Multiverse Cosmologies?

[lpetrich]

I think that for as long as humanity existed, people have wondered what's over the horizon -- are there places like the ones they are familiar with? It turns out that there are -- the rest of the Earth's surface.

The sky? The first one to try to measure the sizes of the Sun and the Moon was Aristarchus of Samos about 2300 years ago. He did a good job with the Moon, but the Sun was too far for his method to be accurate. The next step forward was taken nearly 2000 years later; Galileo used a telescope on the Moon 400 years ago. The Moon was already known to be blotchy, but Galileo saw mountains and craters on it, and he showed that the Moon's phases were due to different illuminations of it by the Sun. Here was another world. Looking at the other planets, Venus had phases like the Moon, Jupiter had 4 moons, and Saturn - ? His successors looked in more detail, and even sent spacecraft across the Solar System. Other worlds, yes, but desolate ones.

Outside the Solar System? The first successful distance measurement was of a nearby star by Friedrich Bessel in 1838. As astronomers measured the distances to more and more stars, they concluded that the Sun was a rather ordinary star. They also discovered that many stars were part of multiple star systems, and they asked if other stars could have planets. Our planets formed from material left over from the Sun's formation, and the same could happen at other stars. In recent years, astronomers have indeed discovered both planets and protoplanetary disks orbiting other stars.

Outside our Galaxy? A century ago, there was a big controversy over whether "spiral nebulae" were really systems like our Galaxy; there was even a "Great Debate" on that subject in 1920. It turned out that they were indeed such systems, which is why they are now called galaxies.


I now get to my main subject. Wikipedia has a nice article on the Multiverse, distinguishing between several types. I'll only be concerned with the first two, however.

The first type is rather trivial -- it's the parts of our Universe that are inaccessible to us. According to inflationary cosmology, the inflation phase must have lasted at least 60 e-foldings. Since it is unlikely to have stopped at 60, there must be MUCH more Universe than what is accessible to us.

The second one is the interesting one. In chaotic-inflation cosmology, lots of "bubble Universes" can form with different symmetry-breaking patterns, thus giving them different effective laws of physics. The same thing could happen as a result of Lee Smolin's fecund-universes theory. He proposes that a collapsing black hole produces a new Universe, one that can have different effective laws of physics. Thus, our Universe could be the sort of Universe that most efficiently produces black holes.

The string-theory "landscape" has as many as 10500 ground states. These could correspond to sets of effective laws of physics in bubble Universes, thus producing as many as 10500 possibilities. String theory thus naturally provides a way to produce a multitude of different bubble Universes.


Now to the question of fine tuning. There are many fine-tuning claims that are unsupportable, to put it mildly. The Earth may seem fine-tuned for us, but it is one of an enormous number of planets in the observable Universe, so even if the Earth is very improbable, it is likely not too improbable to happen in our Universe.

But there are a few features that are convenient for us, like the Universe's 3+1 space-time dimensionality. More time dimensions, and we don't have a well-defined direction of time. Fewer space dimensions, and it may be difficult for much complexity to form. More space dimensions, and there won't be any stable orbits. Even so, nearly all of our Universe is inhospitable to us, as if our Universe is barely habitable.

A multiverse cosmology could easily explain such borderline habitability. If most universes are uninhabitable, then the most likely habitable universes are those barely across the line into habitability. Which is the sort of Universe that we see.

I will concede that this is all rather speculative, and that we lack any way of getting access to these other putative universes. But it does explain our Universe's borderline habitability.

[Rum]

Well, so would a God!

Not to dismiss your post - for which thanks as it is interesting! Speculative though as you say.

[Farsight]

I think that for as long as humanity existed, people have wondered what's over the horizon -- are there places like the ones they are familiar with? It turns out that there are -- the rest of the Earth's surface.

