Can objects in space appear to move backwards in time?

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Discussion Overview

The discussion explores the concept of whether objects in space can appear to move backwards in time, particularly focusing on the relativistic effects of high speeds on the perception of time and motion between two objects moving away from each other.

Discussion Character

  • Debate/contested

Main Points Raised

  • One participant suggests that an observer moving at a high speed would see another object moving away from them appear to be "going back in time."
  • Another participant counters that the observer would only perceive the other object's clock running slower than their own, not reversing in time.
  • A further contribution questions whether the observer would see the other object moving away at the speed of light, noting that speeds cannot exceed the speed of light and suggesting that the other object's clock would appear to stop or move slowly if receding at light speed or less.
  • One participant recommends using the addition of velocity theorem and time dilation theorem to analyze the situation.

Areas of Agreement / Disagreement

Participants express differing views on the perception of time and motion between the two objects, with no consensus reached on whether one object can appear to move backwards in time.

Contextual Notes

Discussion includes assumptions about relativistic speeds and the effects of time dilation, but lacks detailed mathematical analysis or definitions of terms used.

Matthieu
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Let's assume we have two "somethings" in space, they get away from each others. The speed of one of them is around 150,000kms/sec, very fast but less than the speed of light, the other one goes the totally opposite way at 200,000kms/sec.

An observer on one of these would see the other element "going back in time" wouldn't he?
 
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no, he would just se the other ones clock go slower than his own.
 
Wouldn't the observer see the other object flying away at the speed of light? No matter what the speeds of the two objects are their speeds can never add up to more than c, right? So his clock would be moving at normal speed and he would see the other object's clock either stop if it was receding at c, or moving extremely slowly if it was receding at less than that, correct?

Would this observer see the other object moving away at c or slightly less?
 
Use addition of velocity theorem and time dilation theorem.
 

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