Thanks for your responses. I agree with those who pointed out that the Pioneer effect and the spacecraft flybys “mystery” are not clearly understood. They can’t be with our current knowledge of gravitation. I tried to explain the two effects with GRT – no success.
I would not trust...
Thank you all for your responses. I agree with bcrowell.
1. Has someone investigated the effect of variations in the Earth's gravitational field or in the classical gravitational constant on the Pioneer effect and/or the Earth spacecraft-flyby effect?
2. Can someone get me in contact with one...
This is what I know so far.
1. The Pioneer anomaly is due to thermal (kinetic) effect. Probably heat is from the spacecraft itself.
2. I believe only the NEAR spacecraft to an asteroid showed some significant flyby effect around Earth. At present they have fitted a curve with the data. They have...
I just happen to see the original question by student34 at Post 71. Here is one physicist's intuition.
1. I want you to recall Newton's 2nd law: Force vector = Rate of change of momentum vector. If you keep mass and the direction of velocity vector fixed, then force = (Inertial...
To stevendaryl at Post 694:
The choice of word "equivalent" was unfortunate. As a matter of fact this word is not quite correct in the case of mass either.
In the case of mass -- the pseudo gravity field is equal in magnitude but opposite in direction to the accleration.
In the case of electric...
As I said before, here is my take on POE-related topics.
The principle of equivalence
The genesis of the principle of equivalence is in the following equation:
(Gravitational mass) ∙ (Gravitational field intensity) = (Inertial mass) ∙ (Acceleration) (1)
That is, a mass in...
To PeterDonis -
After rereading my statement (2) and then reading yours, I think I found the problem. I restate (2) as follows:
A mass at rest in a frame is equivalent to being in a "gravitational field" when the frame is acclerating.
To PAllen: I will read your post and come back to you after...
To PeterDonis: Answer to "What makes you think that?
I get lost in mathematical jungle. I am a physicist, and I like to think in terms of physical models. I recall Feynman also: The glory of mathematics is that you don't have to say what you are talking about.
The genesis of POE is in...
What’s your understanding of the principle of equivalence?
In the literature, I find two meanings:
(1) Gravitational mass is numerically equal to inertial “mass.” (This is a postulate.)
(2) A mass at rest in a frame is equivalent to being in a “gravitational field” in an accelerated frame...
I have already done an extensive search of the literature. Will do so more.
"Genesis" means origin/beginning/creation/.... as you said.
So, Planck time is a fact!
I have come to realize that I am not going to understand gravity without time and its origin.
Is there a quantum of time?
What’s the smallest interval of time in which acceleration can place? – on the earth? – on the sun? – on a black hole?
A chronon is the time that light takes to cover classical electron radius. The other is the Planck time. But these won't serve my purpose, when I...
To Jjjxy at Post 5:
I did not get a clear answer as to how I can change my username! I don't know what "hotmail" is related to PF?
I think there should be a thread where people can discuss freely outside the box.
To cosmik debris at Post 190:
Sound waves. I agree the sound waves need media to travel. But the underlying interactions and their strengths determine the speed of propagating waves.
EM waves. There is no medium. Only fluctuations of coupled electric and magnetic fields. It's the coupling...
I used my model. I get total gravitational radiation power from PSR 1913+16 to be 7.87 x 10**26 watts. Moreover radiation from the various points on the orbits is not uniform.
Of course, the wave equations was was formulated with c.
To nicksauce at Post 1238:
Thank you for the answer. I know that gravitational waves have not veen detected (by LISA or LIGO). But there are indirect evidences from observing PSR 1913+16. I have been away from general relativity. I am catching up, but I thought I may have missed something...
I need a reference. The orbits of pulsars PSR 1913+16 are shrinking. It seems that is because of the energy the pulsars are losing by emitting gravitational waves. General relativity predicts that. So far, so good; now the question.
Is there an article where I can find the...
I copy below a file, but the figure may not show up.
Very briefly I will present my understanding of relativistic aging.
Special relativity (SR): (“Moving” below means motion at a constant speed along a straight line.)
(1) If we observe an object moving past us with a...
First, an accelerating rocket is not an inertial frame.
As I understand "equivalent" -- it means "as if" but not real. There are so far four fundamental forces: the strong, the weak, electromagnetic, and gravitational. In that sense I understand that the pseudogravity directed opposite to an...
I am late. Looks like the discussion has gone well beoynd the scope.
Please see the Pseudogravity thread and my statements.
George Gamow in his popularization series "Gravity" (Dover, 2002; p. 126) addresses this twin paradox. (Here he missed a point though. He ignored the effect of the earth's...
I don’t understand as to which statement your “I don’t think so” applies!?
And, regarding “… but the consequences of general relativity are absurdly well tested.” I have not seen related experiments. Can you please cite me a book or a journal article?
I will approach this problem another way...
I have a question on pseudogravity as invoked in thought experiments related to the principle of equivalence.
One invents ‘gravity’ opposite to an accleration to explain weightlessness, the bending of light beam, the dilatation of time period, and twin paradox. I can explain all of the above...
I have two questions. I couldn't find a suitable thread(s)! So, I am here.
(1) How do I change my user name and password?
(2) Where is a thread where physicists can present/discuss out-of-mainstraem topics?
I did some searching. Here is what I found.
Venus' orbital precession rate: 204 arc-sec/century; special relativistic correction: 8.6 arc-sec/century.
An observer measures Mercury's orbital precession rate to be 5600 arc-sec/century. After filtering out observer-Mercury relative motions...