The sky? The first one to try to measure the sizes of the Sun and the Moon was Aristarchus of Samos about 2300 years ago. He did a good job with the Moon, but the Sun was too far for his method to be accurate. The next step forward was taken nearly 2000 years later; Galileo used a telescope on the Moon 400 years ago. The Moon was already known to be blotchy, but Galileo saw mountains and craters on it, and he showed that the Moon's phases were due to different illuminations of it by the Sun. Here was another world. Looking at the other planets, Venus had phases like the Moon, Jupiter had 4 moons, and Saturn - ? His successors looked in more detail, and even sent spacecraft across the Solar System. Other worlds, yes, but desolate ones.

Outside the Solar System? The first successful distance measurement was of a nearby star by Friedrich Bessel in 1838. As astronomers measured the distances to more and more stars, they concluded that the Sun was a rather ordinary star. They also discovered that many stars were part of multiple star systems, and they asked if other stars could have planets. Our planets formed from material left over from the Sun's formation, and the same could happen at other stars. In recent years, astronomers have indeed discovered both planets and protoplanetary disks orbiting other stars.

Outside our Galaxy? A century ago, there was a big controversy over whether "spiral nebulae" were really systems like our Galaxy; there was even a "Great Debate" on that subject in 1920. It turned out that they were indeed such systems, which is why they are now called galaxies.

Good stuff.

I now get to my main subject. Wikipedia has a nice article on the Multiverse, distinguishing between several types. I'll only be concerned with the first two, however.

The wikipedia article introduces Tegmark's classification. Max Tegmark is the author of The Mathematical Universe which was accepted by Foundations of Physics in September 2007 (see other thread!) This paper proposes that "our physical world is an abstract mathematical structure". According to Tegmark, "there is only mathematics; that is all that exists.” See this Discover interview. Also see the wikipedia article, which says "It has been forcefully criticised", and "many scientists have raised the point that the MUH is not empirically testable, and therefore does not constitute a scientific theory". Further down you can read "Tegmark[11] has replied to some of these criticisms by positing an External Reality Hypothesis (ERH), stating that an external physical reality exists independently of humans. Tegmark argues that given a sufficiently broad definition of mathematics, the ERH implies the MUH. He then formalizes the Ultimate Ensemble as the 'Level IV Multiverse'". So you, with demonstrable disregard for scientific evidence, are discussing the first of two classifications from a guy who thinks the world is made out of mathematics. LOL. Not a good start, lpetrich.

The first type is rather trivial -- it's the parts of our Universe that are inaccessible to us. According to inflationary cosmology, the inflation phase must have lasted at least 60 e-foldings. Since it is unlikely to have stopped at 60, there must be MUCH more Universe than what is accessible to us.

I'm happy with elements of inflation theory, though not with all aspects. For example the "inflaton field" is hypothetical, and there are significant issues with proper time in e-foldings. I don't have an issue with significant parts of the universe being beyond our particle horizon. However when we turn back to the wikipedia article we see this:

Level I: Beyond our cosmological horizon
A generic prediction of cosmic inflation is an infinite ergodic universe, which, being infinite, must contain Hubble volumes realizing all initial conditions.

Accordingly, an infinite universe will contain an infinite number of Hubble volumes, all having the same physical laws and physical constants. In regard to configurations such as the distribution of matter, almost all will differ from Earth's Hubble volume. However, because there are infinitely many, far beyond the cosmological horizon, there will eventually be Hubble volumes with similar, and even identical, configurations. Tegmark estimates that such an identical volume should be about 10^10^115 meters away, (a number larger than a googolplex).

I'm afraid this is speculative sleight-of-hand. We've gone from "a larger universe than we can see" to "an infinite universe" with "an infinite number of Hubble volumes". We have no evidence whatsover to support this claim.

The second one is the interesting one. In chaotic-inflation cosmology, lots of "bubble Universes" can form with different symmetry-breaking patterns, thus giving them different effective laws of physics...

Darn. I have to go. I'll get back to you.

[lpetrich]

... So you, with demonstrable disregard for scientific evidence, are discussing the first of two classifications from a guy who thinks the world is made out of mathematics. LOL. Not a good start, lpetrich.

