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Author Topic:   Is the speed of light constant between galaxies?
cavediver
Member (Idle past 994 days)
Posts: 4129
From: UK
Joined: 06-16-2005


Message 46 of 66 (680213)
11-18-2012 1:59 PM
Reply to: Message 45 by Percy
11-18-2012 1:35 PM


Re: Constant Speed of Light
I thought the path followed by both matter and energy simply followed the curved shape of space

Yes, it does. But in the pseudo-Riemannian geometry of 4d space-time, there are different types of path for massive and massless particles - we call these time-like geodesics and null (or light-like) geodesics. In our everyday Euclidean geometry, there is only type of path (or geodesic) so this is unfamiliar behaviour.


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NoNukes
Member
Posts: 9324
From: Central NC USA
Joined: 08-13-2010
Member Rating: 2.6


Message 47 of 66 (680219)
11-18-2012 2:33 PM
Reply to: Message 44 by sunshaker
11-17-2012 6:20 PM


And try to stick to what can be proved

But you offer no proof, nor any reason to believe what you say. You just recite stuff and then make up more nonsense when you are caught in an error.

How about giving us one observation that your proposal explsins that is not explained by standard cosmology?


Under a government which imprisons any unjustly, the true place for a just man is also in prison. Thoreau: Civil Disobedience (1846)

The apathy of the people is enough to make every statue leap from its pedestal and hasten the resurrection of the dead. William Lloyd Garrison.

If there is no struggle, there is no progress. Those who profess to favor freedom, and deprecate agitation, are men who want crops without plowing up the ground, they want rain without thunder and lightning. Frederick Douglass


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Percy
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Posts: 15491
From: New Hampshire
Joined: 12-23-2000
Member Rating: 4.3


Message 48 of 66 (680253)
11-18-2012 9:16 PM
Reply to: Message 46 by cavediver
11-18-2012 1:59 PM


Re: Constant Speed of Light
When you say "massive particle", is that any particle with mass?

Do the different paths through Reimannian space correspond to different paths in Euclidean space? In other words, we can observe massive and massless particles following these different paths?

--Percy


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 Message 49 by NoNukes, posted 11-18-2012 10:59 PM Percy has acknowledged this reply
 Message 50 by Son Goku, posted 11-19-2012 4:33 AM Percy has acknowledged this reply
 Message 52 by cavediver, posted 11-19-2012 7:07 AM Percy has responded

    
NoNukes
Member
Posts: 9324
From: Central NC USA
Joined: 08-13-2010
Member Rating: 2.6


Message 49 of 66 (680277)
11-18-2012 10:59 PM
Reply to: Message 48 by Percy
11-18-2012 9:16 PM


Re: Constant Speed of Light
Is the wikidepdia article on Geodesics helpful? The GR I've picked up from watching Susskind's video series on General Relativity only dealt with timelike geodesics.

http://en.wikipedia.org/wiki/Geodesics_in_general_relativity


Under a government which imprisons any unjustly, the true place for a just man is also in prison. Thoreau: Civil Disobedience (1846)

The apathy of the people is enough to make every statue leap from its pedestal and hasten the resurrection of the dead. William Lloyd Garrison.

If there is no struggle, there is no progress. Those who profess to favor freedom, and deprecate agitation, are men who want crops without plowing up the ground, they want rain without thunder and lightning. Frederick Douglass


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 Message 48 by Percy, posted 11-18-2012 9:16 PM Percy has acknowledged this reply

    
Son Goku
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Posts: 1059
From: Ireland
Joined: 07-16-2005
Member Rating: 3.5


Message 50 of 66 (680323)
11-19-2012 4:33 AM
Reply to: Message 48 by Percy
11-18-2012 9:16 PM


Re: Constant Speed of Light
Massive particle is indeed any particle with mass.

The different paths in spacetime followed by massive and massless particles will be visible to us as the particles following different paths through space.

As cavediver said, this is what makes geometry with a time dimension very different to purely spatial geometry. When all the dimensions are spatial there is only one type of path, our normal intuitive idea. When there is a time dimensions there are three separate types of paths.

