Multiverse Cosmologies?

[ChildInAZoo]

How is science to advance if nobody ever comes up with new theories?

Science advances via new theories that are testable and which relate to reality, not to speculative woo that sneers at good science by good scientists who find it difficult to get their papers into journals. There's professional physicists out there with their feet on the ground who can't get into print and who can't get into the media because of trash like "string theory is the only game in town" along with branes and time travel and parallel worlds.

I thought you read Lee Smolin; he has personally documented many different alternatives to string theory not including the one that he works on. He also documents that string theory is only prominent in North America.

[Farsight]

There you go again, Farsight. You didn't get my point about how atomism could easily be dismissed as an absurd speculation before the 20th cy.

Amazing. You still haven't done any research whatsoever. Atomism was accepted in the 19th century. The electron was discovered in 1896. It's a sub-atomic particle.

Horseshit. All of it is consistent with constant c -- that's the way that relativity works out, and no amount of quote mining can change that.

Again, you're in denial. What do you think time dilation is? Two 299,792,458 m/s measurements are not the same when the seconds are different.

The space-time metric imposes a distinction between spacelike, timelike, and lightlike (null) directions. We have a well-defined direction of time because we move in a timelike trajectory through space-time.

No, we don't move through space-time. Don't you ever take anything in? You can't move through space-time because you need time to move, and that means you'd need an another time dimension! And there isn't one.

Like who?

I'm not saying.

You're full of denial and delusion lpetrich. Your multiverse is absurd, and it isn't science.

[ChildInAZoo]

There you go again, Farsight. You didn't get my point about how atomism could easily be dismissed as an absurd speculation before the 20th cy.

Amazing. You still haven't done any research whatsoever. Atomism was accepted in the 19th century. The electron was discovered in 1896. It's a sub-atomic particle.

You didn't read what he wrote and thus you did not understand his point.

Horseshit. All of it is consistent with constant c -- that's the way that relativity works out, and no amount of quote mining can change that.

Again, you're in denial. What do you think time dilation is? Two 299,792,458 m/s measurements are not the same when the seconds are different.

Time dilation is something that one identifies between frames. Since you deny the existence of frames, it seems that you cannot accept time dilation. Regardless, claiming that the speed of light is a constant c is something that does not depend on time dilation. It is rather the reverse, as Einstein demonstrated in 1905.

The space-time metric imposes a distinction between spacelike, timelike, and lightlike (null) directions. We have a well-defined direction of time because we move in a timelike trajectory through space-time.

No, we don't move through space-time. Don't you ever take anything in? You can't move through space-time because you need time to move, and that means you'd need an another time dimension! And there isn't one.

All one needs for motion is an index. Learn the relevant geometry.

Like who?

I'm not saying.

So we are supposed to simply take your statements on faith? Thank you, Pope Farsight.

And I am still waiting for the evidence that you used to determine that "spatial" gravity can account for exactly the rotation curves of galaxies (and galaxy clusters and the CMB anisotropies...).

[Farsight]

You didn't read what he wrote and thus you did not understand his point.

I read what he wrote and understood his point exactly. I pointed out that one can apply his "point" to the existence of fairies, and I pointed out that the evidence of atomism long predated the 20th century, by which time atomism was considered to have been proven and evidence existed for sub-atomic particles. He still won't admit his error, and for you to side with him merely illustrates your dishonesty.

Time dilation is something that one identifies between frames. Since you deny the existence of frames, it seems that you cannot accept time dilation. Regardless, claiming that the speed of light is a constant c is something that does not depend on time dilation. It is rather the reverse, as Einstein demonstrated in 1905.

You know full well that I do accept it. I explain it in Time Explained. And I've merely denied the existence of reference frames as real observable phenomena as opposed to artefacts of measurement. Plus I talk at length about Einstein's 1905 postulate and his later move to a variable speed of light in How gravity Works.

So we are supposed to simply take your statements on faith? Thank you, Pope Farsight.

No, you examine the copious evidence that I offer. But I will not divulge the names of those physicists who share privy information with me.

And I am still waiting for the evidence that you used to determine that "spatial" gravity can account for exactly the rotation curves of galaxies (and galaxy clusters) and the CMB anisotropies.

