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