# Questions tagged [gravitational-redshift]

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### What does the $O$ mean in "$O(v^4)$"?

I am currently studying General Relativity and I am using the book by Schutz. I encountered a problem when I was reading about the gravitational redshift experiment. Here is the website (it is not the ...
1 vote
31 views

### Is a star that orbits a black hole, emitting different spectra while close or far from the black hole?

Is a star that is orbiting a black hole emitting different spectra respectively while close and far from the black hole? Also is that star light, when reaching our eyes, some kind of delayed while the ...
149 views

### How the wavelength of a photon is affected by an uniform gravitational field

In the presence of a uniform gravitational field two observers at fixed positions obtain different measurements of frequency of the same photon. One observer at the origin of some coordinate system ...
1 vote
206 views

### Exercise 4, Chapter 6 in Wald's book [closed]

I would like to understand the solution of point b) in the mentioned exercise, which reads Let $(M,g_{ab})$ be a stationary spacetime with timelike Killing field $\xi^a.$ Let $V^2=-\xi^a\xi_a$. a) ...
149 views

### Hughes argument (based on Schild's argument) for gravitational redshift

In his lecture notes on General Relativity (2nd page of the pdf, labelled page 7) and in the lecture itself, Scott Hughes puts forward a thought experiment to justify the existence of gravitational ...
254 views

### Is energy conserved in a geodesic?

In old school physics we know that Work done (resulf of energy) $=$ Force $×$ displacement. But, according to Einstein, free-fall is not a result of a force but just the result of objects following ...
373 views

### Light scattering on the rotating black hole in the Kerr geometry

To simulate light scattering on the rotating black hole we have used this paper and this code. First, we made animation for light beam scattering in the equatorial plane For not equatorial plane the ...
1 vote
39 views

### If an astrophysical jet contains gamma rays does it mean that at the source poles there is small gravitational redshift?

If an astrophysical jet contains gamma rays does it mean that even though the source has incredibly strong gravitational pull, at the source poles there is small gravitational redshift? Maybe there is ...
1 vote
62 views

### Has anyone considered a gradual change in Gravitational Potential across the universe as a cause for cosmic red shift?

Since the formation of fundamental particles at the beginning of the universe (roughly the time of the CMB emission, and after the inflationary epoch of Big Bang theory), the gravity wave front of all ...
1 vote
126 views

### Would light emitted from a white hole be red-shifted or blue-shifted?

if it's not that straight-forward, what factors would effect the resulting appearance of light emerging from a white hole?
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### If I live on a planet that is heavy enough, would the CMB get blue shifted to be in the visible spectrum?

If I live on a planet that is heavy enough, would the CMB get blue shifted enough in the atmosphere of this heavy planet, due to gravitational blue-shifting, that the CMB would be in the visible ...
179 views

### Gravitational red shift and equivalence principle

Two persons A, B are uniformly accelerating in the positive z direction by amount $g$. $A$ flashes two pulses of light with an interval $T_a$. The time interval between two flashes of light in $A$ ...
1 vote
46 views

### Redshift + Collapse [closed]

Let a radio transmitter on the surface of a collapsing spherical star emit monochromatic waves, let the distant observer, at the same theta and phi, as the transmitter, receive the waves. Show that at ...
1 vote
159 views

### Mössbauer effect to verify the gravitational redshift

"The tower used by Pound and Rebka in 1960 to exploit the Mossbauer effect is only about h = 20 meters high, and so the effect (gravitational redshift) is only $(GM/(Rc^2))(h/R) ∼ 10−15$! How ...
82 views

### Does matter redshift light via gravity?

Imagine a photon passes by a stationary atom in a large void of empty space. We know that the gravity of the atom will bend the path of the photon. It will also blue shift as it approaches the atom ...
203 views

### Gravitational redshift in terms of wavelength

I know that Einstein’s theory of general relativity predicts that the wavelength of electromagnetic radiation will lengthen as it climbs out of a gravitational well. Photons must expend energy to ...
261 views

### Does the Hubble law make sense?

The Hubble law says that if an object is at a distance $r$, it should have a velocity $Hr$ and therefore any light signal from that object will be correspondingly redshifted. However, the light ...
641 views

### How accurately has general relativity's prediction of gravitational redshift been measured?

According to Einstein's general relativity, massive bodies should cause gravitational redshift. How accurately has this been measured?
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### Is color perception of an celestial object effected by red shifting?

Assuming I stand on the edge of the gravitational well formed by our Sun. If I was to move infinitely closer to the Sun- and was staring at it without a filter (and wasn't harmed in doing so)- would ...
1 vote
61 views

### What is the frequency of a freely falling light-source measured by observer standing on planet?

Assume that a light source is falling freely on a planet with a nearly uniform gravitational field. If the light source, reaching a velocity $v$, emits a photon towards an observer standing on the ...
According to relativity , if there is a light source $B$ with a frequency $\nu_B$ at a distance $d$ from an observer $A$ inside a uniform gravitational field of $g$, the frequency of the light ...