speed of gravity

[Stiganator]

Having done no research on the topic at all, I imagine it working this way. Gravity comes from a superposition of 3 more dimension, a time dimension where it is a scalar value instead of a vector value. As it exists in a time dimension, It is a parameter across all possible times (thus can "propagate instantly", but it's not propagating at all because in the time domain it just exists.) The impression of that other 3 dimensions onto our tangible 3 dimensional world imposes the scalar value onto the spatiality(spatial vectors) of 3 dimensions.

Basically think of 3 dimensions as an NxNxN(Length, Width, Height) matrix of unit vectors describing every unit particle in existence. In the other 3 dimensions, there exists an NxNxN (Time, Parameter, Value) matrix of the coefficients describing parameters of our 3 dimensions. Existence entangles these two systems in such a way that a parameter cannot exist for a particle that does not exist.

Perception = E x C

So, the Existence matrix (E) multiplied by the Coefficients Matrix (C) = Effect of C on E or Our Perception of the physical universe. I'm pretty sure quantum entanglement would take care of changes in the system propagated instantly inter dimensionally.

What do you think of that?

 

[RideFree]

I always thought of it as 4 dimensions...
L W D T
Length, Width, Depth & Time.

However, that said, I'm fairly comfortable with Witten's M-theory as described at low energies by 11-dimensional supergravity.

 

[CycloWizard]

Originally posted by: Stiganator
Having done no research on the topic at all, I imagine it working this way.

Stop right there... So we should neglect the mounds of evidence of a finite propagation velocity of gravity because you've imagined something else? No thanks. I can imagine a lot of crazy things, but that doesn't mean that they describe our physical universe. The data doesn't need to fit your imagination - the model has to fit the data.

 

[silverpig]

Originally posted by: Stiganator
Having done no research on the topic at all, I imagine it working this way. Gravity comes from a superposition of 3 more dimension, a time dimension where it is a scalar value instead of a vector value. As it exists in a time dimension, It is a parameter across all possible times (thus can "propagate instantly", but it's not propagating at all because in the time domain it just exists.) The impression of that other 3 dimensions onto our tangible 3 dimensional world imposes the scalar value onto the spatiality(spatial vectors) of 3 dimensions.

Basically think of 3 dimensions as an NxNxN(Length, Width, Height) matrix of unit vectors describing every unit particle in existence. In the other 3 dimensions, there exists an NxNxN (Time, Parameter, Value) matrix of the coefficients describing parameters of our 3 dimensions. Existence entangles these two systems in such a way that a parameter cannot exist for a particle that does not exist.

Perception = E x C

So, the Existence matrix (E) multiplied by the Coefficients Matrix (C) = Effect of C on E or Our Perception of the physical universe. I'm pretty sure quantum entanglement would take care of changes in the system propagated instantly inter dimensionally.

What do you think of that?

I went to a "general audience" talk by the guy who wrote the GR textbook I studied from. He spoke of quantum mechanics, GR, the big bang, cosmology etc. There was a wide ranging audience from physicists to biologists to arts students. He explained the probabilistic nature of quantum mechanics during the talk which prompted one of the artsies to ask the question:

Artsie: "Does quantum mechanics apply to itself?"
Speaker: ?
Artsie: "Like, does it mean that quantum mechanics is sometimes true, but sometimes not?"
Speaker: Uh... well, I don't know of any quantum mechanical wavefunction for truth...

So to answer your question: What the heck is an existence matrix? And what the heck is a perception matrix? Can you calculate the atomic spectrum of hydrogen with it?

 

[hellokeith]

Originally posted by: CycloWizard
So we should neglect the mounds of evidence of a finite propagation velocity of gravity

You keep repeating this but fail to provide such evidence. Alluding to Hawking is no more evidence than me alluding to Einstein not believing in instantaneous quantum spin "communication" between photons. Just because one important scientist has an informed opinion does not make it a law of physics.

