Why Do Events Freeze For Me at the Speed of Light?

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Discussion Overview

The discussion revolves around the concept of how events are perceived by an observer accelerating towards the speed of light, particularly focusing on the phenomenon of "freezing" events as one approaches light speed. The scope includes theoretical implications of relativity and the effects of acceleration on the perception of time and light from a distant source.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants propose that as one accelerates towards the speed of light, the perception of events, such as someone waving, slows down and eventually appears to freeze due to the last photons received.
  • Others argue that while there is a last instant of information from Earth that can be perceived, this does not occur at the speed of light, as one cannot reach that speed.
  • It is suggested that the light from Earth continues to arrive until it passes beyond the observer's Rindler horizon, although practically, the observer will see the Earth fade into darkness due to redshift.
  • One participant notes that the effects described are not inherently relevant to the theory of relativity, as classical mechanics allows for hypothetical scenarios where one could exceed light speed, leading to different perceptions.
  • Another viewpoint discusses that a constantly accelerating rocket can outrun a light beam, indicating that the observer will not see light emitted after a certain point unless they stop accelerating.
  • The motion of the rocket is described as hyperbolic, with the light beam acting as an asymptote that the rocket never reaches.

Areas of Agreement / Disagreement

Participants express multiple competing views regarding the perception of events at high speeds, particularly concerning the implications of relativity and the nature of light and acceleration. The discussion remains unresolved with no consensus on the interpretations presented.

Contextual Notes

There are limitations regarding the assumptions made about the observer's experience and the definitions of terms like "Rindler horizon" and "hyperbolic motion." The discussion also highlights the dependence on the conditions of acceleration and the nature of light propagation.

RobbyQ
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TL;DR
Why Events Freeze For Me
Is my thinking correct ?
Assuming I can see you throughout my journey... If I accelerate away from Earth towards the speed of light and you are waving to me, I start to see your waving slow down and eventually at speed to light your waving stops like a photographic image. Almost like the last image I took of your photons relative to my speed. There is now no new information reaching me. i.e that last image is stuck with me forever ?
 
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RobbyQ said:
TL;DR Summary: Why Events Freeze For Me

Is my thinking correct ?
Assuming I can see you throughout my journey... If I accelerate away from Earth towards the speed of light and you are waving to me, I start to see your waving slow down and eventually at speed to light your waving stops like a photographic image. Almost like the last image I took of your photons relative to my speed. There is now no new information reaching me. i.e that last image is stuck with me forever ?
Yes, there is a last instant of your home world's future that you will ever see.

However, this last instant is not seen when you reach the speed of light. It can't be. Because you never reach the speed of light. Instead, there is an instant (on Earth) when it passes beyond your Rindler horizon. Ideally, the light speed information from Earth never stops arriving. Though as a practical matter you'll see the Earth fade into red-shifted darkness long before that.
 
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What you see in a scenario like this depends on the travel time of light from an event on Earth to your spaceship. This sort of effect is not in itself relevant to the theory of relativity.

Indeed, in classical mechanics, you could in principle exceed the speed of light and you would see all sorts of weird effects in such a scenario.

Although the special theory of relativity can describe accelerating reference frames, it's more usual to present the basic theory in terms of inertial frames of reference.
 
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RobbyQ said:
TL;DR: Why Events Freeze For Me

Is my thinking correct ?
Assuming I can see you throughout my journey... If I accelerate away from Earth towards the speed of light and you are waving to me, I start to see your waving slow down and eventually at speed to light your waving stops like a photographic image. Almost like the last image I took of your photons relative to my speed. There is now no new information reaching me. i.e that last image is stuck with me forever ?

You can't move at the speed of light, but it turns out you that relativity depicts what you describe.

There's another way of saying this - given a head start, a rocket with a constant acceleration can outrun a light beam. In the case of a rocket accelerating at approximately 1g (the exact number i am using is actually 9.5 m/s^2, which is equal to one light year/year^2), a rocket with a headstart of one year will outrun a light beam as long as it continues to accelerate.

The equations for the motion of the rocket are detailed in the wiki article https://en.wikipedia.org/wiki/
Hyperbolic_motion_(relativity)

The rocket can continue to outrun the light beam only as long as it keeps accelerating, though. So, an observer on the rocket will never see a photon emitted one year after they leave their point of origin (presumed to be the Earth) unless they stop accelerating. If they stop accelerating, the photon will eventually catch up to them.

Because the accelerating rocket is always further away from the Earth than the light beam, they will never see the light beam. In order to see the light beam, it would need to catch up to the rocket so it was in the same place as the rocket, and it never does, the rocket is always ahead of it. The rocket never reaches the speed of light, but because of it's head start and the details of the motion, it's always further away from the earth than the light beam.

On a space-time diagram, the path of a rocket is a hyperbola (this is why it's called hyperbolic motion), and in the example I described, the light beam emitted one year after the rocket takes off is the asymptote of the hyperbola. And the hyperbola never reaches it's asymptote.

File:HyperbolicMotion.svg
 
The OP is unable to respond any longer, so this thread is closed. Thanks to all who posted for the good responses.
 

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