Relativity

[AV1611VET]

In a perfectly circular orbit, a satellite is accelerating, but its energy remains constant.

Which reminds me of God.

Since the factors for angular momentum are mass, velocity and radius; a planet must slow down as it reaches apogee* and speed up as it achieves perigee.

Look at it this way:

5 x 4 x 2 = 40

Let 5 be the radius, 4 the velocity, and 2 the mass.

As the radius increases, say to 10, the conservation of energy law states that another factor has to change to compensate and keep the product at 40.

Since the size of the planet doesn't change, the velocity has to change to 1.

* Or maybe it's aphelion & perhilion -- whatever.

 

[Justatruthseeker]

Originally Posted by essentialsaltes

In a perfectly circular orbit, a satellite is accelerating, but its energy remains constant.​

​

Which reminds me of God.

Since the factors for angular momentum are mass, velocity and radius; a planet must slow down as it reaches apogee* and speed up as it achieves perigee.

Look at it this way:

5 x 4 x 2 = 40

Let 5 be the radius, 4 the velocity, and 2 the mass.

As the radius increases, say to 10, the conservation of energy law states that another factor has to change to compensate and keep the product at 40.

Since the size of the planet doesn't change, the velocity has to change to 1.

* Or maybe it's aphelion & perhilion -- whatever.

Just a simple law of physics actually.

Charged Particle in a Magnetic Field

That's what happens with charged bodies. The orbit only fluctuates with the net energy input. Why planetary orbits are almost never perfectly circular. The electric and magnetic fields are time varying.

 

[Michael]

What? No.

You claim to accept GR. In a GR universe that looks somewhat like ours, the only choices are expansion, contraction, and staying the same.

But all of those various configurations of matter/energy can occur *without* "space expansion"! You're still not copping to the fact that GR theory is *not* dependent upon your space expansion claims. Furthermore that claim, unlike time dilation, is *not* a *demonstrated feature* of GR in any controlled experiment. You're essentially slipping that space expansion claim in the back door and trying to ride the coattails of GR theory even though GR theory is *not* dependent upon your claim!

IMO you don't understand GR. What you've described is stuff moving in spacetime.

Objects in motion will stay in motion, so an expanding spacetime will indeed expand without the need for "space" to do any expansion tricks.

That is not the same as the dynamics of spacetime itself.

You didn't actually demonstrate any other "dynamics of spacetime itself" in any controlled experimentation.

The problem for you is that I do know enough about GR to know the difference between the GR theory that Einstein taught to his students, and the blunder theory your using to prop up one otherwise falsified cosmology theory.

The real problem is that you never demonstrated what you're calling the "dynamics of spacetime", whereas spacetime expansion of objects and energy can be demonstrated.

No, I'm presenting all the possible options. However, your option, EM, does not work, because EM is described by the standard EM stress-energy tensor, and it does not have the exotic properties required to keep a universe stable.

Bah! You wouldn't know because your industry has never actually *tried to make it work*. Instead you folks keep trying to falsify an entire empirical theory of spacetime with a single handwave of an argument, at least typically.

I have no problem with that at all. However, it cannot produce a stable universe. Only an expanding or contracting one. Only some type of exotic matter (that I am not praying for... I'm just providing all the possible options) with negative pressure could keep the universe stable.

What you're calling a "negative pressure" does not exist in the context of a vacuum. Vacuums can and do only contain *positive* pressure because they can only contain positive kinetic energy. Your mythical negative pressure savior device does not actually exist in nature, only in cosmology "lore". It's rather ironic your giving J a lecture about kinetic energy while trying to create a 'negative pressure vacuum'.

Look, you allege you have no problem with GR defining spacetime. All I did was take that definition and show how it is made of (surprise surprise) space and time.

Um no, actually you provided a relatively accurate description of SR and GR and they ascribed GR with a property you can't actually demonstrate in any lab in a controlled experiment. It's a pure leap of faith on your part apparently, and GR is *not* dependent upon your claim.

Time dilation is tangible evidence on earth. Time and space are linked, as you said. If you accept GR, then you must accept that "if clocks wiggle, then rulers wobble".