Farsight, that's an effort in guilt by association that would make a creationist proud. I'm discussing the multiverse question independently of Max Tegmark's more far-out hypotheses.

I'm happy with elements of inflation theory, though not with all aspects. For example the "inflaton field" is hypothetical, and there are significant issues with proper time in e-foldings. I don't have an issue with significant parts of the universe being beyond our particle horizon.

I'm pleasantly surprised, though I don't see how an inflaton particle could meet Farsight's exacting standards of proof as regards elementary particles.

From the amount of primordial fluctuations that survived the inflationary epoch, one can estimate the mass scale of the inflaton, and it's about 1015 - 1016 GeV. That's way beyond what our accelerators can produce.

(quote from Wikipedia...)

We've gone from "a larger universe than we can see" to "an infinite universe" with "an infinite number of Hubble volumes". We have no evidence whatsover to support this claim.

If a continually-inflating Universe is infinite in time, it would be hard for it to be finite in space; that is easy to see from the Friedmann-Robertson-Walker cosmological solutions. If it was finite in space, then its total effective size would become smaller and smaller as one looks into the past, until it becomes Planck-sized.

The second one is the interesting one. In chaotic-inflation cosmology, lots of "bubble Universes" can form with different symmetry-breaking patterns, thus giving them different effective laws of physics...

Darn. I have to go. I'll get back to you.

Excellent argument.

[Farsight]

The second one is the interesting one. In chaotic-inflation cosmology, lots of "bubble Universes" can form with different symmetry-breaking patterns, thus giving them different effective laws of physics.

Here it is: http://en.wikipedia.org/wiki/Chaotic_Inflation_theory. Again it's a total speculation. There's no evidence to support the idea of multiple bubble universes. Nor is there any evidence to support different symmetry-breaking patterns and different laws of physics. Even if we allow that different regions of a very large universe are undergoing expansion and the big bang is a local phenomenum, we ought to be treating our own region as typical as per the cosmological rule-of-thumb.

The same thing could happen as a result of Lee Smolin's fecund-universes theory. He proposes that a collapsing black hole produces a new Universe, one that can have different effective laws of physics. Thus, our Universe could be the sort of Universe that most efficiently produces black holes.

Groan: "The theory surmises that a collapsing black hole causes the emergence of a new universe on the "other side", whose fundamental constant parameters (speed of light, Planck length and so forth) may differ slightly from those of the universe where the black hole collapsed. Each universe therefore gives rise to as many new universes as it has black holes. The speed of light varies in our own universe, and it is zero at the black hole event horizon. Nothing happens. A black hole isn't another universe. Note that Lee Smolin is on the Editorial board of Foundations of Physics.

The string-theory "landscape" has as many as 10^500 ground states. These could correspond to sets of effective laws of physics in bubble Universes, thus producing as many as 10^500 possibilities. String theory thus naturally provides a way to produce a multitude of different bubble Universes.

And it's a busted flush that people are kicking into the long grass because after forty years it still predicts nothing and isn't testable. It isn't science, it's doesn't qualify as a theory, it's quackery. We've been through all that.

Now to the question of fine tuning. There are many fine-tuning claims that are unsupportable, to put it mildly. The Earth may seem fine-tuned for us, but it is one of an enormous number of planets in the observable Universe, so even if the Earth is very improbable, it is likely not too improbable to happen in our Universe.

Geddoutofit. Fine-tuning is verging on mythology, and is the sort of thing that Intelligent Design guys use to say look, it's a Goldilocks universe, it must have been deliberately made that way. I suggest you read the wikipedia article instead of trying to pass it off as a given.

But there are a few features that are convenient for us, like the Universe's 3+1 space-time dimensionality. More time dimensions, and we don't have a well-defined direction of time.