 

[CycloWizard]

Originally posted by: hellokeith
You keep repeating this but fail to provide such evidence. Alluding to Hawking is no more evidence than me alluding to Einstein not believing in instantaneous quantum spin "communication" between photons. Just because one important scientist has an informed opinion does not make it a law of physics.

The evidence has already been posted. Your ignoring it doesn't invalidate it. However, for the sake of tradition, I'll post it again.

http://phyun5.ucr.edu/~wudka/P.../Notes_www/node98.html
http://en.wikipedia.org/wiki/T..._of_general_relativity

I cite Hawking because he is likely somewhat well-read in this field and one might do well to accept his understanding of the data. Or not.

 

[hellokeith]

Originally posted by: CycloWizard
The evidence has already been posted. Your ignoring it doesn't invalidate it. However, for the sake of tradition, I'll post it again.

http://phyun5.ucr.edu/~wudka/P.../Notes_www/node98.html

problems with current theory of precession

Originally posted by: CycloWizard
http://en.wikipedia.org/wiki/T..._of_general_relativity

Problems with GR gravity

We can play the "posting links" game ad infinitum, still waiting for that mountain of evidence.

 

[Born2bwire]

Originally posted by: hellokeith

Originally posted by: CycloWizard
The evidence has already been posted. Your ignoring it doesn't invalidate it. However, for the sake of tradition, I'll post it again.

http://phyun5.ucr.edu/~wudka/P.../Notes_www/node98.html

problems with current theory of precession

Originally posted by: CycloWizard
http://en.wikipedia.org/wiki/T..._of_general_relativity

Problems with GR gravity

We can play the "posting links" game ad infinitum, still waiting for that mountain of evidence.

Except his links are based upon peer reviewed research from Phd's and other members of the academic and scientific community.

And the only problem you can find with GR is the fact that a theory that was devised prior to quantum mechanics is *shock* incompatible with quantum mechanics.

 

[PowerEngineer]

Originally posted by: hellokeith

problems with current theory of precession

We can play the "posting links" game ad infinitum, still waiting for that mountain of evidence.

I'll give you the benefit of the doubt here. I'll presume that you did just latch onto this link as a means to extend the "game" -- that you really aren't suggesting that the assertions of the "Binary Research Institute" (no obvious agenda in their name...) should be taken as a serious alternative to GR's explanation of the precession of Mercury.

I note on their site that we can look forward to the 5th annual "Conference on Precession and Ancient Knowledge" Here's the list of books written by the experts who will speak at the conference (I've bolded a few of my favorites):

The Lost Cities Series (Six Books)
A Hitchhikers Guide To Armageddon
The Anti-Gravity Handbook
Anti-Gravity & the World Grid
Anti-Gravity and the Unified Field
Vimana Aircraft of Ancient India & Atlantis
The Free-Energy Device Handbook
The Time Travel Handbook
Atlantis & the Power System of the Gods
Pirates and the Lost Templar Fleet
The Mystery of the Olmecs
Supervolcano
PSIence
Looking For God In All The Wrong Places
Angels and Archetypes: An Evolutionary Map of Feminine Consciousness
Robert Fludd, Hermetic Philosopher and Surveyor of Two Worlds
Athanasius Kircher, A Renaissance Man and the Quest for Lost Knowledge
Mystery Religions in the Ancient World
Harmonies of Heaven and Earth, The Spiritual Dimension of Music from Antiquity to the Avant-Garde
Music and the Occult
The Mystery of the Seven Vowels in Theory and Practice
Arktos. The Polar Myth in Science, Symbolism, and Nazi Survival
The Theosophical Enlightenment
The Pagan Dream of the Renaissance
The Real Rule of Four
Lost Star of Myth and Time
The Great Year (DVD - Documentary)
The Science of the Dogon: Decoding the African Mystery Tradition
Sacred Symbols of the Dogon: The Key to Advanced Science in the Ancient Egyptian Hieroglyphs
The Parapsychology Revolution: A Concise Anthology of Paranormal and Psychical Research
Voices of the Rocks : A Scientist Looks at Catastrophes and Ancient Civilizations
Pyramid Quest: Secrets of the Great Pyramid and the Dawn of Civilization
Voyages of the Pyramid Builders: The True Origins of the Pyramids from Lost Egypt to Ancient America
Seed of Knowledge, Stone of Plenty: Understanding the Lost Technology of the Ancient Megalith-Builders
Serpent in the Sky: The High Wisdom of Ancient Egypt
Mystery of the Sphinx (DVD - Documentary)
Magical Egypt (DVD - Documentary Series)

