# Is there lag in mirrors?



## Haloman800 (Feb 5, 2014)

When I see a reflection in a mirror, is there any lag between me waving my hand and it appearing in the mirror? Something like .000000000000000000000001 maybe?


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## Black-Ice (Feb 5, 2014)

Let me ask you this,
How can mirrors be real If our eyes aren't real?


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## Clarky (Feb 5, 2014)

how many funny cigarettes have we smoked tonight?


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## Youkai (Feb 5, 2014)

yes there is as the light needs time to travel back and forth


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## Isaac (Feb 5, 2014)

A very, very, very, very, very, very, small, indiscernible by human means amount of lag.


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## Danny350 (Feb 5, 2014)

The light would reflect so fast that there would be no practical delay, but light does take time to travel so it wouldn't be instant in reality. The time it would take would be so insignificant that no human could ever detect it with our own eyes.

So simply put, there is a delay in a REALLY short scale of time, but we're talking about some of the smallest units of time we know.


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## FAST6191 (Feb 5, 2014)

The bigger question is would the lag be significant in light of thermal effects in the mirror?

Also amusing


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## grossaffe (Feb 5, 2014)

You have to deal with the speed of light through whatever medium(s) separate you from the mirror.  Based on that speed and the distance separating you from the mirror (times two as the light must travel there and back) give you your propagation delay.


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## Vulpes Abnocto (Feb 5, 2014)

So there you have it. The serious question got a serious answer. There is indeed an imperceptible lag at the typical mirror-viewing distance. 

Now lets get some not-so-serious ones.


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## GameWinner (Feb 5, 2014)

We need to go deeper...


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## grossaffe (Feb 5, 2014)

Vulpes Abnocto said:


> So there you have it. The serious question got a serious answer. There is indeed an imperceptible lag at the typical mirror-viewing distance.
> 
> Now lets get some not-so-serious ones.


 

Well if you want to start getting crazy, I always enjoyed toying with the idea of setting up a series of Mirrors around the planet in orbit or something that would give us the ability to look into the past.


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## chavosaur (Feb 5, 2014)

Have you checked your Drivers speeds? Are you running Windows or Is this a legit mirror?


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## Chocolina (Feb 5, 2014)

Actually no. Because lag isn't the best term to describe speed of light.
.
Theres always going to be a latency between your eyes, the mirror (or any surface reflecting light) and your eyes again, but theres never any lag because light is a constant speed that doesn't slow down under normal and most extreme conditions. Theres no lag because you're still getting the light at the fastest speed possible in the laws of physics, so as long as the speed of light can't fluctuate up and down between you and the mirror, then lag doesn't exist, because lag can't exist when something is going so fast that it literally cannot go any faster and at the same time doesn't slow down..


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## Cyan (Feb 5, 2014)

GameWinner said:


> We need to go deeper...


Why myopia (short-sightedness) is not fixed when looking into a mirror while the mirror is placed at a short distance from your eyes?


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## Luigi2012SM64DS (Feb 5, 2014)

GameWinner said:


> We need to go deeper...


 
Fuck im in Limbo.


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## marcus134 (Feb 5, 2014)

light speed is about 3*10^8 m/s and described by the letter C (like E=MC²)
if you stand at one meter of a mirror, you'll see yourself as you were exactly 2/C, 6.667*10^-9 or 0.00000000667 second earlier

at light speed, it takes:
1.2 to 1.3 sec for a one way to the moon
8 min 20 sec for a one way to the sun


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## Gahars (Feb 5, 2014)

There may be a slight delay between you asking the man in the mirror to change his ways and making the world a better place.

Better question: Does the wind have a pattern? If so, how does one follow it?


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## slingblade1170 (Feb 6, 2014)

Latency yes there is.


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## FAST6191 (Feb 6, 2014)

Gahars said:


> Better question: Does the wind have a pattern? If so, how does one follow it?



I would have thought the wind would be a good example of Brownian motion.


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## Gahars (Feb 6, 2014)

FAST6191 said:


> I would have thought the wind would be a good example of Brownian motion.


 

Not with vitiligo, it isn't!


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## AlanJohn (Feb 6, 2014)

Vulpes Abnocto said:


> So there you have it. The serious question got a serious answer. There is indeed an imperceptible lag at the typical mirror-viewing distance.
> 
> Now lets get some not-so-serious ones.


HOLY SHIT, VULPES ABNOCTO IS BACK


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## FailName (Feb 7, 2014)

Chocolina said:


> Actually no. Because lag isn't the best term to describe speed of light.
> .
> Theres always going to be a latency between your eyes, the mirror (or any surface reflecting light) and your eyes again, but theres never any lag because light is a constant speed that doesn't slow down under normal and most extreme conditions. Theres no lag because you're still getting the light at the fastest speed possible in the laws of physics, so as long as the speed of light can't fluctuate up and down between you and the mirror, then lag doesn't exist, because lag can't exist when something is going so fast that it literally cannot go any faster and at the same time doesn't slow down..


