dewclaw said:There is much more mass in the center of a galaxy than just the central black hole though. There are other black holes and a vast majority of the stellar mass.
Gravitational time dilation is a phenomenon in which time appears to pass slower in regions with stronger gravitational fields. This is due to the curvature of spacetime around massive objects, which causes time to flow at different rates for observers in different locations.
The gravitational time dilation effect can cause the rotation of galaxies to appear different from what is predicted by traditional Newtonian physics. This is because the velocity of stars at the edges of galaxies is affected by the gravitational pull of the galaxy's center, which causes time to pass at a slower rate for those stars compared to the stars closer to the center.
The galaxy rotation curve is a graph that shows the rotational velocity of stars in a galaxy as a function of their distance from the galaxy's center. This curve does not match the predicted velocities based on the visible matter in the galaxy, leading scientists to hypothesize the existence of dark matter, which could account for the missing mass and explain the observed rotation curve.
Gravitational time dilation can be measured using precise clocks and measuring the difference in the passage of time between two locations with different gravitational fields. This has been demonstrated through experiments such as the Hafele-Keating experiment and the Pound-Rebka experiment.
Yes, gravitational time dilation is a real phenomenon that can be observed in everyday life. For example, GPS satellites have to take into account the effects of time dilation due to their position in Earth's gravitational field in order to provide accurate navigation. Gravitational time dilation also plays a role in the aging process, with time appearing to pass at a slightly slower rate for individuals living at higher altitudes compared to those living at lower altitudes.