Split Thread Michael Mozina's thread on Dark Matter, Inflation and Cosmology

[DazzaD]

I don't see how that analogy applies, but I'm fighting a cold today so maybe I not following you very well. Atoms show up in real experiments and I can do things to them. I can even classify them based upon their various properties and weights and there is nothing "unusual" about them from the standpoint of empirical physics with the possible exception of the Higgs particle. Maybe that would be a more appropriate analogy?

I will take this one first.

I am not being flippant but how do you KNOW that atoms exist?

Forget them being the basis of much of modern science... what direct experimental evidence is there for their existence?

This is very very important and something I try to impress upon all my GCSE and A Level students....this is no small matter but hits at the heart of much of what we have discussed on this thread.

 

[phunk]

True, but Birkeland's very first rough calculation of the mass of the universe that was not found in stars was orders of magnitude "greater than" what we actually observe, even with all that "dark matter".

And?

 

[DazzaD]

You can't and I'm not asking you to do so. You can produce electromagnetic emissions on Earth. If you want to say that other objects emit light, you're not adding anything "new" that you can't demonstrate. If however you tell me it emits "magic energy", you've introduced a new variable that requires a physical demonstration of concept. Where does the magic/dark energy come from? Where do I get a gram of "dark matter" to play with in a lab? What's the source of "dark matter" that I might use as a control mechanism somehow in the experiment?



Again, gravity shows up in real empirical experiments on Earth. The analogy is therefore inapplicable.

NO you mentioned it in the context of a "control" (your term not mine) for an experiment.

In that same sense, if you wish to discuss the issue of electromagnetic emissions surely you would have to be able to "control" for that too.

Or gravity?

No? Or did I misunderstand your point about control in that dark matter experiment?

 

[phunk]

But you can't demonstrate such a form of matter even exists. It may not be "dark" at all, but instead those photons may simply be being absorbed or scattered another direction. How do you know that the missing mass doesn't interact with light of the EM field?

An object that absorbs must also emit. And how would all of the energy be scattered away from us no matter what the orientation of the emitting galaxy?

 

[Reality Check]

You can't and I'm not asking you to do so. You can produce electromagnetic emissions on Earth. If you want to say that other objects emit light, you're not adding anything "new" that you can't demonstrate. If however you tell me it emits "magic energy", you've introduced a new variable that requires a physical demonstration of concept. Where does the magic/dark energy come from? Where do I get a gram of "dark matter" to play with in a lab? What's the source of "dark matter" that I might use as a control mechanism somehow in the experiment?

No one says that something emits dark energy - that is a result of your ignorance.
Likewise there is no source of dark matter. If they are SUSY particles then they were created in the conditions of the early universe. If they are exotic particles then they were created in the conditions of the early universe.

The ability to turn off the source of emitted stuff has little effect on an experiment or observation. We cannot turn off solar neutrinos. But we still detect them in neutrinos observatories. We cannot turn off a solar flare but observations of a solar flare still gives valid data.
It is usually desirable to control background sources so that they cannot be confused the signal that is being looked at. That is why there is shielding in neutrinos observatories and dark matter detection experiments.

 

[Reality Check]

As I asked in a previous (of course ignored by MM) post in another thread

Originally Posted by Reality Check

Originally Posted by Michael Mozina
Got a gram of "dark matter"?

Got a gram of quarks?
Got a gram of the Sun's core?
Got a gram of the degenerate matter in a neutron star?
Got a gram of neutrinos?
Got a super massive black hole in your lab?
Got a gram of antimatter? (Fermilab in 20 years of operation has produced about 2.3 billionth of a gram).
Got a gram of W bosons?
Got a gram of quark-gluon plasma?

I really should have mention that fact "exotic matter" is not the leading candidate for dark matter. The leading candidate is SUSY particles. We know that the Standard Model has flaws, e.g. cannot account for the observed neutrino oscillations (evidence for massive neutrinos). The addition of supersymmetry (SUSY) to the standard model is one way to fix its flaws. SUSY has weakly interacting massive particles that are as "exotic" as any other particle, e.g. electrons.

 

[Michael Mozina]

I will take this one first.

I am not being flippant but how do you KNOW that atoms exist?

Well, I can "see" them for one thing:

http://www.ornl.gov/info/press_releases/get_press_release.cfm?ReleaseNumber=mr20040415-00

Forget them being the basis of much of modern science... what direct experimental evidence is there for their existence?