Light does slow down and refract while going through the glass in other material in the mirror before reflecting off of the silver or aluminum or whatever in the back, causing light hitting the mirror at an angle to come off at a slightly different point. 






And there also seems to be a delay in the time it takes for your brain to process what your eyes are seeing, but I wouldn't know anything about that.


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## Chocolina (Feb 7, 2014)

FailName said:


> Light does slow down and refract while going through the glass in other material in the mirror before reflecting off of the silver or aluminum or whatever in the back, causing light hitting the mirror at an angle to come off at a slightly different point.
> 
> 
> 
> ...


Light refracted twice is not light slowed down, even if light is refracted multiple times, the 1st refraction is not obstructed so you're still getting the light at the fasted speed possible, and the other refractions also don't slow down, they go the same speed of light as they always have but must cover more distance. This is still a latency issue, not a lag issue.

The brain can have lag as it's not something thats a constant like light. The synapses in the brain can differ slightly between people and fluctuate based on brain chemistry and physical traits, even a diet. However OP asked "is there any lag between me waving my hand and it appearing in the mirror?" Taking this question literally, we're all just assuming that she wants to see her own hand waving. Before the light can even reflect and refract, the light is already inside the mirror. We don't need to go from point A to B to C to so-on, we can just stop at B. The brain isn't even part of the question and the eyes have no place because all that matters is the light appearing in the mirror, she didn't specify she wanted to see it, we just assumed. Its akin to the "If a tree fell" question.


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## grossaffe (Feb 7, 2014)

Chocolina said:


> Light refracted twice is not light slowed down, even if light is refracted multiple times, the 1st refraction is not obstructed so you're still getting the light at the fasted speed possible, and the other refractions also don't slow down, they go the same speed of light as they always have but must cover more distance. This is still a latency issue, not a lag issue..


Incorrect.  What you know of as the speed of light is actually the speed of light through a vacuum.  Light does travel at different speeds depending on what medium it's traveling through, and refraction is a side-effect of this.  When the light hits the other medium at an angle, you essentially have one side hitting the medium first, so if this is a medium that causes the light to slow down, it causes the light to curve in that direction.  Think of it like driving a car into the mud.  If you go in at an angle, the side that hits the mud first will slow down compared to the side that's still on solid pavement, causing the car to turn towards the side that hits the mud first.

I believe the concept you are thinking of--speed of light being a constant--is an idea of relativity.  Normally, the speed of an object depends on the observer.  For example, if I'm traveling 10 MPH with reference to, oh, I dunno, a stop sign, and you're traveling 20 MPH in the same direction in reference to the stop sign, then you are also traveling 10 MPH in reference to me.  With light, on the other hand, regardless of the inertial frame of the observer, they will all see light as traveling at the same speed in regards to themselves (that is, the speed light would travel through whichever medium it is traveling).  So if you were to try to measure when a particular beam of light crossed some arbitrary line, different observers in different inertial frames would come up with different results.


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## Sterling (Feb 7, 2014)




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## Chocolina (Feb 7, 2014)

grossaffe said:


> Incorrect. What you know of as the speed of light is actually the speed of light through a vacuum. Light does travel at different speeds depending on what medium it's traveling through, and refraction is a side-effect of this. When the light hits the other medium at an angle, you essentially have one side hitting the medium first, so if this is a medium that causes the light to slow down, it causes the light to curve in that direction. Think of it like driving a car into the mud. If you go in at an angle, the side that hits the mud first will slow down compared to the side that's still on solid pavement, causing the car to turn towards the side that hits the mud first.
> 
> I believe the concept you are thinking of--speed of light being a constant--is an idea of relativity. Normally, the speed of an object depends on the observer. For example, if I'm traveling 10 MPH with reference to, oh, I dunno, a stop sign, and you're traveling 20 MPH in the same direction in reference to the stop sign, then you are also traveling 10 MPH in reference to me. With light, on the other hand, regardless of the inertial frame of the observer, they will all see light as traveling at the same speed in regards to themselves (that is, the speed light would travel through whichever medium it is traveling). So if you were to try to measure when a particular beam of light crossed some arbitrary line, different observers in different inertial frames would come up with different results.


But speed of light is only relative to moving objects. If two people stand in front of a mirror, the speed of light relative to them is at a constant. If both people are stationary, their speed of light is the same, but if one of them moves, their speed of light adjusts with that object's speed of light, even if their speed of light is faster than a stationary person's, the speed at which that light leaving both of them is still 186,000 miles per second.

