• Quick note - the problem with Youtube videos not embedding on the forum appears to have been fixed, thanks to ZiprHead. If you do still see problems let me know.

Lambda-CDM theory - Woo or not?

Status
Not open for further replies.
Michael Mozina said:
No, but there was nothing about "physics in general" that requires the existence of any form of exotic matter and you don't seem the least bit willing to rethink your position even after it failed a major 'test'?

Er no. Inflation is "dead". It no longer exists in nature even if we belief you that it once did exist in nature. It cannot ever be demonstrated 'empirically' because you killed it.

Dark energy isn't "measurable" here in the solar system according to your theory, so it too is beyond our ability to ever "test". It's evidently really shy around anything that is gravitationally bound, and humans, well, we're gravitation bound to pretty much everything we get close to. :(

That leaves us with only one thing that might actually show up in a real science experiment here on Earth, your "dark matter" friend. Unfortunately for you, he too has been a "no show" to date. In fact all SUSY theories have so far failed to show up in the lab. So where now does that leave you in terms of empirical physics?

How would you suggest we even go about trying to test dark energy here on Earth?
Click to expand...

Michael Mozina said:
I wouldn't be inclined to simply "throw it out" anymore than you threw out the BB theory based on SN data. I wouldn't however be inclined to simply stuff it full of ad hoc nonsense just to make it fit.

All it tells me is that the model needs work. It doesn't justify my stuffing it full of "metaphysical baggage" just to hammer out a decent fit!

I don't have to "pretend" anything. If it's the 'best' empirical option that I have to work with at the moment without resorting to "pretend entities", I suppose I'll have to live with it for the time being. If however it can be tweaked to fit the observations more closely, without interjecting metaphysics, then it's certainly worth modifying the model.

That solar wind and those million degree loops tell me it's right. I know it's right because that has actually been "lab tested".
Click to expand...

Michael Mozina said:
Nothing goes "bang" without inflation ben. No 'bang", no "background". You're ignoring the question because you don't like the implication of the question.

But ben, if something didn't put the "bang" in the big bang theory, you wouldn't have anything to look at in the first place!

You guys are the ones that cannot even seem to agree on anything. You can't blame me for simple confusion when even DRD doesn't seem to buy the whole inflation thing.

It's logically impossible to test for a dead and gone (inflation) deity in the present moment regardless of your budget! How would we even test "dark energy' ben if it's shy around anything and everything that is gravitationally bound? You've created *IMPOSSIBLE* things to even test for in the present moment. When your theory does fail (like the DM test), do you even acknowledge it?
Click to expand...

Michael Mozina said:
Since we could say the same thing about the topic of God, how exactly does your "science" differ from religion Tim?
Click to expand...


You clearly intend a meaning different than the common usage for the words and phrases you put in quote marks, so please provide your definitions for those quoted and double quoted terms from your comments above that I've added to the list below. (There are others included from previous comments, also.) Until you can define these terms, what you wrote above is incoherent rambling. Thanks.

  • act of faith
  • ad hoc
  • background
  • ballpark
  • bang
  • believer
  • best
  • better
  • caught on
  • correct
  • creativity
  • dark energy
  • dark matter
  • dead
  • decent
  • discovery
  • emotional
  • empirically
  • flavors
  • hairy inflation
  • in the ballpark
  • inflation
  • invented
  • lab tested
  • logically impossible
  • measurable
  • metaphysical baggage
  • narrow the range
  • negative pressure
  • no show
  • physics in general
  • postdicted
  • postdicting a fit
  • predicted
  • pretend
  • pretend entities
  • properties
  • put faith
  • religion
  • ruled in
  • science
  • sciences
  • superiority
  • test
  • throw it out
  • tweak
  • tweaked
  • tweaked to fit
  • unseen
  • unusual
  • verification
  • verify
  • woo
 
Tim Thompson said:
On the contrary, dark energy is firmly rooted in the known laws of physics,....
Click to expand...

Which laws Tim? You made it up!

First, dark energy is constrained by observation, which makes it empirical.
Click to expand...

No, "acceleration" is constrained by observation Tim. Acceleration is empirical. "Dark energy" is a myth and unrelated to "acceleration" in any empirical manner.

Second, dark energy is constrained by the fundamental laws of physics, by which I mean, for example, that it must conserve energy & momentum
Click to expand...

It does neither!

and obey the laws of thermodynamics, just like everything else.
Click to expand...

Thermodynamics? How in the world did you demonstrate any link between "dark energy" and "thermodynamics'?????

Dark energy is no more "magical" than is gravity;
Click to expand...

False. Gravity has a real tangible effect on experiments on Earth. Dark energy does not. It's a giant no show in the lab, whereas gravity shows up in the lab every time.
 
Michael Mozina said:
Massive objects can somehow "expand" away from each other at faster than the speed of light. No specific prediction actually allows us to falsify anything related to your theory. That's really what makes it "woo". There's no logical foundation for any of it, and no logical way to falsify [it]
Click to expand...
I think you're referring to the GR-based prediction of an expanding universe.

