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View Full Version : Redshift magnification and flat rotational galaxy curves...



WaxRubiks
2009-Feb-10, 07:23 AM
I was going to post in Nereidís http://www.bautforum.com/against-mainstream/84365-flat-rotational-curve-defies-mainstream-theory-gravity.html thread, but I see it was closed.

What I was wondering was: if galaxies were magnified by the amount that the wave length from the starís light was lengthened(red shifted), and thus the distance of stars from the galactic centres was really much smaller; would this account for galaxiesí flat rotational curves, or maybe it would exacerbate it?


I think that redshift magnification is ATM, but I just wondered if it were applied in this situation it would explain the flat curve observation...

Jens
2009-Feb-10, 08:30 AM
I'm not sure, but my first thought is this: the problem isn't that the redshifts are wrong, but merely that all the stars in the galaxy have the same redshifts or blueshifts, whereas those further out should have smaller redshifts or blueshifts. So I think your idea would change it on a galaxy-by-galaxy level, whereas what you really need to "solve" the problem is to change it on a star-by-star level, within the same galaxy. I'm not sure if that's clear.

Cougar
2009-Feb-10, 02:57 PM
if galaxies were magnified...

I don't get this. Are you asking, If distances within a galaxy are actually a lot smaller than we think, would this explain the flat rotation curves?

If that's essentially the question, the answer is no. Nor does it explain the dark matter question. However far the edge stars are, according to Kepler and Newton and even Einstein, they should be orbiting a lot slower than stars closer to the center. They aren't. They are orbiting with about the same velocity. If (almost) every galaxy is embedded in a huge blob of dark matter, that would explain it. Weak lensing observations of the Bullet Cluster (http://en.wikipedia.org/wiki/Bullet_Cluster) strongly support the dark matter scenario.

WaxRubiks
2009-Feb-10, 03:16 PM
I don't get this. Are you asking, If distances within a galaxy are actually a lot smaller than we think, would this explain the flat rotation curves?


Yes.

I didn't think the magnification would be enough to account for the flat curve.

My thinking was that if some of the stars appeared further from the hub than they really were, then that would account for their higher speed....or is that the wrong way round..(?)

WaxRubiks
2009-Feb-10, 03:39 PM
oh, I got that wrong.

If a star appeared a greater distance from the hub than it really was, then that would account for its slow speed. Or maybe that's still wrong...