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Ahmed Samra
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How does the gravitational red shift causes time dilation?
Ahmed Samra said:Is there any relationship between the gravitational red shift and gravitational time dilation? What is it?
- http://en.wikipedia.org/wiki/Gravit...l_redshift_versus_gravitational_time_dilationWhen using special relativity's relativistic Doppler relationships to calculate the change in energy and frequency (assuming no complicating route-dependent effects such as those caused by the frame-dragging of rotating black holes), then the Gravitational redshift and blueshift frequency ratios are the inverse of each other, suggesting that the "seen" frequency-change corresponds to the actual difference in underlying clockrate. Route-dependence due to frame-dragging may come into play, which would invalidate this idea and complicate the process of determining globally agreed differences in underlying clock rate.
While gravitational redshift refers to what is seen, gravitational time dilation refers to what is deduced to be "really" happening once observational effects are taken into account.
1977ub said:someone at the wikipedia had this to say:
- http://en.wikipedia.org/wiki/Gravit...l_redshift_versus_gravitational_time_dilation
I agree.PAllen said:the separation between gravitational redshift and ordinary Doppler is itself coordinate dependent, thus I don't view them as separate phenomena
Please read my last post. All questions you ask are fully answered there. Given an emitter and receiver at the top and bottom of a tall building, analyzed from the point of view of a free falling observer you find the detectible effect is 100% due to velocity difference between the emitter at emission time and receiver at reception time. Thus, who is observing (more precisely, which coordinates you use) determines whether a given observation is explained by Doppler, gravitational red shift, or any mixture.P.Schuurmans said:Doesn't Doppler work on different velocities whereas Gravitational redshift works only in gravitational fields ? (or according to EEP to accelerating frames)
That is an important difference, I think.
I agree with Topicwriter that Timedilation and Gravitational Redshift seem to work opposite in stead of in similar direction.
Gravitational red shift is the phenomenon in which light emitted from a source in a strong gravitational field appears to have a longer wavelength when observed from a distant location. This is due to the gravitational bending of light as it travels through the strong gravitational field.
Gravitational red shift is a key prediction of Albert Einstein's theory of general relativity. According to this theory, the curvature of spacetime by massive objects, such as planets or black holes, can cause light to appear to have a longer wavelength when observed from a distance.
Gravitational time dilation is a phenomenon in which time appears to pass at a slower rate in a region with a strong gravitational field. This means that clocks in a strong gravitational field will run slower than those in a weaker gravitational field, or at a distance from the source of gravity.
Gravitational time dilation is a very small effect and is only noticeable in extreme gravitational fields, such as near black holes. In our daily lives, the effects of gravitational time dilation are negligible and have no significant impact on our daily activities or experiences.
Yes, both gravitational red shift and gravitational time dilation can be observed in our solar system. For example, the red shift of light from the Sun's surface has been measured and is in agreement with predictions from general relativity. Additionally, atomic clocks on Earth have been found to run slightly slower than identical clocks in space due to the difference in gravitational fields.