APOD: The Same Color Illusion (2012 Oct 07)

Comments and questions about the APOD on the main view screen.
User avatar
APOD Robot
Otto Posterman
Posts: 4684
Joined: Fri Dec 04, 2009 3:27 am

APOD: The Same Color Illusion (2012 Oct 07)

Post by APOD Robot » Sun Oct 07, 2012 4:06 am

Image The Same Color Illusion

Explanation: Are square A and B the same color? They are! To verify this, either run your cursor over the image or click here to see them connected. The above illusion, called the same color illusion, illustrates that purely human observations in science may be ambiguous or inaccurate. Even such a seemingly direct perception as relative color. Similar illusions exist on the sky, such as the size of the Moon near the horizon, or the apparent shapes of astronomical objects. The advent of automated, reproducible, measuring devices such as CCDs have made science in general and astronomy in particular less prone to, but not free of, human-biased illusions.

<< Previous APOD This Day in APOD Next APOD >>
[/b]

Ron

Re: APOD: The Same Color Illusion (2012 Oct 07)

Post by Ron » Sun Oct 07, 2012 4:34 am

There appears to be a clear colour gradation along the connecting path ?!!!?

Rohan

Re: APOD: The Same Color Illusion (2012 Oct 07)

Post by Rohan » Sun Oct 07, 2012 4:48 am

But if you edit the pic, do a cut-n-paste and move squares around to compare colours, the ilusion shows itself quite clearly. Fascinating.

Is the shadow of the green column essential to make this work ?

BTW, I've seen the moon rise out in some dry country air (not near the sea), and, just once, mid-winter the moonrise occupied probably fully a 1/4 of the eastern horizon. Some sort of huge lensing effect. Called folks out to look and marvel. No pic, sadly.

In coastal regions, never see anything like that - humidity related ??

ianchristie
Asternaut
Posts: 3
Joined: Wed Aug 31, 2011 9:48 am

Re: APOD: The Same Color Illusion (2012 Oct 07)

Post by ianchristie » Sun Oct 07, 2012 6:52 am

Ron;
The "apparent" colour gradient along the connecting strip is an illusion itself! I have done the cut and paste trick to compare the squares without the rest of the image and they really are the same.
And Rohan;
I'm going to try editing out the green column and its shadow and see what it looks like.
I'll keep you informed.
Cheers
Ian

ianchristie
Asternaut
Posts: 3
Joined: Wed Aug 31, 2011 9:48 am

Re: APOD: The Same Color Illusion (2012 Oct 07)

Post by ianchristie » Sun Oct 07, 2012 7:13 am

Okay; I have done a cut and paste to remove the column and shadow.
http://dl.dropbox.com/u/10566986/Cheque ... on%202.jpg
I replaced the squares which were at least partly shadowed with copies of the two bottom right hand edge squares. There is a small amount of perspective distortion in the original picture so when I pasted the squares they weren't a perfect fit. Any square which wasn't in shadow or obscured by the column I left as original.
Cheers
Ian
Last edited by ianchristie on Sun Oct 07, 2012 8:31 am, edited 1 time in total.

Boomer12k
:---[===] *
Posts: 2691
Joined: Sun Apr 22, 2007 12:07 am

Re: APOD: The Same Color Illusion (2012 Oct 07)

Post by Boomer12k » Sun Oct 07, 2012 7:46 am

There are several other illusions associated with Astronomy.

1. The Illusion of Light. We don't see things in real time. We see things as they were...minutes, years, thousands of years, millions of years, hundreds of millions of years, and billions of years ago. It takes 8 minutes for the sun to reach us. Thus when we look in the direction of the sun, (without looking directly at the sun, of course), we don't really see where the sun actually is, but where it was 8 minutes ago. When we see a nebula like the Great Nebula in Orion, we see it as it looked 1500 years ago, and so on.

2. Thus, along with the Illusion of Light we have the illusion of time, as it is not real time, but a type of projection.

3. I, personally, see things in nebula, objects, faces, like in Earth's Clouds...and of course that is just an association with a shape...it is not the actual object, of course. The constellations are this kind of illusion also. Different cultures have connected the dots differently. Also, The Man In The Moon....I can actually see the Energizer Rabbit, Drum and all....ask Ann.