Well, for starters we've got all kinds of imaging techniques that allow us to see them to the individual atom. We know there are different elements and we know what makes each element "different" from another element. Different elements have distinct properties associated with that "type' of element on the periodic table. Different elements emit different patterns of light based on valence shell configurations. I could continue if you like....

Try the Higgs, it's a "better" analogy.

This is very very important and something I try to impress upon all my GCSE and A Level students....this is no small matter but hits at the heart of much of what we have discussed on this thread.

 

[Michael Mozina]

NO you mentioned it in the context of a "control" (your term not mine) for an experiment.

Who asked you to "experiment" with the sun? It wasn't me.

In that same sense, if you wish to discuss the issue of electromagnetic emissions surely you would have to be able to "control" for that too.

True and many devices right here on Earth do exactly that. We can create all sorts of very specific wavelengths from very specific elements. We can create lasers on Earth. Nobody with eyesight has to accept the presence of light on 'faith'

Or gravity?

Add mass and you get gravity. Take it away you remove gravity. The control mechanism for gravity in Newton's case was simply the release of the apple from his fingers. Gravity then manifests itself rather nicely in the present moment.

No? Or did I misunderstand your point about control in that dark matter experiment?

I think you missed my point, but it's likely my own fault. I'm fighting a flue and it's busy at work and I'm not really up to par today. Let's try it another way:

Gravity isn't shy around a lab. We might argue about why gravity attracts other objects of mass or why it bends space, or how it works, but we can absolutely, positively duplicate it's direct effect on experiment after physical experiment. The control mechanism need not be fancy. It can be something as simple as an on off switch in the case of electrical current. It can be something as simple as a release mechanism in the case of gravity. In either case we know the source of the item in question (battery/objects of mass), and we can see it manifest itself before our very eyes in this very moment. We therefore can demonstrate that gravity exists in nature, right now.

Compare that to say "inflation" that is today "non existent" and can *never* have any effect on any physical experiment or have any effect on me personally in this present moment. Whereas gravity and electrical current can even be "experienced" by the observer in the moment, inflation is dead and will forever be a no-show in the lab.

Whereas we can isolate a source of gravity (mass) and a source of photons, what's the "source' of "dark energy"? What's the "source" of "dark matter"? I can control normal matter in an experiment of gravity here on Earth by increasing or decreasing the mass of various objects to see if has some effect on my experiment. How do I get a specific quantity of "dark matter" to play with?

 

[Michael Mozina]

No one says that something emits dark energy - that is a result of your ignorance.
Likewise there is no source of dark matter. If they are SUSY particles then they were created in the conditions of the early universe. If they are exotic particles then they were created in the conditions of the early universe.

If so then your "dark energy" acceleration process should have been fastest at the start and slowed down over time. Care to explain?

 

[Reality Check]

If so then your "dark energy" acceleration process should have been fastest at the start and slowed down over time. Care to explain?

Dark energy has a negative pressure.

 

[Michael Mozina]

And?

And in his model "dark matter" would be located in "flying electrons and flying electric ions of all kinds."

 

[Michael Mozina]

Dark energy has a negative pressure.

Besides the audacity of claiming that anything in space has "negative pressure", your answer doesn't even make sense. If the volume were smaller and the 'negative pressure' was more "condensed' in terms of unit of DE/negative pressure per cubic meter, your whole thing should have *IMPLODED* due to concentration of "negative pressure". Your answer is illogical.

 

[Reality Check]

Besides the stupidity of claiming anything in space has "negative pressure", your answer doesn't even make sense. If the volume were smaller and the 'negative pressure' was more "condensed' in terms of unit of DE/negative pressure per cubic meter, your whole thing should have *IMPLODED* due to concentration of "negative pressure". Your answer is illogical.

Besides the stupidity of you not understanding that negative pressure is standard physics, dark energy is roughly equivalent to a small repulsive component of gravity but the force it exerts does not obey the inverse square law - it varies linearly with distance (increases with distance).

Stanford University has a YouTube series of Professor Leonard Susskind presenting a series of lectures on GR. The second lecture starts with a discussion of dark energy and what it does in everyday situations.

Your answer reveals your ignorance of dark energy.

 

[Michael Mozina]

Let's go down that list of yours shall we?

Got a gram of quarks?

Their existence has been verified via controlled experimentation. Their lack of stability in raw form prohibits me from handing you a gram of them in a bottle, but they show up in the present moment in real "experiments".