Edited by Son Goku, : Small addition.


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Dr Adequate
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Posts: 15475
Joined: 07-20-2006
Member Rating: 3.9


Message 51 of 66 (680334)
11-19-2012 6:42 AM
Reply to: Message 44 by sunshaker
11-17-2012 6:20 PM


Because i know what the "vechicle" is and the purpose of said "vechicle", but that is to far beyond this, that is why for now i am looking at the workings of the "piston".

Then I'm going to guess that you are either a looney or a troll.


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cavediver
Member (Idle past 994 days)
Posts: 4129
From: UK
Joined: 06-16-2005


Message 52 of 66 (680335)
11-19-2012 7:07 AM
Reply to: Message 48 by Percy
11-18-2012 9:16 PM


Re: Constant Speed of Light
When you say "massive particle", is that any particle with mass?

Yes, no matter how small a mass.

Do the different paths through [4d]Reimannian space[-time] correspond to different paths in [our everyday 3d] Euclidean space?

Yes, though I don't think we'd ever be able observe the difference without some decent source of curvature, such as a black hole. I have mentioned this photon orbit that exists half again as far from the centre of Schwarzschild black hole as the event horizon. Photons will zip around on this circular orbit quite happily, but anything with mass will spiral into the event horizon.

ABE: ah, SG beat me to it - that's what happens when you write a post then forget to submit it for several hours

Edited by cavediver, : No reason given.

Edited by cavediver, : write not right as it was written right.


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Percy
Member
Posts: 15491
From: New Hampshire
Joined: 12-23-2000
Member Rating: 4.3


Message 53 of 66 (680357)
11-19-2012 8:52 AM
Reply to: Message 52 by cavediver
11-19-2012 7:07 AM


Re: Constant Speed of Light
NN, SG and CD,

Thanks for the info, one more question. CD's answer about needing "some decent source of curvature" hints that we don't yet have experimental or observational confirmation of massive and massless particles following different paths - is that true?

--Percy


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sunshaker
Member (Idle past 130 days)
Posts: 49
From: England
Joined: 10-25-2012


Message 54 of 66 (680367)
11-19-2012 10:18 AM
Reply to: Message 37 by sunshaker
11-16-2012 8:12 PM


If dark matter is anti matter, matter and light would be pushed away,
but also light(photons) are in effect there own anti particle, which would mean when a photon comes into contact with dark matter it would be both a photon and an anti photon, the photon would be pushed away in the opposite direction and the anti-photon which would then pass through dark matter, where upon leaving dark matter it would then again be a photon and also send an anti photon back into the dark matter.
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sunshaker
Member (Idle past 130 days)
Posts: 49
From: England
Joined: 10-25-2012


Message 55 of 66 (680370)
11-19-2012 11:06 AM
Reply to: Message 51 by Dr Adequate
11-19-2012 6:42 AM


Sticks and Stones, i am only trying to put to words what i see, think of me as you will, i mean no offense to anyone, or there beliefs,
I can understand why you may call me a "looney or a troll",
I myself think of many "humans" as "one dimensional entities" who may live in this world but never really understand what is in front of them, being unable to see beyond their conditioning.

It is hard enough trying to put how i see this small part, so if i jumped to beyond this, you would not be the only one calling me a looney, as there is yet no "science" around that comes close to explainning,
There are a few of us who are no longer held, who can move between these boundaries.
We had to find new ways to still exsist in this "human reality", This is one of mine, Trying to understand the science behind it all.
It keeps me from losing myself completely, so i may carry on being a father and grandad.


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Taq
Member
Posts: 6014
Joined: 03-06-2009
Member Rating: 3.6


Message 56 of 66 (680379)
11-19-2012 11:54 AM
Reply to: Message 54 by sunshaker
11-19-2012 10:18 AM


If dark matter is anti matter, matter and light would be pushed away,

No they wouldn't. It would produce copious amounts of photons as matter and anti-matter annhialite. It would be the most luminous matter in the universe, the very opposite of dark matter.

