Understanding Cosmology (Post 6)

[Meow Mix]

Dark matter was finished up in the last couple of posts, so now I'm going to move on to another topic people are frequently asking about: dark energy. This is a little harder to talk about at the very basic level these posts have tried to maintain, but I will continue trying to do this.

In the early posts, we discussed the Friedmann equations and deriving them from Einstein's equations. The base Friedmann equations model the expansion of space under the assumption of homogeneity and isotropy in the universe. We need to understand the evolution of the energy density in the universe, so we use another equation called the Fluid Equation. Lastly, we need to understand how the scale factor might accelerate as it changes, so we use another equation called the Acceleration Equation.

Only two of these are independent, and we have three unknowns (the scale factor, the energy density, and the pressure): we need to be able to relate the energy density and the pressure to be able to solve problems and answer questions with these equations.

So we are arriving to a concept called the equation of state, which is something that will connect a couple of these concepts: in this case, we need an equation of state that will relate cosmological energy density to pressure.

I will post the equations here, but don't expect to understand them just from looking at them (especially devoid of any derivation context); I mainly want you to see that they contain many of the same terms:

[GALLERY=media, 9516]Eqns by Meow Mix posted Jun 30, 2021 at 2:17 AM[/GALLERY]

We need something that connects epsilon (the energy density) and P (pressure): this would be called an equation of state.

Since no equation of state equation accurately predicts the properties of all things under all conditions, we need to introduce an additional term that we'll call the equation of state parameter. So, for instance, we'll have an equation of state for everything that looks like this:

[GALLERY=media, 9517]Eoseqn by Meow Mix posted Jun 30, 2021 at 2:21 AM[/GALLERY]

Where the lowercase omega (the w) is our equation of state parameter: this thing will be different depending on whether we're talking about matter (w = 0 for non-relativistic matter, this is an approximation), radiation (w = 1/3 for photons, calculated from statistical mechanics), and from the acceleration equation* we get that for an accelerating universe, dark energy would have to have an equation of state parameter that's less than -1/3.

(* -- you can do this yourself by taking the acceleration equation and plugging in the equation of state; you will see that in the parentheses, a critical value for w is -1/3 such that if w is more negative than that, the acceleration will be non-zero and non-negative!)

So, even if you didn't quite follow everything above, an important thing is that an equation of state parameter that's less than (more negative than) -1/3 describes a universe that is accelerating its expansion.

What are some examples of things that might have an equation of state parameter like this?

The first example of a negative pressure like this that causes the universe to "push outwards" is Einstein's cosmological constant, lambda. This would be a constant equation of state parameter w = -1 (for calculus folks, it's actually an integration constant set to lambda rather than zero, so it is a true constant).

Einstein's reasoning for this at the time was that the universe appeared to be static to him (he didn't know at the time it was expanding). But there's a problem: all the mass in the universe should have been causing it to be contracting in on itself (or with the caveat that the universe might be infinite with an infinite amount of balanced matter, any small perturbation would cause it to fall apart like a house of cards). So, Einstein introduced this lambda term to counterbalance the "damage" that he presumed gravity may have done to a static universe model.

He famously considered this one of his greatest blunders: it was a really ad hoc decision, and it of course turned out the universe isn't static, so it was introduced for the wrong reasons.

So, Einstein's cosmological constant was forgotten for a long time in physics. I've had instructors tell me that before 1998, they were always told in astrophysics and cosmology classes, "by the way, there might be this thing, but we're pretty sure lambda = 0," so they'd have to learn cosmological equations including lambda terms for about a week before forgetting them.

However, then a thing happened in 1998: the discovery of evidence that the universe was accelerating as it expanded.

Scientists in 1998, being the mindful folk that they are, were plotting very distant (high redshift) supernovae against different possible universe models, including some models that included lambda being nonzero, and to their utter astonishment, it looked like the data best fit models with nonzero lambda.

