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

[PingOfPong]

Wouldn't ice, in a lab, here on Earth, studied by real scientists a la Mozina, have a negative pressure as it melts and contracts? Pressure causes expansion so an implosion should yield a negative pressure.

I suppose pressure is a bit like voltage. Voltage only makes sense as a difference between two points. You may object and say that voltage could be a measurement relative to "true ground" but the fact is that true ground is extremely elusive from a measurement standpoint.

 

[Michael Mozina]

No it isn't. As the Casimir effect quite clearly demonstrates.

Here we go around in circles....

It is clear that you are talking rubbish. For example, Guth got a degree, a master's and his doctorate from one of (if not) the foremost institutions for physics in the world. His PhD thesis was on "was an exploration of an early model of how quarks combine to form the elementary particles that we observe". You, on the other hand, get your research from wikipedia.

Oh ZING! Even I laughed.

You can appeal to authority all you like but there is no physical way in the universe to get "negative pressure' out of a "vacuum". The lowest possible energy state of the vacuum is *ZERO*, not negative infinity.

 

[DazzaD]

That's absurd IMO. The scientific method has always included them. It's only astronomers that seem to have a tough time with the concept of a "control mechanism". It's not my fault you chose to put your faith in things you can't physically do anything with. If I asked you to "control" current flow you could install something like a simple switch to do so. It's only because you can't demonstrate DE or inflation exists, let alone "control" it, that you seem to think *MY* definition of control is "unreasonable". No other branch of science would whine about it.

Hold fire there my friend.

My point is some people in this thread are giving subtly different versions of what they mean by "control" in an experiment which leads to a bit of confusion.

I dont think that point warranted that attack to be fair.

It may also interest you that I teach mathematics, physics and chemistry so I am pretty much aware, in a day to day sense, what we mean by "control" in an experimental sense.

I never said in any way, shape or form your definition was "unreasonable".

That particular debate/disagreement came from Guth's slight of hand where he tried to claim that space had a 'negative pressure". What did you folks propose to add to a "perfect/pure" vacuum to achieve a "negative pressure"?

I misunderstand this bit.

Is it the existence of negative pressure per se that you take issue with?

Or is it the modifying of what you see as a "perfect" vaccum? (which I am sure you are well aware is a misnomer in itself).

 

[Michael Mozina]

Wouldn't ice, in a lab, here on Earth, studied by real scientists a la Mozina, have a negative pressure as it melts and contracts?

Be careful which ideas you try to compare, and be careful about the difference between "relative" and 'absolute". Guth specifically needs "negative pressure" from his "vacuum". That is physically impossible. All "pressure" that the vacuum might contain would point *INWARD*, into his near-singularity thingy. The lowest energy state of the vacuum is zero. It can contain no kinetic energy. A "vacuum" cannot cantain a "negative pressure" of any sort.

 

[Pythonic]

It may also interest you that I teach mathematics...

The use of "negative infinity" must drive you nuts then!

 

[DazzaD]

Pure slanderous BS. From a "math" standpoint it's just a minus sign. Anyone that has learned to add and subtract "understands" the mathematical meaning of a minus sign. It's at the level of real kinetic energy physics where his (your) argument goes to hell in a handbasket.

Just a minus sign? Just?

Does that mean we neednt pay attention to it then?

So I can remove it, from say, Newtonian Gravitation and have gravity be a repulsive force with no serious issues?

Or did I take that out of context?

 

[DazzaD]

Now I'll HAVE to go read some of Bjarne's threads!

I've come across comments in a similar vein several times before (not just wrt MM), and I'm beginning to think that there might be a powerful pedagogical technique here somewhere, one that I don't recall having seen in any teacher training materials.

If there are any educators reading this, would you mind commenting? Specifically, do you know if the sort of exchange that is common in this (and other MM) thread(s) is used in a known teaching methodology (and if so, what)? Lurkers (students) certainly do seem to enjoy reading along, and they also certainly do seem to learn stuff that might otherwise be very hard to learn ...

Oh it can be very useful.

People can watch and see and learn what makes a scientific debate and what is evidence. They can see others asking those "stupid" questions they themselves are too afraid to ask.

They can learn to gauge the responses and learn that some people know a lot but find it hard to communicate it well, some people who dont know much can communicate well and so forth across the spectrum.

It can be a very powerful learning tool, its just damn hard to implement formally and in a planned way!

 

[Dancing David]

Just a minus sign? Just?

Does that mean we neednt pay attention to it then?

So I can remove it, from say, Newtonian Gravitation and have gravity be a repulsive force with no serious issues?

Or did I take that out of context?

Please don't mention the Casmir effect or we will get the arrows and pictures again.

 

[Pythonic]

Please don't mention the Casmir effect or we will get the arrows and pictures again.

