energy hypothesis is that the large-scale structure of spacetime is mathematically like GR but with the "Lambda" constant renamed "God Energy"---yes, that hypothesis (with God energy = 0.7 omegac) is consistent with the data, and therefore passes all present observational tests.

Your "God energy" hypothesis is now about thirty years ahead of the EU/PC hypothesis.

 

[Reality Check]

It's only a term until you start claiming that 71 percent of the universe is made of "God energy" or "magic energy". Now you've taken a simple observation of acceleration and turned it into a "religion".

MM, no one execpt you talks about "God energy" or "magic energy".
It is you who is taking a simple observation of acceleration and turned it into a "religion".

ETA To be more exact, displaying the delusion that changing the term used for something to include 'God' or 'magic' makes that thing religious.

On the tiny, tiny chance that you will finally understand the science:
Scientists took the simple observation of acceleration. They looked at the properties that any cause of that observation would have

• does not emit light.
• acts like an energy.

Thus they called the cause of the simple observation of acceleration: dark energy.

The next step in the scientific process is to look for a hypothesis to explain the empirical data.
The simplest hypothesis is a non-zero cosmological constant. This is within our known physics.
We can go to more speculative theories such as Quintessence (physics).
We can even look at replacements for General Relativity that do not need a non-zero cosmological constant to explain dark energy, e.g. f(R) theories.

That constant isn't a "cause" anymore than any constant in any formula is a PHYSICAL CAUSE sol.

In GR a non-zero cosmological constant is an obvious CAUSE of dark energy.

The PHYSICAL CAUSE is that it may turn out that the universe makes a volume of space have some intrinsic, fundamental energy. This is no stranger than the universe making a particle have some intrinsic, fundamental angular momentum (spin).

 

[Michael Mozina]

The constant you refer to is dark energy.

When you can accept that this statement of yours is a "statement of faith" on your part, and it's one that I don't share with you, then it's probably worth trying to continue. As long as you continue to insist that some a constant in a math formula is a physical "cause", I don't think we'll ever see eye to eye. Thanks for trying, but I just do not agree with you. It is just a constant in a math formula. The "cause" of any sort of acceleration is something completely different from that constant in terms of physics. We both agree that there is a physical cause and a physical reason for acceleration. I just think that the statement "dark energy did it" is a combo of logical fallacies, specifically a non-sequitur and an affirming the consequent fallacy. There's no empirical link between acceleration of matter and magic energy or dark energy.

 

[Michael Mozina]

Is that what you're doing? That would be a great improvement over what you've been doing in the past.

a) You'd be agreeing that the cosmological data are well-explained by some sort of acceleration.

I've never had a problem with that concept, just the concept "God/dark energy did it".

b) You'd be agreeing that something other than baryons, attractive gravity, and normal baryonic physics was needed to explain the observations.

Not really. You'll have to leave off that whole baryonic limitation you imposed.

I'm not even convinced that dark energy is even warranted after discovering that galaxies are twice as bright as first predicted. It seems to me that the whole technique is predicted on outdated data! Secondly, the only force of nature I know of that MIGHT cause plasma to accelerate is a rather "ordinary" field.

c) You'd be agreeing that it was possible to learn new physics---even at as vague a level as "there's some sort of extra acceleration out there"---using precision cosmology data, without being able to isolate this phenomenon in a late-20th century Earth lab experiment.

Ya, but then all I did is throw up my hands and claim "God did it". That hardly sounds like "new physics" to a skeptic. It sounds like more of the same human ignorance to me.

So: sure, call it whatever idiotic thing you want. Science is about the hypothesis/data comparisons, not about the names you attach to the hypotheses. If you get to the point that you're willing to write down the "God energy" hypothesis, state that the God energy hypothesis is that the large-scale structure of spacetime is mathematically like GR but with the "Lambda" constant renamed "God Energy"---yes, that hypothesis (with God energy = 0.7 omegac) is consistent with the data, and therefore passes all present observational tests.

Your "God energy" hypothesis is now about thirty years ahead of the EU/PC hypothesis.

Which only demonstrates that anyone can create a religion that fits your criteria. It's much harder to do it with actual empirical physics.