The Sphere
 

Imagine....

You are floating in the middle of a 30' diameter sphere. The inside of the sphere is a perfect mirror. You are holding a flash light.

What do you see when you turn on the light?

A guy holding a flaslight.

The view as if you were behind yourself?

Blinding light from the all the light being reflected to the spot where you're floating, maybe?

You wouldn't be blinded, since the light from the flashlight would only provide a limited amount of energy. I guess you'd see a huge, magnified, curved image of yourself holding a flashlight, like looking into any other concave mirror.

Come on Manx, what's the secret?

A perfect mirror from the inside of a 30' diamter sphere?

I haven't yet been able to collect the resources necessary to reproduce the environment. But if you would like to make a donation, please let me know. So I can't tell you for certain. I have attempted to model it in Alias Wavefront's Studio 3D modeling software. It crashed during the render (go figure!)

For some strange reason, I have been thinking about this question for over a decade. Don't ask me why.

My conclusion:

You will see a field of brown-ish color.

I came to this conclusion based on my understanding of incandescent light. Essentially, what will happen is, the waves of light will spread out from the source and bounce off the mirror in an infinite number of directions, which will again bounce off the mirror in an infinite number of directions, and again - slowly bouncing fewer and fewer times due to the lack of energy in the flash light (i.e. after a certain distance, a light wave will become weaker and weaker, not because the power source in the flash light runs out). While the light waves are bouncing around the mirror in an infinite number of directions, they are also bouncing off of you and the flash light. Since each person is an assortment of varying colors, the end result is that those colors will all wash together as they are bounced around and around in an infinite number of directions. It becomes an additive color source due to the body (clothing, skin, hair, flashlight) absorbing portions of the spectrum.

Result: brown.

If you were wearing primarily red, the brown would be warm in tone. If you were wearing blue, cool in tone.

I'm open to alternative theories.

Is there gravity in the sphere .... yes I do realise we're floating... but the lack of gravity would change the diffusion of light. In my guess making the light continue to reflect an infinite amount of time.
Maybe

That's an interesting point. I do not know if gravity has an affect or a significant affect on the diffusion of light.

Ok, this was killing me. I cheated.

I made a sphere with a reflective inside with OpenGL and put the camera in the center. At first I didn't see anything, so I put a square in the center of the sphere (the camera doesn't physically exist). So the square represents the person. I then made a light source emminate in the angle the camera was looking.

I saw just the reflection of the illuminated side of the square. If I reversed the direction of the light (have it point in the antipode of the camera's angle), then I saw a shadow of the square. It looked just like a solar eclipse, only.. with a square.

So, sorry, I cheated. :( I'll try to post pics once I get a host. I need to write a screen-capture thingie first though. Window's print screen isn't latching onto the window I made. Writing screen-capture code will take longer than the sphere demo. I don't have the time for it right now because of midterms. I'll get back to you guys in a few days.

Of course, this isn't the real world so lets look at a few things:

Manx: Brown wouldn't be the color. Light doesn't refract when it's reflected, so it can't be split into a specific part of the visible spectrum.

Prosequence: Light can't continue infinately in the sphere because light cannot cover an infinite distance. Certainly light can cover a VERY long distance, but not with flashlights. From the origin of the flashlight to the edge of the sphere, the light will travel 15'. With every reflection after that the light will travel a maximum of 30'. Even less because that is the distance from the centerpoint... which is blocked by the person.

sen_tom: This is what the effect looks like. Nothing special unfortunatly :(

So you have pictures of it or you don't?

Asta!!

No. When I do there's still the issue of a host for them.

When I use Window's print screen, my application is all blank. So I need to write my own print-screen function for the demo. That'll take a few days :/

That's not what I am suggesting when I propose it is brown. The brown color is produced due to the light which reflects off of all the objects in the sphere - namely, you.

I would be suspicious of any computer generated images which do not entirely follow the properties of light. As I mentioned, I tried modeling this scenario with Alias Wavefront Studio - a 3D modeling package for product development (electronics, cars, anything). It's a $10,000 software product. It crashed during the raytrace rendering.

Holy Geez. The mind boggles. When did you first think of this? Or possibly why? Wouldn't the image directly in front of your eyes, show your eyes, and then everything would distort outward from there???

Man, I hope this doesn't keep me up all night...

thought about this a bit and i'm guessing you're asking what you see when you look at the sphere. I mean if you just look down you'll mostly just see yourself, but if you look beyond that and into the mirror I dont think you'd see brown. Mainly because although the light bounces off everything only a few paths goes to your eyes. So while there are many colors, they shouldn't overlap to fuse in any such way. Not sure if what i'm saying makes sense, but yah.........

I haven't exactly been thinking of this, but I've had somewhat similar thoughts of what a sphere (small or large) would look like with 2-way glass, having the reflective side faced inward. ANy ideas on that one?

if it was mirrored in all round wouldn't you get a feedback loop (like when you stand in between two mirrors and see yourself reflected into infinity).

I originally thought of this scenario many years ago, one night, when I had smoked too much (?) pot.