4. And people have been fooled by camera artifacts, and object blurs, that give an impression of something else, or something strange and unworldly. I had a Black and White CCD camera. Hooked up to the TV, when I was STILL, I appeared solid, but if I moved, I appeared to become transparent, you could see the background through me,....slow camera...an artifact, but made a cool illusion. Some people have photographed strange multi-winged bugs. 6 sets of wings....a too slow camera, 30 fps can do this... a slow motion camera, 2000 fps, shows it to be a normal bug.

We live in a Fish Bowl. An atmosphere that can distort things. That is why we need equipment in space.

We also have ELECTIONS....another illusion....

There are many illusions and delusions in life...I hope you can see through yours with good understanding.

:---[===] *

henrystar
Ensign
Posts: 97
Joined: Sun Feb 28, 2010 11:40 am

Re: APOD: The Same Color Illusion (2012 Oct 07)

Post by henrystar » Sun Oct 07, 2012 9:50 am

Try dropping a pencil in front of a crowd of people. They all know it is accelerating, but ask them if it LOOKS as if it is accelerating. Only about 5 - 10 % of the people say they can see the speeding up. But then, using "elephant-one, elephant-two, elephant-three..." as a timer, drop the pen six inches to a hard surface: result is "elephan..." or about half a second. Then do the same thing but dropping the pen all the way to the floor. Result is "elephant-" namely just a tiny bit longer. The acceleration is enormous, BUT most people cannot see it at all! This is presumably "deliberate" by evolution to assist us in some way. I stumbled on this myself, and have never seen it written up or commented on. It seems to me that the only way to accomplish this is to have our sense of the rate of passage of time "decelerate" during the motion. If anyone knows of any reference on this please let me know: henry@jhu.edu

User avatar
geckzilla
Ocular Digitator
Posts: 9169
Joined: Wed Sep 12, 2007 12:42 pm
Location: Modesto, CA

Re: APOD: The Same Color Illusion (2012 Oct 07)

Post by geckzilla » Sun Oct 07, 2012 12:47 pm

Maybe we can't see it accelerating very well but I know for certain if the pencil is dropped without acceleration such as with an animation, the animation looks very wrong. So a better way to go about asking people if they can detect the acceleration might be to show an animation of two objects falling--one with and one without--and ask which one looks more natural. I'm betting the one with the simulated gravity will be chosen most of the time.
Just call me "geck" because "zilla" is like a last name.

User avatar
JohnD
Tea Time, Guv! Cheerio!
Posts: 1505
Joined: Wed Feb 16, 2005 2:11 pm
Location: Lancaster, England

Re: APOD: The Same Color Illusion (2012 Oct 07)

Post by JohnD » Sun Oct 07, 2012 3:50 pm

I'm doing a neufer here, but:
Click to play embedded YouTube video.

I saw that gradation in the 'bridge' between the two squares. But there are other illusions where shades and colours deceive.
For instynace, the fourth from the top, here:
http://www.premierphotographer.com/humor_1.html
Therec is a shadow at every intersection of the grid of black squares, except the one you are looking at.
You KNOW they're not there, but you can see them!

John

Marek44

Re: APOD: The Same Color Illusion (2012 Oct 07)

Post by Marek44 » Sun Oct 07, 2012 8:01 pm

Simple evolution. Toxic, red toadstool must be a toadstool for our brain in the sunlight and in the shadow.

User avatar
Chris Peterson
Abominable Snowman
Posts: 16650
Joined: Wed Jan 31, 2007 11:13 pm
Location: Guffey, Colorado, USA

Re: APOD: The Same Color Illusion (2012 Oct 07)

Post by Chris Peterson » Sun Oct 07, 2012 8:32 pm

Boomer12k wrote:There are several other illusions associated with Astronomy.

