Universe expansion

[A Tripolation]

 

" It is easier to believe that gravity, which we have known all our lives, is bending the light instead of the "warping" of space.

 

And how do you propose this happens when photons have no mass to be affected by gravity (they only have momentum)? Magic?

 

Gravity and curved spacetime are not two competing ideas. Gravity IS the effect of spacetime that is distorted by some stuff that is given by the stress-energy tensor. Newton's "simple" version of gravity had no explanation or mechanism. Which is bad.

 

 

Nevertheless, each of the examples you stated could also be explained by gravity effecting the light or radio waves. However, can you quote a experiment in which gravity was excluded as the cause? Everything I have heard is of light passing by a very massive object (the Sun, a galaxy, ect.) Which by the way have gravity.

 

It's hard for me to tell you that it's not gravity affecting the EMR when it's gravity affecting the EMR. Gravity caused by the curvature of that locality.

I do not understand why this is a difficult leap for you. Like has been suggested previously, you really ought to buy this book.

[ox1111]

Dark energy and dark matter is clearly a problem. Truth be told the problem is only reason they exist is because our current model doesn't account for the actions of gravity properly. The simplest answer is usually the correct one. Is it easier to believe that 90% of our universe is made up from something that we have no idea what is, or is it easier for us to believe that our understanding of gravity is inaccurate. I believe the latter. Einstein's theories mathematically help us to understand planets in orbit and also help launch one of mechanics. But just because his mathematical equations create the correct answer doesn't mean that his physical definitions accurately describe nature.

[juanrga]

Some remarks made above by several posters regarding the nature of gravity are not correct. As Feynman states in his lectures on gravitation:

It is one of the peculiar aspects of the theory of gravitation, that is has both a field interpretation and a geometrical interpretation. [...] the fact is that a spin-two field has this geometrical explanation [...] The geometrical interpretation is not really necessary or essential to physics.

The geometrical formulation interprets gravitational phenomena in terms of spacetime curvature. This is the GR approach reported above by several posters:



However, the modern non-geometrical approach interprets the same phenomena in terms of a force mediated by the interchange of gravitons:



Notice that the spacetime is flat in the non-geometrical approach.

I would add that the graviton approach is more fundamental and that the geometrical approach of GR (recall that GR is a classical theory) is only an approximation; somehow as geometrical optics is an approximation to a non-geometrical theory of photons.

Edited December 24, 2012 by juanrga

[zapatos]

Is it easier to believe that 90% of our universe is made up from something that we have no idea what is, or is it easier for us to believe that our understanding of gravity is inaccurate.

The relative ease with which you believe something has no bearing on its existence.

[ox1111]

Occam's razor states that the simplest answer is usually the correct one. Dark energy and dark matter what not just exist in empty space would exist right in front of you right now. Many times people want a picture dark energy and dark matter they picture this empty space between galaxies, it's easy to forget that it would exist right under your nose.

[Roger_XR]

Hey, Some REALLY good stuff guys. But back in the real world it's nearly Christmas and I have small children. I'll be back

 

MERRY CHRISTMAS TO ALL (relatively speaking)

 

[StringJunky]

Some remarks made above by several posters regarding the nature of gravity are not correct. As Feynman states in his lectures on gravitation:

 

 

The geometrical formulation interprets gravitational phenomena in terms of spacetime curvature. This is the GR approach reported above by several posters:

 

I would add that the graviton approach is more fundamental and that the geometrical approach of GR (recall that GR is a classical theory) is only an approximation; somehow as geometrical optics is an approximation to a non-geometrical theory of photons.

 

 

 

Some remarks made above by several posters regarding the nature of gravity are not correct. As Feynman states in his lectures on gravitation:

 

The links I provided is from the Stanford University website run by Emeritus Professor of Astrophysics Francis Everett who is also the Principal Investigator of the Gravity Probe B Project which was successful in its mission and supported the predictions of GR it was tasked to find . If GR was obsolete they wouldn't also be testing it now with LIGO.