Sorry, but one statement can be true, and the other one doesn't have to be. You're *assuming* both are true, much like assuming that both the E and B fields have a source and a sink because the E field definitely has them. Sorry, but that isn't how nature always works. Symmetry isn't always a given.

It does follow. Different observers see space and time converted into each other.]/quote]

In controlled experiments on Earth they don't see the "space expansion" claim that you're making. They do see *ordinary* expansion as I've described however.

Different observers do not see charges turning into magnetic monopoles.

The reason that neither monopoles nor space expansion shows up in controlled experimentation is because they don't exist in nature. They may exist in a few otherwise falsified scientific theories, but that's the only place you'll find either monopoles or space expansion claims.

 

[essentialsaltes]

You're still not copping to the fact that GR theory is *not* dependent upon your space expansion claims.

You're still denying that space expansion (or contraction) is a prediction of GR. As you agreed earlier, the reason Einstein inserted his 'blunder' cosmological constant is because GR predicts a non-static universe.

even though GR theory is *not* dependent upon your claim!

It's a prediction of GR. You can't accept GR without accepting non-static space (or a blunder, or fairy dust).

Objects in motion will stay in motion, so an expanding spacetime

No, that's just moving objects. That's not what spacetime expansion is.

You didn't actually demonstrate any other "dynamics of spacetime itself"

That is what GR is. It's a theory that provides us with a way of calculating the spacetime derivatives of the metric (i.e. our clocks and rulers (i.e. spacetime (i.e. space and time))). It's a theory that tells us how clocks wiggle and rulers wobble.

The problem for you is that I do know enough about GR to know the difference between the GR theory that Einstein taught to his students, and the blunder theory

Again, the blunder theory is what gives us a static universe. That's what you apparently want. You should be supporting the blunder theory. The unblundered theory predicts expansion or contraction. The reason that Einstein considered the cosmological constant a blunder is because he was wrong to assume that spacetime was not expanding or contracting. Hubble's data showed that it is expanding. Einstein immediately smacked his forehead and went back to the unblundered theory that you profess to accept. But that unblundered theory predicts spatial expansion.

"Einstein later referred to his failure to accept the validaton of his equations; when they had predicted the expansion of the universe in theory, before it was demonstrated in observation of the cosmological red shift, as the "biggest blunder" of his life."

Previously you agreed this was the case. And yet here you are still claiming to adhere to the nonblunder theory. Einstein's nonblunder theory predicts spatial expansion. And yet this is precisely what you deny. You're just wrong.

Bah!

Bah, yourself. You keep repeating the same wrong and inconsistent talking points.

 

[Justatruthseeker]

[FONT=&quot]Originally Posted by Michael[/FONT]
[FONT=&quot]You're still not copping to the fact that GR theory is *not* dependent upon your space expansion claims.[/FONT]

You're still denying that space expansion (or contraction) is a prediction of GR. As you agreed earlier, the reason Einstein inserted his 'blunder' cosmological constant is because GR predicts a non-static universe.

So why is mainstream trying to put it back in?

https://en.wikipedia.org/wiki/Cosmological_constant In cosmology, the cosmological constant (usually denoted by the Greek capital letter lambda: &#923 is equivalent to an energy density in otherwise empty space. It was proposed by Albert Einstein as a modification of his original theory of general relativity to achieve a static universe. Einstein abandoned the concept after the observation of the Hubble redshift indicated that the universe might not be stationary, as he had based his theory on the idea that the universe is unchanging. However, a number of observations including the discovery of cosmic acceleration in 1998 have revived the cosmological constant. The Lambda-CDM model of the Universe (the most accepted modern cosmological model) asserts that Λ is positive, although negligible even on the scale of the Milky Way.