1. The Illusion of Light. We don't see things in real time. We see things as they were...minutes, years, thousands of years, millions of years, hundreds of millions of years, and billions of years ago.
That's not an illusion, and in general it produces no illusions. It is almost always meaningless to consider when something "really" happened. Because spacetime is defined in part by the speed of light, "now" is dependent upon the frame of the observer. Things happen when the photons reach that observer, not before.
Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

User avatar
neufer
Vacationer at Tralfamadore
Posts: 18805
Joined: Mon Jan 21, 2008 1:57 pm
Location: Alexandria, Virginia

Re: APOD: The Same Color Illusion (2012 Oct 07)

Post by neufer » Sun Oct 07, 2012 8:50 pm

Click to play embedded YouTube video.
Chris Peterson wrote:
Boomer12k wrote:There are several other illusions associated with Astronomy.

1. The Illusion of Light. We don't see things in real time. We see things as they were...minutes, years, thousands of years, millions of years, hundreds of millions of years, and billions of years ago.
That's not an illusion, and in general it produces no illusions. It is almost always meaningless to consider when something "really" happened. Because spacetime is defined in part by the speed of light, "now" is dependent upon the frame of the observer. Things happen when the photons reach that observer, not before.
Art Neuendorffer

User avatar
geckzilla
Ocular Digitator
Posts: 9169
Joined: Wed Sep 12, 2007 12:42 pm
Location: Modesto, CA

Re: APOD: The Same Color Illusion (2012 Oct 07)

Post by geckzilla » Sun Oct 07, 2012 9:13 pm

Man, it's really weird how all of these science videos are all presented in the format of a hand drawing cartoons. Just a fad or is it the best way to convey science education?
Just call me "geck" because "zilla" is like a last name.

User avatar
Chris Peterson
Abominable Snowman
Posts: 16650
Joined: Wed Jan 31, 2007 11:13 pm
Location: Guffey, Colorado, USA

Re: APOD: The Same Color Illusion (2012 Oct 07)

Post by Chris Peterson » Sun Oct 07, 2012 9:20 pm

geckzilla wrote:Man, it's really weird how all of these science videos are all presented in the format of a hand drawing cartoons. Just a fad or is it the best way to convey science education?
It provides nice visuals with a very low budget.
Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

Wadsworth
Science Officer
Posts: 131
Joined: Tue Jun 20, 2006 3:12 pm
Location: TX

Re: APOD: The Same Color Illusion (2012 Oct 07)

Post by Wadsworth » Sun Oct 07, 2012 9:26 pm

geckzilla wrote:Man, it's really weird how all of these science videos are all presented in the format of a hand drawing cartoons. Just a fad or is it the best way to convey science education?
Weird? I'd say effective. At the very least, they are effective in getting one to watch and listen to the entire segment.
Try watching one with the sound turned off, or just listening to one without watching the video. Of course it won’t be nearly as captivating.

I don’t think these types of educational videos are meant to give a deep understanding to anything in particular. More just to scratch the surface in an interesting sort of way.
I like them.

jhnmg4b@gmail.com

Re: APOD: The Same Color Illusion (2012 Oct 07)

Post by jhnmg4b@gmail.com » Sun Oct 07, 2012 9:56 pm

i agree with the participat who noted the gradation as the strip itself moved from A to B. further notice the mismatech between the strip, which is supposed to be grey at that point, and the box to its right.
Apparently A, which is grey, is not the same color as the box immediately below and to the right. Hence,grey is not grey.

Boomer12k
:---[===] *
Posts: 2691
Joined: Sun Apr 22, 2007 12:07 am

Re: APOD: The Same Color Illusion (2012 Oct 07)

Post by Boomer12k » Sun Oct 07, 2012 11:25 pm

Chris Peterson wrote:
Boomer12k wrote:There are several other illusions associated with Astronomy.

1. The Illusion of Light. We don't see things in real time. We see things as they were...minutes, years, thousands of years, millions of years, hundreds of millions of years, and billions of years ago.
That's not an illusion, and in general it produces no illusions. It is almost always meaningless to consider when something "really" happened. Because spacetime is defined in part by the speed of light, "now" is dependent upon the frame of the observer. Things happen when the photons reach that observer, not before.
I am saying many things here to cover the subject from many angles with many examples...