And you still haven't read Time Explained! The time dimension is a derived dimension. It's derived from motion through the space dimensions. There is no direction of time, any more than there's a direction of all the ongoing motion in the universe. And "more time dimensions" is just abstract mathematical garbage. Really, how can you possibly speculate on this whilst refusing to understand the time dimension we have already?

Fewer space dimensions, and it may be difficult for much complexity to form. More space dimensions, and there won't be any stable orbits.

Ah, flatland and hyperspace. Wooo!

Even so, nearly all of our Universe is inhospitable to us, as if our Universe is barely habitable.

Barely habitable? When there's trillions of planets out there? Come on, get a grip.

A multiverse cosmology could easily explain such borderline habitability. If most universes are uninhabitable, then the most likely habitable universes are those barely across the line into habitability. Which is the sort of Universe that we see. I will concede that this is all rather speculative, and that we lack any way of getting access to these other putative universes. But it does explain our Universe's borderline habitability.

No it doesn't. The multiverse explains nothing at all. It's a tottering tower of speculation., there's not one jot of evidence for any of it, it isn't testable, and It isn't science at all. It's woo, it's no better than religion. and your quackometer reading is off the scale.

How you can take all this stuff seriously whilst airily dismissing things supported by evidence, like the self-trapped-photon electron, just takes my breath away.

[ChildInAZoo]

Here it is: http://en.wikipedia.org/wiki/Chaotic_Inflation_theory. Again it's a total speculation. There's no evidence to support the idea of multiple bubble universes. Nor is there any evidence to support different symmetry-breaking patterns and different laws of physics. Even if we allow that different regions of a very large universe are undergoing expansion and the big bang is a local phenomenum, we ought to be treating our own region as typical as per the cosmological rule-of-thumb.

Look, we understand that you are not well read in science, but why are you parading your ignorance? At least in this case, you are talking about a somewhat more obscure part of physics. The reason that this speculation has some interest is because the standard model of particle physics itself has examples of symmetry breaking. This seems to be a reasonable thing to use as the basis of hypothesis creation in physics. And while I agree that using our own region as the basis for the beginning of investigation, it is extremely foolish to limit all investigation to the claim that the rest of the universe is like our specific region. As far as distribution of things is concerned, the solar system is not like the Earth, the galaxy is not like the solar system, and the galaxy is not like the universe at larger scales.

The same thing could happen as a result of Lee Smolin's fecund-universes theory. He proposes that a collapsing black hole produces a new Universe, one that can have different effective laws of physics. Thus, our Universe could be the sort of Universe that most efficiently produces black holes.

Groan: "The theory surmises that a collapsing black hole causes the emergence of a new universe on the "other side", whose fundamental constant parameters (speed of light, Planck length and so forth) may differ slightly from those of the universe where the black hole collapsed. Each universe therefore gives rise to as many new universes as it has black holes. The speed of light varies in our own universe, and it is zero at the black hole event horizon. Nothing happens. A black hole isn't another universe. Note that Lee Smolin is on the Editorial board of Foundations of Physics.

What Smolin proposes is exactly another universe in the sense presented in most multiple universe theories under discussion. I know that Smolin agrees with this because I have seen him talk about this on many occasions. People who work on physics often talk to each other. You are shut out of the discussion because you do not meet the basic criterion laid out by Smolin of understanding and being able to use the technical details of the science (and this explicitly includes the mathematical details.)

Now to the question of fine tuning. There are many fine-tuning claims that are unsupportable, to put it mildly. The Earth may seem fine-tuned for us, but it is one of an enormous number of planets in the observable Universe, so even if the Earth is very improbable, it is likely not too improbable to happen in our Universe.

Geddoutofit. Fine-tuning is verging on mythology, and is the sort of thing that Intelligent Design guys use to say look, it's a Goldilocks universe, it must have been deliberately made that way. I suggest you read the wikipedia article instead of trying to pass it off as a given.

Why are you attacking him for a position he does not have? Is it because you lack the reading skills that would allow you to draw any conclusion other than the one you want to reach?