But you take it out it adds problems, you leave it in it adds problems

Observations announced in 1998 of distance–redshift relation for Type Ia supernovae indicated that the expansion of the universe is accelerating. When combined with measurements of the cosmic microwave background radiation these implied a value of ..., a result which has been supported and refined by more recent measurements. There are other possible causes of an accelerating universe, such as quintessence, but the cosmological constant is in most respects the simplest solution. Thus, the current standard model of cosmology, the Lambda-CDM model, includes the cosmological constant, which is measured to be on the order of 10−52 m−2, in metric units. Multiplied by other constants that appear in the equations, it is often expressed as 10−35 s−2, 10−47 GeV4, 10−29 g/cm3. In terms of Planck units, and as a natural dimensionless value, the cosmological constant, λ, is on the order of 10−122.
As was only recently seen, by works of 't Hooft, Susskind and others, a positive cosmological constant has surprising consequences, such as a finite maximum entropy of the observable universe (see the holographic principle).
A problem arises with inclusion of the cosmological constant in the standard model: i.e., the appearance of solutions with regions of discontinuities (see classification of discontinuities at typical matter density). Discontinuity also affects the past sign of the pressure of the cosmological constant, changing from the current negative pressure to attractive, with lookback towards the early Universe. Another investigation found the cosmological time, dt, diverges for any finite interval, ds, associated with an observer approaching the cosmological horizon, representing a physical limit to observation for the standard model when the cosmological term is included. This is a key requirement for a complete interpretation of astronomical observations, particularly pertaining to the nature of dark energy and the cosmological constant. All of these findings should be considered major shortcomings of the standard model, but only when the cosmological constant term is included.

It's a prediction of GR. You can't accept GR without accepting non-static space (or a blunder, or fairy dust).

Exactly, now you are catching on.

No, that's just moving objects. That's not what spacetime expansion is.

Really? because all I see and measure is moving objects.

That is what GR is. It's a theory that provides us with a way of calculating the spacetime derivatives of the metric (i.e. our clocks and rulers (i.e. spacetime (i.e. space and time))). It's a theory that tells us how clocks wiggle and rulers wobble.

And does it well for the 1% of the universe where it applies. To the vast majority of unbound Plasma 99% it just doesn't explain those wiggles and wobbles without the addition of Fairie Dust.

Again, the blunder theory is what gives us a static universe.

And its what gives us a static universe, depending on what value the constant is set at. Or a contracting universe or an expanding one. It gives one whatever one needs. Maybe it's not the equation that is the problem, but the dark matter and redshift theories that rely on certain conditions not observed.

 

[Michael]

You're still denying that space expansion (or contraction) is a prediction of GR.

Hmmm. I'm not sure I actually agree with you, in fact I'm sure I do not.

"Spacetime" (as in object movement) expansion/contraction is a *prediction* of GR, but not 'space' expansion. That's ultimately the claim that was never demonstrated. It's true that spacetime would tend to expand or contract on it's own, but this kind of movement is related to *object* movement, not "space expansion/contraction'. You're effectively *intentionally* blurring the meaning of the formulas from my vantage point. You and I can both agree that GR predicts the expansion or contraction of spacetime, but we cannot agree that it relates to 'space' expansion/contraction. You're simply "misinterpreting the meaning" of the formulas IMO to see what you wish to see, not what's actually there.

As you agreed earlier, the reason Einstein inserted his 'blunder' cosmological constant is because GR predicts a non-static universe.

Correct, space*time* expansion/contraction (object movement) will prevail. Either the mass/energy will expand, or it will contract, but it will likely not stay "static" without other inputs.

Of course you keep ignoring the fact that EM fields are the "other inputs" that Lambda-CDM simply ignores.

It's a prediction of GR. You can't accept GR without accepting non-static space (or a blunder, or fairy dust).

Again, I can *only* agree that 'spacetime' contraction/expansion is a "prediction" of GR. That is *not* the same as claiming that "space" expansion/contraction is a "prediction" of GR. We keep going around in circles over this distinction.

No, that's just moving objects. That's not what spacetime expansion is.

I know full well that your claim is a completely *different* claim than the "spacetime expansion" that can be demonstrated in a lab, and that causes photon redshift. That is why I find it so darn annoying when your industry uses 'bait and switch' devices like balloons (spacetime expansion) and Doppler shift (spacetime expansion) as evidence to support *your* supernatural claims.