[GALLERY=media, 9518]1998supernovae by Meow Mix posted Jun 30, 2021 at 2:45 AM[/GALLERY]

(How to read this plot: the x axis is redshift, which cosmologists call "z," so remember higher numbers of redshift = further out in the universe, further back in time as we are looking at it because light takes time to reach us. The y axis is the magnitude [brightness] of the supernovae being plotted. Assume for now that we can align these axes if we know how far a special type of supernovae is by knowing how bright it is at its peak. The different dotted lines represent different models of the universe with different possible density parameters. The data falls along the lines of the model with a nonzero lambda term, not on the models that ignore lambda!)

Coming up in Post 7: the deceleration parameter (hint: they named it this before they suspected it would turn out to be negative, and thus become an acceleration parameter in all but name!), Type 1a supernovae, and the cosmic history of density parameters and their relation to the acceleration and fate of the universe. (All of this means: more dark energy post for Post 7).

 

[Native]

Dark matter was finished up in the last couple of posts,

I don´t think "dark matter" was/is "finished up" by other ways that you´ve described the standing consensus ideas of this delusive and theoretic multi-task "force".

Scientists in 1998, being the mindful folk that they are, were plotting very distant (high redshift) supernovae against different possible universe models . . .

What if scientists, "being mindful" as they surely are, have overlooked some facts of "slowing down" or dispersion effects of cosmic "constant" light sources? How would this affect the idea of an expanding Universe?

 

[Meow Mix]

I don´t think "dark matter" was/is "finished up" by other ways that you´ve described the standing consensus ideas of this delusive and theoretic multi-task "force".

I was as thorough as I could be at a layperson level; and responded (I'm pretty sure) to every question asked in the comments. I think I did okay

What if scientists, "being mindful" as they surely are, have overlooked some facts of "slowing down" or dispersion effects of cosmic "constant" light sources? How would this affect the idea of an expanding Universe?

Can you rephrase this? Overlooked what?

 

[Native]

was as thorough as I could be at a layperson level; and responded (I'm pretty sure) to every question asked in the comments. I think I did okay

Yes you did ok according the standard descriptions but you apparently intellectually take all theories as concrete facts - which they are not.

Can you rephrase this? Overlooked what?

If "light" can be "slowed down" or dispersed to its way to telescopes, this would give false light constant measurement.
How would this influence on the "expansion idea"?

 

[Meow Mix]

Yes you did ok according the standard descriptions but you apparently intellectually take all theories as concrete facts - which they are not.

Ooh, I'd hate to be anyone that actually takes all physics theories as established and worthy, do you have any idea how exhausting that would be?

In any case, I don't just "take all theories as concrete facts." I assess them based on their foundations, their ability to predict the outcome of experiment, their metaphysics, and their cohesiveness with other physics.

If "light" can be "slowed down" or dispersed to its way to telescopes, this would give false light constant measurement.
How would this influence on the "expansion idea"?

Are you talking about variable speed of light ideas, that c is not constant?

 

[Heyo]

Yes you did ok according the standard descriptions

Which was her goal.

And remember, @Meow Mix is still studying. Go try to study physics and bring up crackpot ideas like the electric universe and see how you do. I'd only look at such things when I had tenure.

 

[Native]

In any case, I don't just "take all theories as concrete facts." I assess them based on their foundations, their ability to predict the outcome of experiment, their metaphysics, and their cohesiveness with other physics.

I know. This is the scientific method approach - but in the everyday cosmological comments and descriptions it all is expressed as if everything is carved in concreate stones.

"Predict outcome of experiments"? How can you make experiments with anything in the Universe?

Are you talking about variable speed of light ideas, that c is not constant?

If you absolutely need the mathematical letter for it instead of plain words and sentences, then yes.

Edit: I though don´t accept the "vacuum premises" addition in this c-constant, as there is no such thing as vacuum in space.

 

[Native]

And remember, @Meow Mix is still studying. Go try to study physics and bring up crackpot ideas like the electric universe and see how you do. I'd only look at such things when I had tenure.

