Light Reflection Question: Velocity and the Infinite Mirror

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Discussion Overview

The discussion revolves around a thought experiment involving light reflection from an infinite mirror while moving at relativistic speeds. Participants explore the implications of relative motion on the behavior of light and the geometry involved in such scenarios.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant poses a scenario where they are moving at a velocity close to the speed of light and questions where the reflected light beam will hit them.
  • Another participant suggests that more specific details about geometry, distances, and speeds are necessary to provide a definitive answer, indicating that the beam would likely hit the back of the moving participant.
  • A different participant agrees with the initial setup but emphasizes the need for clarity regarding the frame of reference, stating that the laser beam would hit the participant in their rest frame.
  • Further elaboration includes an assumption about the distance to the mirror and the participant's speed, reinforcing the need for precise parameters to answer the question accurately.
  • Some participants express confusion about the implications of a stationary ether in relation to the problem, with one asserting they have never believed in the concept of ether.
  • There is a correction made regarding the understanding of the light beam's behavior in different frames of reference, with one participant acknowledging a misunderstanding of the geometry involved.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the outcome of the thought experiment, with multiple competing views and interpretations of the scenario remaining unresolved.

Contextual Notes

Participants note the importance of defining the geometry and relative speeds involved in the scenario, indicating that assumptions about distances and velocities can significantly affect the conclusions drawn.

Snip3r
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Consider i m moving at a velocity considerable to the speed of light. Above me there is a mirror stretching to infinity . It doesn't move with me. Now if i shine light on the mirror where will the reflected beam hit me?right on me, back of me or infront of me?
 
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You'll need to be more specific in the geometry / distances / speeds for there to be an answer

EDIT: but if I understand your general drift, it will be "back of you"
 
Snip3r said:
Consider i m moving at a velocity considerable to the speed of light. Above me there is a mirror stretching to infinity . It doesn't move with me. Now if i shine light on the mirror where will the reflected beam hit me?right on me, back of me or infront of me?
I assume you move parallel to the mirrors surface and you shine a laser perpendicular to the mirror surface as measured in your rest frame? The laser will hit you then. In the mirrors rest frame it will not be perpendicular to the mirror surface.
 
A.T. said:
I assume you move parallel to the mirrors surface and you shine a laser perpendicular to the mirror surface as measured in your rest frame? The laser will hit you then. In the mirrors rest frame it will not be perpendicular to the mirror surface.

Assume he is a light year from the mirror and is traveling at half of c. Now do you see why I content that geometry/speed/etc are required in order to answer the question?

EDIT: DOH! Ok, I'm a doofus. I even have a diagram that explains time dilation that also answers this question, and I forgot about it:

http://www.phinds.com/time%20dilation/
 
Last edited by a moderator:
A.T. said:
I assume you move parallel to the mirrors surface and you shine a laser perpendicular to the mirror surface as measured in your rest frame?
thats correct. As far as distance u can take any distance between me and mirror

also you can take my velocity any value considerable to speed of light
 
Snip3r said:
thats correct. As far as distance u can take any distance between me and mirror

also you can take my velocity any value considerable to speed of light

see my link in the above post. As AT said, it will hit you
 
phinds said:
EDIT: but if I understand your general drift, it will be "back of you"

haha that's exactly the reason i asked. Although now you have taken back this, for a moment you were convinced of some stationary ether isn't it?i want to know what convinced you about both the stands? because i am perplexed
 
Snip3r said:
haha that's exactly the reason i asked. Although now you have taken back this, for a moment you were convinced of some stationary ether isn't it?i want to know what convinced you about both the stands? because i am perplexed

No, I have never believed in the "ether" since before I ever had a chance to believe in it I read that it was nonsense.

I just got the geometry wrong because I forgot to keep the beam of light in your frame of reference.
 
Snip3r said:
haha that's exactly the reason i asked. Although now you have taken back this, for a moment you were convinced of some stationary ether isn't it?i want to know what convinced you about both the stands? because i am perplexed
Why do you think the answer would be any different if there were a stationary ether?
 
  • #10
Snip3r said:
haha that's exactly the reason i asked. Although now you have taken back this, for a moment you were convinced of some stationary ether isn't it?i want to know what convinced you about both the stands? because i am perplexed
Don't read anything into that. Phinds corrected his statement as soon as he understood the setup clearly.

There is no evidence for a luminiferous aether.
 

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