That is what GR is. It's a theory that provides us with a way of calculating the spacetime derivatives of the metric (i.e. our clocks and rulers (i.e. spacetime (i.e. space and time))). It's a theory that tells us how clocks wiggle and rulers wobble.

Again however, like the EM field example, clocks can wiggle, without rulers wobbling. You're *assuming* both are true, when only one must be true and only one has been shown to be true. It's the equivalent of *assuming* that monopoles exist.

Again, the blunder theory is what gives us a static universe.

I'd happily let you insert EM field components of plasma into a GR formula in some effort to achieve a 'static' configuration of 'spacetime'. What I won't let you do is stuff a supernatural construct in there and claim that 'space' does expansion tricks, and spacetime expanded faster than 2C.

The only one that is being inconsistent is you. The balloon analogies and the Doppler shift comparisons are directly and *specifically* and *only* related to object expansion. They are *not* related to your supernatural claims about 'space expansion'.

IMO is highly amusing that you have such a powerful 'faith' in a concept (space expansion) that you actually cannot demonstrate in a lab, nor could you ever hope to demonstrate in a lab.

At least my 'faith in God' could actually one day be verified on Earth in a lab, if not in my personal lifetime. That kind of empirical verification on Earth is more than you could ever even hope for. It turns out that your unwavering faith in the unseen (in the lab) is actually far 'greater' than mine.

 

[essentialsaltes]

It's true that spacetime would tend to expand or contract on it's own, but this kind of movement is related to *object* movement, not "space expansion/contraction'.

Wrong. There are solutions to the Friedmann equations for an empty universe that still have expansion or contraction. (Ex. see slide 6)

The dynamics of spacetime is not the same as objects moving in spacetime.

GR is a theory of the dynamics of spacetime.

Of course you keep ignoring the fact that EM fields are the "other inputs" that Lambda-CDM simply ignores. ... I'd happily let you insert EM field components of plasma into a GR formula.

I have already shown that the EM stress-energy tensor cannot provide the negative pressure required for a static universe. Whether you are happy about it or not, it won't work.

Again, I can *only* agree that 'spacetime' contraction/expansion is a "prediction" of GR. That is *not* the same as claiming that "space" expansion/contraction is a "prediction" of GR. We keep going around in circles over this distinction.

Because your distinction is phony. Spacetime is space and time. Different inertial observers see space and time mingled. Clocks wiggle. Therefore rulers must wobble.

It's the equivalent of *assuming* that monopoles exist.

No it isn't. Your analogy is to charges and magnetic monopoles. Different observers do see space and time intermingled. Different observers do not see charges and magnetic monopoles intermingled (and therefore obviously this would not be a reason to assume monopoles exist). You can't defeat my argument with a faulty analogy.

The balloon analogies and the Doppler shift comparisons are directly and *specifically* and *only* related to object expansion.

No, they are most emphatically not!

The typical balloon analogy is to tape pennies (to represent galaxies, i.e. objects) to the balloon. The rubber of the balloon represents space. When you blow up the balloon, what expands?

Is it the rubber, i.e. space?
Or is it the pennies, i.e. objects?

Space expands. Redshift is direct experimental evidence. GR provides the theoretical framework.

 

[Michael]

Wrong. There are solutions to the Friedmann equations for an empty universe that still have expansion or contraction. (Ex. see slide 6)

Ok, I'll bite, what exactly *is* (from the standpoint of physics) an empty universe? Is this where astronomers go all Buddhist suddenly? What exactly *is* expanding/contracting in an *empty* universe?

The dynamics of spacetime is not the same as objects moving in spacetime.

You technically haven't demonstrated that the former is actually separate from the latter. You seem to confuse 'math myth-making" with physics.

GR is a theory of the dynamics of spacetime.

You're trying to take the mass/energy out of GR theory. Sorry, that isn't GR theory. GR theory describes the curvature of *spacetime* that is caused by/changed by the concentration of mass/energy. You can't take the mass/energy out of GR and still have GR.

I have already shown that the EM stress-energy tensor cannot provide the negative pressure required for a static universe. Whether you are happy about it or not, it won't work.

Whether you are happy about it or not, your claim won't work in a lab, or anywhere else.

