Speed of light

[apodman]

Would it be fair to say that neither a positive nor a negative universe curvature would result in an answer other than infinity? Since the respective <180 and >180 degree total angular sum somehow incorporates base angles that can only be found in singularities. The math in our 4D existence, one would think, would say so. I can only perhaps postulate that the math in the other two scenarios for those beings would be seen as valid for them since length of baselines is a critical factor.

In a purely technical sense, a 2D universe could never have a triangle. And a 3D universe could only have a 2D triangle. I don't feel that our 4D math works in the other two except perhaps on paper. Correct me please if I missed the boat on this one!

It has been a long time since I formally studied General Relativity, and I'm having trouble finding clear explanations that address my questions about the shape of space (or space-time). I may have to dig out Einstein's own explanation and see if I can hack it these days. Your question appears to address the shape of space as it curves into a potential well (a location of mass and source of gravity). Reading various authors' descriptions of what Einstein was supposed to have said leave me not knowing exactly which curvature of space (the shape of the universe in general, or the gravity-assisted ride down to the bottom of a well) he was talking about in which instance. It makes sense to me that the shape/geometry of one would be part and parcel of the other, but that alone doesn't make it so and I can't find anyone who has come out and said so in so many words. It is there that I could use some authoritative help. The triangle represents my hope of visualizing the problem and solution, as we can consider 3D space and 4D space-time while only having to deal with a (perhaps distorted, but nonetheless visualizable) 2D triangle. I think you at least know where the boat is, but - about missing it - I'd have to be fully aboard to know. And I'm still hung up on considering time a linear parameter while all the curvature is in the spatial dimensions, even though I know that all four dimensions are involved in the curvature in the presence of gravity.

[astrolabe]

Hello apodman,

Very good. Your thoughts are rich in the kind quality thinking that makes being a member of this Forum so worthwhile.

[harry]

G'day from the land of ozzzzzzzz

The following paper writes on the intabilities that are within the jets.

http://arxiv.org/abs/0903.2658
Weibel, Two-Stream, Filamentation, Oblique, Bell, Buneman... which one grows faster ?

Authors: A. Bret
(Submitted on 15 Mar 2009

Abstract: Many competing linear instabilities are likely to occur in astrophysical settings, and it is important to assess which one grows faster for a given situation. An analytical model including the main beam plasma instabilities is developed. The full 3D dielectric tensor is thus explained for a cold relativistic electron beam passing through a cold plasma, accounting for a guiding magnetic field, a return electronic current and moving protons. Considering any orientations of the wave vector allows to retrieve the most unstable mode for any parameters set. An unified description of the Filamentation (Weibel), Two-Stream, Buneman, Bell instabilities (and more) is thus provided, allowing for the exact determination of their hierarchy in terms of the system parameters. For relevance to both real situations and PIC simulations, the electron-to-proton mass ratio is treated as a parameter, and numerical calculations are conducted with two different values, namely 1/1836 and 1/100. In the system parameters phase space, the shape of the domains governed by each kind of instability is far from being trivial. For low density beams, the ultra-magnetized regime tends to be governed by either the Two-Stream or the Buneman instabilities. For beam densities equalling the plasma one, up to four kinds of modes are likely to play a role, depending of the beam Lorentz factor. In some regions of the system parameters phase space, the dominant mode may vary with the electron-to-proton mass ratio. Application is made to Solar Flares, Intergalactic Streams and Relativistic shocks physics.

[JimJast]

The triangle represents my hope of visualizing the problem and solution, as we can consider 3D space and 4D space-time while only having to deal with a (perhaps distorted, but nonetheless visualizable) 2D triangle. I think you at least know where the boat is, but - about missing it - I'd have to be fully aboard to know. And I'm still hung up on considering time a linear parameter while all the curvature is in the spatial dimensions, even though I know that all four dimensions are involved in the curvature in the presence of gravity.

Hi, apodman: There may be also curvatures of time-space surfaces (one time dimension and one spatial dimension; unless spatial dimension is in direction parallel to gravitational field). So you may have triangles with non 180 degrees also on time-space surfaces of 4-D spacetime. In Einstein's GR the time side of the triangle is always a little bit shorter than in Euclidean space. Fortunately, all sides of triangle in spatial directions are always a little bit longer than in Eucledean space. That's why in Einstein's GR both effects may compensate for each other in a 4-D spacetime. So spacetime may remain flat in the sense of intrinsic curvature, despite that there are curvatures of 3-D spaces. As I explained before the principle of conservation of energy requires such flat spacetime and Einstein's GR delivers it.