 

Quantum Gravity is just an idea that still lives only on paper.

[juanrga]

The links I provided is from the Stanford University website run by Emeritus Professor of Astrophysics Francis Everett who is also the Principal Investigator of the Gravity Probe B Project which was successful in its mission and supported the predictions of GR it was tasked to find . If GR was obsolete they wouldn't also be testing it now with LIGO.

 

Quantum Gravity is just an idea that still lives only on paper.

 

Yes you cited a website for the general public, whereas I cited the lecture notes on gravitation by Feynman and coworkers

 

http://www.amazon.com/Feynman-Lectures-Gravitation-Frontiers-Physics/dp/0813340381

 

which includes a foreword by John Preskill and Kip S. Thorne (yes the same Thorne of the MTW textbook) praising the modern approach by Feynman. As correctly emphasized in the above reviews of Feynman lectures:

 

This is a more fundamental approach than the usual differential geometric framework and shows what the equivalence principle really means in terms of fundamental symmetries.

 

There is one part of my previous message that it seems was not entirely clear. The non-geometrical approach has a classical description which is derived from the graviton theory. This classical description describes the same phenomena than GR and, in fact, several astrophysical predictions regarding pulsars were first made by the non-geometrical approach.

 

Gravity is described by a warped spacetime only in the old geometrical approach and, as emphasized by Feynman in his textbook, the geometrical approach is neither needed nor fundamental for physics.

Edited December 24, 2012 by juanrga

[StringJunky]

 

Yes you cited a website for the general public, whereas I cited the lecture notes on gravitation by Feynman and coworkers

 

http://www.amazon.com/Feynman-Lectures-Gravitation-Frontiers-Physics/dp/0813340381

 

which includes a foreword by John Preskill and Kip S. Thorne (yes the same Thorne of the MTW textbook) praising the modern approach by Feynman. As correctly emphasized in the above reviews of Feynman lectures:

 

 

There is one part of my previous message that it seems was not entirely clear. The non-geometrical approach has a classical description which is derived from the graviton theory. This classical description describes the same phenomena than GR and, in fact, several astrophysical predictions regarding pulsars were first made by the non-geometrical approach.

 

Gravity is described by a warped spacetime only in the old geometrical approach and, as emphasized by Feynman in his textbook, the geometrical approach is neither needed nor fundamental for physics.

 

Is this site not a portal for the general public? 'Approximation' does not equal incorrect. Your whole approach is wrong. Within it's domain of vailidity Newtonian gravity is correct. Within its domain of validity GR is correct and so it shall be for a quantum description of the macro universe when it's verified. There are no sharp lines delineating from one successive theory to the next and the previous ones are not discarded, that's not how science works; it stands on the shoulders of each of its giants with each theory blending into the next with connecting zones of agreement. The certainty with which you speak does no service to the dissemination of science in the public sphere and can give it a bad name

 

Think of a hypothetical scenario, say 100 years into the future, and Quantum Gravity is as old, mature and.'conventional' like GR is now, what are you going to say when it hits the inevitable brick wall like GR is with sub-Planck -scale stuff now? It's wrong? Scientists will always be 'incorrect' because they will eventually find things that their prevailing theory can't describe...history proves this. Science will never be right but it can be less wrong.

 

It's all relative old chap.

Edited December 24, 2012 by StringJunky

[juanrga]

Is this site not a portal for the general public?

 

One thing is to give a superficial presentation of a basic formalism, omitting details or more advanced stuff, and another thing is to say plain wrong stuff in a science forum.

 

My complain here started when one poster asked for a description of gravity that does not use warped spacetime and several replies said him that "gravity is warped spacetime" and cannot be explained in any other way. This is false. One poster even said that light bending only can be explained by warped spacetime because, he said, "photons are massless". That is also wrong. Light bending in flat spacetime is perfectly explained using the non-geometrical approach discussed in Feynman lectures on gravitation.

 

'Approximation' does not equal incorrect.