Because your distinction is phony. Spacetime is space and time. Different inertial observers see space and time mingled. Clocks wiggle. Therefore rulers must wobble.

Nope. One claim doesn't necessitate the other. Even if they both "wobbled" anywhere it would necessarily be *near and directly around* the mass/energy concentration of the universe, not in some mythical place where no mass exists. You're trying to remove cause/effect relationships altogether.

No it isn't. Your analogy is to charges and magnetic monopoles. Different observers do see space and time intermingled. Different observers do not see charges and magnetic monopoles intermingled (and therefore obviously this would not be a reason to assume monopoles exist). You can't defeat my argument with a faulty analogy.

You're defeating your own faulty logic. One claim does not necessitate the other. Even if both are true, the 'wobble' would take place *near the mass energy concentration*, not "far away from it".

No, they are most emphatically not!

Yes they are! Both are examples of *spacetime* expansion, not "space" expansion.

The typical balloon analogy is to tape pennies (to represent galaxies, i.e. objects) to the balloon. The rubber of the balloon represents space.

So you are peddling an aether theory after all? Space has some physical structures like rubber?

When you blow up the balloon, what expands?

The rubber! You're physically stretching a physical object!

Is it the rubber, i.e. space?

So space is composed of small particles like rubber is composed of small particles that can 'separate'? What particles is 'space' made from?

Or is it the pennies, i.e. objects?

We're good with the pennies being galaxies. The bait and switch routine seems to occur in the rubber/space comparison.

Space expands.

How? Rubber expands because the molecules get stretched apart. Rubber has a physical definition and structure. You're effectively defining "space" as something akin to an expanding aether, but you failed to physically define the particles that do the "expanding" in your "space" thingy, when you compared space to a rubber sheet.

Redshift is direct experimental evidence.

False. It's is only experimental evidence of moving objects, not space expansion. Moving objects are not the same as expanding space. Your claim is therefore false.

GR provides the theoretical framework.

Since you can stuff any supernatural and non-demonstrated construct into a GR formula (like the one you did), it's also a theoretical framework for the supernatural, particularly 'blunder' theory.

 

[Loudmouth]

Nope. One claim doesn't necessitate the other. Even if they both "wobbled" anywhere it would necessarily be *near and directly around* the mass/energy concentration of the universe, not in some mythical place where no mass exists.

Where have you shown this?

Yes they are! Both are examples of *spacetime* expansion, not "space" expansion.

If you change one the other must change as well. That is why it is called spacetime.

So you are peddling an aether theory after all? Space has some physical structures like rubber?

The rubber! You're physically stretching a physical object!

So space is composed of small particles like rubber is composed of small particles that can 'separate'? What particles is 'space' made from?

We're good with the pennies being galaxies. The bait and switch routine seems to occur in the rubber/space comparison.

How? Rubber expands because the molecules get stretched apart. Rubber has a physical definition and structure. You're effectively defining "space" as something akin to an expanding aether, but you failed to physically define the particles that do the "expanding" in your "space" thingy, when you compared space to a rubber sheet.

I guess you don't understand how analogies work? The rubber is meant to represent a non-aether spacetime with no mass. If you are going to dismiss every analogy because it does not perfectly match the system it is illustrating then you will need to reject every analogy ever made.

False. It's is only experimental evidence of moving objects, not space expansion. Moving objects are not the same as expanding space. Your claim is therefore false.

If moving objects is not expanding space why do you continually confuse the two? Essentialsaltes is consistently talking about the expansion or contraction of spacetime, and yet everytime you try to convert it into moving masses. Why is that?

Since you can stuff any supernatural and non-demonstrated construct into a GR formula (like the one you did), it's also a theoretical framework for the supernatural, particularly 'blunder' theory.

This doesn't even make sense.

 

[Michael]

Where have you shown this?

Nowhere, the very same place you showed 'space' does expansion tricks.

If you change one the other must change as well. That is why it is called spacetime.

Nope. Spacetime can expand as objects move such as in the balloon analogy. No "space" did any expanding in that balloon demonstration, but the objects did move in the rubber sheet as well as on the rubber sheet.

I guess you don't understand how analogies work?