Don´t you worry Heyo. I´m fully aware of students conditions et all.

If cosmological and astrophysical teachers on Universities cannot connect the electromagnetic qualities in atoms to an Electric Universe in large, they should find another job which doesn´t require logical thinking.

 

[Meow Mix]

I know. This is the scientific method approach - but in the everyday cosmological comments and descriptions it all is expressed as if everything is carved in concreate stones.

"Predict outcome of experiments"? How can you make experiments with anything in the Universe?

If you absolutely need the mathematical letter for it instead of plain words and sentences, then yes.

Edit: I though don´t accept the "vacuum premises" addition in this c-constant, as there is no such thing as vacuum in space.

What do you mean "how can you make experiments with anything in the universe?" I am guessing you mean the fact that astronomy, astrophysics, cosmology etc. are observational sciences? This still entails having observations that match modeling, and the occasional experiment (e.g. detecting gravitational waves).

As for space and vacuums, it is close enough. The mean free path for a photon is enormous.

 

[Native]

As for space and vacuums, it is close enough. The mean free path for a photon is enormous.

So why is it that cosmic clouds of "dust and gas" blocks ordinary light telescopes from having a clear view everywhere in cosmos?

 

[Meow Mix]

So why is it that "dust and gas" blocks ordinary light telescopes from having a clear view everywhere in cosmos?

The same reason the walls of your house block your view, but you wouldn't say the atmosphere is made out of wall

 

[Native]

The same reason the walls of your house block your view, but you wouldn't say the atmosphere is made out of wall

Ergo:

The mean free path for a photon is enormous.

Isn´t enormous at all as thought in the light constant theory. Which affects and skews the cosmic distance measurements to believe in an expanding Universe.

 

[Meow Mix]

Ergo:

Isn´t enormous at all as thought in the light constant theory. Which affects and skews the cosmic distance measurements to believe in an expanding Universe.

I'm not sure what you're trying to say. Gas in sufficient amount to significantly reduce the mean free path isn't ubiquitous.

 

[Native]

I'm not sure what you're trying to say. Gas in sufficient amount to significantly reduce the mean free path isn't ubiquitous.

I´m saying that there are no free paths for light at all as thought by the c-"constant", hence the cosmic distance measuring and an "universal expansion" idea aren´t valid.

 

[Meow Mix]

I´m saying that there are no free paths for light at all as thought by the c-"constant", hence the cosmic distance measuring and an "universal expansion" idea aren´t valid.

I'm curious, do you think we don't account for absorption and emission from gas clouds when doing astro? I could just say so, but I'm more curious by your thought process here.

 

[Native]

I'm curious, do you think we don't account for absorption and emission from gas clouds when doing astro?

Well, earlier you dogmatically asserted space to be a vacuum which then isn´t a fact, hence the dogmatic light constant isn´t valid either.

. . .but I'm more curious by your thought process here.

In the very basics my thought process are that "anything" is taken into the account for an assumed Big Bang which isn´t strict scientific sound as something cannot come from nothing. This is pure science fiction and even a superstitious idea.

 

[Meow Mix]

Well, earlier you dogmatically asserted space to be a vacuum which then isn´t a fact, hence the dogmatic light constant isn´t valid either.

Vacuum is understood to be approximal, though.

In the very basics my thought process are that "anything" is taken into the account for an assumed Big Bang which isn´t strict scientific sound as something cannot come from nothing. This is pure science fiction and even a superstitious idea.

Big Bang cosmology doesn't posit "something came from nothing." In fact it doesn't posit anything prior to the Planck time, there isn't enough data. We can philosophize and make educated guesses, such as from consequences of eternal inflation; but that isn't considered part of the science, and doesn't have scientific consensus.

 

[Native]

Big Bang cosmology doesn't posit "something came from nothing." In fact it doesn't posit anything prior to the Planck time, there isn't enough data.

Thanks for this concession and just keep that in mind in your works.

