curvature of light b/n parallel mirrors

Feb 7, 2020
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hello!

i exactly can not say where this question fits in but it is like this and i thought it could be related to astronomy and cosmology as well, when thinking about and applying properties of light.

i go to a departmental store in which a section, brightly illuminated and laid with multiple items, looks endlessly long. at first sight, i thought it protruded out of the wall and looked out. it was not there. then i measured distances b/n items or looked for similarities - realising that there was a mirror there, reflecting the items into it so that they are endless. but why endless?

today, i looked in the other direction and found another mirror. the craftsmanship is so neat that you wouldn't suspect a mirror so in either direction the items are stretching in endlessly long rows as a result of dual direction reflections b/n the parallel mirrors.

upon gazing at the end of the reflection in the mirror on either side, the shelves were not going into the axis perpendicular to the mirror rather straight but looked to be having some curvature as a slow departure from the same axis, mild curvature. this was the same on this side too, in the other mirror.

any takes on this? space-time curvature applications? how do we explain?

well thank you for reading in advance!
 
Akashrao, I think you have explained the phenomenon quite accurately. It is a well known property of facing mirrors, at least I (and certainly many others) have known about it for decades.

I cannot think of any practical applications, but will be interested to see any suggestions.

Cat :)
 
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Oct 15, 2020
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It may be that it's a matter of "Perspective" where two parallel lines appear to join at infinity, just as a chair looks smaller in the distance than it does when it's closer to you, the lines appear to come closer together. See the work of Italian architect Fillipo Bruneslleschi who was an architect in Florence, Italy in the early 15th century. I think he was the first to really apply Perspective to his work and develop the mathematics of it. Good luck with your search. Rich :mask:
 
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Apr 5, 2020
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space-time curvature applications?
Hmm... To be frank, I haven't ever thought of it from this angle. By Newtonian thoughts, if two mirrors are placed perfectly parallel to each other, it will appear like, in each mirror, there is a mirror and it goes on infinitely, perfect illusion, just second to life.

Hmm... But, now when I come to think of it, it doesn't continue infinitely, when you consider the fact that light has speed, therefore energy, theregore mass and therefore it too curves Spacetime. And now, as it has mass, every photon is attracted by earth. And therefore, with every time the light gets reflected, it goes down a little bit. Cool thoughts. :) ;)
 
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Hmm... To be frank, I haven't ever thought of it from this angle. By Newtonian thoughts, if two mirrors are placed perfectly parallel to each other, it will appear like, in each mirror, there is a mirror and it goes on infinitely, perfect illusion, just second to life.

Hmm... But, now when I come to think of it, it doesn't continue infinitely, when you consider the fact that light has speed, therefore energy, theregore mass and therefore it too curves Spacetime. And now, as it has mass, every photon is attracted by earth. And therefore, with every time the light gets reflected, it goes down a little bit. Cool thoughts. :) ;)
Hi IG

"as it has mass, every photon is attracted by earth. "
What if you do the experiment in remote space, far from significant influences?
Also to view (to avoid off-centre viewpoint) observe through a hole in the centre of one mirror.

Cat :)
 
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What if you do the experiment in remote space, far from significant influences?
Look, Cat, gravity is everywhere. There is no place in space where there is no gravity. Gravity is a universal thing, it's bound to be everywhere. And, if we do the experiment in remote space, photons are bound to go the way the gravity is stronger in. Therefore, the experiment is true everywhere in the universe

Also to view (to avoid off-centre viewpoint) observe through a hole in the centre of one mirror.
What will happen if I observe the hole?
 
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IG, it is great to see you again. How is the study work going?

What I mean is, if you have two mirrors facing one another, your eye (to observe) will be off the centre line between the mirrors. Thus you will get a skewed view. So make a hole in one mirror and the effect will then continue (in theory, as you pointed out) to infinity. Otherwise the reflected images back and forth will leave the opposite mirror in the direction opposite to the eye from centre (of first mirror).

Cat :)
 
Apr 5, 2020
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IG, it is great to see you again. How is the study work going?
Oh, thank you, Cat. My study always goes well. Hehe. :) ;)

What I mean is, if you have two mirrors facing one another, your eye (to observe) will be off the centre line between the mirrors. Thus you will get a skewed view. So make a hole in one mirror and the effect will then continue (in theory, as you pointed out) to infinity. Otherwise the reflected images back and forth will leave the opposite mirror in the direction opposite to the eye from centre (of first mirror).
Actually, Cat, I have observed this illusion in a saloon. Actually, the illusion will stay the same no matter your view point. As, not every photon gets reflected infinitely between the mirrors, there are many which scatter out and reach our eyes, thank goodness they do, otherwise we wouldn't have even been able to see it. ;)
 
IG, gravity may be everywhere - but in some places it is "infinitely" weak. Imagine there is just you "here" in a space suit and alpha Centauri. Tell me the gravity on you would be as it is now when you stand on Earth. You won't.

Re mirrors. It will not be as perfect as if you viewed through a hole in the centre of one mirror.
BTW, if the mirrors were remote from significant gravitational influence, the light would be effectively in straight lines. See bending of light in curved space time. Depends on mass.

Cat :)
 

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