We only see Visible Light...we need instruments to "see" the rest of the Electromagnetic Spectrum. So right there we see an illusion of light...and not the whole thing. We feel heat. We see a mirage that is actually the heat radiation warming the air and it rising in waves and it refracts the ground around it, into a shimmering illusion of "water". So a Mirage is an illusion of light.

I was in love many times, but that turns out to be a DELUSION as well as an illusion...and at 59, I STILL FALL FOR IT!!!! :lol2: :lol2: :lol2:

It is an illusion, in and of itself. "Things happen when the photons reach that observer, not before", is a matter of perception and perspective, and can be an illusion all its own.

That phrase is a very convenient thing to say...but it is not true...actions in the Universe happened LONG before they reach us...To me...it is important to realize things happened LONG before I was ever here...it brings my ego down to reality. A Supernova in another galaxy happened millions, tens of millions of years ago...when I see that I realize that it is I who does not matter...our self importance is an Illusion. So that PHRASE is a convenient way to look at things for your purpose, and goal. That is the way YOU as a scientist need to look at it...so you say that is the way it is...not necessarily so....

"Now" is the same for you and I. But the CLOCKS on the walls might say different for our personal convenience, we don't have to use Greenwich Mean Time to calculate our time....it is the same instant for both of us, even on opposite sides of the world...The other is an "illusion of Time"...For me it is 3pm, in New York, it is 6pm...but it is the same instant. Now is Now for everyone...the clocks and locations might be different because we differentiate time and places...as we are separated by greater and greater distances, and for our immediate daily lives. It may SEEM irrelevant to you from your perspective...but when I call you at 3pm my time, and it is 3AM your time....I think it will be VERY relevant to you. :lol2:

We do not know yet, if Betelgeuse has exploded yet or not...it may have, and we just don't see it as the light has not reached us...THUS what we DO see may be AN ILLUSION...not the real event.

So....Actually Chris, you just described why it is an illusion of light...it takes time for the photons to reach the observer, long after the event, and that is ALL we are actually SEEING...photons...We don't SEE MARS...we see photons bouncing OFF of Mars... (Just because it seems irrelevant to you in your line of work to look at it that way, and it helps your perspective, and you have to take things "as they come in", does not mean it is irrelevant or meaningless. You are evidently very patient, as I would expect from one in your position, which I appreciate.)

A star, 450 light years away is not in the same position when we see the photons 450 years later. (although you might accept it for what it appears to be...) It is in reality, 450 years further along in its path around the galaxy, and its other motions at is speed. If we were to race towards that star, we would see the star LIGHT move very quickly towards its present, actual location. The Star would appear to move. That is why we have to "LEAD THE DUCK" to hit it where it is going to be. As we approach the star, we see the light coming closer to its actual location....thus it is an "illusion of light" that we see...even if you discount it in your work as a matter of convenience as it does not matter to you when that event occurred, only that you detect and capture it for data, analysis, and understanding, (You are a scientist). So, in truth, we don't really see an object...we only see the light that left that object or area...and we are waiting for the next frame of the projection, so to speak. To us, FOR us, it is happening Now...but in truth...that is an illusion, and only our limited perspective. NOW, at the other location is different as the photons leaving there will show us in due time... I think you understand that very well, you just discount it in your work, as it does not matter when that photon left...but you are not looking at the actual object...you are only looking at the PHOTONS that left that object, or area...that is the "Illusion of Light"....it makes you THINK you are seeing the actual object. An illusion in and of itself..as I stated above.