We can philosophize and make educated guesses, " . . . ." but that isn't considered part of the science, and doesn't have scientific consensus.

Why not? Modern cosmology and astrophysics already makes all kinds of guesses, even unqualified such.

What I wonder much about, is how modern science can have an universal law of energy conservation and STILL have an assumption of a BEGINNING of the Universe. You see? This is how natural philosophical ponderings works, asking logical questions - which should be taught in Universities too.

Maybe you´ll have nothing of it, but our ancient ancestors all over in different cultures had the Universe to be infinite and eternal and where everything underwent eternal cyclical changes between formations, dissolutions and re-formations.

There you have the ancient perception of cosmic motions and formation to obey the consensus law of energy conservation. They had this cosmo-logical perception many thousands of years ago.

Strangely, this cosmological intuitive knowledge has disappeared from modern education and have being exchanged with all kinds of far astray dogmatic consensus speculations.

 

[gnostic]

I know. This is the scientific method approach - but in the everyday cosmological comments and descriptions it all is expressed as if everything is carved in concreate stones.

"Predict outcome of experiments"? How can you make experiments with anything in the Universe?

If “you know”, @Native about the approach of scientific method being used to “test” explanations/descriptions and to “test” the predictions in the model, then “you would know” that for anyone to justify their own alternative cosmological models (for instance, like your Electric Universe model), they must have explanations/predictions (including equations) in these alternative models that are “testable”...otherwise, those alternative models “are not scientific” - they are nothing than biased pseudoscience opinions.

If you want to justify Electric Universe to replace the Big Bang cosmology, then you must present testable explanation, testable sets of equations and testable sets of predictions - all of which to replace the observations of the Big Bang model.

In all the threads and posts you have posted up, you haven’t done that.

You want to replace all 3 known fundamental interactions — gravitational force, weak nuclear force & strong nuclear force — with a single electromagnetic force, but you have failed to justify your claim, with alternative prediction of current observations, and have failed to present a single “testable” EM equation to replace the Friedmann Equations or the more recent equations of acceleration of universe from ΛCDM model (1998).

This is why no one but handful of physicists take Electric Universe model seriously. Even theoretical physicists of Cyclical Universe model, Superstring Theory and Multiverse model, don’t take Electric Universe as a serious challenge.

I remember you posting up one charts to support your claims about EU, but those charts/graphs provide no contexts to your claims, meaning there were no supporting equations to base your graphs/charts.

Showing graphs with no supporting logical descriptors (like equations or metrics), showed that you have no concept of what graphs need to be to have contexts.

So every time when you reply to one us in threads you created, and one of us (not just me) ask you to show some supporting logics, like requests of alternative EM equations from your Electric Universe cosmology, you always either dismiss the requests or make evasive excuses.

That have always been your tactics. You tried to dismiss arguments from @Meow Mix or from @Polymath257 or from others, but you often present arguments that are dismissible.

You disagree with @Meow Mix explanations and her illustrations (graphs/equations), then present alternative explanations, graphs plus “EM equations” from your EU model.

 

[Native]

If “you know”, @Native about the approach of scientific method being used to “test” explanations/descriptions and to “test” the predictions in the model, then “you would know” that for anyone to justify their own alternative cosmological models (for instance, like your Electric Universe model), they must have explanations/predictions (including equations) in these alternative models that are “testable”...otherwise, those alternative models “are not scientific” - they are nothing than biased pseudoscience opinions.

There you go again with your boring theoretical theories and "scientific methods".

If you want to justify Electric Universe . . .

Once you´ve grasped that all atoms and molecules have electromagnetic properties and qualities, you´ll be able to grasp an Electric Universe too. And that also goes for all other proponents of Newtons occult ideas.

As for the rest of your usual boring comments, I don´t care as long as you deny/ignore the obvious electromagnetic cosmological facts.

PS: I´m not in general opposition to Meow Mix´s posts. I´m just underlining some points where I think there is room for some cosmological/logical/natural improvements.