Light in a house of mirrors--what will happen?

I saw a varriation of this in the 1980s in some science magazine. I forget the question, but the basics of it make me wonder what would happen from time to time. As today at work was boring, it was one of those times. So, have at it both math folks and anyone with an idea of the physics involved. Note it is a three part question.


The premise is that in the suburbs of say Las Vegas you have a typical 2-story, 2,500 square foot home. Typical on the outside. Inside every surface is a perfect mirror, nothing absorbs any light and there are no doors to seal off any room. Other than that, it has various rooms and hallways. IOW, it is not an empty box. You have the ability to flash a light the intensity of a birthday candle for one second. Assume some "magic" here in that the light is made in mid-air in a random place and nothing involved before or after causes an absorbtion of light. (ie: it is still all mirrors and no "dust" from the burning to make the light, no flash-cord to ignite it--pure magic for want of a better term.) After the second is up, the light flows outward in every direction. Now, knowing that, what do you feel would happen:

1. After the one second. Would the entire room be a low-intensity light, would there be shadow areas, would it equalize? (NOTE: At the time the article said that science proved the light would eventually hit every surface in any such set of rooms. At the speed of light, of course!)

2. What if a person was in a room away from the light, dressed normally. Would they see a flash and then dark as they absorbed the light, or something else?

3. Instead of one second of flash, assume the light was steady. With more and more light form the candle-source, would the room soon be as bright as the sun, or something else?

I do not know the answers, but thought it might be a bit of scientific discussion.

Don't mirrors just direct light, not magnify it? How would they make
light brighter?

There was an interesting Mythbusters along these lines. Had to do with some mirror lighting scheme in one of The Mummy films. They lit a hall and a room in the pyramid with mirrors and sunlight. Check it out, may give some insight to the answers you seek.

I hold a degree in physics, so maybe that will qualify me for answering.

1. question: If each surface has zero absorbtion and the candle is lit only on a short time, the entire building will encase a low-intensity light field. Unless very specific (resonant) arrangements on the mirror surfaces are present, each tiny little volume of the house will hold the same light intensity.

3. question: If you leave the candle in the house (and it has unlimited fuel) the light field in the entire house will reach a thermal equilibrium with the candle, meaning that the candle heats the house as well as the house heats the candle. The outside of the candle has a temperature of about 1000°C, and so will be each room.
It will not be as bright as the sun (which has an outside temperature of about 5500°C) and will have a different color spectrum.

2. When the person is present in a room (or any other absorbant material of comparable size) the light field will not reach an equlibrium state due to those heavy losses. They will not see a flash of the candle. However if you leave the candle in the room for a long long time burning with unlimited fuel, at some time the person will be quite uncomfortable hot.

Quote: MangoJ

I hold a degree in physics, so maybe that will qualify me for answering.


3. question: If you leave the candle in the house (and it has unlimited fuel) the light field in the entire house will reach a thermal equilibrium with the candle, meaning that the candle heats the house as well as the house heats the candle. The outside of the candle has a temperature of about 1000°C, and so will be each room.
It will not be as bright as the sun (which has an outside temperature of about 5500°C) and will have a different color spectrum.

Those are some great answers, thanks. But this answer adds another question. What if it is just the light of the candle and not any real heat? I guess imagine it is the same "magic" LED. Will the light intensity keep increasing forever due to the "new supply" of light or is temperature somehow related?

Quote: EvenBob

Don't mirrors just direct light, not magnify it? How would they make
light brighter?

The mirrors are bouncing the light, but the candle continues to generate light.

Eventually, the entire house will be as bright as the center of the candle flame.

Quote: MangoJ

2. When the person is present in a room (or any other absorbant material of comparable size) the light field will not reach an equlibrium state due to those heavy losses. They will not see a flash of the candle.

I have to disagree. The light that hits the observer's eye directly from the candle should register an image.

Intead of a candle, what if the light source was a laser? Would the house still fill up? I imagine that there probably would be several areas where the mirrors would not direct the light, but I am not sure.

I estimate, that a candle would emit about 2 billion photons in one second. If the total area of the house is 2500 square feet, and the ceilings are, say, 7 feet high, that gives us 17500 cubic feet of volume, or about 114 photons per cubic meter.
In a way, one could say the house would be "filled with light", but in reality the concentration of 114 photons per cubic meter is, probably, darker, than you have ever seen :) Hardly "a flash" in any reasonable sense of the word.

Quote: Ayecarumba

I have to disagree. The light that hits the observer's eye directly from the candle should register an image.

Intead of a candle, what if the light source was a laser? Would the house still fill up? I imagine that there probably would be several areas where the mirrors would not direct the light, but I am not sure.

Ok, I understood the original question about the "flash" was identical to the previous stated buildup of energy in the empty house as there were no losses.
If the "flash" is just the image of the candle, things are different as long as you have an optical mapping between the candle and the retina of the observer. Then the observer will indeed see an image of the candle. But when structure of the house is very complex (i.e. small facets, bended surfaces), there will be no such optical mapping.

Regarding using a the laser instead of a candle: In such an environment a laser will not work, as eventually some light will be reflected back into the laser itself, destroying phase coherence in the amplifying medium. A laser will then only emit fluorescent light and is - depending on the type of laser - very comparable to a candle.

Wouldn't it be easier to pay the electric bill, instead of buying all those mirrors ?

Quote: MangoJ

Regarding using a the laser instead of a candle: In such an environment a laser will not work, as eventually some light will be reflected back into the laser itself, destroying phase coherence in the amplifying medium. A laser will then only emit fluorescent light and is - depending on the type of laser - very comparable to a candle.

Very interesting, I didn't consider that. Thanks Mango!

What is light anyway? It's so strange to think about. These little packets of ..energy?.. whizzing around all over the place. We are able to see the presence of an object due to these particles bouncing off of them, and moving at a specific frequency, right? But what is light to the universe? If there is no observer, aren't they just a bunch of things, like electrons and dark matter and anti-matter moving all over the place, but really not doing much?

Quote: ewjones080

What is light anyway?

A wave/field/particle and a property of "empty" space. Just like everything else in the universe, except maybe gravity and dark energy.