 

Who said the contrary?

 

Your whole approach is wrong.

 

What approach?

 

Within it's domain of vailidity Newtonian gravity is correct. Within its domain of validity GR is correct and so it shall be for a quantum description of the macro universe when it's verified. There are no sharp lines delineating from one successive theory to the next and the previous ones are not discarded, that's not how science works; it stands on the shoulders of each of its giants with each theory blending into the next with connecting zones of agreement.

 

I do not know why you repeat essentially what I have said in #65.

[StringJunky]

The first point above, I can see what you mean...I took it as an attack on GR.

 

The second point I interpreted what you said that: GR is only an approximation therefore it's incorrect...i can accept my error on this.

 

The third point about your approach, is to do with the way you come across as though some new, as-yet-unverified advanced physics has completely superseded current established physics.

 

Point 4 you quoted I actually found strange because you seemed to be contradicting what you said in post #65, which I agreed with and actually positively repped you for it. i somehow felt compelled to reiterate, in my own way, what you said there because you seemed to me to have forgotten that.

 

Rightly or wrongly, you were coming across to me that GR is "old hat" and that's not actually how it is in the public sphere. As far as I have seen on this forum so far, GR is the accepted description of gravity and this is the one that is disseminated by SFN's scientists.

[juanrga]

The first point above, I can see what you mean...I took it as an attack on GR.

 

The second point I interpreted what you said that: GR is only an approximation therefore it's incorrect...i can accept my error on this.

 

The third point about your approach, is to do with the way you come across as though some new, as-yet-unverified advanced physics has completely superseded current established physics.

 

I do not know what do you mean by "as-yet-unverified advanced physics". I mentioned here the non-geometrical approach to gravity, which is taught to students (see Feynman lectures on gravitation) and used by astronomers and astrophysicists to make predictions about gravitational phenomena.

 

Point 4 you quoted I actually found strange because you seemed to be contradicting what you said in post #65, which I agreed with and actually positively repped you for it. i somehow felt compelled to reiterate, in my own way, what you said there because you seemed to me to have forgotten that.

 

Rightly or wrongly, you were coming across to me that GR is "old hat" and that's not actually how it is in the public sphere. As far as I have seen on this forum so far, GR is the accepted description of gravity and this is the one that is disseminated by SFN's scientists.

 

The geometrical picture given by GR is only a formulation of several possible. The geometrical formulation is the more popular, because it is the older and the simpler, but in more advanced applications we use other formulations. Advanced courses in gravitation deal with those formulations. General public does not know those advanced formulations of gravity, but if someone is asking us about alternatives to "warped spacetime" (as someone did in this thread), we would inform him about the alternatives such as the non-geometrical approach, and provide to him literature, as I did when cited Feynman lectures on gravitation; instead of saying to him incorrect stuff as several posters did. This is not characteristic of gravity, but the rule in physics and would be the rule in SFN.

 

For instance, the wavefunction approach to QM is only a formulation of several possible. The wavefunction formulation is the more popular, because it is the older and the simpler, but in more advanced applications we use other formulations. Advanced courses in quantum theory deal with those formulations. General public does not know those advanced formulations of quantum theory, but if someone is asking us about alternatives to wavefunctions, we would inform her/him about the alternatives and provide literature on those alternatives.

 

The same about electrodynamics, thermodynamics...

Edited December 25, 2012 by juanrga

[StringJunky]

OK, Thanks for the clarification Juanrga, I see where you are coming from now.

Edited December 25, 2012 by StringJunky

[Jdizz]

Sorry to derail, I was told to post here instead of creating a new thread.

 

I would immensely appreciate it if fellow colleagues can examine a decade or so of studies by R.M. Santilli (See his CV: http://www.world-lecture-series.org/santilli-cv ) establishing that the redness of the sun at the horizon is due to an apparent new mechanism for direct sunlight losing energy to a cold medium (or gaining energy in the case of a hot medium.) I feel that Prof. Santilli is correct with his mechanisms and am looking for additional comments to point out any holes.