In Wheeler's GR (BBT GR) the spacetime must be curved but which way we don't know since it can't be predicted theoretically how much energy can be created (and stay created, unlike in quantum fluctuations). So the theoretical problem is if we believe Einstein (as I do) or Wheeler (as most astronomers do). So far, to prove that they are right, they had to invent the expansion of space, dark energy, and non conservation of energy in Wheeler's GR (suggesting that there is only one GR discovered by Wheeler -- e.g. Chris didn't answer the question which GR he calls "GR"). They still need to explain the observed acceleration of expansion and why we see just right amount of Hubble redshift complying with the stationary universe model. And last but not least, what's the mechanism of making energy out of nothing. Neither of which is needed in Einsteins GR since Einstein's GR explains all those things with non symmetric metric tensor (while it is symmetric in Wheeler's GR). Wheeler didn't even mention in his 1973 "Gravitation" that Einstein in 1950 admitted that the "metric tensor of spacetime must be non symmetric" since Einstein must have realized that otherwise energy couldn't be conserved (which apparently didn't bother Wheeler).

So if we discuss curvatures we should rather know which GR we consider valid. Einstein's or Wheeler's. They predict different things. At least Chris, as the best informed of us all should explain this. Everybody may think about Einstein's GR while Chris might have in mind Wheeler's.

[aristarchusinexile]

after all, not being a gravity theorist, he didn't likely feel he was missing a lot by skipping gravity conferences

It might be his reason but I worry about creatinists getting into science through cosmology ... ?

Creationists opposed to science? The Word I read says, "science falsely so-called." My understanding is that the author recognized the existance of true science and false science. False science will promote and publish theories as truth, and will neglect promotion of theories casting doubt on the 'truths' of the false science.

[JimJast]

Creationists opposed to science? The Word I read says, "science falsely so-called." My understanding is that the author recognized the existance of true science and false science.

Hi, aristarchusinexile: Science is something that is "true" which means that if we apply it to the real world we get "true" results (such as we expected). If we don't get expected results it might be (except other things) a "false science".

E.g. the Supenove Project was set to confirm that the expanson of universe is decelerating, to prove, as Hawking demanded, that BBT is science. It turned out that BBT is only a "false science" since the result was that the expansion is doing just opposite. To change BBT into science again BBT folks had to reverse the prediction of deceleration through invention of "dark energy" that allegedly causes the acceleration of expansion (how? through action at a distance?), and BBT bacame science again. Only now they have to find this "dark energy" somewhere and explain the mechanism of action at a distance and they'll be all set. Until it turns out sometime in the next century that the expansion of universe is an illusion. Then they can always go back to Einstein's GR which predicted it already that in 1917 ("Some physical theories are often wiser then their creators" [Hertz]). Then they need only to explain why they hadn't noticed it that the Hubble redshift is caused by the time dilation in deep space that always goes with curved space and is proportional to its curvature (and so the Hubble constant is just the curvature of space, times c). But going back to Einstein's GR requires to give up the idea that the universe was created. Which might be painful to creationists and not admissible if creationists are controlling the science by then.

[BMAONE23]

http://www.space.com/searchforlife/0904 ... itten.html
Try publishing your discenting opinions and see if they have merit

[JimJast]

Try publishing your discenting opinions and see if they have merit

I know that they have merit since Einstein already published them and none of them was falsified yet, just not understood. So it looks like progress in science is slow. My opinons that one has to look into Einstein's GR to slove most problems won't make it any faster. So we have to wait until the BB hypohtesis turns out looking so wrong that believing in it would be ridiculous. But then "everybody starts writing papers like mine since then everybody and his brother starts noticing the obvious and everybody jumps on the bandwagon" -- an opinon of one of my physics techers who had the same idea as mine, but knew it is too early for it, and trying to publish it can have only an effect of him losing his job, without the paper being published anyway. Since now every editor and referee believes that the universe is expanding and energy can be created form nothing and it is taught in universities. We have to wait untill all atempts to prove BBT fail and folks start believing that maybe Einstein's GR is right and the universe is not expanding at all? It may take long time though. Till then we may just chat unless we'll be banned also fom this forum for propagating Einstein's GR instead of Wheeler's GR with symmetric metric tensor and all silly things resulting from it.