I know they aren't supposed to used as bait and switch devices the way you're using them.

The rubber is meant to represent a non-aether spacetime with no mass.

What is it made of? How does it "expand"?

If you are going to dismiss every analogy because it does not perfectly match the system it is illustrating then you will need to reject every analogy ever made.

I'm not dismissing the analogy at all. It perfectly illustrates 'spacetime' expansion. I'm dismissing your *misuse* of the analogy as a blatant bait and switch device.

If moving objects is not expanding space why do you continually confuse the two?

I'm not, you are. You're the one misusing the analogies right and left. Any confusion by anyone is *your* fault to begin with.

Essentialsaltes is consistently talking about the expansion or contraction of spacetime, and yet everytime you try to convert it into moving masses. Why is that?

Spacetime can only expand or contract when the objects move. You cannot demonstrate anything to the contrary in a lab, nor can you even come up with an analogy that doesn't depend upon the movement of objects.

This doesn't even make sense.

A "blunder" theory can *easily* be kludged with anything from invisible faeries to magical unicorns that do all sorts of magical space expansion/space contraction tricks. The metaphysical sky is the limit in supernatural blunder theories.

 

[essentialsaltes]

Ok, I'll bite, what exactly *is* (from the standpoint of physics) an empty universe?

From the standpoint of GR, an empty universe is one without matter or radiation. i.e. the elements of the stress-energy tensor are zero.

What exactly *is* expanding/contracting in an *empty* universe?

The spacetime, obviously. GR gives us a differential equation for the metric of spacetime, not the stuff living in spacetime.

You can't take the mass/energy out of GR and still have GR.

Sure you can. GR says that Einstein's tensor equals the stress-energy tensor. If there's no mass or energy, the right hand side is zero. Even in this simple case, you can have expanding spacetime.

Even if they both "wobbled" anywhere it would necessarily be *near and directly around* the mass/energy concentration of the universe

Wrong. As I've demonstrated, wobbling can occur even in the absence of mass and energy.

The rubber!

Correct, it is the spacetime that is expanding in this analogy.

 

[essentialsaltes]

nor can you even come up with an analogy that doesn't depend upon the movement of objects.

What, the theory is wrong because there is no analogy that satisfies you?

Fine, let's dispense with analogy. Here's the Einstein tensor:
http://upload.wikimedia.org/math/8/2/d/82d282358db7d6ad00c944aa613c86b3.png

As you can plainly see, all there are are some Kronecker deltas, the metric, and the spacetime derivatives of the metric.

The metric is our rulers and clocks.

If the metric has nonzero derivatives, then our rulers and clocks are changing.

Wiggling and wobbling. Space and time.

 

[Loudmouth]

Nowhere,

Then why keep claiming it?

Nope. Spacetime can expand as objects move such as in the balloon analogy. No "space" did any expanding in that balloon demonstration, but the objects did move in the rubber sheet as well as on the rubber sheet.

The baloon is only an analogy. Why don't you understand that? Essentialsaltes puts it best:

"GR gives us a differential equation for the metric of spacetime, not the stuff living in spacetime."

I know they aren't supposed to used as bait and switch devices the way you're using them.

You are the one using the bait and switch with the analogy.

What is it made of? How does it "expand"?

Essentialsaltes already discusses this. Spacetime is a metric, and it expands and contracts.

I'm not dismissing the analogy at all.

You are forgetting that it is an analogy. It is only meant as an illustration, not a one-to-one example. Just because the analogy uses flexible rubber does not mean that space is made of flexible rubber. It isn't that hard to figure out. When you start taking an analogy literally you are missing the whole point of using an analogy.

Spacetime can only expand or contract when the objects move.

Please support this claim with evidence.

 

[Justatruthseeker]

Hmmm. I'm not sure I actually agree with you, in fact I'm sure I do not.