While a photon is on its way here, back at the point of origin, things are changing NOW...Otherwise you would not see changes in positions and movement in objects like Nebula...Those changes occurred after the photon we see left the area...but they ACTUALLY happened hundreds of years AGO, and more...it is not happening at the same time the photon reaches the observer...One observer closer to the action sees it all sooner than an observer farther away. It takes time for light, and even sound to reach different points. Thus setting up the illusion of now and real time...we "think" it is real time, it is real time to us... just like we "think" the APOD illustration is a different color, without realizing that we are being fooled by our perceptions. Something in the SHADE should be darker...they TRICKED US...like our politicians, :x ... When we see a galaxy, we do not see it as it is, just the image of light as it was millions of years ago...."NOW"...right now...it is completely different, more turned, a supernova we just don't see yet, or we would see that supernova right now, not 10 million years from now....we see an image...not really the object...a photograph is the same thing. The photo image is from the light gathered, not really the object itself...just the light reflected or absorbed, or projected, like with a star, and the lens captures it. That is another illusion of light. The same with Astronaut communication from the Moon, the time lag...we hear the voice, but it was over a second ago....right now the astronaut is doing or saying something else....that we will get in about a second and a half...the same with the rovers on Mars...what is it, 18 minutes to see the result of the actions sent from Earth? I forget what the wait is.... We just don't "THINK" it is an illusion...that is why it is one....
I used to think...Mass attracted Mass...but I don't anymore....that it the "illusion of Gravity"...that two or more object's MASS are "ATTRACTING" each other...they are not...it is a lack of understanding the mechanism...just like we don't understand a "MAGIC SHOW" Trick... Or can David Copperfield really walk through the Great Wall of China??? I saw him do that on TV...it MUST BE TRUE!!!! :shock:

Thanks for your input, Sir, I really, really, appreciate it...and that is NOT an illusion. :D

:---[===] *

User avatar
Chris Peterson
Abominable Snowman
Posts: 16650
Joined: Wed Jan 31, 2007 11:13 pm
Location: Guffey, Colorado, USA

Re: APOD: The Same Color Illusion (2012 Oct 07)

Post by Chris Peterson » Sun Oct 07, 2012 11:43 pm

Boomer12k wrote:We only see Visible Light...we need instruments to "see" the rest of the Electromagnetic Spectrum. So right there we see an illusion of light...and not the whole thing. We feel heat. We see a mirage that is actually the heat radiation warming the air and it rising in waves and it refracts the ground around it, into a shimmering illusion of "water". So a Mirage is an illusion of light.
A mirage is an illusion, but the light itself is not- including those parts of the spectrum that we transform so we can see them.
That phrase is a very convenient thing to say...but it is not true...actions in the Universe happened LONG before they reach us...
Not really. Modern physics tells us that events happen when they are observed.
We do not know yet, if Betelgeuse has exploded yet or not...it may have, and we just don't see it as the light has not reached us...THUS what we DO see may be AN ILLUSION...not the real event.
No. It has not exploded. When we look at it, we aren't seeing an illusion, merely photons that were created hundreds of years ago.
So....Actually Chris, you just described why it is an illusion of light...it takes time for the photons to reach the observer, long after the event, and that is ALL we are actually SEEING...photons...
I don't see how that can be called an illusion. Our senses are not being fooled in any way, which seems to me a prerequisite for an illusion.
Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

User avatar
neufer
Vacationer at Tralfamadore
Posts: 18805
Joined: Mon Jan 21, 2008 1:57 pm
Location: Alexandria, Virginia

Re: APOD: The Same Color Illusion (2012 Oct 07)

Post by neufer » Mon Oct 08, 2012 12:41 am

Wadsworth wrote:
I don’t think these types of educational videos are meant to give a deep understanding to anything in particular.
More just to scratch the surface in an interesting sort of way. I like them.
This one was sure a lot of Fun :!: : [Image]

[Mmmmm...the illusion of the flow of strawberry cheesecake :!: ]
Art Neuendorffer

User avatar
bystander
Apathetic Retiree
Posts: 21020
Joined: Mon Aug 28, 2006 2:06 pm
Location: Oklahoma

Re: APOD: The Same Color Illusion (2012 Oct 07)

Post by bystander » Mon Oct 08, 2012 2:14 am

Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk.
— Garrison Keillor

abhagwat
Ensign
Posts: 13
Joined: Wed May 11, 2011 1:37 am

Re: APOD: The Same Color Illusion (2012 Oct 07)

Post by abhagwat » Mon Oct 08, 2012 4:14 am

It would be nice to explain why optical illusions occur.

Confused
Ensign
Posts: 92
Joined: Sat Mar 25, 2006 6:50 pm
Location: Los Angeles

Re: APOD: The Same Color Illusion (2012 Oct 07)

Post by Confused » Mon Oct 08, 2012 4:32 am

The important thing is that the proof is not a proof. Someone was quick to say that the strip appears to show a gradual change in color in the strip from A to B. The reply was that that is also an illusion. Therefore the strip does not do what it claims to do. A highly convincing proof is not easy to do in a format such as this, or if it is easy, it needs more creativity. In other words, it would be possible to move the sqares around and that would show the illusion, but some people would be more likely to assume that the squares change in color as they move. In other words, it would not be a proof.

