On the inside of a spherical mirror

[Leovinus]

If you were floating in 0-gravity on the inside of a perfectly enclosed spherical mirror with a flashlight.<br /><br />1) What would you see?<br />2) Could you tell how far away you were from the mirror?<br />3) Could you tell how big the mirror was?<br /><br />Assume we're talking about visuals only. No fair using sounds and echoes for answering 2 & 3. Do not assume you are in the center of the mirror, although that is a special case you can consider. <div class="Discussion_UserSignature"> </div>

 

[vogon13]

I think I am developing a new phobia, previously unknown to science. I am getting very uncomfortable just thinking about being in your fiendish mirror ball.<br /><br /><img src="/images/icons/tongue.gif" /> <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>

 

[jurgens]

1) depends, if you aim it straight from the center to the mirror you wouldnt really see anything at all except for any light that leaks from the flashlight. On the other hand, if you aim the flashlight off the center of the mirror you will see lots of reflections of light =) and it will get brighter and brighter and brighter as the light reflects from the mirror, of course it wont get too bright because some light will be absorbed by your clothes.<br /><br />2) Aim it off the center and measure the angle of the reflect light compared to where the flashlight is. Of course you would have to know where the center of the sphere is to do this... or there could be some geometry calculations you could do.<br /><br />3) by how bright the mirror becomes, it will be brighter inside of a smaller mirror sphere then in a bigger one =)<br /><br /><br />By off the center I mean say you have a dot in the center of the sphere, going anywhere away from that would be off of the center.

 

[Saiph]

1) You'd see yourself, as the light is reflected off the mirror, then you, then back again.<br /><br />2 & 3: Yes, by watching how the image shifts around as you move around the focal point. Of course, you've gotta know what you're looking for.... <div class="Discussion_UserSignature"> <p align="center"><font color="#c0c0c0"><br /></font></p><p align="center"><font color="#999999"><em><font size="1">--------</font></em></font><font color="#999999"><em><font size="1">--------</font></em></font><font color="#999999"><em><font size="1">----</font></em></font><font color="#666699">SaiphMOD@gmail.com </font><font color="#999999"><em><font size="1">-------------------</font></em></font></p><p><font color="#999999"><em><font size="1">"This is my Timey Wimey Detector.  Goes "bing" when there's stuff.  It also fries eggs at 30 paces, wether you want it to or not actually.  I've learned to stay away from hens: It's not pretty when they blow" -- </font></em></font><font size="1" color="#999999">The Tenth Doctor, "Blink"</font></p> </div>

 

[aetherius]

If the sphere were large enough you would only see into the darkness as far as the power of your light would allow but there would not be a visually detectable reflection. If the sphere were very small the single beam of the flashlight would reflect in many directions and light the entire sphere. So, given the diameter and power of the beam it should be possible to derive a formula that allows one to approximate the dimensions of the sphere based on the observed brightness. (Up to the point where there is no detectable reflection. Beyond that limit it would not be possible to determine the size of the sphere.)<br /><br />You could also rotate the light around your body 360 degrees and observe how the brightness of the reflection changes. Continue to rotate the light at various angles until you have mapped the sphere based on the brightness of the reflection in all directions. From the center there would be no change in brightness regardless of the angle.

 

[aaron38]

I think it really depends on the dimensions of the sphere. A sphere 10-20 feet across would probably be pretty freaky and confusing inside. If you were right up against it though, your body would block reflections from all around you and everything would be normal.<br /><br />With a sphere hundreds of feet across the curvature would be so slight being against the surface wouldn't be appreciably different than being against a normal full length mirror.

 

[emperor_of_localgroup]

I'm not sure where are you leading us with this question. Are you guessing what would happen if the edge of the spherical universe is a perfect reflector of light? Which, as certain group of people claiming for a long time, means the number of stars are not as many as it seems. <div class="Discussion_UserSignature"> <font size="2" color="#ff0000"><strong>Earth is Boring</strong></font> </div>

 

[Leovinus]

I was thinking that if you were in the center of a spherical mirror, then everywhere you looked would be perpindicular to your line of sight and hence would be one big blurry fuzzy nightmare. Then I wondered what the effect would be if you moved off-center. Then I wondered whether or not you could tell how big the sphere was.<br /><br />So I posed the questions. <div class="Discussion_UserSignature"> </div>

 

[Leovinus]

Example: Look at the bowl of a shiny spoon. You will appear upside down. But as you move the spoon closer to your eye, you reach the focal point where the image wipes itself out. Then if you move closer, the image is right-side up. At the center of the spherical mirror, I assume that is the focal poiint. If you move off center, then on the close side I'd assume you'd appear right side up and on the far side you'd appear upside-down. But I'm not sure. <div class="Discussion_UserSignature"> </div>

 

[igorsboss]

The results will depend, partially, on just how perfect the mirror surface is.<br /><br />If the surface has a slightly rough texture, the light will be scattered slightly on each reflection. This would affect your perception. I doubt if you would be able to detect any kind of edge, however. If you floated (as in zero-G) towards the wall, you would not be able to figure out when you were about to hit.