Got a gram of the Sun's core?

Unless your trying to claim it's made of something we do not find on the periodic table, that is irrelevant. You aren't introducing anything new that has never been seen on Earth by claiming the sun's core is made of a particular element.

Got a gram of the degenerate matter in a neutron star?

No, but like all the items on your list, neutrons show up in real lab experiments. They aren't dead and impotent in the present moment like your beloved dead inflation deity.

Got a gram of neutrinos?

No, but again, they have a real tangible effect on real objects in real experiments in the present moment and I know where they come from like I know where all the other stuff comes from.

Got a super massive black hole in your lab?

No, but I'm willing to let you scale any known force of nature to any size you like as long as you can demonstrate it exists here on Earth. Since gravity shows up here, I can certainly accept that gravity shows up everywhere that contains mass and more mass will produce more gravity.

Got a gram of antimatter? (Fermilab in 20 years of operation has produced about 2.3 billionth of a gram).

The operative word there is "produced them". They too show up in real labs on Earth. See a pattern here to all these things on your list? All of them related to real things that show up right here, right now on Earth.

Got a gram of W bosons?

Same answer as quarks. So far we're batting 1000 for empirical physics.

Got a gram of quark-gluon plasma?

Ditto for all unstable subatomic components.

The point the reader should note is that RC's list contains things that have all been seen in a lab, with the exception of a black hole.

 

[Tubbythin]

Zero? More than zero, more than 10, more than 100, more than 1000, 10,000, 100,000?

Last time I looked the answer was 0? So?

 

[DeiRenDopa]

Wow, even with MM on IGNORE these are massive threads, maybe the dark posts effect the mass of them.

And as far as I can tell, well over 90% of the posts go over ground that has been covered before, often many times, on older JREF Forum threads ... with the same outcomes.

Question for DazzaD, Perpetual Student, RC, Tubbythin, and Tim Thompson (did I miss anyone?): in your exchanges with MM in this thread, have you learned anything new, in terms of the case MM seems to be trying to make?

If so, what (I'm really quite interested)?

 

[Michael Mozina]

Besides the stupidity of you not understanding that negative pressure is standard physics, dark energy is roughly equivalent to a small repulsive component of gravity

Repulsive component of gravity? Huh? Let's see you jump your way off the planet with that repulsive force you're talking about. What repulsive component of gravity?

Your definition of "negative pressure" is pointless and meaningless in terms of actual physics because no such thing exists in the physical world.

 

[Michael Mozina]

Last time I looked the answer was 0? So?

So we don't even have the technology to see something the size of Earth in our *OWN* galaxy, and you expect me to believe we can account for all the mass in galaxies that are millions of light years if not billions of light years away? Don't you find that the least bit "hard to swallow"?

 

[Tubbythin]

It is possible to turn on and off a source of them.
http://neutrons.ornl.gov/

Right. But you never asked about sources of dark matter.

Yes is does. That cave amounts to "shielding" for the experiment, it's not a "control mechanism" in terms of turning on and off a known source of something, like a reactor was used to turn "on and off" a known/suspected source of neutrinos. What's the known source of "dark matter", and how do I turn it on and off like neutrinos or electron, or protons, or neutrons or photons or anything else that is known to empirically exist in nature? How do I "control" dark matter?

As I explained previously, and you completely ignored, scientific control mechanisms are not, in general, on off switches. Control mechanisms are things that help you to measure one thing by reducing, removing or otherwise accounting for other things that could effect the experiment. Eg, placing the experiments hundreds of metres under ground is a very clear and obvious control mechanism for reducing (by a large factor) the effect plain old boring cosmic rays can have on your experiment. If you do not understand how this is a control mechaism I suggest you go back to your science books from when you were approximately aged ten or so and read through them again.
Much of particle physics in the early 20th century was based around looking at what interesting things happened to pass through your detector. I'm sure I could think of plentiful other examples.

 

[Tubbythin]

Which observation? Not the observation of homogeneity?

CMBR.

The point is that "inflation" came from a human imagination of a single human being, with no previous scientific history of any sort. It's non existent. It was "postdicted" to fit what it fits, and it still being postdicted to fit whatever someone wants it to fit like any handy-dandy metaphysical "Gumby" theory. How handy that it's dead now so we can never "test" any of the "properties" being assigned to Gumbyflation.

Rephrase the above paragraph in the manner of a fully grown adult rather than a kid on his first day in primary school and I might bother to waste my time on a response.