[Farsight]

... So you, with demonstrable disregard for scientific evidence, are discussing the first of two classifications from a guy who thinks the world is made out of mathematics. LOL. Not a good start, lpetrich.

Farsight, that's an effort in guilt by association that would make a creationist proud. I'm discussing the multiverse question independently of Max Tegmark's more far-out hypotheses.

You share some similarities with Tegmark. You're so "lost in maths" that you disregard the scientific evidence I supply for mundane things like time gravity and electromagnetism, and you disregard the lack of scientific evidence for this multiverse bullshit.

I'm pleasantly surprised, though I don't see how an inflaton particle could meet Farsight's exacting standards of proof as regards elementary particles. From the amount of primordial fluctuations that survived the inflationary epoch, one can estimate the mass scale of the inflaton, and it's about 1015 - 1016 GeV. That's way beyond what our accelerators can produce.

I'm happy with inflation, but not with the inflaton. Perhaps we need a separate "big bang" thread as to why.

If a continually-inflating Universe is infinite in time, it would be hard for it to be finite in space; that is easy to see from the Friedmann-Robertson-Walker cosmological solutions. If it was finite in space, then its total effective size would become smaller and smaller as one looks into the past, until it becomes Planck-sized.

There's still no scientific evidence. You're treating mathematics as evidence again. And your smaller-and-smaller inference all the way down to Planck length is another speculation. Einstein cautioned against that. Again let's talk about it on a big-bang thread. I'll start one if you like.

So how have you defended yourself against the charge that the multiverse is a tottering tower of unfounded speculation which is totally unsupported by even a shred of scientific evidence, and is totally untestable? No you haven't. It isn't looking good lpetrich, because if there's no evidence and if it isn't testable, it isn't science, it's pseudoscience. Quackery. Snake-oil. And you're pushing it. What amazes me is that you carry on blindly and you just won't listen to anything you don't like the sound of. But you won't listen to me saying that either. Or anything else.

[colubridae]

because if there's no evidence and if it isn't testable, it isn't science, it's pseudoscience. Quackery. Snake-oil. And you're pushing it. What amazes me is that you carry on blindly and you just won't listen to anything you don't like the sound of.

Mayfair's quote of the month.

[Farsight]

Look, we understand that you are not well read in science, but why are you parading your ignorance?

I'm very well-read thanks, and I'm demonstrating my knowledge.

At least in this case, you are talking about a somewhat more obscure part of physics. The reason that this speculation has some interest is because the standard model of particle physics itself has examples of symmetry breaking. This seems to be a reasonable thing to use as the basis of hypothesis creation in physics.

But it isn't reasonable to then stack hypothesis on top of hypothesis and promote it as science. It's speculation, not science.

And while I agree that using our own region as the basis for the beginning of investigation, it is extremely foolish to limit all investigation to the claim that the rest of the universe is like our specific region. As far as distribution of things is concerned, the solar system is not like the Earth, the galaxy is not like the solar system, and the galaxy is not like the universe at larger scales.

Yes, but to then posit different bubble universes with different laws of physics is pick'n mix speculation, not cosmology. It goes totally goes against the grain of the cosmological principle and the FLRW metric which "starts with the assumption of homogeneity and isotropy of space".

What Smolin proposes is exactly another universe in the sense presented in most multiple universe theories under discussion. I know that Smolin agrees with this because I have seen him talk about this on many occasions. People who work on physics often talk to each other. You are shut out of the discussion because you do not meet the basic criterion laid out by Smolin of understanding and being able to use the technical details of the science (and this explicitly includes the mathematical details.)

I'm not shut out. Your appeal to authority cuts no ice. Smolin's proposal is wrong. A black hole isn't another universe. Shall we have a thread on black holes?

Why are you attacking him for a position he does not have?

I challenged him to start a multiverse thread and said I'll demolish it for the speculative quackery it is. I see you can't defend it.