One of ben's recent posts reminded me that a direct, empirical observation of the expansion of space is, indeed, at an early stage of planning (it involves some clever observations of high-z quasars, using the E-ELT, over a ten year period). An upscale version of the same thing would also provide direct, empirical evidence of DE, at considerably lower cost than ben's proposed method.

If I provide you with a reference, do you promise to read it? And ask questions about the bits you don't understand? And having read, and understood, it, do you promise to cease posting nonsense about the logical impossibility of falsifying DE?
 
Michael Mozina said:
I wouldn't be inclined to simply "throw it out" anymore than you threw out the BB theory based on SN data. I wouldn't however be inclined to simply stuff it full of ad hoc nonsense just to make it fit.
Click to expand...

We DID throw out the "BB theory with no DE" which was gradually disproven by the high-precision data. The modern "BB theory with DE"---exactly one extra parameter, whose value is 10^-29 g/cc---is in perfect agreement with all the data.

All it tells me is that the model needs work. It doesn't justify my stuffing it full of "metaphysical baggage" just to hammer out a decent fit!
Click to expand...

So get to work. Go back to the woodshed, if indeed you've ever been there, and figure it out. "A decent fit" is not a luxury---a correct model must produce a fit much better than vaguely "decent" it must describe the data within the error bars. A poor fit means your model is wrong.

Your model is wrong. Don't tell us that you hope for it a future tweaked model to be right---just put out the model. If you were serious about this at all, you'd log off this (and all other) discussion boards, and we wouldn't hear a peep from you until you put a paper up on the ArXiV containing the PC/EU equations that allow you to fit the Hubble curve, the CMB temperature/blackbody spectrum, and the CMB angular anisotropy spectrum. Go do it; stop promising that it'll be perfect when it's done; just do it.
 
DeiRenDopa said:
I think you're referring to the GR-based prediction of an expanding universe.

One of ben's recent posts reminded me that a direct, empirical observation of the expansion of space is, indeed, at an early stage of planning (it involves some clever observations of high-z quasars, using the E-ELT, over a ten year period). An upscale version of the same thing would also provide direct, empirical evidence of DE, at considerably lower cost than ben's proposed method.

If I provide you with a reference, do you promise to read it? And ask questions about the bits you don't understand? And having read, and understood, it, do you promise to cease posting nonsense about the logical impossibility of falsifying DE?
Click to expand...

I'll be happy to read it. I'm still trying to figure out how ben's proposed method isn't a "dark energy of the gaps" argument in the final analysis. It seems to be predicated on excluding all other known options, but doesn't actually demonstrate a direct cause/effect relationship between "Dark energy" and "acceleration". I don't see the empirical cause/effect connection between "observed acceleration" and "dark energy" in ben's proposal.
 
Michael Mozina said:
No, "acceleration" is constrained by observation Tim. Acceleration is empirical. "Dark energy" is a myth and unrelated to "acceleration" in any empirical manner.
Click to expand...
Untrue. The Einstein field equationsWP imply quantitative relationships between acceleration and mass/energy. Those relationships have been tested by a variety of astronomical observations.

That is why, when we see more acceleration than can be accounted for by the mass/energy we see, it is reasonable to hypothesize that some form of mass/energy we can't see is causing the acceleration.

It's a reasonable hypothesis. You don't believe in it, so you call it a myth, but that's a statement of your beliefs rather than an argument.
 
Last edited:
Michael Mozina said:
No, "acceleration" is constrained by observation Tim. Acceleration is empirical.
Click to expand...
Hold on!

Acceleration, of the 'that's what observations of high-z supernovae show' kind is only empirical within the framework of the collective body of most of contemporary physics ... great swathes of which you reject!

Trying to have your cake and eat it too, MM?

Second, dark energy is constrained by the fundamental laws of physics, by which I mean, for example, that it must conserve energy & momentum
Click to expand...
It does neither!
Click to expand...
Pretend I'm from Missouri, the 'Show me' state; show me (that it does not conserve energy, and that it does not conserve momentum).

Dark energy is no more "magical" than is gravity;
Click to expand...
False. Gravity has a real tangible effect on experiments on Earth. Dark energy does not. It's a giant no show in the lab
Click to expand...
How would you know?

You've never even thought about how to perform such an experiment, have you?

From whence comes your apparent absolute certainty about what future experiments might show? What magic gives you insight into the workings of the universe, an insight that trumps all future experimentation?
 
Last edited:
DeiRenDopa said:
Cite?


Almost certainly (but let's see your evidence).
Click to expand...

I doubt I could find the conversation again without spending all day on it. As I recall it had something to do with quintessence?, but I could be mistaken. I will simply accept that I was wrong if you actually believe in inflation.

I do find it a little amusing that you need me to cite something for you to to be sure that I misquoted you. :)

If I misquoted you, I apologize.
 