We all know that mathematics isn't evidence. And we all know that any mathematics I offer will not distinguish between energy in the form of spatial energy and energy tied up as matter. So we all know that your repeated wailing is a sham, and that you refuse to accept a very simple explanation because it demolishes the case for WIMPs. Here it is again:

Note that it’s energy that causes gravity, not matter per se. Matter only causes gravity because of the energy content. See The Foundation of the General Theory of Relativity and look at page 185 where Einstein says "the energy of the gravitational field shall act gravitatively in the same way as any other kind of energy". A gravitational field is a region of space that contains extra energy and in itself causes gravity, hence an integration approach is required, as per page 201. But we don't consider a gravitational field to be dark matter. We don’t go looking for WIMPs. Yes, space is "dark", and the mass of a system is a measure of its energy content, so if you defined the space around a planet as a system, it has a mass of sorts. But it isn’t matter. It’s just space. What did Einstein say about space? Neither homogeneous nor isotropic. What does the FLRW metric say? ”The FLRW metric starts with the assumption of homogeneity and isotropy of space.” Spot the difference? Gravitational anomalies aren’t evidence for dark matter. Dark matter is just a hypothesis that attempts to explain them. And those who promote it sweep the raisins-in-the-cake analogy under the carpet. The universe expands, but the space within the galaxies doesn’t, because galaxies are gravitationally bound. So each and every galaxy is surrounded by a halo of inhomogeneous space. That’s a gμν gradient. It’s a gravitational field without any matter on the end of it. So when you hear people talking about the hunt for dark matter, bear this in mind.

[lpetrich]

There you go again, Farsight. You didn't get my point about how atomism could easily be dismissed as an absurd speculation before the 20th cy.

Amazing. You still haven't done any research whatsoever. Atomism was accepted in the 19th century. The electron was discovered in 1896. It's a sub-atomic particle.

The electron could have been interpreted as a continuous fluid.

Turning to atomism in more detail, the main empirical evidence for it before the 19th cy. was mixture and diffusion and the like. However, that could be interpreted as blobs of continuous materials getting intermixed, so that was a weak argument for atomism. In fact, an opponent of atomism could say "Look around you! The materials of our world look continuous!! No granularity in sight!!!"

Toward the end of the 18th cy., French chemist Joseph Louis Proust showed that some mixtures obeyed a "law of definite proportions"; we now call them compounds. A few years later, John Dalton expanded on Proust's work, proposing a table of atomic weights. His successors found flaws in his molecular formulas and proportion values, but the basic idea was sound. In the second half of the 19th cy., the kinetic theory of gases provided more support for atomism. Also supporting atomism was the study of crystalline structure. Every type of crystal shape could be interpreted as produced by repetition of some building block over some lattice.

But some physicists were still not convinced that atoms existed, notably Ernst Mach. In fairness to them, there was still no observation that could be related to an absolute size or mass of an atom -- only relative sizes and masses.

But all that was to change in the early decades of the 20th cy. Einstein and Smoluchowski worked out an expression for the Brownian-motion diffusion constant as a function of temperature and drag coefficient, and in 1908, Perrin found it to be correct. Soon after, Ernest Rutherford and his colleagues did some alpha-particle scattering experiments on gold foil. Most of the alphas kept going forward, though often with some deflection. The more deflection, the fewer scattered, but they discovered a great surprise: some alphas were being scattered backward! Yet more evidence for the existence of atoms -- and even evidence that "atoms" are a misnomer. This was soon followed by X-ray diffraction experiments with crystals. The scattered X-rays emerged in well-defined directions, as if those crystals were acting like diffraction gratings. At that time, Millikan did his famous oil-drop experiments, thus finding the elementary electric charge. Niels Bohr worked out his "Bohr atom" model about then with the help of early quantum mechanics, thus explaining the spectra of hydrogenlike atoms. Complete with agreement between the observed value of the "Rydberg constant" and its prediction from other measured values.

So by 1915, the existence of atoms became very strongly supported, as a result of several lines of research, and I don't know of any notable physical scientist who has denied their existence since then.

[lpetrich]

What do you think time dilation is?

A side effect of the relativity of time and the constancy of c.