Yes! Let's move on. What is exactly wrong with the inflation theory? I get that testing in a lab has proven elusive so far, but, as has been brought up so many times already, so have most things in theoretical physics at one time or another. So, I don't think that's grounds to dismiss it entirely. What is the *theoretical* argument against inflation theory? Where does it breakdown or seem questionable? Isn't it something already measured in the universe? (As a layman, I also get that distant measurements seem fantastic. For example, I've often wondered if the red shift indicating acceleration wasn't also caused by gravitational effects from space debris or just the effect of such a long distance; something else other than acceleration. But since I'm not formally trained in this subject, I'm pretty sure that has either been considered before or is just not relevant. That is, I think it is highly unlikely I'm going to out-think the great thinkers based on so little knowledge.)

 

[DazzaD]

Thanks.

I too went from taking what MM wrote as serious attacks on what I'd been taught, what I'd learned, and what I in turn had taught (and, early on, learned a fair bit about what is essential/fundamental, what is distracting/superfluous, what is easy to explain and what not, etc), to being interested in what makes MM and his ideas tick.

Have you come across anyone similar to MM, here in the Science section of JREF Forum?

Quite a few.

If you look at the few posts I have made on here most have been in replying to similar threads

 

[DazzaD]

Yes! Let's move on. What is exactly wrong with the inflation theory? I get that testing in a lab has proven elusive so far, but, as has been brought up so many times already, so have most things in theoretical physics at one time or another. So, I don't think that's grounds to dismiss it entirely. What is the *theoretical* argument against inflation theory? Where does it breakdown or seem questionable? Isn't it something already measured in the universe? (As a layman, I also get that distant measurements seem fantastic. For example, I've often wondered if the red shift indicating acceleration wasn't also caused by gravitational effects from space debris or just the effect of such a long distance; something else other than acceleration. But since I'm not formally trained in this subject, I'm pretty sure that has either been considered before or is just not relevant. That is, I think it is highly unlikely I'm going to out-think the great thinkers based on so little knowledge.)

No you are quite right to question it.

It has been considered.

It is not as easy to tease apart as some might think.

The overall consensus is that, yes, there is a large residual component that cannot (easily) be explained away without invoking something drastic (e.g. inflation/dark energy)

 

[Michael Mozina]

Just a minus sign? Just?

Does that mean we neednt pay attention to it then?

So I can remove it, from say, Newtonian Gravitation and have gravity be a repulsive force with no serious issues?

Or did I take that out of context?

Maybe a little.

Mathematically speaking, it's implications are clear enough. It's at the level of physics that it becomes just as clear that a "negative pressure" in a "vacuum" is physically impossible.

Anytime we might setup a mathematical formula we have to (correctly) understand and correctly represent the physical limits of what we are attempting to describe. While a "vacuum" could potentially achieve a "zero" energy state, from the level of kinetic energy, a 'vacuum' cannot ever become 'less than zero'. The "mathematical error' that Guth made, is by not setting a correct lower limit boundary condition to zero.

If we simply ignore that "mistake", sure the rest of his "math" related to his mythical 'negative pressure in a vacuum" works out just fine. If however we look at the physics involved in "pressures" in a "vacuum", he used an impossible boundary condition for the possible 'pressure' states in a 'vacuum'.

 

[DazzaD]

The use of "negative infinity" must drive you nuts then!

In the sense that infinity is not a "number"... yes

 

[DazzaD]

Maybe a little.

Mathematically speaking, it's implications are clear enough. It's at the level of physics that it becomes just as clear that a "negative pressure" in a "vacuum" is physically impossible.

Anytime we might setup a mathematical formula we have to (correctly) understand and correctly represent the physical limits of what we are attempting to describe. While a "vacuum" could potentially achieve a "zero" energy state, from the level of kinetic energy, a 'vacuum' cannot ever become 'less than zero'. The "mathematical error' that Guth made, is by not setting a correct lower limit boundary condition to zero.

If we simply ignore that "mistake", sure the rest of his "math" related to his mythical 'negative pressure in a vacuum" works out just fine. If however we look at the physics involved in "pressures" in a "vacuum", he used an impossible boundary condition for the possible 'pressure' states in a 'vacuum'.

Ah this is quite important then.

What is the reasoning for this bottoming out of energy at zero then?

Are we allowed to invoke QM here? (which I believe you are quite happy with).

And what does this "zero" represent exactly? is it a function of a chosen scale (like zero degrees Celsius in temperature) or is it a physical property of a system (more like the Kelvin scale in temperature) or is it a mathematical countable 'thing'?

 

[Michael Mozina]

Yes! Let's move on. What is exactly wrong with the inflation theory?

IMO, everything! It's dead. It's 'made up'. It's mythical. It's metaphysical. It's impossible to empirically demonstrate now and forever. It's faith, not science, and I know the individual that came up with it. Besides the obvious physical warts, nothing much. Other than that, it's mathematically rather attractive.

I get that testing in a lab has proven elusive so far, but, as has been brought up so many times already, so have most things in theoretical physics at one time or another.

