What does a mirror look like if you arn't looking at it?

This is something i have thought about pretty much throughout my life and i haven't settled on an answer, i'd love to see what other people think and maybe, if there are any students of physics here, see some theories... or maybe the answer is surprisingly simple.

Some context, but this is pretty self explanatory...

Light reflects off the shiny surface of the mirror into our eyes, we see a table in the mirror due to the angle of reflection into the camera lens, what we see in the mirror changes as our viewing angle changes, but if you look away there's no angle of reflection, the mirror isn't projecting an image toward you it's just a shiny surface.

So, if you arn't looking at it, what does it look like?
The most sensible answer would be that it just looks like the colour of the glass, sort of... grey... shiny, but shiny means reflective so... bright grey? Hmm.
Or you could go the other way and try to imagine what it looks like when it's reflecting everything, is there some kind of infinite image of every single angle in front of the mirror being reflected forever?
Does the true nature of the world suddenly unravel when physics are confronted by a shiny surface, resulting in an explosion of matter, antimatter, time?
Is it just the face of a person screaming for all eternity? Am i screaming?

Um... please post your thoughts below!
(pretty sure it's just grey...or blue... why blue?)

@cikame: This really sounds a like a freshman philosophy/stoner question. Why stop at mirrors? Technically light reflects off everything into your eyes.

What does everything look like when you aren't looking at it?

So you're asking what does a mirror look like when it's not reflecting anything? I'm guessing like grey glass or something...

Is there a way to make a mirror not reflective?

Is this like the 'tree falls in the forest' thing?

Yes, the tree makes a sound when no one is around to hear it and a mirror exists in the same form whether you're looking at it or not. If there's no light to reflect, it doesn't reflect it, therefore it looks like nothing. The same goes for every object that doesn't emit light.

I don't know because I assume a non reflective mirror is not a thing that exists?

@the_greg: It looks like nothing? So black then?
It would make sense as perhaps light does not settle on reflective surfaces, just bounces off, but i don't imagine a regular mirror is perfect at reflecting all light, so it would be illuminated by it to some degree.

If you look away the mirror is still projecting an image toward you, your eyes just aren't receiving it. Have a fun trip duder.

It reflects what is in front of it. less photons from greater distances react with an electron and then send a photon back out, if I understand right. It would simply be the same if you were not there, and more so since you (speaking figuratively) aren't there blocking incoming.

PS, if I am wrong about the attempt at science, please tell me.

@bybeach: By "what is in front of it" do you mean... everything in front of it? Since there's no viewing angle that's 180° of "world" in front of it, what does that look like?

Unrelated, light is a real tangible thing (tangible?), to bring mirror's into it a mirror in a pitch black dark room with zero light simple wouldn't be visible, it's still there however, you can ask the question "but what does the mirror look like when there's no light?", but we need to avoid saying that because you wouldn't be able to see it, because there's no light, we need light for the mirror to be visible, we're just not allowed to look at it :P.
Ideally we need something akin to an infrared camera, except we need to transmit a form of light that doesn't exist in known science, which would somehow not be reflected by the mirror into the camera but would still be visible by the camera... and somehow processed so that we can see it... sorry i just confused myself.

Lets just ignore the actual answer here hahaha

@nutter said:

And then someone in 2014 invented a color called “Vantablack,” which was incredibly non-reflective, absorbing 99.96 percent of the human visual range light that hit it. And that was now more blacker!

Then in 2016 a pigment by same company, Surrey NanoSystems, created Vantablack 2.0; which researchers describe as a “coating so black that our spectrometers can’t measure it!”

So, how much more 'blacker' can things get? Well, seemingly only 0.3% and then it just totally absorbs all light in the human visual range.

@monkeyking1969: Science has no place in freshman philosophy or Spinal Tap, good sir!

They don't, because mirrors aren't real, much like our eyes aren't real, because ain't no planet x coming cause ain't no space cuz ain't not globe earth. #flatmirrortruthers #wakeupsheeple

All vision takes place entirely in your brain. Objects have physical properties, but what it *looks* like depends on you. It makes sense if you understand that what you're seeing is neither correct or incorrect. The Mantis Shrimp has far more photoreceptor cells than us and can therefore see a greater range of colors. However, an object that a Mantis Shrimp is observing is the same one we're looking at, with the exact same physical properties.

what if your eyes are just tiny mirrors reflecting back your soul and the darkness in your heart......... KINGDOM HEARTS!!!!!!!!!!!

