Trapping Light: An Infinite Source of Energy?

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Discussion Overview

The discussion revolves around the theoretical possibility of trapping light between two mirrors and whether this could serve as an infinite source of energy. Participants explore concepts related to perfect mirrors, the behavior of light, and the implications of energy loss in such a scenario.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants propose that if perfect mirrors existed, light could theoretically be trapped indefinitely, but this would not create a usable light source.
  • Others argue that even with perfect mirrors, an object placed in the center would either absorb light or need to be a perfect mirror itself, which would prevent visibility.
  • It is noted that mirrors inherently cause energy loss, which complicates the idea of trapping light for infinite illumination.
  • Some participants mention that photons do not multiply themselves and that only a finite number of photons could be trapped, leading to the conclusion that infinite illumination is impossible.
  • There is a discussion about the misconception that photons have mass, with some participants questioning the validity of such claims.
  • A later reply suggests that practical considerations, such as the absence of perfect mirrors, further invalidate the original premise.

Areas of Agreement / Disagreement

Participants generally agree that perfect mirrors do not exist and that trapping light indefinitely is not feasible. However, there are competing views on the implications of trapping light and the nature of photons, particularly regarding their mass and energy behavior.

Contextual Notes

Limitations include the assumption of perfect mirrors, the dependence on definitions of light behavior, and unresolved questions about the nature of photons and energy loss in practical scenarios.

Mutsi
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Knowing that light goes on in infinity. Would it theoretically be possible to trap light between two mirrors? And have an infinite source of light which would require no energy once it has been trapped.
 
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Welcome to PF.

1. No. There's no such thing as a perfect mirror.
2. If the light is trapped between two mirrors, it doesn't provide a source of light - it's trapped!
 
Well, assuming it was a perfect mirror, then you could trap the light forever.

However, it would not be a source of light. If you let the light out to illuminate something, it would no longer be in the box, it would be bouncing off the illuminated object so that you could see it.

So theoretically you could "trap" the light, but not use it as a light source. You can't have your photon and see it too.

Edit to add: As Russ said, there is no such thing as a perfect mirror.
 
Disconnected said:
You can't have your photon and see it too.
Nice.
 
Absolutely logical answers which I did not think of.
I did not knew a mirror would cause a loss of energy although obvious!

Now assume that I would have a perfect cube of perfect mirrors and have an object in the center. In that case I would have an illuminated object for infinity. Right?EDIT: Wait the object in the center would cause a loss of energy or be a perfect mirror itself and then no light would be visible.
 
Mutsi said:
Absolutely logical answers which I did not think of.
I did not knew a mirror would cause a loss of energy although obvious!

Now assume that I would have a perfect cube of perfect mirrors and have an object in the center. In that case I would have an illuminated object for infinity. Right?
Only if the object was a perfect mirror and didn't absorb any of the light!
 
Disconnected said:
Only if the object was a perfect mirror and didn't absorb any of the light!

You beat me there I edited the previous comment but I was to late. In the above case of course still no light would be visible.
 
Some folks say photons have mass. Would a really fine scales provide clue to remaining light without peeking? Just to prove it worked if it possibly could. (It cannot, but that is beside the point.)
 
Discord7 said:
Some folks say photons have mass.
What folks?
 
  • #10
Discord7 said:
Some folks say photons have mass

Some folks say they found the higgs boson
 
  • #11
Mutsi said:
Absolutely logical answers which I did not think of.
I did not knew a mirror would cause a loss of energy although obvious!

Now assume that I would have a perfect cube of perfect mirrors and have an object in the center. In that case I would have an illuminated object for infinity. Right?


EDIT: Wait the object in the center would cause a loss of energy or be a perfect mirror itself and then no light would be visible.

Mutsi, light "self propagates" but DOES NOT multiply itself while travelling.

Infinity is ONLY with respect to a photons travel through entirely unimpeded space.

This DOES NOT mean that photons are infinitely created when the source is shut-off and the photons "trapped"
ONLY a set number of photons are "trapped" between ideal mirrors and ONLY the same set number of photons are available. There is no increase in the amount of photons.

As such, infinite illumination in this case is impossible.
 
  • #12
DaveC426913 said:
What folks?

Well, to the casual observer, folks explaining gravitational redshift seem to be making that implication.
 
  • #13
You know that the OP is straight of troll physics.
 
  • #14
Discord7 said:
Well, to the casual observer, folks explaining gravitational redshift seem to be making that implication.

That light has mass? No.
 
  • #15
DaveC426913 said:
That light has mass? No.

Pleading no contest.
 
  • #16
Mutsi said:
Some folks say they found the higgs boson
Yep, it was in my closet right behind the bowling ball! Forgot I put it there.

Now assume that I would have a perfect cube of perfect mirrors and have an object in the center. In that case I would have an illuminated object for infinity. Right?
Yes, but no one could see it so it wouldn't matter if it were illuminated or not!
 
  • #17
HallsofIvy said:
Yes, but no one could see it so it wouldn't matter if it were illuminated or not!

No, wrong, that object would absorb and re-radiate energy as a different wavelength, probably heat, and escape the mirrors, conductively.
 
  • #18
pete20r2 said:
No, wrong, that object would absorb and re-radiate energy as a different wavelength, probably heat, and escape the mirrors, conductively.
If we want to argue about what could actually happen in practice, it comes back to not having perfect mirrors in the first place.
 
  • #19
Lets end this topic since my question was answered and we are in no need of needless discussions. Thank you.
 

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