[ChildInAZoo]

Yes, but to then posit different bubble universes with different laws of physics is pick'n mix speculation, not cosmology. It goes totally goes against the grain of the cosmological principle and the FLRW metric which "starts with the assumption of homogeneity and isotropy of space".

How is science to advance if nobody ever comes up with new theories? In the case of multi-verse theories, even though I disagree with them, I can at least see how one might provide evidence for them.

What Smolin proposes is exactly another universe in the sense presented in most multiple universe theories under discussion. I know that Smolin agrees with this because I have seen him talk about this on many occasions. People who work on physics often talk to each other. You are shut out of the discussion because you do not meet the basic criterion laid out by Smolin of understanding and being able to use the technical details of the science (and this explicitly includes the mathematical details.)

I'm not shut out. Your appeal to authority cuts no ice. Smolin's proposal is wrong. A black hole isn't another universe. Shall we have a thread on black holes?

You are the one appealing to authority. I simply pointed out that you again have Smolin wrong (by citing Smolin, so the appeal is correct) and I again pointed out that you appeal to someone who would reject your "science" out of hand given his own criteria.

Why are you attacking him for a position he does not have?

I challenged him to start a multiverse thread and said I'll demolish it for the speculative quackery it is. I see you can't defend it.[/quote]
Like most of your "answers", this is an evasion. When you do this, you seem transparently insecure.

[lpetrich]

There's no evidence to support the idea of multiple bubble universes. Nor is there any evidence to support different symmetry-breaking patterns and different laws of physics.

Whatever Farsight considers acceptable evidence. Seems like Farsight thinks that everything other than what's well-established at the present time is nothing but wild speculation. That's why I considered what he would have thought of atoms in decades and centuries past, because what's well-established now was also once wild speculation.

(Lee Smolin's black-hole universes...)

Groan: "The theory surmises that a collapsing black hole causes the emergence of a new universe on the "other side", whose fundamental constant parameters (speed of light, Planck length and so forth) may differ slightly from those of the universe where the black hole collapsed. Each universe therefore gives rise to as many new universes as it has black holes. The speed of light varies in our own universe, and it is zero at the black hole event horizon. Nothing happens. A black hole isn't another universe.

I don't know where you mined that quote from, but Lee Smolin himself would not have agreed with variable c. Quote mining Einstein doesn't prove anything, either.

(string theory...)

And it's a busted flush that people are kicking into the long grass because after forty years it still predicts nothing and isn't testable. It isn't science, it's doesn't qualify as a theory, it's quackery. We've been through all that.

By your standards, atomism was also quackery for most of humanity's history.

(Farsight's dismissal of fine tuning...)
I think that it has to be tested rather than dismissed out of hand.

But there are a few features that are convenient for us, like the Universe's 3+1 space-time dimensionality. More time dimensions, and we don't have a well-defined direction of time.

And you still haven't read Time Explained!

I once waded through that big load of bullshit. Space and time are coequal parts of the space-time continuum.

And "more time dimensions" is just abstract mathematical garbage. Really, how can you possibly speculate on this whilst refusing to understand the time dimension we have already?

Multiple time dimensions are not an absolute absurdity. Consider an object's trajectory P(T), its space-time coordinates as a function of its proper time T. That parameter can be generalized as the "affine parameter" for handling null trajectories as well as spacelike and timelike ones. Take the n-velocity
U = dP/dT

The absolute square of the n-velocity is U.g.U, where g is the metric tensor, with its overall sign selected so that U.g.U = +1 for a massive particle.

Select the coordinates so that g is diagonal, which will simplify the analysis. Each component of U will make a contribution to U's absolute square.

The components of U along timelike coordinates will make positive contributions to U.g.U, while the components along spacelike coordinates will make negative contributions to U.g.U -- that's how one defines timelike and spacelike.

So if there is more than one component of U that makes a positive contribution, there is thus more than one time coordinate.

Fewer space dimensions, and it may be difficult for much complexity to form. More space dimensions, and there won't be any stable orbits.