[The Code]

hi JimJast.

The ''Matter'' that created that huge ''Bang'' in Japan, in 1945 was no more than a crisp Dollar Bill. Something i had to question and try to understand myself. How can all that energy come from such a small thing? There has to be a hidden source of energy.. But i can not see getting energy from nothing is the answer. But i can see getting energy from something undiscovered.. It is my belief, that when they split Atoms/particles they released our creator ( I do not mean God ). Matter/energy after the event horizon takes on another form. A form that we can not comprehend at the moment. It came from there and spends all its time trying to get back there. A project i,m still working on, as every body else is.

Mark

[JimJast]

The ''Matter'' that created that huge ''Bang'' in Japan, in 1945 was no more than a crisp Dollar Bill. Something i had to question and try to understand myself. How can all that energy come from such a small thing? There has to be a hidden source of energy.

There are no hidden source. All this energy is visible to us through its mass since energy=mass*c^2. c^2 is of course 9x10^16Ws/kg, so only 0.1g of mass contains in it more than 20 million kWh of energy and such energy released within a fraction of a second may look spectacular. It's the same energy that in Einstein's theory is called "gravitational energy" from which comes the "gravitational force". The force that looked to many people who didn't understand the mechanism of producing this force like "attraction" through a "spooky action at a distance". No other hidden energy is needed to make stars looking spectacular sometimes when this energy is transformed into kinetic energy in various cosmic events.

[The Code]

Question, WHY they annihilate is not answerable? cos they like each other and want to go home. before the ''BB''
Where is home?

Mark

[aristarchusinexile]

If your 'scientific' definition of 'observation' varies from the common meaning of observation you have strayed from reality.

We've spent enough time discussing the methods of modern science. I'll limit myself to addressing simple factual errors.

Instead of explaining your definition of scientific observation?

I do not have to repeat that BBT and GR are both seriously shaken by recent observations including non-locality, but for the casual visitor to the forum I will and I have done so.

This is completely false. Both theories are stronger than ever. GR is basically accepted as fact by the entire community, and the BBT continues to gain acceptance as additional observations support it, and as the theories are fleshed out.

Neither of us at this point are providing urls or other reference, Chris, so our statements are almost valueless except to express our personal opinions and perhaps stimulate investigation by a curious reader.

[aristarchusinexile]

What is the subject here?

If it's what we think about the paper cited in the initial post, there's not enough information in the abstract to make an informed comment, so that can't be the subject.

So the subject must be the question of whether we think the universe is flat or curved. So if anyone has an explanation of theory or observation that can help decide the issue, let's hear it in terms we can all understand. Because word salad with physics terms does nothing to move the subject forward. And arguing from ignorance only makes you look bad to anyone who can tell the difference (to be clear: Chris, Doum, astrolabe, and I have written things for the attempted good of the thread, while everyone else has simply displayed their own ego while providing no enlightenment whatever).

Ego according to Wikipedia: "the organized realistic part of the psyche is the "ego," http://en.wikipedia.org/wiki/Ego so Apodman's observation is accurate, as so far I seem to be the only person mentioning non-locality and what it might mean to consensus cosmology, and I think I see that non-locality is viewed by the consensus as a threat to consensus cosmology, so it is not surprising I am seen as providing no enlightenment. I have provided urls about non-locality in the past, as well as a list of PHD written books. Of course, if non-locality is classed as 'absurd paranormal speculation' instead of science all discussion on non-locality by the so-classifying person will be biased in the extreme.

http://en.wikipedia.org/wiki/Non_Locality "... Action at a distance is incompatible with relativity ..."

Perhaps a better Wiki statement, one which would open the doorway to consideration and discussion of non-locality, might be, "action at a distance appears incompatible with relativity." However, human discussion seems centred on, as Apodman (forgive me apodman if you see as non-constructive my suggestion which follows) may have made clearer by saying "pride" instead of ego, and pride can dictate construction of sentences to support itself. However again, perhaps the Wiki writer knows something I don't, that non-locality really is incompatible with relativity, in which case, relativity is out because non-locality has been demonstrated in laboratories.

[Chris Peterson]

So the subject must be the question of whether we think the universe is flat or curved. So if anyone has an explanation of theory or observation that can help decide the issue, let's hear it in terms we can all understand.