@cikame: At the risk of perhaps not understanding your question, I will respond this way. All photons that are not cut off by an edge of non-reflectivity will interact with an electron, and a new photon will be emitted back. It is where an observer position is constrained with the edges of no-reflectivity that changes the view. You might see it as a subset of all light 'reflected' back

@bybeach: You're going to have to dumb that down a lot.

@cikame: It becomes a matter of imagination. Since an observer both blocks photons and is constrained if in a non-moving position, one might still get an idea. Move back and forth to the edges of the mirror till reflectivity cuts off. do the same up and down. Now remove yourself from the picture and imagine in total what you saw.

The key thing here is that it doesn't really need an observer. the physics still apply. But some highest forms intelligences of life and us monkeys get a particular kick out of it. And we even get attached overmuch to the concept of an observer.

@the_greg: Not necessarily. It depends how you define "sound." A tree falling in the forest with no one around does produce a waveform, but if there is no auditory receiver to interact with the waveform and interpret it, is it actually a sound? Is a sound the waveform or the interpretation of the waveform?

Same goes for the mirror here.

Either way, hope everyone enjoys a healthy quantity of whatever drugs are decriminalized in their locality before pondering too hard on this.

@fezrock: How is sound not the just the waveform? Theres already a sepperate word for the interpretation of these waveforms called 'hearing'. Its what you and I do with our ears. :p Im not a native English speaker though nor a physics guy so maybe its not as clear cut as I think?

The only reason for doubt regarding the fallen tree's waveforms as far as I see is the fact that when you cant measure the waveforms you cant be 100% they are actually being emitted. But theres also no proof of the contrary soooooooo, pretty much shrodingers cat.

I honestly used to always take the classic question of the falling tree as more of a 'spiritual' one, to make you think about the fact that just because you weren't around something happening doesnt mean it didnt happen.

@lestephan: Its sort of a philosophical question, does the act of interpretating/measuring/interacting with something change what it is and define it? For instance, take that fallen tree. When its lying there in the forest, its a tree. If someone later on hiking in the woods comes across that tree and decides to rest on it, it becomes a seat, which it wasn't before. (E.g. If two people were hiking past the tree, neither would say "Look at the seat!" but, if one of them decided to rest on it for a while, saying "I'm not getting up from this seat for another 5 minutes!" is conceivably something that could be said). Though it also remains a tree.

So, with sound, it depends on your definition of what it is. The act of hearing a waveform does change what it is to some extent, because it as that point that someone might say "That sound is beautiful/annoying/reminds me of X" which is characteristic that did not exist until this moment of intrepretation by the listener. And since this change does occur, and post-change it is definitely a sound, is it also a sound beforehand as well?

There is an experiment where they found that light behaves like a beam when the human eye is involved, but it behaves like a wave when no one is looking. Here:

Reflection is just due to the physical structure of the object. When you observe an object, the image you observe is comprised of many photons of different frequencies arriving at your eye in a particular phase. If the path of the photons is disturbed, either through scattering or phase changes, the image is distorted or even destroyed (Think of looking at an apple trough a glass of water. It's certainly an apple, but the image is distorted because of the transit through the glass) A mirror is special in that it does not disturb the photons in a perceptible way when they bounce off the surface, so the image is effectively redirected.

Now with all of this in mind consider a sheet of steel. Unpolished, the sheet of steel might be dull grey because of how the light bounces off of it in an erratic manner, breaking up the wavefront of the image, resulting in a Grey blur. If you polish the steel well enough it will behave like a mirror and preserve the wavefront of the image when it bounces off the surface. Now, the piece of steel didn't vanish or change into some object with supernatural properties in this process, it just does a better job reflecting light. So if you aren't there to look at a mirror, it will just keep reflecting light as if you weren't there in the same way that the unpolished steel would.

I had a similar thought the other day. I was wondering what sphere or cube of one-way mirrors would look like from the outside looking in. My guess ultimately was that it would just be black, because there's no light getting in to reflect. That was kind of a bummer of a realization because I thought I stumbled onto something cool. Still, if you google it, there are some neat sculptures based off that concept.

It would reflect nothing, or whatever there is or isn't there. If you are in a pitch black room, you wouldn't see the mirror. But are you asking 'what if there was no pitch black room though if there was absolutely nothing?.; I think that's getting into a question that's deeper than just having to deal with a mirror. Kind of reminds me or black holes.