And I can' help but add a snippet about the ancient knowledge they're talking about:

So far our collective efforts show that there appears to have been a relatively advanced civilization all over the globe at a time when our textbooks tell us we were simple hunter-gatherers. The people had in-depth knowledge of geometry, mathematics, celestial motions, efficient and sustainable agriculture, specialized soils still un-reproducible today, plant hybridization, animal husbandry, hydraulics, poetry, music and epic story telling, and of course the ability to build huge carefully engineered structures that aligned to mirror the heavens. More difficult to believe is further evidence that suggests they had fantastic memories and understood principles of subtle energies of which we are still unaware, and quite possibly, telepathy and clairvoyance, or other higher age sciences, we still cannot conceive.

So, Keith... Please confirm that citing this link is just part of your "game". (If not, reread my first post.)

 

[hellokeith]

Originally posted by: Born2bwire

Except his links are based upon peer reviewed research from Phd's and other members of the academic and scientific community.

And the only problem you can find with GR is the fact that a theory that was devised prior to quantum mechanics is *shock* incompatible with quantum mechanics.

They are? I saw no mention of PhD's in the quick scan-through.

But how about this one on page 4 of this thread:

The metric slowly changes as the Sun and planets move (relative to the center of mass of the solar system). Since v/c is small, the changes in the gravity field are slow compared with the assumed speed of propagation and so we can't really prove or disprove that the speed of gravity is the speed of light or not, though we do know that the speed is much faster than the speed of the planets.

Dr. William Folkner, JPL NASA

I find it fascinating that a JPL NASA PhD scientist who calculates orbits for a living says that propogation speed of gravity has not been determined. And the link he provided to someone he considers to be an expert in gravity wrote a paper disproving the "controversial" Jupiter occultation speed-of-gravity claim.

Yeah, I think I like my sources better.

 

[Born2bwire]

Originally posted by: hellokeith

Originally posted by: Born2bwire

Except his links are based upon peer reviewed research from Phd's and other members of the academic and scientific community.

And the only problem you can find with GR is the fact that a theory that was devised prior to quantum mechanics is *shock* incompatible with quantum mechanics.

They are? I saw no mention of PhD's in the quick scan-through.

But how about this one on page 4 of this thread:

The metric slowly changes as the Sun and planets move (relative to the center of mass of the solar system). Since v/c is small, the changes in the gravity field are slow compared with the assumed speed of propagation and so we can't really prove or disprove that the speed of gravity is the speed of light or not, though we do know that the speed is much faster than the speed of the planets.

Dr. William Folkner, JPL NASA

I find it fascinating that a JPL NASA PhD scientist who calculates orbits for a living says that propogation speed of gravity has not been determined. And the link he provided to someone he considers to be an expert in gravity wrote a paper disproving the "controversial" Jupiter occultation speed-of-gravity claim.

Yeah, I think I like my sources better.

I find it fascinating that this has absolutely no mention about the validity of GR, nor do the papers that were published in response to the Jupiter measurements.

 

[CycloWizard]

Originally posted by: hellokeith
I find it fascinating that a JPL NASA PhD scientist who calculates orbits for a living says that propogation speed of gravity has not been determined. And the link he provided to someone he considers to be an expert in gravity wrote a paper disproving the "controversial" Jupiter occultation speed-of-gravity claim.

Yeah, I think I like my sources better.

You mean your anecdotal letter from someone who is admittedly not an expert in this area? I know people in the JPL too, but getting a letter from them says nothing of the current state of knowledge in a given area (unless it happens to be jet propulsion or other area of their direct interest, of course). Not only that, but you had to mischaracterize his research to support your own agenda. The guy doesn't calculate orbits at all: he uses radar to measure them, which is a completely different ballgame.

 

[PolymerTim]

Originally posted by: hellokeith

Originally posted by: CycloWizard
The evidence has already been posted. Your ignoring it doesn't invalidate it. However, for the sake of tradition, I'll post it again.

http://phyun5.ucr.edu/~wudka/P.../Notes_www/node98.html

problems with current theory of precession

Here is my favorite part of that website in the "about us" section where organizations usually spend a great deal of time composing a concise description of who they are:

The Binary Research Institute was formed in 2001 to support and fund research regarding the hypothesis that the Sun is part of a binary star system. It is the goal of the Binary Research Institute to present evidence for this theory, showing that the motion of the sun along a binary orbital path can result in and better explain the same precessional motion that current LuniSolar and Earth Wobble theories attempt to account for.

Now that's a great example of the scientific method right there. Let's see, so you come up with a theory and then you find evidence to support that theory... wait a sec

Originally posted by: hellokeith

Originally posted by: CycloWizard
http://en.wikipedia.org/wiki/T..._of_general_relativity

Problems with GR gravity

Seems to me that the only problem stated in this section is that general relativity is not a complete theory and can not be extrapolated to high energies. Last time I checked, it was pretty common for theories to have limits and boundaries. I doubt future theories will invalidate GR, but rather fit it into a bigger picture.

 

[brad310]

I havent read all the posts, but I have to ask this....

Why can we assume that the speed attribute can even be applied to gravity? IMHO, that would be similar to applying speed to something like knowledge.

I havent given the topic as much thought as some here obviously, but I would have to reason that gravity has no "speed", rather that gravity has an effective distance, at which the objects are immediately affected, however small the value would be given that outer limit distance.

Also, if something has a speed, the medium through which it travels effects that speed. For example, light being under water travels slower. I can imagine no medium that would slow gravity, only distance affecting whether or not the orbiting object was being affected by gravity, and the objects acceleration.

It just seems like apples and oranges, unrelated topics.

 

[silverpig]

Originally posted by: brad310
I havent read all the posts, but I have to ask this....

Why can we assume that the speed attribute can even be applied to gravity? IMHO, that would be similar to applying speed to something like knowledge.

I havent given the topic as much thought as some here obviously, but I would have to reason that gravity has no "speed", rather that gravity has an effective distance, at which the objects are immediately affected, however small the value would be given that outer limit distance.

Also, if something has a speed, the medium through which it travels effects that speed. For example, light being under water travels slower. I can imagine no medium that would slow gravity, only distance affecting whether or not the orbiting object was being affected by gravity, and the objects acceleration.

It just seems like apples and oranges, unrelated topics.

You're kind of on the right track.

Gravity is a force. The other forces all have some characteristic particle associated with them which is deemed the force carrier. These carriers move at some finite speed. For most of our daily lives all the forces we experience (save gravity) are due to electromagnetism and the forces are carried by the photon which is a ripple in the EM field which permeates all space.

We can just as easily describe a gravitational field which permeates space. In GR this field also perturbs space and time. Small ripples in the gravitational field should be gravitons, should be spin 2, and should interact weakly with matter. We can't quite make all the math work out for gravitons though, and we haven't discovered them, so they remain a theory.

You can't apply a speed to something abstract like knowledge, but you can to something like information. According to GR/SR the fastest that any piece of information can travel is c. Going faster than c is tantamount to going back in time.

If gravity was instantaneous, it would permit instant communication across the galaxy... something forbidden by relativity. For instance, if the sun were to just vanish, we would not see it happen for ~8 minutes as that is how long it takes for light from the sun to reach us. According to relativity the information that the sun is gone cannot be transmitted to us faster than c, yet if gravity was instantaneous we would be able to know instantly. There is a contradiction here that can only be resolved if relativity is wrong, or if gravity is not instantaneous. Since we know more about relativity than we do about gravity, we basically operate under the assumption that gravity is not instantaneous, figure out what that means, then look for some of the consequences.

Light travelling through water is a complex phenomenon, and it isn't quite accurate to say the speed of light changes. c is c no matter if you're in water, air, or vacuum. You can probably find a better explanation of why light travels slower in water than in vacuum than I could provide in a simple forum post.

 

[PolymerTim]

Originally posted by: silverpig
Light travelling through water is a complex phenomenon, and it isn't quite accurate to say the speed of light changes. c is c no matter if you're in water, air, or vacuum. You can probably find a better explanation of why light travels slower in water than in vacuum than I could provide in a simple forum post.

I tried looking up a little info on that, but I'm having trouble finding one that goes into that much detail. Most sources say that light does go slower through matter, but I found one that notes it as the "effective velocity" through matter. I'm guessing this is one of those situations where, technically, light doesn't slow down, but for most intents and purposes in the real world we can consider it to have slowed down. Is that close?

 

[Born2bwire]

Originally posted by: PolymerTim

Originally posted by: silverpig
Light travelling through water is a complex phenomenon, and it isn't quite accurate to say the speed of light changes. c is c no matter if you're in water, air, or vacuum. You can probably find a better explanation of why light travels slower in water than in vacuum than I could provide in a simple forum post.

I tried looking up a little info on that, but I'm having trouble finding one that goes into that much detail. Most sources say that light does go slower through matter, but I found one that notes it as the "effective velocity" through matter. I'm guessing this is one of those situations where, technically, light doesn't slow down, but for most intents and purposes in the real world we can consider it to have slowed down. Is that close?

Light does travel slower through matter. More or less what happens is that the photons are absorbed and re-emitted by the atoms in the matter, the light does not pass through unimpeded. However, c is still the speed limit in this case. That is, irregardless (that's right, I said that wrong) of the environment, information cannot propagate faster than c, though this does not mean that light can only travel at c. There are also other terms you might hear in regards to light and matter, phase velocity and group velocity. These often are used when we are interested in guided wave behavior. If we are sending light down a long tube (or say optic fiber), we are mainly concerned with it's propagation along the length of the tube. In reality, light often travels at an angle to the length of the waveguide, bouncing around. In this case, the group velocity of light is slower than c (if it is an air filled waveguide) because the light is not traveling perfectly straight in the direction of interest.

 

[PolymerTim]

Originally posted by: Born2bwire

Originally posted by: PolymerTim

Originally posted by: silverpig
Light travelling through water is a complex phenomenon, and it isn't quite accurate to say the speed of light changes. c is c no matter if you're in water, air, or vacuum. You can probably find a better explanation of why light travels slower in water than in vacuum than I could provide in a simple forum post.

I tried looking up a little info on that, but I'm having trouble finding one that goes into that much detail. Most sources say that light does go slower through matter, but I found one that notes it as the "effective velocity" through matter. I'm guessing this is one of those situations where, technically, light doesn't slow down, but for most intents and purposes in the real world we can consider it to have slowed down. Is that close?

Light does travel slower through matter. More or less what happens is that the photons are absorbed and re-emitted by the atoms in the matter, the light does not pass through unimpeded. However, c is still the speed limit in this case. That is, irregardless (that's right, I said that wrong) of the environment, information cannot propagate faster than c, though this does not mean that light can only travel at c. There are also other terms you might hear in regards to light and matter, phase velocity and group velocity. These often are used when we are interested in guided wave behavior. If we are sending light down a long tube (or say optic fiber), we are mainly concerned with it's propagation along the length of the tube. In reality, light often travels at an angle to the length of the waveguide, bouncing around. In this case, the group velocity of light is slower than c (if it is an air filled waveguide) because the light is not traveling perfectly straight in the direction of interest.

That makes sense. I imagine that being absorbed and re-emitted would have effects on things like the polarization and direction of the light as well. I'll have to go do some more reading.

So I guess, given that the constant c(sub zero) is the speed of light in a vacuum, then the speed of light in a medium will be the same minus the time spent being absorbed/re-emitted; leading us to an effectively slower velocity.

 

[RideFree]

Don't know who this belongs to

So far our collective efforts show that there appears to have been a relatively advanced civilization all over the globe at a time when our textbooks tell us we were simple hunter-gatherers.

WHAT? You mean this isn't so? The Bible talks of the Angels frolicking with the daughters of men (those lusty things).
Now, don't tell me that Velikovsky was wrong and more importantly, Zecharia Sitchin???And how could have I left out von Däniken???

 

[silverpig]

Originally posted by: Born2bwire

Originally posted by: PolymerTim

Originally posted by: silverpig
Light travelling through water is a complex phenomenon, and it isn't quite accurate to say the speed of light changes. c is c no matter if you're in water, air, or vacuum. You can probably find a better explanation of why light travels slower in water than in vacuum than I could provide in a simple forum post.

I tried looking up a little info on that, but I'm having trouble finding one that goes into that much detail. Most sources say that light does go slower through matter, but I found one that notes it as the "effective velocity" through matter. I'm guessing this is one of those situations where, technically, light doesn't slow down, but for most intents and purposes in the real world we can consider it to have slowed down. Is that close?

Light does travel slower through matter. More or less what happens is that the photons are absorbed and re-emitted by the atoms in the matter, the light does not pass through unimpeded. However, c is still the speed limit in this case. That is, irregardless (that's right, I said that wrong) of the environment, information cannot propagate faster than c, though this does not mean that light can only travel at c. There are also other terms you might hear in regards to light and matter, phase velocity and group velocity. These often are used when we are interested in guided wave behavior. If we are sending light down a long tube (or say optic fiber), we are mainly concerned with it's propagation along the length of the tube. In reality, light often travels at an angle to the length of the waveguide, bouncing around. In this case, the group velocity of light is slower than c (if it is an air filled waveguide) because the light is not traveling perfectly straight in the direction of interest.

That's not right. When a photon is absorbed and re-emitted it goes in some random direction. When light passes through glass it goes through in the same direction.

The reason why visible light passes through glass is because glass has a large band gap at that energy. Light doesn't get absorbed because there are no electrons which can be excited to another band at that energy. When a material has electrons able to absorb light at a given frequency, they will do so and radiate the energy either as phonons (heat) or re-emit the light in some random direction.

I guess it's sort of like skiing on moguls. The photon's EM waves get perturbed by the local charges.

As for a rigorous explanation of light traveling through a medium, I can't quite give it, but I know it's complicated. For all intents and purposes light travels slower through a medium, but still, c is c.

 

[Born2bwire]

Originally posted by: silverpig

Originally posted by: Born2bwire

Originally posted by: PolymerTim

Originally posted by: silverpig
Light travelling through water is a complex phenomenon, and it isn't quite accurate to say the speed of light changes. c is c no matter if you're in water, air, or vacuum. You can probably find a better explanation of why light travels slower in water than in vacuum than I could provide in a simple forum post.

I tried looking up a little info on that, but I'm having trouble finding one that goes into that much detail. Most sources say that light does go slower through matter, but I found one that notes it as the "effective velocity" through matter. I'm guessing this is one of those situations where, technically, light doesn't slow down, but for most intents and purposes in the real world we can consider it to have slowed down. Is that close?

Light does travel slower through matter. More or less what happens is that the photons are absorbed and re-emitted by the atoms in the matter, the light does not pass through unimpeded. However, c is still the speed limit in this case. That is, irregardless (that's right, I said that wrong) of the environment, information cannot propagate faster than c, though this does not mean that light can only travel at c. There are also other terms you might hear in regards to light and matter, phase velocity and group velocity. These often are used when we are interested in guided wave behavior. If we are sending light down a long tube (or say optic fiber), we are mainly concerned with it's propagation along the length of the tube. In reality, light often travels at an angle to the length of the waveguide, bouncing around. In this case, the group velocity of light is slower than c (if it is an air filled waveguide) because the light is not traveling perfectly straight in the direction of interest.

That's not right. When a photon is absorbed and re-emitted it goes in some random direction. When light passes through glass it goes through in the same direction.

The reason why visible light passes through glass is because glass has a large band gap at that energy. Light doesn't get absorbed because there are no electrons which can be excited to another band at that energy. When a material has electrons able to absorb light at a given frequency, they will do so and radiate the energy either as phonons (heat) or re-emit the light in some random direction.

I guess it's sort of like skiing on moguls. The photon's EM waves get perturbed by the local charges.

As for a rigorous explanation of light traveling through a medium, I can't quite give it, but I know it's complicated. For all intents and purposes light travels slower through a medium, but still, c is c.

I looked it back up and found that it wasn't the atoms but the phonons that were doing to absorption and re-emission. In the classical model, the induced dipole moments in the medium create secondary fields which through superposition are combined with the incident wave that create a wave at the same frequency but slower speed. Quantum mechanically, the photons interact with phonons, either supporting a phonon mode and being absorbed completely (thus an opague medium), or exciting an unsupported mode and thus being re-emitted after a miniscule delay.

 

[silverpig]

Originally posted by: Born2bwire

I looked it back up and found that it wasn't the atoms but the phonons that were doing to absorption and re-emission. In the classical model, the induced dipole moments in the medium create secondary fields which through superposition are combined with the incident wave that create a wave at the same frequency but slower speed. Quantum mechanically, the photons interact with phonons, either supporting a phonon mode and being absorbed completely (thus an opague medium), or exciting an unsupported mode and thus being re-emitted after a miniscule delay.

Like I said, it's complicated

But yeah that sounds about right from what I remember.

 

[firewolfsm]

I think the easiest way to explain that is that light may be slowed down in water, glass, air or whatever, but other things, like gravity, nuetrinos, etc. will still travel at c, as we know it in a vacuum.

 

[Gannon]

Originally posted by: firewolfsm
I think the easiest way to explain that is that light may be slowed down in water, glass, air or whatever, but other things, like gravity, nuetrinos, etc. will still travel at c, as we know it in a vacuum.

What I'm curious about is if you stretch space-time/fold it technically you should be able to make light get to places technically faster in the sense that you'd have space-time stretched in certain places but not others, even though no law was violated.

Imagine you have a series of 'c travel dots' (just to make this easy) on a rubber band of space time, and say this rubber band is capable of being significantly stretched without breaking, etc, each of 'c those travel dots' would would be stretched so technically light would travel at c along the surface but the 'legal' travel positions where light exists would technically be spaced farther apart.

According to einstein reality is one continuous field, there are no 'objects' as such

"Since the theory of general relatively implies the representation of physical reality by a continuous field, the concept of particles or material points cannot play a fundamental part, ... and can only appear as a limited region in space where the field strength / energy density are particularly high. (Albert Einstein, 1950) "

This would mean that particles are not truly 'fundamental'. since they are artifacts of strong fields, of some deeper non particle reality.

Perceiving propagation at 'speeds' may be a little strange even when we think about it since we are really refering to space-time relationships, and interactions of light with matter would not be interactions 'with matter' but with a field that is significantly strong and whos field effects space-time in such a way as to cause light to 'slow down'.

 

[CycloWizard]

There is no doubt that light is slowed down in any medium. The definition of refractive index is c_0/c, where c_0 is the speed of light in a vacuum and c is the speed of light in the medium. As to the atomic reasoning for why that is true, others can better explain. I do know some qualitative things regarding why certain atoms have a large impact on the speed of light in that medium, and it has to do with the orbital configuration. For example, sulfur uses lots of pi bonding and will, therefore, have a much more dramatic impact on refractive index than will carbon, which uses sigma bonding (almost) exclusively. If anyone remembers what these bonds look like, it makes sense because the pi bonds extend outward from the atoms bonded by them while sigma bonds are relatively compact. Thus, it's much more likely a photon will strike a pi bond than a sigma bond. I'm extrapolating outside of what I know for sure, but it makes sense to me at least.