Since I don't know the math of arm waving,  I'm just counting the girl as a stationary object since she wasn't talking about moving forward or backward from the mirror. But that speed of light traveling from the girl to the mirror is still going as fast as it's able to. If she steps forward the speed of light is 186,000 per second relative to her momentum forward, and if she stepped backward, it's still the same 186,000 per second relative to the motion going back. If you shoot a beam of light and its going 186,000 miles a second, and if a hypothetical form of space were to travel alongside that light at the same speed, then the light would have gone no where relative to it's location and would have been perceived as to be stationary, it would have  still traveled that same 186,000 miles per second. Whether or not theres more or less space for her light to cover since the light is going as fast as it's able to, its still just latency going from point A to B, not lag.

The motion of the girl is only changing the relative distance between her and her mirror, but thats still doesn't effect the actual speed of the light. Its latency, not lag. If you want light to lag, then you have to obstruct the actual energy/photons of light itself. Seeing as theres no black hole or absolute zero temperatures between the girl or the mirror, I don't know what else can make light energy lag.


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## grossaffe (Feb 7, 2014)

Chocolina said:


> But speed of light is only relative to moving objects. If two people stand in front of a mirror, the speed of light relative to them is at a constant. If both people are stationary, their speed of light is the same, but if one of them moves, their speed of light adjusts with that object's speed of light, even if their speed of light is faster than a stationary person's, the speed at which that light leaving both of them is still 186,000 miles per second.
> 
> Since I don't know the math of arm waving, I'm just counting the girl as a stationary object since she wasn't talking about moving forward or backward from the mirror. But that speed of light traveling from the girl to the mirror is still going as fast as it's able to. If she steps forward the speed of light is 186,000 per second relative to her momentum forward, and if she stepped backward, it's still the same 186,000 per second relative to the motion going back. If you shoot a beam of light and its going 186,000 miles a second, and if a hypothetical form of space were to travel alongside that light at the same speed, then the light would have gone no where relative to it's location and would have been perceived as to be stationary, it would have still traveled that same 186,000 miles per second. Whether or not theres more or less space for her light to cover since the light is going as fast as it's able to, its still just latency going from point A to B, not lag.
> 
> The motion of the girl is only changing the relative distance between her and her mirror, but thats still doesn't effect the actual speed of the light. Its latency, not lag. If you want light to lag, then you have to obstruct the actual energy/photons of light itself. Seeing as theres no black hole or absolute zero temperatures between the girl or the mirror, I don't know what else can make light energy lag.


 
I'm not sure what you're arguing here.  You quoted my whole post, but it seems like you're only responding to the part about relativity and not about how light does have different speeds through different mediums.  And even the response to relativity, I'm really not sure what you're trying to say.


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## Luigi2012SM64DS (Feb 8, 2014)

This is the EOF guys.
Not Bill Nye the science guy.


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## DinohScene (Feb 8, 2014)

Luigi2012SM64DS said:


> This is the EOF guys.
> Not Bill Nye the science guy.


 
Why do you keep on ruining perfectly good EoF threads?


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## Gahars (Feb 8, 2014)

Luigi2012SM64DS said:


> This is the EOF guys.
> Not Bill Nye the science guy.


 

Consider the following: Stop.


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## Veho (Feb 8, 2014)

Yeah, there's a lag in mirrors ever since they outsourced them to China. 



Gahars said:


> Better question: Does the wind have a pattern? If so, how does one follow it?


Better question: when you paint with all the colors of the wind, do you use an oil or a water-based solvent?


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## MelodieOctavia (Feb 8, 2014)

Gahars said:


> There may be a slight delay between you asking the man in the mirror to change his ways and making the world a better place.
> 
> Better question: Does the wind have a pattern? If so, how does one follow it?


 

Have you ever heard the wolf cry to the blue corn moon?
Or asked the grinning bobcat why he grinned?
Can you sing with all the voices of the mountains?
Can you paint with all the colors of the wind?

Edit: Goddammit, Veho.


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## Ryukouki (Feb 8, 2014)

Well, here I was expecting the usual EoF madness. Surprisingly this thread is actually pretty decent, and taking a physics course that is dealing with optics, this topic is highly relevant.  I like this.


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## grossaffe (Feb 8, 2014)

Ryukouki said:


> Well, here I was expecting the usual EoF madness. Surprisingly this thread is actually pretty decent, and taking a physics course that is dealing with optics, this topic is highly relevant.  I like this.


Play with polarizing light yet?


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## Ryukouki (Feb 8, 2014)

grossaffe said:


> Play with polarizing light yet?


 

I was doing some of that with a polarimeter in my organic chemistry lab. Fun stuff. As far as the physics class went, we're sorta doing that stuff, with the Snell's law applications and whatnot.


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