You might also read about positron emission tomography, otherwise known as PET scans. This technique acutally uses anti-matter to produce photons.

Also, anti-matter absorbs light just like regular matter, so again we have the problem if scattered or absorbed light which is not seen.


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Taq
Member
Posts: 6014
Joined: 03-06-2009
Member Rating: 3.6


Message 57 of 66 (680381)
11-19-2012 11:57 AM
Reply to: Message 55 by sunshaker
11-19-2012 11:06 AM


Sticks and Stones, i am only trying to put to words what i see,

It seems as if you are just making it up as you go. Reference to evidence in the real world would be very helpful at this point.

I myself think of many "humans" as "one dimensional entities" who may live in this world but never really understand what is in front of them, being unable to see beyond their conditioning.

It would appear that person is you because you simply don't understand how reality works. Instead, you have a fantasy that you have invented which you "see", but can never evidence.

as there is yet no "science" around that comes close to explainning,

You have made it abundantly clear that you don't understand what the science actually is, nor the current state of the evidence.


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cavediver
Member (Idle past 994 days)
Posts: 4129
From: UK
Joined: 06-16-2005


Message 58 of 66 (680387)
11-19-2012 12:18 PM
Reply to: Message 53 by Percy
11-19-2012 8:52 AM


Re: Constant Speed of Light
CD's answer about needing "some decent source of curvature" hints that we don't yet have experimental or observational confirmation of massive and massless particles following different paths - is that true?

Almost certainly true - we don't have observational confirmation of this. I think you would need a handy black hole and some distant oribital platforms to house a laser, a particle accelerator, and a couple of detectors.


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sunshaker
Member (Idle past 130 days)
Posts: 49
From: England
Joined: 10-25-2012


Message 59 of 66 (680399)
11-19-2012 1:18 PM
Reply to: Message 57 by Taq
11-19-2012 11:57 AM


I do understand how reality works, i am just trying to understand how light behaves with dark matter, i know light is bent around high gravitational masses, but i also know that light travels through dark matter, the evidence is there, but it as been interpreted wrong,
physics first went off tracks when the "big bang" theory was put forward, at roughly the same time as the universal background radiation was detected, because they seemed to fit each other it became excepted by most, which as threw science back decades, now all "evidence" is made to fit into this big bang theory.

There is nothing in the big bang theory that does not fit better in a free falling expanding universe in lower d space,
it explains dark matter, blackholes, gamma ray bursts , gravity , galaxy formation, and much more.

The evidence is there, it is how it is interpreted, YOU WILL ALWAYS BELIEVE WHAT YOU HAVE BEEN "TAUGHT".

You have not got the ability to see a complete picture.

We are argueing over a wheel nut and missing the car.


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 Message 57 by Taq, posted 11-19-2012 11:57 AM Taq has responded

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Taq
Member
Posts: 6014
Joined: 03-06-2009
Member Rating: 3.6


Message 60 of 66 (680403)
11-19-2012 1:30 PM
Reply to: Message 59 by sunshaker
11-19-2012 1:18 PM


the evidence is there, but it as been interpreted wrong,

What is this evidence you are talking about?

physics first went off tracks when the "big bang" theory was put forward, at roughly the same time as the universal background radiation was detected, because they seemed to fit each other it became excepted by most, which as threw science back decades, now all "evidence" is made to fit into this big bang theory.

Lemaitre proposed the Big Bang in 1927. The CMB was not detected until 1964. The CMB was a prediction of the BB model for almost 40 years before it was finally discovered. The Big Bang was first proposed because of the observed correlation between distance and redshift for distant galaxies.

now all "evidence" is made to fit into this big bang theory.

Umm, no. The model is changed to fit the evidence. The latest evidence demonstrates that the expansion is accelerating, so this has been incorporated into the BB model.

There is nothing in the big bang theory that does not fit better in a free falling expanding universe in lower d space,
it explains dark matter, blackholes, gamma ray bursts , gravity , galaxy formation, and much more.

What evidence is there for "lower d space"?

You have not got the ability to see a complete picture.

Apparently not since you have dark matter being made up of ions which just doesn't work.


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