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January 29th, 2016, 06:06 PM   #1
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Another shot in the dark

Dear MyMathForum community :
Could it be that the reason that we cannot detect dark matter directly is that the photons that emanate from it do not exhibit wave motion? Thank you.


Sincerely yours,
Carl Mesaros
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January 29th, 2016, 07:47 PM   #2
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Originally Posted by Carl James Mesaros View Post
Dear MyMathForum community :
Could it be that the reason that we cannot detect dark matter directly is that the photons that emanate from it do not exhibit wave motion? Thank you.


Sincerely yours,
Carl Mesaros
First: Light always has a waveform unless you are talking QM and calling them photons. Dark matter may scatter light but once the light has passed the dark matter then there is no reason why it should be any different than other light waves, though the interaction may polarize them.

Second: No one has any good idea of what dark matter is. There any number of candidates but so far all we have been able to do is rule out one idea or another. That being said dark matter is "dark" because light apparently doesn't interact with it. If it did then we should be able to detect the dark matter as it is heated by the light and we'd see it using infrared technology. (The exception is gravity. Dark matter and light both feel gravity but the interaction as with just about everything gravitational is very hard to detect.)

-Dan
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February 1st, 2016, 03:14 AM   #3
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Quote:
Originally Posted by Carl James Mesaros View Post
Dear MyMathForum community :
Could it be that the reason that we cannot detect dark matter directly is that the photons that emanate from it do not exhibit wave motion? Thank you.


Sincerely yours,
Carl Mesaros
In addition to what TopSquark posts..

The origin of dark matter came from studies of galactic rotation profiles. The technique is this: you take images of spiral galaxies and you take spectra of the stars or gas in that galaxy. Using knowledge of spectral lines in the lab and comparing them with the observed ones, we can estimate the shift caused by the doppler effect, which itself allows the speed to be calculated. With some transformations and corrections it possible to derive the rotational speed of the stars around the center of the galaxy.

Now, the issue is, if you plot observed profiles with theoretically predicted ones, they don't match. They can be made to match if there is some unobserved "extra mass" currently not catered for in the theoretical predictions.
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February 1st, 2016, 07:08 AM   #4
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What suggests how that "extra mass" is distributed?
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February 1st, 2016, 07:36 AM   #5
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What suggests how that "extra mass" is distributed?
Observation only at this point in time. The outer edges of the Milky Way (and other galaxies) are rotating too fast about the center for the visible mass to explain. This means that matter is "clumped" more densely than it should be. We can also see this between galaxies: The Andromeda and Milky Way galaxies are on an intercept course and the attraction is again too large for only the visible matter to explain. We can chart the anomalous accelerations (by comparing Doppler readings) of the galaxies and find that the distribution of dark matter shows up as filaments between the galaxies.

-Dan
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February 1st, 2016, 08:09 AM   #6
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What suggests how that "extra mass" is distributed?
If the dark matter problem can be resolved by accounting for additional matter, then the particular shape of the rotation profile suggests a distribution. Most measured rotation profiles are "flat" (except near the galactic center), so the distribution of dark matter required is almost always skewed out towards the halo. I'm not an expert on galactic dynamics (stellar evolution is my game), but whatever that distribution is, it is definitely not homogeneous.
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