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Gravitational Red Shift

# Gravitational Red Shift

Posted in the Physics Forum

nakayama

Yokohama, Japan

#1 Sep 6, 2011
In some books, a thought experiment (an elevator cabin is accelerating upward ; in non-gravitational field) is shown. Frequency that is observed at the floor is written to be different from the frequency of light source (set at the roof). Now, allow me to modify it. A star light (coming from above) is entering a hole on the roof and reach floor. Frequency at the roof and at the floor will be the same.
nakayama

Yokohama, Japan

#2 Sep 12, 2011
General relativity says, in an accelerating frame (e.g. elevator cabin ; supposed to be upward), frequency of light source at the roof is observed differently to an observer at the floor. And difference is related to the distance between the both.
- Trial of disproof- On the roof, there are two light sources (frequency is the same). In the middle of the one light path, there is a relay point. Frequency at the relay point is the same to the frequency of the other light path (point ; the same height). It will be able to regard this relay point as new light source (relay point is able to move to the floor limitlessly).
nakayama

Yokohama, Japan

#3 Sep 28, 2011
Imagine a unit time h/c second (h is height of this elevator cabin). In this accelerated cabin, one light source is switched on. And after 99 h/c second, the other light source (frequency is the same) is switched on. At the moment (the latter light reaches floor), number of waves that exists in both light paths will be the same. Thus, phenomenon gravitational redshift (books say, difference of frequency is not appearance) is unthinkable.
nakayama

Yokohama, Japan

#4 Sep 28, 2011
i confess, this problem (in elevator cabin scale) must be considered under Ritz's emission theory. Wave length of light path becomes longer. Besides, this change will increase as the source recedes (also, speed of waves [relative to the cabin] will increase). Though, in the cabin, state will be constant (because, acceleration is uniform).
nakayama

Yokohama, Japan

#5 Oct 4, 2011
In many books, an experiment (done at a tower at Harvard University [height is 25 meter]) is shown. Now, a mirror is set at upper part of the tower. From the ground (just below ; point A), a light ray is emitted to the mirror (supposed to be 30 seconds), and reflected light is observed. Emitted light and reflected light at point A seem to be the same (on frequency also). How does relativity explain ?
nakayama

Yokohama, Japan

#6 Oct 8, 2011
Are there any errors in the following passages ?

From non-gravitational field to gravitational field, a light ray is emitted. When two waves (from the start of emission, A+1th and A+2th [in these turn]) are emitted, the second light ray (frequency is the same) is emitted. Behavior of four waves (two are the front waves of second ray) in gravitational field will be the same. Phenomenon time dilation will be impossible.
nakayama

Yokohama, Japan

#7 Oct 14, 2011
Several books (e.g. “Raum, Zeit, Materie” by H Weyl) say, “frequency from the source (supposition ; an atom that emits characteristic frequency) stays (at a standstill) in a different gravitational field is the same to the frequency that an observer receives. But it’s different from the frequency that the same atom at hand emits”. By interference of this two lights (one waves pass the other waves ; different from interference of MM experiment), it seems to be clarified whether phenomenon gravitational redshift occurs or not (after enough time ; even by earthly experiment).
nakayama

Yokohama, Japan

#8 Oct 18, 2011
If phenomenon gravitational redshift is true, explanation (quantitative) as follows seems to be possible on an elevator cabin stays in a gravitational field. Light speed is slower in a gravitational field. So, speed of light emitted upward becomes faster and wavelength becomes longer. Then, redshift occurs.
&#12298;P.S.&#12299;In an elevator cabin in a uniform accelerated motion (upward), this change is contrary.
nakayama

Yokohama, Japan

#9 Oct 25, 2011
Gravitational redshift (both in a gravitational field and in a uniform accelerated frame) will be invisible. Because, colors are caused by the difference of frequency (not by wavelength).
nakayama

Yokohama, Japan

#10 Oct 29, 2011
In an accelerated elevator cabin (upward ; uniformly), behavior of every wave will be the same. So, difference of frequency at the roof and at the floor will be impossible (in an elevator in gravitational field, it will be the same).
nakayama

Yokohama, Japan

#11 Oct 31, 2011
Value of gravitational redshift is shown to be “gh / cc” (cc is square of c). However, it seems to be impossible that this formula is valid on scale of scores of meters and on astronomical distance also.
nakayama

Yokohama, Japan

#12 Nov 2, 2011
On Harvard Tower Experiment

No book seems to touch on difference of atmospheric pressure (a tube [set vertically] was filled with helium).
nakayama

Yokohama, Japan

#13 Dec 15, 2011
There is a space ship (accelerating upward). Books say that "gravity" at roof and floor is different.

Disproof ; There are two probes (accelerating upward). Position of the two is apart vertically (distance is the height of the space ship). "Gravity" at the two will be the same.
nakayama

Yokohama, Japan

#14 Dec 16, 2011
Correction & Apology

i am sorry. Yesterday, i made a wrong post (because of a book ; in Japanese ; 2008). In a space ship, "gravity" is uniform.
nakayama

Yokohama, Japan

#15 Dec 17, 2011
Bending of Light by Gravity

Many books explain bending of light with an elevator cabin in free fall. Now, two elevator cabins are falling before an observer's eyes. Falling speed of the two is different because starting points of falling is different. Does the observer observe different bending of light (gravity g is the same)?
nakayama

Yokohama, Japan

#16 Dec 22, 2011
P.S. In many books, light ray is coming from the outside of the elevator cabin. In some books, light source is set on the wall of the cabin. In the former, falling of the cabin will have no effect on light ray (imagine a cabin without wall). In the latter (if the emission theory is true), behavior of light ray will be easy to imagine.
nakayama

Yokohama, Japan

#17 Dec 27, 2011
P.S. to the second post (Sep 12, 2011)
Distance will be related not to frequency but to wavelength and light speed (if the emission theory is true).
nakayama

Yokohama, Japan

#18 Jan 24, 2012
Bending of Light by Gravity

In some books, with an elevator accelerating upward, bending of light is explained (horizontal light ray is coming from the outside of the cabin). Now, imagine an elevator moving upward in a uniform motion. Light ray is straight and will incline downward (degree of incline is changed by the speed of the elevator). This incline will be visible not only in the cabin but also in the outside of it. This phenomenon must be interpreted only geometrically. It will be the same about accelerated elevator.
nakayama

Yokohama, Japan

#19 Jun 28, 2012
For a 10 seconds, an elevator cabin accelerated upward and stopped. Number of waves of light that appears and vanishes during that time will be the same.

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