More specifically, to my attentive understanding, part of sunlight is lost due to scattering resulting in the colors of Earth's atmosphere that are beautifully represented by Rayleigh scattering and others.

Santilli's new mechanism called IsoRedShift (IRS) deals with the remaining part of direct sunlight that has not scattered but reaches us along a straight line. The numerous measurements which have been conducted on two continents established the apparent existence of an IRS for the entire spectrum of direct sunlight from the zenith to the horizon of about 100nm.

In particular, the blue light at the zenith completely disappears at the horizon and the red light is shifted into the infrared frequency not existing at the zenith. In view of these numerous measurements now available for both sunset and sunrise, it appears that all of the above is an experimental reality.

I am soliciting comments by qualified colleagues following the studies of scientific literature, on Santilli's consequential reduction of no expansion of the universe because the IRS of the entire spectrum of sunlight at the horizon is virtually identical to the cosmological redshift of far away galaxies and the former occurs without any relative motion.

Additionally and most seriously, Santilli has apparently proved the dismissal by Hubble, Zwicky, and De Broglie, of the expansion of the universe because its "acceleration" implies a return to the middle ages with Earth mandated at the center of the universe. Hubble's law established the proportionality of the cosmological redshift with the distance for all possible radial direction from Earth.

Please inspect Santilli's diagram establishing the inconsistency of the conjecture of the expansion of the universe because the relative acceleration between galaxies solely occurs for Earth and does not occur for other observers throughout the universe.



In fact, under the Doppler's interpretation z = v/c of the Hubble law z = H d, the galaxies G_2 and G_1 have the cosmological redshifts z_2 = v_2/c and z_1 = v_1/c with v_2 = 2 v_1 since d_2 = 2 d_1, thus implying that the galaxy G_2 accelerates away from G_1 when seen from Earth E. However, when z_2 and z_1 are measured from the galaxy G, we have z_2 = z_1 since the two galaxies are located at the same distance d_2 from G, thus establishing that the galaxy G_2 has no acceleration away from G_1 when seen from G.

Note that the inconsistency persists under the far fetched conjecture of the expansion of space itself or of any far fetched preferred geometry since the latter must verify Hubble's law, thus having Santilli's diagram in the local tangent plane. In view of this clear inconsistency, Santilli's diagram ends one century of controversies by disproving the expansion of the universe and related conjectures, but confirms the original conception by Hubble and, therefore, its interpretation via Santilli IRS, see the comprehensive experimental verifications in the paper

http://www.santilli-foundation.org/docs/IRS-confirmations-212.pdf

[swansont]

Sorry to derail, I was told to post here instead of creating a new thread.

 

!

Moderator Note

Where were you told to do that? It's certainly not what I told you to do, which was to post in your existing thread.

[Jdizz]

 

!

Moderator Note

Where were you told to do that? It's certainly not what I told you to do, which was to post in your existing thread.

 

Sorry, what?

 

You said:

 

You have other posts and threads where isoredshift is discussed. Limit your conversation to those threads.

 

Here: http://www.scienceforums.net/topic/71879-apparent-lack-of-expansion-of-the-universe/

 

I thought this thread where redshift was previously discussed by myself and others would be appropriate.

Edited January 4, 2013 by Jdizz

[swansont]

 

Sorry, what?

 

You said:

 

 

Here: http://www.scienceforums.net/topic/71879-apparent-lack-of-expansion-of-the-universe/

 

I thought this thread where redshift was previously discussed by myself and others would be appropriate.

 

!

Moderator Note

You thought a thread where you had been hijacking so that posts had to be moved (IOW, Santilli was not under discussion in this thread), and where you posted using a sockpuppet (another rules violation) would be OK? NO. You do not get to leverage previous rules violations to do this.

 

Let me clarify: discuss this ONLY in Speculations and ONLY in threads YOU are listed as having already started (there are two)

 

I trust that is sufficiently clear.