Around the same time I also decided to question the conventional wisdom that two mirrors, facing each other, was infinity. I had taken some physics books out of the library - one of which made that claim. I had an epiphany that it was not infinity. Here is why: what you are seeing when you place two mirrors face to face, (wrongly) assuming you could even make them perfectly aligned in such a manner, is nothing more than light bouncing from one to the other. Because light is traveling so quickly, there is instantly over a billion reflections (the precise number of reflections would depend on how far apart the mirrors happen to be). I actually took the time to calculate how many reflections would exist in 1 second if the mirrors were exactly 1 foot apart. It was over 1 billion reflections. So, although that is quite a large number, it is not infinity - nor would it ever be infinity unless time is infinite (in which case, nothing is not infinity - but then we start to get into the area of physics which is much more like mushrooms and less so like pot).

And recall, this assumes that the mirrors are in perfect alignment, which would be impossible to attain. Even the smallest misalignment would result in the eventual end of reflection. Much like two lines, if not perfectly perpendicular will eventually meet at one end, and drift further apart at the other.

;)

Even if the mirrors were perfectly aligned, for ever, no-one would ever be able to see infinity because by looking, you'd get in the way of the reflections.

Should submit this paradox to 'mythbusters' they have the resources to actually produce it, which would be damned cool.

okay, its getting a little off thread now - but I can see I've opened a new can of worms with the offhand reflection into infinty remark, but whislt the above is true you can setup a feedback loop in a variety of different ways which will not have the subject interfering with it. draw a circle on a bit of acetate, connect a tv up to a video camera and film the tv through the acetate- voila - instant infinity

It's not actually infinity, for all the same reasons I listed above that demonstrate it is nothing more than billions of repititions per second based on the speed of the travel of light and the inherent imperfection of alignment.

the example I've given does not require light bouncing back and forth for the feedback loop, the inherent imperfection of alignment is also taken care of as you can adjust the angle of the camera so the circles repeat inside each other

It is still a visual representation. It requires light to travel through the camera lens in order to reproduce the effect. The initial light bounces off the TV, it travels to the camera, through the lens, is processed and displayed on the TV, which then illuminates and travels to the camera lens.

Repeat about 1 billion times per second, depending on the distance of camera to TV.

Also, adjusting the circles to line up would not be a perfect alignment. Even with the most precise measurement tool ever invented.

Infinity is unknowable.

okay point taken, anyway would you get the billions (actual amount dependant on length of time in sphere and diameter) of reflectons?

This sounds like a physics problem to me.

And good thinking, Robaggio, using OpenGl and all :)

First I need to define my view of the starting situation:
You are floating in the middle of a 30 foot perfect sphere, the inside of which is a perfect mirror. There is nothing other than you and a flashlight in the sphere, not even air, but we are ignoring your requirements for life at the moment. You switch on the flashlight.

Now for what you would see:
The sphere is focused on one point, the center. If you were to look from that exact point then you would see your eye (or retina). However, because the light source is not in the exact center you will have more interesting things happen.
You would first probably see yourself, distorted by the curved surface. If you remained perfectly still then it would be a stable system as your body eventually would absorb all of the energy the flashlight was putting out (some paths of the light might be extremely long, and take some time to reach you). If you moved your head you might see interesting things, such as images of previous moments in the sphere that were still bouncing around, but most likely they would be smeared beyond recognition. After some time I think you would see an even glow of the average wavelength your body and clothing reflects and the color of the flashlight. If your flashlight did not ever run out of batteries, you would eventually burst into flame and your observations would end.

Flashlights can do that!!!! I have never seen a warning on them

How would you burst into flames? That would imply that energy is being added to the system. From what you described, you have only made it so that energy does not become depleted by imperfections in the mirror(s).

Is the light bouncing directly back and forth between two points, or randomly? That would make a difference, as with the former you would have to be in the path of the light in order to see it (I'm assuming the light isn't being reflected by air particles which would ruin the "perfect mirror" setup).

Light is being added to the system without end because the flashlight never runs out of battery power. That glowing piece of wire is adding energy to the system with every moment.

The light is not bouncing back and forth between only two points, nor is it bouncing randomly. Since the diffuse light source is not in the exact center of the sphere you could get certain paths of light that go around the sphere for many revolutions before meeting a part of your body. I am not familiar with the visual output of a reflection of a person after being reflected billions of times from slanted concave mirrors, but I am guessing that by moving your head and catching paths of light you did not before would be very unlikely to yield a focused image.

Supposedly if you lay light onto a curve of a perfect sphere, you can defy time. So technically I would see the past/future while exsisting in the present. (Assuming that's what would actually happen) I would be in the middle of trying to compress my mortal mind in the cruch of times, hopefully surviving the newborn awe.

Either that, or the inside of the sphere turns into a giant lightbulb.

From where do you come to the conclusion that time will break just because you managed to loop light? You would not see the future because it has not happened yet, but you would eventually absorb all the light put into the sphere and so would experience every portion of your past (most in several different angles).

Ah, I misread it. I thought you added the light to the system and turned off the flashlight.

About the flames thing: It would be hard to say. Can the sphere conduct heat (inside the system and outside)? If so, and if a vacuum conducts heat, then you would need one bigass flashlight to burn yourself.

It would theoretically heat your body over time, but homeostasis would keep your body temp neutral and release the excess heat. The heat would be conducted into (and out of) the sphere. The only way I could see a flashlight burning you is if it was focused on a really, really small point. Like the sun and a magnifying glass scaled down.