User avatar
JohnD
Tea Time, Guv! Cheerio!
Posts: 1505
Joined: Wed Feb 16, 2005 2:11 pm
Location: Lancaster, England

Re: APOD: The Same Color Illusion (2012 Oct 07)

Post by JohnD » Mon Oct 08, 2012 9:22 am

abhagwat wrote:It would be nice to explain why optical illusions occur.
It's because despite appearances, the eye is not a camera. There is extensive processing of the signals from rods and cones, both at retinal level and in the brain. For instance, looking at a coloured material in artificial light for the first time may give you a wrong impression of how it will appear in natural, white light, its 'true' colour. However, if you already 'know' its true colour, then you will see it as that colour even in artificial light.

In this example, the same grey is placed both in an area that the brain perceives as well lit, so it appears dark, and shadowed, so it appears light. The brain processes the signals differently in the light [!] of the context.

Other illusions occur because of edge and movement processing.
This site offers a number, with some explanation.
http://www.colourlovers.com/blog/2008/0 ... illusions/
My favourite is the Lilac Chaser, which may be due to retinal processing, whereas our first is due to brain processing.
John

Boomer12k
:---[===] *
Posts: 2691
Joined: Sun Apr 22, 2007 12:07 am

Re: APOD: The Same Color Illusion (2012 Oct 07)

Post by Boomer12k » Mon Oct 08, 2012 10:37 am

Chris Peterson wrote:
Boomer12k wrote:We only see Visible Light...we need instruments to "see" the rest of the Electromagnetic Spectrum. So right there we see an illusion of light...and not the whole thing. We feel heat. We see a mirage that is actually the heat radiation warming the air and it rising in waves and it refracts the ground around it, into a shimmering illusion of "water". So a Mirage is an illusion of light.
A mirage is an illusion, but the light itself is not- including those parts of the spectrum that we transform so we can see them.
That phrase is a very convenient thing to say...but it is not true...actions in the Universe happened LONG before they reach us...
Not really. Modern physics tells us that events happen when they are observed.
We do not know yet, if Betelgeuse has exploded yet or not...it may have, and we just don't see it as the light has not reached us...THUS what we DO see may be AN ILLUSION...not the real event.
No. It has not exploded. When we look at it, we aren't seeing an illusion, merely photons that were created hundreds of years ago.
So....Actually Chris, you just described why it is an illusion of light...it takes time for the photons to reach the observer, long after the event, and that is ALL we are actually SEEING...photons...
I don't see how that can be called an illusion. Our senses are not being fooled in any way, which seems to me a prerequisite for an illusion.

Point 1. The light is being warped by the effect, so as not to represent the true state of the objects. Pavement for example. Thus the light is contributing to the illusion, and light, in the form of heat, infrared light, is causing the illusion in the first place, a light we don't see with our eye. Second part: As our eyes perceive things, we do not see the radiation that fills the blackness of space. Thus it is an illusion, to us, that the night sky is "empty". That is why I said we need instruments. The light may not be the illusion, but our eye perceives it as one, by not seeing what IS there. That space is empty is an illusion, we only see a select part of the EM spectrum. It is like those composite shots of visual, x-ray, ultra violet images of like a galaxy, and you see the regular visible galaxy, then the x-ray shows the gas jet, etc... things we did not know were there with just our vision...thus the illusion of only light we see. So we had an incomplete picture. You can call that an illusion of the EYE if you want to...but it is the different wavelengths of light that is doing it also. The result is an illusion.