Ah, flatland and hyperspace. Wooo!

Farsight, I'm considering what alternate sorts of universes there can be. Don't you have any imagination?

Even so, nearly all of our Universe is inhospitable to us, as if our Universe is barely habitable.

Barely habitable? When there's trillions of planets out there? Come on, get a grip.

Most of which are inhospitable to us, if the known planets are any guide. Furthermore, there are oodles of more-or-less empty space in the Universe.

The multiverse explains nothing at all. It's a tottering tower of speculation., there's not one jot of evidence for any of it, it isn't testable, and It isn't science at all. It's woo, it's no better than religion. and your quackometer reading is off the scale.

You haven't considered my borderline-habitability argument in any detail.

How you can take all this stuff seriously whilst airily dismissing things supported by evidence, like the self-trapped-photon electron, just takes my breath away.

Because that self-trapped-photon electron is unsupportable -- it doesn't explain why electrons follow the Dirac equation so well.

[lpetrich]

And while I agree that using our own region as the basis for the beginning of investigation, it is extremely foolish to limit all investigation to the claim that the rest of the universe is like our specific region. As far as distribution of things is concerned, the solar system is not like the Earth, the galaxy is not like the solar system, and the galaxy is not like the universe at larger scales.

Yes, but to then posit different bubble universes with different laws of physics is pick'n mix speculation, not cosmology. It goes totally goes against the grain of the cosmological principle and the FLRW metric which "starts with the assumption of homogeneity and isotropy of space".

That's a good approximation for our Universe for size scales greater than the sizes of the largest galaxy clusters. However, it may not be very meaningful in a multiverse, though the basic idea might be, that our Universe is nothing special.

[Farsight]

Whatever Farsight considers acceptable evidence. Seems like Farsight thinks that everything other than what's well-established at the present time is nothing but wild speculation. That's why I considered what he would have thought of atoms in decades and centuries past, because what's well-established now was also once wild speculation.

You were a century out with the atomism. And you dismiss patent evidence like pair production whilst clinging to speculative woo like this multiverse garbage.

I don't know where you mined that quote from, but Lee Smolin himself would not have agreed with variable c. Quote mining Einstein doesn't prove anything, either.

There's direct evidence of variable c. Clocks clock up motion, gravitational time dilation is a fact, and so are light clocks. So your appeal to authority, and what Smolin thinks, doesn't matter.

By your standards, atomism was also quackery for most of humanity's history.

Straw man. Do some research, and have the decency to admit when you got it wrong. You were a century out.

(Farsight's dismissal of fine tuning...) I think that it has to be tested rather than dismissed out of hand.

Bollocks. you know it isn't testable. What are you going to do? Hop across to another universe to check it out? Whilst ignoring gravitational time dilation and the fact that the fine structure constant is a running constant?

I once waded through that big load of bullshit. Space and time are coequal parts of the space-time continuum.

Bullshit. If they're so co-equal,I'll jump back a metre, and you jump back a second.

Multiple time dimensions are not an absolute absurdity. Consider an object's trajectory P(T), its space-time coordinates as a function of its proper time T. That parameter can be generalized as the "affine parameter" for handling null trajectories as well as spacelike and timelike ones. Take the n-velocity U = dP/dT The absolute square of the n-velocity is U.g.U, where g is the metric tensor, with its overall sign selected so that U.g.U = +1 for a massive particle. Select the coordinates so that g is diagonal, which will simplify the analysis. Each component of U will make a contribution to U's absolute square. The components of U along timelike coordinates will make positive contributions to U.g.U, while the components along spacelike coordinates will make negative contributions to U.g.U -- that's how one defines timelike and spacelike. So if there is more than one component of U that makes a positive contribution, there is thus more than one time coordinate.

Surreal. There is no proper time. It's merely a cumulative measure of local motion. Your multiple time dimensions are another confection of speculation. They are absurd.