There's only one answer to that, which is we don't know. The best theories don't require one or the other (because the current state of the Universe is exquisitely sensitive to initial conditions, which are unknown), and the best measurements only tell us that the Universe is very nearly flat, but with a margin of error that would allow it to have a slight positive or negative curvature.

The good news is that this question is answerable, and is likely to be answered with a high degree of certainty in the next few years because of improvements in observations brought about by technical advances.

[aristarchusinexile]

So the subject must be the question of whether we think the universe is flat or curved. So if anyone has an explanation of theory or observation that can help decide the issue, let's hear it in terms we can all understand.

There's only one answer to that, which is we don't know. The best theories don't require one or the other (because the current state of the Universe is exquisitely sensitive to initial conditions, which are unknown), and the best measurements only tell us that the Universe is very nearly flat, but with a margin of error that would allow it to have a slight positive or negative curvature.

The good news is that this question is answerable, and is likely to be answered with a high degree of certainty in the next few years because of improvements in observations brought about by technical advances.

What if the universe is wavey .. flat, but with waves like the ocean? If so, it would be seen to be both flat and curved.

[Chris Peterson]

What if the universe is wavey .. flat, but with waves like the ocean? If so, it would be seen to be both flat and curved.

No, the question of whether the Universe is flat or not has nothing to do with local curvature. Even a flat universe has regions of locally curved space. AFAIK, there's no theory that predicts a flat, wavy universe, but that's a separate issue. Such a universe would be considered flat.

[aristarchusinexile]

What if the universe is wavey .. flat, but with waves like the ocean? If so, it would be seen to be both flat and curved.

No, the question of whether the Universe is flat or not has nothing to do with local curvature. Even a flat universe has regions of locally curved space. AFAIK, there's no theory that predicts a flat, wavy universe, but that's a separate issue. Such a universe would be considered flat.

Well I propose a wavy universe which is not flat, but wavey.

[The Code]

Thought you guys might like to read this,,,,

http://news.bbc.co.uk/1/hi/sci/tech/7440217.stm

Mark

[harry]

G'day from the land of ozzzzz

The paper was writen as a journal a paper to sell.

The logic behind is this. The image shown is about 13.3 Gyrs and at that distance we have 10^9 galaxies observed.

Think of the complexity of just one galaxy containing billions of stars.
Than think of the life of one star being 12 Gyrs phase. Many stars go through many phases and rejuvination.

Now try to work it out.

How can one galaxy form in just 400 million years?
How can a cluster of galaxies form in just 400 million years?
How can a super cluster, which is a cluster of clusters of local clusters of galaxies formed in just 400 million years?

[apodman]

I remember the idea that universes can bubble off their parents enjoying some popularity in the 1980s. Since then, not much has been made of it, ostensibly because such an idea is not easily testable as a scientific theory ideally should be. But maybe the signature in the CMB radiation that this article talks about can suggest a test of sorts, at least to see if such a theory is compatible with other favored and tested ideas. The article is a little soft on science, though, and its reference to the Big Bang is a bit casual - in my thinking, the universe being created by bubbling off a parent universe is an alternative to the Big Bang as opposed to an extension of it, specifically involving a region of space that is far from being a singularity and specifically not involving the creation of matter in a manner consistent with a Big Bang. Lately I'm more given to thinking that "bubbling off" is less a physical separation from a parent universe as just being isolated from the rest of the universe by receding beyond the viewable horizon. Look for references to "Hubble Spheres".

[The Code]

Hi folks.
I will try to explain this the best i can...
Take a look at this picture: http://en.wikipedia.org/wiki/File:Plasma-lamp_2.jpg Take no notice, its a plasma ball. I am using it as a diagram.. If I am able to travel at 3/4 the speed of light I am able to speed time up.. ( This i have read) Time is a physical thing that can be manipulated (This I have also read). If i have the power i can pretty much do as i like with time..

Energy can not be created or destroyed (I have read this also) http://en.wikipedia.org/wiki/Conservation_of_energy
I have for a long time wondered about this. So where is all the energy going?

Back to black holes: I am made of matter. And a black hole is made of matter. The only thing we have in common is Matter at speed, Manipulates time and a black hole has plenty of speed. Spinning on its own axis. I have read that a black hole has that much power it can create a vortex in time.. http://science.nasa.gov/headlines/y2005/16nov_gpb.htm

The, so called big bang created everything, including time.. Scientists are trying to understand why light can not escape a black hole after the event horizon. If a ''black hole'' carves a vortex in time, can light travel back in time? or more over how can an object shine or reflect if its no longer there? Can we see a vortex in space time? Can we see curved space time around our sun? But we know its there, from brilliant scientists who showed us the way..