"Spacetime" (as in object movement) expansion/contraction is a *prediction* of GR, but not 'space' expansion. That's ultimately the claim that was never demonstrated. It's true that spacetime would tend to expand or contract on it's own, but this kind of movement is related to *object* movement, not "space expansion/contraction'. You're effectively *intentionally* blurring the meaning of the formulas from my vantage point. You and I can both agree that GR predicts the expansion or contraction of spacetime, but we cannot agree that it relates to 'space' expansion/contraction. You're simply "misinterpreting the meaning" of the formulas IMO to see what you wish to see, not what's actually there.

No, don't fall for the trap. GR plainly states that it is *Matter* that causes spacetime to bend, and nothing else at all. And only as it is bent by matter, does it "dare we say move"? Is it not "frozen in" around binary pulsars to explain the light-time needed from one to the other because of their orbital speed? Is it not "Frozen in lock-step" to explain how it avoids the light-time delay devastating to planetary orbits because of transit delay and aberration?

Conveniently they forget this so they can now make it expand to meet their incorrect theory on redshift and supernova. Such would destroy their frozen in concepts. We know redshift is due to plasma, and we know how well their theory on our sun has worked out, so distant supernova prove accelerating expansion, really? I'd say they still don't understand a relatively stable star like the sun, let alone any highly electrically active, or that had their Double Layer collapse.

Yes, GR is an excellent theory for describing matter in close confines, it works quite well in the solar system. But we all know that this is its limit. Why? Because it is based on the 1% of matter we observe on this Earth, that we have used to base theories on the other 99%, plasma.

We have just recently begun to study its behavior in space, and our lessons have just begun. Right now the majority are in High School getting ready to be sent back to Kindergarten.

 

[Justatruthseeker]

Wiggling and wobbling. Space and time.

So what is spacetime composed of that it can bend and expand and make clocks wobble and rulers wiggle? Does this mean spacetime wobbles and wiggles too since spacetime tells matter how to move? Is a proton bending spacetime so the electron knows how to orbit? I am truly curious as to how nothing does this since spacetime is not composed of an ether? And if it is composed of something that can be bent and expand and wiggle and wobble, shouldn't we at least reconsider ether theories too?

 

[essentialsaltes]

Is a proton bending spacetime so the electron knows how to orbit?

I know this will make you happy, so I will answer this question. Gravity or GR is negligible in atoms, so electromagnetism is the primary force that determines the binding of electrons to the nuclei in atoms.

shouldn't we at least reconsider ether theories too?

No, the Michelson-Morley experiment (and its subsequent refinements) destroyed the ether. Unless you have some new way to interpret those results -- and many have tried (unsuccessfully) -- the ether is gone.

 

[Michael]

From the standpoint of GR, an empty universe is one without matter or radiation. i.e. the elements of the stress-energy tensor are zero.

Ah, sort of like mystical astronomy, like asking the question: What is the sound of nothing expanding?

The spacetime, obviously.

Um, I hate to be the bearer of bad news and all, but no mass/energy, no 'spacetime'. You're trying to remove the physical *cause* from the equation (mass/energy), and turn the equation into "reality". Sorry, you're mystical supernatural brand of spacetime doesn't exist. It's literally 'nothing' at that point. You're trying to make nothing do expansion tricks. Epic fail. There is no spacetime to expand if nothing exists.

GR gives us a differential equation for the metric of spacetime, not the stuff living in spacetime.

Again, you're just tinkering with a mythical brand of gravity which you cannot actually demonstrate on Earth. It's apparently an act of faith on the part of the believer that the trumped up *mathematics* of "nothing" has meaning without physical substance. I'm afraid you blew the doors off of your own claims when you turned 'spacetime' into "nothing" and then claimed that GR applies to nothing.

Sure you can. GR says that Einstein's tensor equals the stress-energy tensor. If there's no mass or energy, the right hand side is zero. Even in this simple case, you can have expanding spacetime.

You have nothing to expand, nothing to contract, nothing to actually "do" anything, give geometry to anything, or to create "spacetime". All you have is a mythical expanding nothing, which of course cannot and does not show up in the lab.

Wrong. As I've demonstrated, wobbling can occur even in the absence of mass and energy.