Farsight, I'm considering what alternate sorts of universes there can be. Don't you have any imagination?

Plenty. But if there's no evidence whatsoever, and never will be because it's insulated from testability, that's when I recognise that it isn't science any more.

Most of which are inhospitable to us, if the known planets are any guide. Furthermore, there are oodles of more-or-less empty space in the Universe. You haven't considered my borderline-habitability argument in any detail.

I have considered it in ample detail. It's absolutely no argument at all. Most of the earth is inhospitable to us. It's called the sea. And the sky. And the interior of the planet. So you're talking rot.

Because that self-trapped-photon electron is unsupportable -- it doesn't explain why electrons follow the Dirac equation so well.

Here we have it. You dismiss patent scientific evidence such as pair production, annihilation, magnetic dipole moment, spin angular momentum, the Einstein-de Haas effect, electron optics, the list goes on. Because of what? An equation? And here you are babbling about the multiverse? When there's no evidence whatsoever? One word, lpetrich: quack.

[Farsight]

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.

In the case of multi-verse theories, even though I disagree with them, I can at least see how one might provide evidence for them.

Like how? Come on, spit it out.

You are the one appealing to authority. I simply pointed out that you again have Smolin wrong (by citing Smolin, so the appeal is correct) and I again pointed out that you appeal to someone who would reject your "science" out of hand given his own criteria.

Not me, I'm pointing to the scientific evidence.

Like most of your "answers", this is an evasion. When you do this, you seem transparently insecure.

LOL. You wish. The only person transperently insecure round here with this multiverse garbage is lpetrich.

[lpetrich]

You were a century out with the atomism.

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. and especially before the 19th cy.

And you dismiss patent evidence like pair production whilst clinging to speculative woo like this multiverse garbage.

Farsight, is making baseless accusations all you can do? I don't dismiss pair production -- it's abundantly observed, and it's well-accounted for in mainstream physics. No wonder you can't get published.

There's direct evidence of variable c. Clocks clock up motion, gravitational time dilation is a fact, and so are light clocks.

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.

By your standards, atomism was also quackery for most of humanity's history.

Straw man. Do some research, and have the decency to admit when you got it wrong. You were a century out.

But before the 20th cy.? That's what I was asking about.

(Farsight's dismissal of fine tuning...) I think that it has to be tested rather than dismissed out of hand.

Bollocks. you know it isn't testable. What are you going to do? Hop across to another universe to check it out?[/quote]

Whilst ignoring gravitational time dilation and the fact that the fine structure constant is a running constant?

You do tests by working out theoretical scenarios to see if they produces universes much like ours.

I once waded through that big load of bullshit. Space and time are coequal parts of the space-time continuum.

Bullshit. If they're so co-equal,I'll jump back a metre, and you jump back a second.

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. Farsight, since you seem to think that quoting authorities is a legitimate form of argument, I will give you a Wikipedia article: Minkowski space

Multiple time dimensions are not an absolute absurdity. (me on how multiple time dimensions would work)

Surreal. There is no proper time. It's merely a cumulative measure of local motion. Your multiple time dimensions are another confection of speculation. They are absurd.

Farsight, you again act as if you have little imagination. I was showing that the idea of multiple time dimensions is not as absurd as it might seem.

Because that self-trapped-photon electron is unsupportable -- it doesn't explain why electrons follow the Dirac equation so well.

Here we have it. You dismiss patent scientific evidence such as pair production, annihilation, magnetic dipole moment, spin angular momentum, the Einstein-de Haas effect, electron optics, the list goes on.

Mainstream physics: the numbers work out right
Farsight physics: qualitative hand-waving
Which is why he can't get published -- his theories are worthless

Because of what? An equation? And here you are babbling about the multiverse? When there's no evidence whatsoever? One word, lpetrich: quack.

Boo hoo hoo hoo hoo. :p

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.

Like who? Farsight, hasn't it ever occurred to you that you can't get published because your theories are worthless?

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.

Like who?