Optical Occultation of the Sun
(youtu.be)
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I completely agree. It isn’t partially incorrect though - it is completely incorrect. The sun does not noticeably/perceptibly shrink in size as it sets. If perspective were the cause of the disappearance of the sun during sunset - it would shrink and get smaller until it disappeared. It would NOT set the way that large ships do.
I think we are generally in agreement here. The path the sun appears to take is significantly affected by perspective, but the movement of it is due to its movement. The sunset is NOT caused by perspective.
Right! The air (medium) through which the light travels is not uniform. It is a gradient. As the light from the sun travels through this density gradient it is curved convexly towards the ground due to refraction. The horizon is an optical illusion, and isn’t involved in the refraction. Perspective is the reason the sun appears to collide with the horizon in the distance, however - in reality - the height of the sun has not changed and though it seems like the rays of the sun are coming straight at you during sunset they are really traveling downwards from a great height through the density gradient which causes the optical illusion of “setting” (this is the same way it works with ships/stars - everything that “sets”)
It is certainly wrong to say that the reason for the sunset is perspective, or at best misleading. Your explanation sounds a little different than that, and you are correct that i do not understand it. It sounds like nonsense. The 3D occults the 2D? It’s all 3D... Can you explain this in any more detail, and more importantly can you demonstrate another example of this 3D occulting 2D on a smaller scale?
Some like me (though i don’t speculate on the source - government or otherwise)! Though, you argued directly against that in the first line of your comment ;)
Let me know if you still don’t agree / understand how refraction is (or at least conceivably could be) causing the illusion of setting, and how your view can be demonstrated/validated correct!
"it would shrink and get smaller until it disappeared. " wrong, things on the same plane as you get as smaller as they recede, THINGS WAY UP IN THE SKY DONT, BECAUSE U CANT PERCIEVE THEIR DEPTH - THE THIRD ASPECT OF 3D THOSE BEING height, WIDTH , AND DEPTH) IF you think this is wrong - simply try to find something ALREADY WAY UP HIGH IN THE SKY (PAST 10 MILES) AND SHOW IT GETTING SMALLER AS IT RECEDEDES? waiting, U CAN'T DO IT , CAUSE IT DOESNT HAPPEN
aIR DOESNT CAUSE REFRACTION, A DENSITY GRADIENT OVER DISTANCE = atmospheric DIFFRACTION. here'S an easy way to remember the difference, if its at a point, its refraction, if its over distance, its diffraction
"The 3D occults the 2D? It’s all 3D..." wrong, things in the sky (like stars {of which the sun technically is}) are only ever perceived in 2d, those two dimensions are called Right Ascension and Declination or Length and Width, not Depth , never depth. You cannot perceive depth of things really far away or really FAR UP. yOUR DEPTH PERCEPTION ENDS AT THE HORIZON, SO THINGS BEFORE IT ARE 3D, THINGS BEYOND IT ARE PERCIEVED AS 2D. sO THE 3D FOREGROUD OCCULTS THE OPAQUE 2D BACKGROUND AT THE HORIZON, THIS IS WHY THE SUN APPEARSD TO SET.
iT SOUNDS LIKE YOU DIDNT WATCH THE VIDEO, IM GURESSING BECAUSE YOU ARE IN ANOTHER COUNTRY AND DONT UNDERSTAND SPOKEN ENGLISH. wHERE ARE U FROM , CHINA?
DONT MIND MY CAPS LOCK BEING ON, MY KEYBOASRD IS BROKEN
Plane has nothing to do with it. