Is the speed of light constant between galaxies?

Dark matter found between galaxies Dark Matter Filament Between Galaxy Clusters Found | Space using gravitional lensing.
Dark Matter Filament Studied in 3D for the First Time | ESA/HubbleWould light (photons) slow down going through these energies or would light bend around "dark matter" and follow its contours and nothing is where we believe (outside of our galaxy)?.HALL OF MIRRORS - SCATTERED PICTURES.If 80-90% of universe is "dark matter" and light does not interact but bends around "dark matter" there would be alot of bending, so are the galaxies where we really think they are?Which in turn would mean if we could ever fly through "dark matter" as the crow flys, could we reach a destination before light, that travels a long and winding path around the dark matter, which would be a long detour if dark matter makes up 80-90% of universe.Or does light slow down while passing through dark matter like it does through glass, retaininng its light speed once it as passed through?Would this also mean that neutrinos cannot travel faster than light but they can travel straighter than light, and pass through dark matter?Is there any real proof, light speed is constant between galaxies?Edited by sunshaker, : No reason given.

Hi SunShaker,I see two ways we could go with this:

• I could tell you that light does not bend around dark matter like air around a car in a wind tunnel, and that light traveling directly at dark matter will travel straight through it, and that the gravity of dark matter bends light the same way as any other matter, and you could say, "Oh. Never mind."
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• Or, you could insist that you're correct and that light does actually bend around dark matter, in which case I'll promote this thread.

There is much guess work about the properties of "dark matter", from what i can deduce light does not interact with dark matter, We can only summise where it is by the effects of gravitational lensing, if this is correct, with the amount of estimated dark matter in our "local universe", i see the possibility of it being like a "Maze" where light enters at one destination and exits at another or multiple others, so we are almost never looking directly at distant galaxies,
Perhaps something like how a periscope works.Sometimes we need to think aloud, and see if we are missing something obvious, i have my picture of how it all fits together, but if i am wrong on parts of that picture it will not be a complete picture, so i would welcome any views on how dark matter effects "light".Or if you wished i could add this to my last post
EvC Forum: Alpha-Omega universes in free fall Alpha-Omega universes in freefall.But i would prefere a new thread, as there are a few ideas i have about "dark matter" that i would like to ask those with a better idea than myself on sub atomic particles.Edited by sunshaker, : added link to old post.Edited by sunshaker, : No reason given.

Thread copied here from the Is the speed of light constant between galaxies? thread in the Proposed New Topics forum.

I will simply point out that it is far from obvious what it might mean to say that the speed of light is constant.One of the things that Einstein taught us, was there there can be no universal measuring scale. How we measure things, such as speed, will depend on our inertial frame.The question, on whether the speed of light is constant, would seem to require a universal scale.

As i said in my other thread, "I" believe "all" matter and energies came from "higher dimensional space" and we are expanding in "lower dimensional space" drawing in, infuseing our universe with lower d space as we continously expand,Galaxies and star are in pockets of lower d space, and that is where we get the speed of light as a constant,
But once we leave a "galaxy bubble" we enter the realms of higher d space (dark matter-energies), where as before light travelled with no resistance through lower d space, it cannot pass through these higher d energies and can only follow the path of lower d space around these dark matter energies.I was thinking as the universe continues to expand and we are infused with more lower d space, these dark matter-energies will continously be "pulled stretched" apart, allowing light and other energies to pass through? but not without some resistance.

I was also thinking, correct me if i am completely off track on this, That basically dark matter is a field of "ions", and as our universe continously expands it causes the ions to be electrcally charged and give of "gamma energy" which we see as these "gamma ray bursts", Seeding new areas of the universe with these new atoms.

But you never leave galaxies. Gravity attracts across all distances. There is nowhere in our universe where you are out of the gravity well of a star or galaxy. There is nowhere in our universe where spacetime is not being distorted by gravity.If I understand my physics correctly, light bends in gravity wells because light does move at a constant speed. The curved path preserves the constant speed of light in areas with distorted spacetime.

Electrons would produce Compton scattering which would be observed as blurred images or opaque areas where light does not pass. That is not what we observe. Dark matter does not appear to interact with light at all, outside of gravitational lensing.

There are many galactic clusters we are part of one, but there is space between each galaxy as there is space between each star in a galaxy, space is different within our solar bubble "heliopause", to the space between each star in a galaxy which is different to the space between galaxies, each is made up of varying degrees of lower and higher dimensional energies, light travels at a constant within our solar bubble as most dark matter as been almost completely infused with lower d space, but between stars in a galaxy there is more higher d energies (dark matter) and between galaxies there is even more, these dark matter energies are continously still being broken down as the universe expands drawing in lower d space, And as you say lights bends in "gravity wells" and follows a curved path, so depending where light is coming from and the path it as to take around untold gravity wells through different densities of space, can we be sure where anything is?

Where did you demonstrate that? Where is the evidence for this? Of course we can. Light is bending around the Earth's gravity well right now. Do you have problems finding anything?

The ions in dark matter only have electrons when they have been electrically charged , this happens as the dark matter is pulled and stretched with the expanding universe, allowing lower d space to rush in, "washing" through dark matter collecting these newly charged particles and depositing them in pockets of lower d space(gamma ray bursts/ black holes), where stars and galaxies will eventually form.

This turns out not to be the case. According to Einstein, the speed of light as measured by an observed does not depend on the motion of the observer as long as the observer is not accelerating. So a universal measure scale is not needed for the speed of light to be constant.

All ions have charges. That is part of their definition.Why do you believe that gamma ray bursts are not associated with regular matter? What is your reason for requiring a dark matter ?explanation for either gamma ray bursts or black holes?

I am not saying that gamma ray bursts are not associated with regular matter, a large percent are, but i do believe that "all" matter and energies(dark matter), first came from a higher dimension, which dropped into this lower d spaces and rapidly expanded, so all matter and energies used to be "dark matter",when something rapidly expands there is a reaction, the result of this reaction is the matter and energies we now see,the universe is still expanding and the reactions are still going on, dark matter is the catalyst for new "regular matter".