Shooting Video on Planet Z Near a Black Hole

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Discussion Overview

The discussion revolves around the effects of time dilation on video recordings made on a planet near a black hole, particularly focusing on how these recordings would be perceived when played back on Earth. The scope includes concepts from general relativity and the implications of time dilation in different gravitational fields.

Discussion Character

  • Conceptual clarification, Debate/contested

Main Points Raised

  • One participant suggests that a video recorded on planet Z would appear normal when played back on the planet but may appear as slow motion when viewed on Earth due to time dilation effects.
  • Another participant clarifies that the DVD and player function as a clock, indicating that time dilation effects are temporary and do not affect the playback of the video once it is recorded.
  • A different viewpoint states that if the video is broadcast into space, a distant observer would see it in slow motion, but if sent directly to Earth, it would appear normal.
  • One participant proposes a scenario involving timelapse photography, arguing that if the playback speed is consistent with the local clock, there should be no perceived slow motion when viewed on Earth.

Areas of Agreement / Disagreement

Participants express differing views on how time dilation affects the playback of video recordings made near a black hole, with no consensus reached on whether the playback would appear slow motion or normal when viewed from Earth.

Contextual Notes

There are unresolved assumptions regarding the nature of time dilation effects and how they apply to recorded media, as well as the implications of broadcasting versus direct transmission of the video.

hypermental
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[Mentor's note: The thread title has been edited to change the level from "A" to the more appropriate "B"]

Suppose there is planet Z revolving around black hole. Astronaut from Earth go in that Planet Z and start video recording and make a DVD . Suppose they played that DVD in the computer in that planet . I hope they will feel every clip i that video is normal. But I think when they come to Earth and play that video clip , i hope it will be slow motion video isn't it? i am little confused.. Help me with your answers please.
 
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You posted this as "A" (advanced) level, but it seems more like a "B" (beginner) question. "A" would mean that you wanted an answer at the level of a graduate course or higher.

The DVD and DVD player in your example are basically just a clock. In GR, the speed of a clock does not depend on any memory of what regions of spacetime it has visited. In other words, effects such as kinematic and gravitational time dilation are temporary, not permanent. There was a theory called the Weyl gauge theory in which such effects were permanent, but that theory is not compatible with experiment.
 
If they broadcast the video out into space, a static observer further away will see it as slow motion. However, if they send the video clip to earth, it will be normal in every way, just as if it were made on earth.
 
Lets say instead of video it is timelapse photography ... the camera shoots 1 picture every second according to a clock sitting next to it.
To watch at normal speed, play back one-frame per second according to a clock sitting next to it.
The projector on the Earth plays back one frame every second according to a clock sitting next to it... so why would it be slow?
 
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Thanks for all replies . I got it .
 

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