@fezrock: hmmm I guess I do understand but just disagree then :p

I believe there is something you can google about the actual color of mirrors. If you place 2 mirrors in front of each other parallel, they reflect everything except green. So in the continual reflections (infinity hall looking image) all colors are reflected except green. So the mirrors are actually green. Something like that

This thread sounds like it is a trap to find out who the Vampires in here are.

P.s Not a Vampire

@cikame: It's all about sunrays, mirror is an extremely smooth surface, with or without you. It doesn't matter. bro :)

It looks like a tree falling in the woods with no one around.

Physics graduate here, asking what something "looks like" when you aren't looking at it doesn't really make sense because what something looks like is basically saying "what do I see when I look at it". If you look in the mirror and see the table and then turn 180 facing away the mirror is still reflecting the image of the table at the back of your head it just isn't hitting your eyeballs. Try standing with your back to a mirror with a torch or a laser pointer aimed at the mirror, you should see the light shining on the wall in front of you if it isn't hitting your back. Nothing about the mirror changes because you aren't observing it. There is an important concept in quantum mechanics where observations change the state of the thing that's observed but there is no need to think about that in this case.

In short, this.

The mournful visages of tmartn, Palmer Luckey and the Konami management team - all appealing for you to mercifully release them from the Phantom Zone.

Actually, there's a really dumb game-development answer to this question. The most common way historically to calculate lighting in games is something called the "Blinn-Phong reflectance model". In that model, light reflected off a surface consists of three components:

• Ambient component: this is light that's not coming from any particular direction, it's just "ambient" in the room
• Diffuse component: this is light that hits the surface and is reflected equally in all directions. Paper, cloth and wood are materials that are very diffuse.
• Specular component: this is the light that hits the surface and is reflected in (mostly) a single direction. They often provide so called "specular highlights" in materials. Metals are very specular materials, as is anything that is wet. Mirrors are (essentially) perfectly specular, reflecting light in only a single direction.

You add these three together, and you get lighting in games. This image sums up the idea:

So, here's the fun part: the ambient and diffuse components are the same, regardless of where you're looking from. It doesn't matter where the camera or eye is, ambient and diffuse are always the same. It's only the specular component that depend on camera position.

In other words: what does mirrors look like in games using Phong or Blinn-Phong shading when nobody is looking at them? They look perfectly diffuse, like a silver sheet of paper.

It looks like the back of my big dumb head.

If a mirror isn't reflecting light, then it is not a mirror.

@theguy: What if you're stood behind the mirror?

@cikame: Not recommended, that's when dark matter and black holes get involved.

Hmm.. The mirror is always reflecting everything. It doesn't project into your eye. The lens of your eye projects onto the retina.

Everything you see is reflecting light like a mirror, but just with less "fidelity".

I dunno. Where's my megatron smoking box?

@treetrunk: That's a decent illustration of the double slit experiment, but the explanation of why the waveform collapses is kind of horseshit. It's designed to sound all mystical, like electrons are somehow aware of when things are looking at them. What the video doesn't state is that in order to observe the electrons, we have to bombard them with photons. There's no such thing as "observing" without also interacting with the electrons. So, the electron waveforms collapse because they're being showered with photons, not because they're aware they're being observed.

@goodeyeclosed: Right but aren't they being bombarded with photons anyway, whether anyone is observing them or not? Does the eye shoot photons? I thought the eyes just receive light.

@treetrunk: No, your eyes don't shoot photons, but it doesn't matter because you can't observe electrons with your eyes. The experiments are carried out in very controlled labs, and in order to observe the photons as they pass through the slits, the slits are illuminated with photons that collapse the electron waveforms.

Gah I really hate that double slit experiment video. It's a classic case of quantum mysticism that grossly misinterprets and misrepresents scientific experiments to push pseudoscience agenda (the video was produced by a cult organization).

@goodeyeclosed: That's right and it may be because photons themselves aren't simply particles or waves either, they behave like a particle or wave depending on the detection apparatus as well, so maybe that has something to do with it.

So perhaps the mirror is initially reflecting light in the form of a wave, perhaps a 3D wave, and once it hits our eye, the eyes constrict the light into a beam. The eyes collapse the waveforms.

Like reflective glass

Well if you are not looking at it will still do the same thing as it does once you look at it.

Glass

I'm so happy right now.