This takes me back to the Plasma ball.. Take a good look at it, spend some time. http://en.wikipedia.org/wiki/File:Plasma-lamp_2.jpg
In this photo of a plasma ball, i am able to see something which, i am now going to point out. But please try and work out what i,m saying. What i can see, is time Fast forward to the extreme.. The outer edge by the glass sphere, 2 inches
in, that represents where our galaxy,s are. the streams of electrons represent the vortex,s in space time. And the dirty great big thing in the middle ( which does not exist in our space time dimension) Is the reason why our universe is here. and will be here again and again and again... is also the reason why galaxy,s and clusters of galaxy,s have had plenty of time to form...is the reason why light has not had time to traverse our current universe. Can you guys see if this could work please..

I will leave you with one final picture... thanks for reading...http://antwrp.gsfc.nasa.gov/apod/ap070827.html

Mark

[JimJast]

Well I propose a wavy universe which is not flat, but wavey.

What do you propose for the cause of those waves?

[bystander]

Cosmologists 'see' the Cosmic Dawn
Science & Technology Facilities Council, UK
STFC Press Release - 09 February 2009

• Scientists have used a computer simulation to predict what the very early Universe would have appeared like 500 million years after the Big Bang.
  ...
  The work combined a massive simulation showing how structures grow in dark matter with a model showing how normal matter, such as gas, behaves to predict how galaxies grow.

New Model of the Early Universe
Space.com - 17 February 2009

• ... The researchers used a computer simulation of dark matter and added to it normal, or illuminated, matter. ...
  
  While dark matter likely started out in small clumps that got larger over time as gravity pulled those stretches of dark matter together, that's not what the researchers found for normal matter in galaxies.
  
  "The picture we have shows there are big galaxies in place at a very early time," ...

Cosmic Dawn z=8.5 shows the Universe 590 million years after the Big Bang
Cosmic Dawn z=5.7 shows the Universe 1.0 (one) billion years after the Big Bang
Cosmic Dawn z=3.3 shows the Universe 1.9 billion years after the Big Bang
Cosmic Dawn z=0 shows the Universe 13.6 billion years after the Big Bang (ie today)

Lopsided Universe Demands Different Explanation
ScienceNews - 2008 Dec 23

Caltech Researchers Interpret Asymmetry in Early Universe
Science Centric - 2008 Dec 17

• WMAP depicts tiny hot and cold spots, no more than 200 microkelvins above or below the average temperature of the cosmic microwave background, the radiation left over from the Big Bang. Possible asymmetries in the data --- slightly larger deviations in the average temperature over one half of the sky than the other --- may indicate that the standard model of the origin of the universe may need to be modified.

Cosmologists aim to observe first moments of Universe
Science Centric - 17 February 2009

• During the next decade, a delicate measurement of primordial light could reveal convincing evidence for the popular cosmic inflation theory, which proposes that a random, microscopic density fluctuation in the fabric of space and time gave birth to the Universe in a hot big bang approximately 13.7 billion years ago.
  
  ... South Pole Telescope (SPT) with a team of scientists from nine institutions in their search for evidence about the origins and evolution of the Universe.
  
  Now on their agenda is putting cosmic inflation theory to its most stringent observational test so far. The test: detecting extremely weak gravity waves, which Einstein's theory of general relativity predicts that cosmic inflation should produce.

[aristarchusinexile]

Well I propose a wavy universe which is not flat, but wavey.

What do you propose for the cause of those waves?

Gravity waves or, sonic waves arising from the words "Let there be light".

By the way, Jim Jast, your postings carry a lot more weight with me since I read 'Reinventing Gravity' (MOG) by John Moffat.
If you haven't read it .. it's very interesting.

[aristarchusinexile]

I know I posted this elsewhere on the forum, but really, the sheer uncommon sense of Big Bang came clear to me last night. Infinite density would require infinite energy to explode it. Infinite energy would explode infinite density to nothingness .. there would be no universe. Also, infinite energy would be required to hold together infinte mass, so there would be no extra energy available to explode it. The whole idea has become, to me, completely comical.