externo Posted April 26 Share Posted April 26 (edited) 18 hours ago, KJW said: In the case of the twin paradox, the redshift and blueshift are due to the relative velocity between the source and receiver. In the case of gravitational redshift and blueshift, equivalent to accelerational redshift and blueshift, there is no relative velocity between the source and receiver. The redshift and blueshift is due to the acceleration itself, and depends on the displacement between source and receiver. If one examines the metric of an accelerated frame of reference, sources that are at rest and above the receiver (note that the acceleration is directed upward) will be blueshifted, while sources that are at rest and below the receiver will be redshifted. It is worth noting that the source that is at rest below the receiver has a greater acceleration than the receiver, and that the source that is at rest above the receiver has a lesser acceleration than the receiver. However, this does not determine the redshift or blueshift, and it might not apply to gravitation. Correct, but how do you explain that acceleration produces a blueshift and redshift from the point of view of the one accelerating if it does not change its speed relative to the waves? ---------------------------------------- 19 hours ago, DanMP said: The traveling twin, after the turnaround, accelerates toward Earth/Sun and he immediately see the light from the Sun blueshifting. As long as he accelerates, the light is blueshifted again and again, due to the increase in speed towards the source of the light (the Sun). So, as long as his accelerometer indicates an acceleration towards the Sun, the light of the Sun is blueshifted again and again. On the Earth surface, say on the South pole, in summer, we also have the accelerometer indicating an acceleration towards the Sun, but the blueshift is not increasing, like in the traveling twin case. So the equivalence principle seems not quite relevant in explaining the blueshift that the travelling twin experiences. If I'm wrong, please explain me how/why I'm wrong. The equivalence principle only works inside the rocket, without the possibility of seeing what is happening outside. You just need to study the blueshift and redshift that emanate from inside the rocket. It is only local, which is why we cannot resolve the twin paradox within the framework of general relativity. Edited April 26 by externo Link to comment Share on other sites More sharing options...
swansont Posted April 26 Share Posted April 26 3 hours ago, externo said: Correct, but how do you explain that acceleration produces a blueshift and redshift from the point of view of the one accelerating if it does not change its speed relative to the waves? ! Moderator Note This was explained to you in your thread 3 hours ago, externo said: ---------------------------------------- The equivalence principle only works inside the rocket, without the possibility of seeing what is happening outside. You just need to study the blueshift and redshift that emanate from inside the rocket. It is only local, which is why we cannot resolve the twin paradox within the framework of general relativity. ! Moderator Note Mainstream threads are not the place to bring up objections to mainstream science. Link to comment Share on other sites More sharing options...
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