Michael Mozina said:
I'm still trying to figure out how ben's proposed method isn't a "dark energy of the gaps" argument in the final analysis. It seems to be predicated on excluding all other known options, but doesn't actually demonstrate a direct cause/effect relationship between "Dark energy" and "acceleration". I don't see the empirical cause/effect connection between "observed acceleration" and "dark energy" in ben's proposal.
Click to expand...
And I will make this prediction: you never will, until you understand things like negative pressure (e.g. Casimir effect), how the Hubble relationship is derivable from GR, how the recently published Reyes et al. test of GR works, and how the recent Chu et al. lab-based test of GR works.

Or, to say it another way, until you trade in your Aristotelian physics glasses for Newtonian ones.
 
Michael Mozina said:
I doubt I could find the conversation again without spending all day on it. As I recall it had something to do with quintessence?, but I could be mistaken. I will simply accept that I was wrong if you actually believe in inflation.

I do find it a little amusing that you need me to cite something for you to to be sure that I misquoted you. :)

If I misquoted you, I apologize.
Click to expand...
I am impressed by your response, thank you Michael.

However, I think you may have misunderstood whatever it is I wrote anyway.

You see, "do you believe in inflation?" (or "do you believe in "inflation"?" has, logically, more than the two answers "yes" and "no". My shortest answer would be something like "it's a meaningless question"; a slightly longer one might be something like "from what I have read, so far, the observational evidence is consistent with inflation", with the giant caveat that we'd need to spend some time making sure we both had the same understanding of what inflation refers to; it's a giant caveat because I doubt that we do, and think it unlikely that we ever could ... inflation - my understanding of it - requires that you view the world with Newtonian physics glasses, but it seems yours are of the Aristotelian kind.
 
Michael Mozina said:
I'll be happy to read it. I'm still trying to figure out how ben's proposed method isn't a "dark energy of the gaps" argument in the final analysis. It seems to be predicated on excluding all other known options, but doesn't actually demonstrate a direct cause/effect relationship between "Dark energy" and "acceleration". I don't see the empirical cause/effect connection between "observed acceleration" and "dark energy" in ben's proposal.
Click to expand...

You are confused, Michael, as usual. The "lambda" in Lambda-CDM is an extra, constant term in the curvature of spacetime. It is NOT " ... and the curvature comes from a Higgs-like scalar field" or "... and the curvature comes from an extra inflaton" or "... and the curvature is just how the Universe happens to be". The Lambda-CDM hypothesis is that there's a constant curvature there, period.

(If someone were to argue, "I agree that there's curvature there but I disagree that it's a dark energy", that could be an intelligent discussion. I presume you aren't making that argument; you never have. Your argument is more in the "everything is wrong" camp.)

The experiment I describe is sensitive to this type of curvature and to nothing else. You can easily rule out non-curvature-related sources for the acceleration; the relevant test masses are completely shielded from EM forces (read up on LISA, or Gravity Probe B, or STEP, or Eotvos, to see how this can be done). The weak and strong forces don't cause long-range acceleration. If those masses accelerate at all, it's gravity (i.e. curvature) doing it. If lambda-CDM is correct, it predicts that these masses see exactly the same constant-curvature term that astronomers use to fit supernovae/CMB/LSS/etc. That is the only possible prediction; there are no tweaks to Lambda-CDM that could make the satellite's view different from the supernova's view. If the satellites don't do what we expect then the theory is falsified. (What's the PC/EU prediction for the accelerations of a spherical shell of EM-shielded masses?)

As usual, no experiment can prove a theory right. Experiments can prove theories wrong. This experiment could prove lambda-CDM wrong if the results came out one way (and, if the experiment was well-done, we'd have to discard this hypothesis); they could be "consistent with lambda CDM" if they came out another way. JUST LIKE EVERYTHING ELSE IN SCIENCE.

Remember falsification, Michael? YOU insisted that Lambda-CDM was "logically" impossible to test. You were wrong. It's expensive and impractical to test. I am still waiting for your justification for why the Universe would refuse to include such phenomena, and what's the maximum lab-test-price-tag on laws of physics that the Universe should stoop to obey.
 
Michael Mozina said:
Actually I'd prefer GR without the metaphysics myself, but alas you don't do "real" (as in empirically real) GR anymore. :)
Click to expand...
Heard of the Pound-Rebka experiment MM?

Did you follow the Chu et al. link in my previous post?

Please don a pair of Newtonian physics glasses - the ones you need to conclude that gravity is real - and tell me how these two do not show that GR is "empirically real". But first, what does "empirically real" mean?
 
Michael Mozina said:
IOh joy, I can hardly wait. :) Start with explaining exactly what you intended to add to a perfect vacuum to achieve 'negative pressure". :) You folks always run from that question. Why is that?
Click to expand...
That is just idiotic.
Many people in this forum have tried to explain the physical reality of negative pressure to you (it is measured in Casimir effect experiments!). The fact that you are not intelligent enough or too set in your religious belief that negative pressure does nor exist is you running away not us.
All you have to do to get negative pressure in a perfect vaccuum is to put it between 2 metallic plates.
All you have to do to get negative pressure in the universe is to put a non-zero cosmolgical constant into GR.

But we will not get into this insanity again. We do not want to remind people just just how many weeks it took you to find the standard definition of pressure :eye-poppi.
 
Status
Not open for further replies.

Back
Top Bottom