Point 2. Like I said...a matter of convenience...That generally refers to Quantum Mechanics, (Quantum Theory), in Physics, where the observer is affecting that which he is observing, just by the act of observing it. So a phenomena does not appear to exist before you observed it. This is Astronomy. We are looking at events that have already taken place, and the photons from the event are reaching us without our creating it, or affecting it just by our participation in observing it. Thus the statement does not truly apply. (My considered opinion.) (Leads into point 3) Just because photons from Betelgeuse do not show an explosion tonight, does not mean they will not show the explosion tomorrow night, and that does not mean it JUST NOW HAPPENED because that is what we observe, as you yourself said, it took hundreds of years for the light to travel here, ergo, it happened hundreds of years ago, Not "when it was observed", (although I realize a Scientist may look at it that way, but that does not make it consistent in all cases)...what we see may well be the truth of that explosion, but the time and distance, that we see it hundreds of years later, is a type of illusion. It is a projection of the light, like a movie, or slideshow, it does reflect and show the true event, it is a result of the event, but it did not just happen now as we observe it, that is an illusion... That is like the illusion of the FLAT EARTH. I can take a 6 foot 2x4 out in the yard, put it down flat, and as it is observed to be flat, claim the world is flat. (there was actually a guy out in the desert that used to do this. Really. You could show him ANYTHING that showed the Earth to be round, and he had some explanation as to why it was WRONG, and the world was flat, impossible to convince him otherwise, a real kook).

Point 4. Not all illusions are deliberately trying to fool you, deceive your senses, etc...This APOD is set up as a trick. As it sets up a supposition that an area in shadow should be darker. A mirage is not trying to fool you on purpose...it just is...You would say, but the photon is just doing the same thing "it just is" also. That is not necessarily the illusion. A Supernova occurs close by, say LMC, Like SN 1987A. How long does that Supernova "appear" to be visible for us without a telescope? (Well, Type 1 any where from hours to days. And Type 2 up to several months) OK...supernova is 168,000 light years away. Happened 168,000 years ago. It was visible maybe for several months with unaided eye. You would say that since you just observed it, that is just happened now??? I would call it a 168,000 year illusion of light, because that event is loooonnng over the main brightness stage over there in the LMC...THAT is the illusion. That it just happened now. It did not. It was observed now, but did not happen now. That is also created by Light, and the vast distance and time that it has to travel. Not that the light is deceiving you, showing you something false on purpose...so an illusion may be "impersonal" in its intent. Like Arctic Mirages of Ice. Nothing personal. Just is. The other illusion is...just because we no longer see SN 1987A with the unaided eye does not mean the event is over with...it is not...it is still continuing and we see that though telescopes which are still observing it...years later as it expands... must be awesome to be there...not too close of course.
Light maybe showing truth...but that truth is not happening when we observe it. We are only observing the photons...NOT THE ACTUAL EVENT! We see only an image...a facsimile of the event, a projection of the event. That is what a photon is, a projection. Not the galaxy...just a projection OF the galaxy...That is an illusion of light. It is an emitted impression. If there was something in the way, it would be blocked, and we would perceive a shadow...a lack of photons, lack of image, lack of projection, but the galaxy is still there.
Thus there is no prerequisite in this case for an illusion...the APOD yes...it is an optical illusion, and it is a trick of how it is set up. I was talking about illusions as related to Astronomy.
Galactic Lensing as an effect is an illusion, there is no true horseshoe shaped galaxy wrapped around the other galaxy...it is an illusion of light, passing through warped space...yes? Not trying to deceive you in anyway...but it is an illusion. It is not really the actual case of being. Einstein predicted that without observing it first. Also, Solar gravitational illusion of a star that is actually hidden behind the Sun, but appears to be already visible...his famous experiment. Predicted before observation. Therefore...warped space, and light, not actually showing the actual case of being, an illusion...but they are not TRYING to deceive your perception in anyway. Nothing personal...just is.

I am not really trying to argue points here, (Truly, not what I am after,) or anything of the sort. I just delineated them for convenience, as you took them as points too... I am trying to give explanations, and examples of what I have put forth, in my previous statements about some of the Astronomical and other illusions we see as it related to this APOD. I have studied this "illusion of light" phenomena for about 5 years. You obviously work with it...but don't acknowledge it as it is probably not necessary for your work.

I admire the work you do, Sir, your comments, and Cloudbait must be just awesome to work at.

:---[===] *
You do not have the required permissions to view the files attached to this post.