No, we don't move through space-time.

Yes we do. We trace out a trajectory in it.

(responding to ChildInAZoo)

I read what he wrote and understood his point exactly. I pointed out that one can apply his "point" to the existence of fairies, and I pointed out that the evidence of atomism long predated the 20th century, by which time atomism was considered to have been proven and evidence existed for sub-atomic particles. He still won't admit his error, and for you to side with him merely illustrates your dishonesty.

The case wasn't quite as strong in the 19th cy. In particular, there was no way to get absolute sizes and masses of atoms, as opposed to relative ones.

And I am still waiting for the evidence that you used to determine that "spatial" gravity can account for exactly the rotation curves of galaxies (and galaxy clusters) and the CMB anisotropies.

We all know that mathematics isn't evidence.

Yes, it is, for quantitative hypothesis testing. Farsight, it's no wonder that your papers get rejected. They involve rejecting a VERY powerful and successful method for testing hypotheses.

And we all know that any mathematics I offer will not distinguish between energy in the form of spatial energy and energy tied up as matter.

That's a VERY bad excuse for not trying to construct testable hypotheses about it.

[ChildInAZoo]

And I am still waiting for the evidence that you used to determine that "spatial" gravity can account for exactly the rotation curves of galaxies (and galaxy clusters) and the CMB anisotropies.

We all know that mathematics isn't evidence. And we all know that any mathematics I offer will not distinguish between energy in the form of spatial energy and energy tied up as matter. So we all know that your repeated wailing is a sham, and that you refuse to accept a very simple explanation because it demolishes the case for WIMPs.

All we need to see is that you can use "spatial" gravity to actually describe a single physical system. So far the evidence is that you cannot.

[Farsight]

Noted re the atomism history. But the Rutherford "rebound" was evidence of atomic structure rather than evidence of atoms, see http://en.wikipedia.org/wiki/Rutherford_model.

What do you think time dilation is?

A side effect of the relativity of time and the constancy of c.

That isn't what it is. It's local motion occuring at a reduced rate. It happens if you take a fast trip through space or when you go to a region of low gravitational potential. The measured constancy of c is because you're subject to an immersive scale change. Electromagnetic and other processes are going slower, but you're "made of light" so you can't measure this locally. That's all it is. There's no magic or mystery or magic to it. The evidence is there in what clocks do, in the definition of the second as per the NIST fountain clock, in the Shapiro delay, the GPS clock adjustment, etc. And it's still relativity. But people would rather believe in time travel, then alternate histories, and so on. People just love their woo. And that doesn't just apply to spiritualists and creationists.

No, we don't move through space-time.

Yes we do. We trace out a trajectory in it.

No, we don't. That trajectory is a worldline in a block universe. You don't travel along it. There is no motion in the block universe. This is a really important point, don't dismiss it, think it through.

That's a VERY bad excuse for not trying to construct testable hypotheses about it.

That's the truth of it. Variations in energy density result in gravity, regardless of how that energy is configured. When you see a gravitational anomaly, you know that the energy density isn't in line with what you'd infer from the visible matter. But you don't know that invisible matter accounts for the difference.

[ChildInAZoo]

No, we don't. That trajectory is a worldline in a block universe. You don't travel along it. There is no motion in the block universe. This is a really important point, don't dismiss it, think it through.

Holy crap! People have been "thinking through" 4D space-time geometries since Descartes! There is an entire history of explanations of what it means to move through these geometries that does not appeal to any idea of a block universe. You are the one parading your ignorance here, and it is ignorance that has arisen because, for whatever reason (fear?), you have avoided learning the relevant mathematics.

[lpetrich]

What do you think time dilation is?

A side effect of the relativity of time and the constancy of c.

That isn't what it is. It's local motion occuring at a reduced rate.

What do you mean by "rate"? Is it a meaningful concept in the absence of time?

There's another thing, Farsight. Why do you continually imply that "the evidence" only supports your theories and no others?

(empty denial of space-time trajectories...)

That's a VERY bad excuse for not trying to construct testable hypotheses about it.

That's the truth of it. Variations in energy density result in gravity, regardless of how that energy is configured. When you see a gravitational anomaly, you know that the energy density isn't in line with what you'd infer from the visible matter. But you don't know that invisible matter accounts for the difference.

