Running real fast while holding a mirror

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    Mirror Running
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Discussion Overview

The discussion centers on the visual perception of one's image in a mirror while running at relativistic speeds, specifically at .99c. Participants explore the implications of special relativity on how the image would appear and the effects of motion on visual perception.

Discussion Character

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

Main Points Raised

  • Some participants propose that if one is running at a constant velocity, they can consider themselves "at rest," leading to the conclusion that the image in the mirror would look identical to that of a stationary observer.
  • Others argue that to stationary observers, the runner might appear distorted, akin to a funhouse mirror effect, while the mirror image remains consistent for the runner.
  • A participant questions the scenario of running towards a stationary mirror, noting that the rest of the world would appear contracted, but raises uncertainty about the mirror image.
  • Another participant suggests that the image in the mirror would be blue-shifted due to the Doppler effect, and that there would be a time delay in perceiving one's actions, complicating the visual experience.
  • One participant humorously states that their image would look "horrible" while running.

Areas of Agreement / Disagreement

Participants do not reach a consensus on how the image would appear, with multiple competing views on the effects of relativistic speeds on visual perception and the nature of the mirror image.

Contextual Notes

Discussions include assumptions about constant velocity and the nature of light and perception at relativistic speeds, as well as the distinction between relativistic effects and classical Doppler effects.

Moneer81
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Hello

if you're running and looking at your own imagine in a mirror you're holding in your hand, how would the image look like? what if you were running at .99c ? and why?
 
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Moneer81 said:
Hello

if you're running and looking at your own imagine in a mirror you're holding in your hand, how would the image look like? what if you were running at .99c ? and why?

It would simply look like you. Although you're running, if you're keeping a constant velocity, then according to the special principle of relativity, you're perfectly justified in calling yourself "at rest". Therefore, the image you will see in the mirror will be identical to the image you will see if you are not running.
 
Moneer81 said:
Hello

if you're running and looking at your own imagine in a mirror you're holding in your hand, how would the image look like? what if you were running at .99c ? and why?
It would be the exact same thing as if you were at rest since in that frame you are. This was one of the thought experiments used by Einstein. He used to wonder what he'd see in his bicycle mirror if he was moving at the speed of light.

Pete
 
Yep, to 'stationary' observers you might look like a funhouse mirror as you run by, but your mirror will never lie to you.
 
What if you were running at a stationary mirror? I know the rest of the world would appear shrunk by a factor of 1/[tex]\gamma[/tex] in a direction parallel to your motion but what about the image in the mirror?
 
Moneer81 said:
if you're running and looking at your own imagine in a mirror you're holding in your hand, how would the image look like? what if you were running at .99c ? and why?
Sweaty, because it is really hard to run that fast. :smile:
 
Underdoped said:
What if you were running at a stationary mirror? I know the rest of the world would appear shrunk by a factor of 1/[tex]\gamma[/tex] in a direction parallel to your motion but what about the image in the mirror?
Your picture in the mirror approaching you at almost c would be extremely blue shifted beyond visible range. And you would "see" your actions delayed by a time offset but executed much faster. So that just before you collide with the mirror, the picture in it almost catches up with your actions.

http://www.spacetimetravel.org has a lot of such simulations.

Also note that the effects I describe above are not really "relativistic". It is simple Doppler-effect and signal delay.
 
Last edited:
If I was running my image would look horrible.
 

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