The difference is that most theoretical physics (even exotic dark matter theories) have some hope of empirical vindication, if not now, somewhere in time by someone. Inflation however is dead. It's non existent. It has no effect on anything anymore according to standard theory. It's no better IMO than a mythical dead deistic religion in terms of empirical physics in the preset moment. Worse yet, Guth can not ever even hope to empirically validate inflation and thumb his nose at me, not even if we both live to be a billion years old.

So, I don't think that's grounds to dismiss it entirely.

From my skeptical view, there's no reason to consider it anymore than I would consider any other dead deistic "god did it' "explanation".

What is the *theoretical* argument against inflation theory?

Inflation is a figment of a single individual's imagination and become a popular "meme" in a subset of human scientists.

Where does it breakdown or seem questionable?

At the level of empirical physics. It will always and forever remain "unseen" to any and all human beings.

Isn't it something already measured in the universe?

No. Photons are measured. One might say homogeneity is also "measured". Guth developed (postdicted) inflation to match those measurements and it is a highly "subjective interpretation" of those measurements. There is a subtle but important difference.

(As a layman, I also get that distant measurements seem fantastic. For example, I've often wondered if the red shift indicating acceleration wasn't also caused by gravitational effects from space debris or just the effect of such a long distance; something else other than acceleration.

But mainstream will crucify you for "doubting" them on this or any other "interpretation" of those same observations. They will insist you interpret a whole host of subjective assumptions about those measurements their way too sooner or later.

But since I'm not formally trained in this subject, I'm pretty sure that has either been considered before or is just not relevant. That is, I think it is highly unlikely I'm going to out-think the great thinkers based on so little knowledge.)

It's only irrelevant if you *assume* we as a species already have almost everything about the universe all figured out. That's silly IMO. Redshift could be related to something other than expansion, but expansion is a valid empirical "interpretation" of that data. It's not expansion I have trouble with, it's the claim about the "causes" of that expansion I have a beef with.

I do however try to stay open minded about the fact that other 'interpretations' of redshift "could be" just a valid, but I personally do favor an expanding universe over a static one just like the mainstream.

 

[Michael Mozina]

Ah this is quite important then.

What is the reasoning for this bottoming out of energy at zero then?

Are we allowed to invoke QM here? (which I believe you are quite happy with).

And what does this "zero" represent exactly? is it a function of a chosen scale (like zero degrees Celsius in temperature) or is it a physical property of a system (more like the Kelvin scale in temperature) or is it a mathematical countable 'thing'?

It's a "kinetic energy" thing and a "physical" thing in the final analysis. The reason for selecting zero as a 'bottoming out of energy" is directly related to the kinetic energy state of the particles in the vacuum. In other words a 'vacuum" can contain particles that move around and deliver kinetic energy from one place to another. They create "pressure" in the vacuum. When we remove all the particles and subatomic energy from the vacuum, we might achieve a "zero' kinetic energy state, and therefore a zero "pressure" in the "Vacuum", there is no way we can add or subtract anything from that zero state to create a negative kinetic energy state or a 'negative pressure" in the vacuum.

 

[DazzaD]

It's a "kinetic energy" thing and a "physical" thing in the final analysis. The reason for selecting zero as a 'bottoming out of energy" is directly related to the kinetic energy state of the particles in the vacuum. In other words a 'vacuum" can contain particles that move around and deliver kinetic energy from one place to another. They create "pressure" in the vacuum. When we remove all the particles and subatomic energy from the vacuum, we might achieve a "zero' kinetic energy state, and therefore a zero "pressure" in the "Vacuum", there is no way we can add or subtract anything from that zero state to create a negative kinetic energy state or a 'negative pressure" in the vacuum.

Ah.

Thats why I wanted to be so careful that you understood some tenets of General Relativity (GR) and Quantum Mechanics (QM).

http://math.ucr.edu/home/baez/vacuum.html

 

[Michael Mozina]

Ah.

Thats why I wanted to be so careful that you understood some tenets of General Relativity (GR) and Quantum Mechanics (QM).

http://math.ucr.edu/home/baez/vacuum.html

I do understand them and you are welcome to use them if you believe they can help your case.

 

[DazzaD]

I do understand them and you are welcome to use them if you believe they can help your case.

Are you familiar with the use of GR to invoke "negative pressure" in the cosmological models?

Say, in particular, a stress-energy tensor?

 

[PingOfPong]

The lowest energy state of the vacuum is zero.

Nope, Einstein found that there was a minimum energy due to virtual particles even in a vacuum. He discovered it with math mysticism way back in 1913. 35 years later, Casimir did some more math on Einstein's idea and found that it would cause two plates to attract each other. The formula predicted empirical results with a high degree of accuracy.

On nano scales, the Casimir effect tends to dominate other forces. Moving into the future, small scale nanomachine tech is going to rely on making accurate calculations of the Casimir effect. Think of it. You may be buying computers in the future that were assembled by little nano scale robots. It might even be available at Wal-Mart.

Don't feel obliged to respond to this post MM. You have plenty of people talking to you now.