Empty word-drool. No wonder your papers don't get accepted.

[Farsight]

What do you mean by "rate"? Is it a meaningful concept in the absence of time?

Yes it's meaningful. You measure time with a clock. A clock clocks up some regular cyclic local motion. If it's a mechanical clock it's the motion of cogs and gears. If it's a quartz clock it's the oscillations of a crystal. If it's an atomic clock it's the microscopic oscillations of an atom resulting in microwaves. When the clock runs slow the rate of motion is slow. You compare one rate of motion with another. That's it. That's all time dilation is. There is no time flowing or any travelling through time.

(empty denial of space-time trajectories...)

Yours is the denial lpetrich. We don't move through spacetime. We move through space, not time, and not spacetime. A world line isn't something you move along. It's just a plot that combines your macroscopic motion through space with the microscopic motion within your electrons, atomic clocks, etc.

There's another thing, Farsight. Why do you continually imply that "the evidence" only supports your theories and no others?

I don't imply that. And these aren't "my theories". But you do continually ignore scientific evidence.

[lpetrich]

What do you mean by "rate"? Is it a meaningful concept in the absence of time?

Yes it's meaningful. You measure time with a clock. A clock clocks up some regular cyclic local motion. ...

But how does one determine that it's regular without using the concept of time? Seems to me like the stolen-concept fallacy - using what you are trying to refute to refute something.

(empty denial of space-time trajectories...)

Yours is the denial lpetrich. We don't move through spacetime.

Farsight, I've done some professional work in relativitstic physics, though it was long ago. Space-time trajectories were an important part of that work. Since you are such a big believer in quote mining, I'd like to ask you why you have chosen to ignore Albert Einstein's stating that space-time is a unified continuum.

There's another thing, Farsight. Why do you continually imply that "the evidence" only supports your theories and no others?

I don't imply that. And these aren't "my theories". But you do continually ignore scientific evidence.

Farsight, do you have any better argument than failing to understand what I've posted? I haven't ignored ANY of your so-called "evidence".

[Farsight]

But how does one determine that it's regular without using the concept of time? Seems to me like the stolen-concept fallacy - using what you are trying to refute to refute something.

You still use the concept of time, but you shed the bit that says you can travel through it. There's no evidence for that. None whatsover. it's just a figure of speech. You take note of this lack of evidence, and you adjust your concept of time to match the evidence that is there. Clocks clock up motion. You measure motion against some other motion. Then you assert it's regular. It always comes down to motion in the end. You don't need time to have motion, you need motion to have time. Stop the clock, and you stop motion, not time. Ditto if you freeze the frame.

Farsight, do you have any better argument than failing to understand what I've posted? I haven't ignored ANY of your so-called "evidence".

Huh? My argument is so good that you can't touch it, I understand everything you've posted, and for the cherry on the cake: you've ignored all the evidence that backs up what I say. Like pair production, electron spin angular momentum, magnetic dipole moment, the Einstein-de Haas effect, and so on. You ignore it all. And yet you believe in woo for which there is no evidence. Like the multiverse.

Quack quack quack.

[lpetrich]

You still use the concept of time, but you shed the bit that says you can travel through it. There's no evidence for that. None whatsover. it's just a figure of speech.

Farsight, no wonder you can't get published in reputable journals. The concept of space-time trajectories is an important part of relativity. It's considering such trajectories that the concept of light cones was devised. Haven't you ever heard of light cones?

[ChildInAZoo]

Yes it's meaningful. You measure time with a clock. A clock clocks up some regular cyclic local motion. If it's a mechanical clock it's the motion of cogs and gears. If it's a quartz clock it's the oscillations of a crystal. If it's an atomic clock it's the microscopic oscillations of an atom resulting in microwaves. When the clock runs slow the rate of motion is slow. You compare one rate of motion with another. That's it. That's all time dilation is. There is no time flowing or any travelling through time.

Weirdly enough, Farsight is half-right here. Einstein used similar reasoning about just letting clocks do what they will to define an arbitrary reference frame in GR. But then this leads to the need to have generally covariant formulations for physical laws and Farsight clearly does not understand this.