ymu
Niall Ferguson's deep-cover sock-puppet
So that the cars in front can read it in their rear view mirrors.
why do mirrors reverse left-to-right but not up-to down?
- Thread starter max_freakout
- Start date
The mirror doesn't reverse anything. It just reflects everything straight back. Your left eye is shown on the left of the mirror (as you look at it) and your right eye is shown on the right of the mirror as you look at it. Just as the top of your head is shown at the top of the mirror and your chin is shown nearer to the bottom of the mirror. Nothing is transposed at all.
It is just that as you look at it the figure in the mirror appears to be the other way around and letters on your T shirt appear to be the wrong way around, but really they are just the straight reflection from the original. The 'image' on the mirror is not there (on the mirror) at all, it is a virtual image, it cannot be captured at the surface of the mirror and if someone else next to you looks in the mirror they don't see the same image that you are looking at. This image is in the eye of the beholder, even if it is not beautiful.
The eye or a camera lens does transpose an image however both vertically and horizontally. This is a real image and can be captured on the retina of they eye or on film in the camera.
It is just that as you look at it the figure in the mirror appears to be the other way around and letters on your T shirt appear to be the wrong way around, but really they are just the straight reflection from the original. The 'image' on the mirror is not there (on the mirror) at all, it is a virtual image, it cannot be captured at the surface of the mirror and if someone else next to you looks in the mirror they don't see the same image that you are looking at. This image is in the eye of the beholder, even if it is not beautiful.
The eye or a camera lens does transpose an image however both vertically and horizontally. This is a real image and can be captured on the retina of they eye or on film in the camera.
ymu
Niall Ferguson's deep-cover sock-puppet
Aye. The image our eyes transmit to the brain is upside down because of this. But our brains adjust to seeing everything the logical way up.
There are special helmets used for experiments that re-reverse the image - people who wear these for a while will start to see things the right way up again once their brain learns to flip the image back - and then they have to readjust when they take the helmet off.
But here you have transposed the sense of depth. What is behind the image is in front of you. What ever way you look at it there has been a topological transformation that can't be undone in three dimensions.
I don't believe there is any difference between real and virtual images. There are just images that are misleading to one degree or another.
cliche guevara
Well-Known Member
The key to this lies in the fact that up/down is not defined in the same way as left/right. Up/down are defined by gravity, wheras left/right is relative to the way you're facing.
max_freakout
Nothing matters
cliche guevara
Well-Known Member
Because the mirror only flips the left/right perception. The reason it hits this, and not the up/down is because the two things are fundamentally different.
ymu
Niall Ferguson's deep-cover sock-puppet
Up/down are defined by gravity, left/right are defined by the way you're facing. Replace left and right by north/south (defined by the earth's magnetic field) and the guy in the mirror is pointing in the same direction as you.
I think you can explain this with an illustration.
Something like this perhaps...
Your Head = O The Mirror = | Left Arm = < Right Arm = >
<.......|........>
O.......|........O
>.......|........<
As you can see, the figure on the right is a reflection of the figure on the left.
So when the light rebounds back from the mirror to your eyes you see the figure on the right if you are standing on the left and the figure on the left if you are standing on the right. The Dots represent the Light travelling back to you from the mirror.
If you look closer, you will note his arms have changed places.
You could remove the mirror and have two people stand facing each other, you will notice that the same 'reversal' that you mention is happening without a mirror. For the person facing you to raise the same arm...from your point of view, they would need to raise their left arm while you raised your right.
Something like this perhaps...
Your Head = O The Mirror = | Left Arm = < Right Arm = >
<.......|........>
O.......|........O
>.......|........<
As you can see, the figure on the right is a reflection of the figure on the left.
So when the light rebounds back from the mirror to your eyes you see the figure on the right if you are standing on the left and the figure on the left if you are standing on the right. The Dots represent the Light travelling back to you from the mirror.
If you look closer, you will note his arms have changed places.
You could remove the mirror and have two people stand facing each other, you will notice that the same 'reversal' that you mention is happening without a mirror. For the person facing you to raise the same arm...from your point of view, they would need to raise their left arm while you raised your right.
snadge
metal alchemist
then why does it still reverse in just one direction? it makes no sense
It makes perfect sense, it's how light travels.