No, you didn't "demonstrate" your claim at all, you *alleged it all the way*. Your claims simply do not 'add up'. Without mass/energy, there is no 'spacetime'. That seems to be the nature of your error in a nutshell. You've turned GR theory into pure mysticism by trying to remove the mass/energy and still claim that "General Relativity" applies to absolutely "nothing". I think you just shot your entire argument in both feet, several times in fact.

Correct, it is the spacetime that is expanding in this analogy.

Your analogy is a bit like asking what is the sound of a universe with nothing in it, or in your case what is the curvature of a universe with nothing in it. There is no net curvature with *nothing* because gravity is a function of *mass/energy*. Without mass/energy, no curvature, no gravity, no spacetime, and no expansion/contraction of spacetime is possible.

 

[Michael]

No, don't fall for the trap. GR plainly states that it is *Matter* that causes spacetime to bend, and nothing else at all.

You're right, that is apparently their problem in a nutshell. They refuse to accept the whole concept of physical cause/effect. The mass/energy, and specifically the concentration of mass/energy is the *cause* of spacetime curvature in GR theory. They want to try to remove the physical *cause* from the equations themselves, still keep the equations, and then elevate the equations to "god like" metaphysical status, *without* any mass/energy to give the equations any physical meaning.

The whole claim about space expansion in one big shell game, one big bait and switch routine, and one giant example of metaphysical "woo" on a stick.

In no other branch of physics would this sort of nonsense be tolerated, let alone elevated to the status of 'science'. What pure hokum.

 

[Michael]

What, the theory is wrong because there is no analogy that satisfies you?

Actually it's a combination of factors, including the bait and switch routines, the "expansion of nothing" claims that you make, and your belief that you can simply remove the concept of physical cause/effect from GR theory. I'm afraid you and I will *never* see eye to eye about the meaning of GR theory in the absence of matter/energy. There is no "meaning" at all at that point. There's *nothing* to expand, *nothing* to contract, and *nothing* to apply GR formulas to. What you've effectively done is kludged a "blunder" theory together based on purely metaphysical claims, none of which you could *ever* hope to demonstrate on Earth.

As I said before, apparently your "pure faith" in the unseen (in the lab) is *far* stronger than any "faith" I've ever had in anything. I can live with "living on faith" in something that at least *might* be demonstrated in lab one day, even if not in my lifetime. You're however apparently content to "have faith" in a concept that *can never* be demonstrated in controlled experimentation. How would one even create an experiment made of "nothing"?

I have no clue what you're trying to apply any energy tensors *to* in the first place *without* matter/energy.

 

[Michael]

Then why keep claiming it?

For the very same reason you folks keep claiming the exact opposite. If you can handwave away and provide no empirical experimental support, I can do the same. You epically failed to demonstrate your claims so I have every right to simply ignore them for lack of evidence.

The baloon is only an analogy. Why don't you understand that?

It's a blatant bait and switch device. Why don't you understand that? If you did something like that in the 'real world' of business, you'd be sued out of existence in a hurry, or the government would close your doors for you. You can't *bait* people with one claim and *switch* your unsupported claims in the back door in the business world.

Essentialsaltes puts it best:

"GR gives us a differential equation for the metric of spacetime, not the stuff living in spacetime."

It's entirely clear based upon his statements about "nothing' being 'spacetime' that he's not describing the physics of matter/energy (as does GR), he's trying to apply GR theory to an imaginary nothing, and make "nothing' do supernatural expansion tricks. Sorry, that just won't fly with me, and it will never fly in the lab.

You are forgetting that it is an analogy. It is only meant as an illustration, not a one-to-one example. Just because the analogy uses flexible rubber does not mean that space is made of flexible rubber. It isn't that hard to figure out. When you start taking an analogy literally you are missing the whole point of using an analogy.

Your so called 'analogy' is not an analogy, it's a bait and switch device. Any confusion caused by such a device is *intentional* to begin with. Blaming me or anyone else for such confusion is pure nonsense. You're the one using bait and switch devices and *intentionally* trying to use them to support *your unsupported claims*!

Please support this claim with evidence.

I just did that in my discussion with E over his mythical expanding nothing claim. In a universe devoid of matter/energy, there is no spacetime, and no spacetime curvature. There is no expansion, and no contraction of "nothing".