The rotation curve problem

[Muser]

I’ve noticed over years of reading books on cosmology and watching documentaries on subjects such as the Big Bang and the rotation curve problem in spiral galaxies, that the element of time in relation to gravity is never really mentioned. It’s accepted of course that gravity effects the rate of flow of time, but is this ever applied to issues like the rotation curve problem?

 

It would seem logical to assume the density of gravity is much higher at the centre of a galaxy and weaker at the outer edges. So unlike planetary orbits, if the rotation curves of spiral galaxies are generally seen to be flatter than what would be expected, how much does this time dilation at the centre actually affect observations?

 

Could the centre of a galaxy be moving much faster than observations imply? And could the flat rotation curve therefore be just a visual illusion?, brought about by time dilation rather than a requirement for Dark Matter?

 

Likewise, as observations suggest the expansion of the universe is accelerating, could the compound effect of weaker gravity and the consequential compound acceleration of time be responsible for what may only be an illusory acceleration?, rather than an actual physical acceleration? I assume there’s no upper limit to the speed at which time can tick?

 

Could this therefore also do away with the need for Dark Energy?

[swansont]

I’ve noticed over years of reading books on cosmology and watching documentaries on subjects such as the Big Bang and the rotation curve problem in spiral galaxies, that the element of time in relation to gravity is never really mentioned. It’s accepted of course that gravity effects the rate of flow of time, but is this ever applied to issues like the rotation curve problem?

 

It would seem logical to assume the density of gravity is much higher at the centre of a galaxy and weaker at the outer edges. So unlike planetary orbits, if the rotation curves of spiral galaxies are generally seen to be flatter than what would be expected, how much does this time dilation at the centre actually affect observations?

 

 

 

Seems like that would be a straightforward estimation. The frequency of a clock will vary like GM/rc^2

 

Our dilation relative to the surface of the sun is a dilation of about a minute per year. So we bump the mass up by 10 million (black hole plus some other mass) and then r increases by 30,000 LY x 60,000AU/LY, so that's 10^7/2 x 10^8. IOW we expect the time dilation at that distance to be around 1/20 of what we experience from the sun.

 

Put another way, even with the mass calculation including ~40x the mass of the black hole at our center, the time dilation at 30,000 LY is about what we experience from the sun. A part in ~525,000. (60 x 24 x 365.25)

 

Hard to think this has any measurable effect.