Crispy
The following psytrance is baṉned: All
The key to this is the mind mistaking a reflection as a rotation.
If you rotate yourself around a vertical axis through the mirror, then you get something that looks like a mirror image, but it is not. Because we are used to seeing other humans, this is what we think we are seeing. However, a mirror image is not a rotation, it is an inversion in the direction perpendicular to the mirror's surface. Only the human body's symmetry allows this optical illusion to happen.
If you rotate yourself around a vertical axis through the mirror, then you get something that looks like a mirror image, but it is not. Because we are used to seeing other humans, this is what we think we are seeing. However, a mirror image is not a rotation, it is an inversion in the direction perpendicular to the mirror's surface. Only the human body's symmetry allows this optical illusion to happen.
WouldBe
Dislicksick
It doesn't. It just makes you think the image has been reversed.
See. Mind control.
stdPikachu
Plughole in bathtub curve
I remembe rreading about an experiment where people looked into "trick" mirrors that didn't reverse the image, to the extent that when people looked in it what they're used to seeing on the right hand side of the mirror was transposed to the left. Those people got very freaked out until they put their hand to their face and realised the "mirror" was fooling them.
As Crispy says, all the cool things about mirrors are in the mind. We don't see a reflection of ourselves, we see another identical human being mimicking us. As the short story posted earlier points out, it's only our bilateral symmetry that makes this sort of mind trick feasible.
max_freakout
Nothing matters
Crispy
The following psytrance is baṉned: All
You're right it's not a human, it's the reflected image of one and posesses no DNA at all.
max_freakout
Nothing matters
stdpikachu was anthropomorphising the mirror image, and i was responding to him
Crispy
The following psytrance is baṉned: All
stdpikachu was implying the process of the brain. eg. the brain interprets the reflected image of a human being as another human being.
stdPikachu
Plughole in bathtub curve
And now you're anthropomorphising a graphical representation of a collection of base 2 numbers using an abstraction of base 26 non-numeric algebraic glyphs used as a visual representation of certain predominantly Latin-based languages. Stop it!
max_freakout
Nothing matters
and i was pointing out that this is an invalid implication, because although it looks like another human being, it is in fact reversed
max_freakout
Nothing matters
teuchter
je suis teuchter
Looking at the image of another human in a mirror is really no different to looking at another human without a mirror. Both are just images constructed by your brain based on the light detected by your eyes. The light recieved via the mirror is no different from the light recieved more directly - it's just taken a slightly more roundabout route.
The mirror image is not really any kind of special case.
ymu
Niall Ferguson's deep-cover sock-puppet
Yes. And that is exactly what Crispy is saying. It looks like another human being [and so your brain assumes it is, but] it is in fact reversed [in the sense that the parts of the image on the right-hand side stay on the right-hand side instead of flipping to the left and vice versa].
How you've managed to come up with some bizarre mystical view of mirrors as a result of this thread is utterly beyond me.
max_freakout
Nothing matters
Mation
real life adventure worth more than pieces of gold
No, that's ^ wrong. Your arms do not change places! Stand in front of a mirror and lift your left hand up to your left eye. You'll see that the image of your hand touching your eye appears on the left side of the mirror. As others have said, the confusion comes because you think you're looking at a person. If you face another person and they raise their left hand to their left eye, it will appear to you to be on the right.
<.......|........<
O.......|........O
>.......|........>
This ^ is correct.
Text from a book looks backwards in the mirror because in order to see the text, you turn the book around as you hold it up. You do the reversing, not the mirror.
Johnny Canuck3
Well-Known Member
then why does it still reverse in just one direction? it makes no sense
It doesn't reverse anything. Your brain does the reversing.
Johnny Canuck3
Well-Known Member
Scary. I look back, and this is an old thread; and I said exactly the same thing, three months ago.
Well, it's good to know that my thoughts on these weird topics remain consistent.
Well, it's good to know that my thoughts on these weird topics remain consistent.
El Jugador
will leave bed for food
In tomorrow's lesson we will be covering Small vs Far away
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