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Sanborn Chase
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Does anyone know the speed of light in dark matter?
Sanborn Chase said:But it's not a vacuum, right?
Sanborn Chase said:And a 'bent" ray takes longer to travel, so we've varied t and r.
Sanborn Chase said:Personally, I think the evidence for a DM halo surrounding our galaxy and others is quite convincing. If that be so it is doubtful mankind has ever clocked the speed of light in anything but dark matter:: the speed of light in dark matter is the conventional measure currently used.
I think you seriously misunderstand the density of dark matter. Inside galaxies where it is prevalent, the density is something less than 10E-20 grams per cubit centimeter which is pretty much a hard vacuum, and remember, that's the AVERAGE. The actual density of matter (regular and dark) outside of solid bodies is WAY less than that. It's not even remotely reasonable to call that a "Medium".Sanborn Chase said:the speed of light in dark matter is the conventional measure currently used.
The local dark matter density is around ##10^{-25}## g/cm3. It goes up as you approach the galactic center.phinds said:Inside galaxies where it is prevalent, the density is something less than 10E-20 grams per cubit centimeter which is pretty much a hard vacuum, and remember, that's the AVERAGE.
This is not how you compute speed. Speed is the magnitude of the instantaneous velocity, not that of the average velocity over a longer time.Sanborn Chase said:But it's not a vacuum, right? And a 'bent" ray takes longer to travel, so we've varied t and r.
On the other hand, if you are wondering if the permittivity and permeability of our 4-manifold may be affected by some property (that seems to define the curvature of that manifold), then your question seems like a good one. Both Paul Dirac and Rob Laughlin (and many others) have wondered about this.Sanborn Chase said:Thanks, Vanadium. As you've already discerned I have no qualms about showing my profound ignorance to the public.
nnunn said:As pointed out by the OP, if the distribution of this substrate is not homogeneous, we've only really measured permittivity and permeability from deep within a well of that 'stuff'.
Hi Drakkith - given the need to interpret those astronomical observations, if permittivity and permeability were not constant along the entire path followed by those observed photons, our interpretation of those observations may be skewed. For example, consider a high precision observation of a quasar, in which the observed photons have followed some path though both cosmic voids and superclusters.Drakkith said:Would you count astronomical observations as measurements of the permittivity and permeability of deep space?
This is not correct. There is no expansion/inflation of space, things just get farther apart during the expansion/inflation of space-time. Space is just geometry, not a thing that can be bent or stretched, etc.nnunn said:... since standard models already accommodate two simple motions of space itself (inflation, expansion)...
nnunn said:Hi Drakkith - given the need to interpret those astronomical observations, if permittivity and permeability were not constant along the entire path followed by those observed photons, our interpretation of those observations may be skewed.
Sanborn Chase said:What if all observations have been skewed, and skewed how is unknown?
Sanborn Chase said:A link in the inductive chain may be in question. Perhaps the question should be the speed of light without dark matter present.
Sanborn Chase said:If you have the power to "shut down" my questions, and they seem to have irritated you in some manner, go ahead.
Thanks Drakkith, and I agree. Which makes me wonder... given that researchers are converging towards two very precise, but different, values for a "Hubble constant", would this qualify as a pointer to something that may turn out to be "difficult for the standard model to explain"?Drakkith said:[...] That's why I stressed the need for observations that are difficult for the standard model to explain.
nnunn said:Thanks Drakkith, and I agree. Which makes me wonder... given that researchers are converging towards two very precise, but different, values for a "Hubble constant", would this qualify as a pointer to something that may turn out to be "difficult for the standard model to explain"?
Sorry for expanding this aside, but let me sum up the article.nnunn said:given that researchers are converging towards two very precise, but different, values for a "Hubble constant", would this qualify as a pointer to something that may turn out to be "difficult for the standard model to explain"?
https://www.scientificamerican.com/...on-universes-expansion-polarizes-scientists1/
Dark matter is a type of matter that makes up a large portion of the universe, but does not interact with light or other forms of electromagnetic radiation. It is invisible and can only be detected through its gravitational effects on other objects.
The speed of light in dark matter is measured using the same methods as in normal matter, such as using lasers and mirrors to bounce light off of objects and measuring the time it takes to travel. However, the speed of light in dark matter may be affected by the presence of dark matter particles.
It is currently unknown if the speed of light is different in dark matter compared to normal matter. Some theories suggest that the speed of light may be slightly slower in the presence of dark matter, but this has not been confirmed by experiments.
The speed of light in dark matter is important because it can help us understand the properties and behavior of dark matter. By studying how light behaves in the presence of dark matter, we can gain insight into the nature of this mysterious substance and its role in the universe.
It is currently not possible to travel at the speed of light in any form of matter, including dark matter. The speed of light is the maximum speed at which any object can travel in the universe, according to Einstein's theory of relativity. Additionally, the properties of dark matter make it even more difficult to achieve such high speeds.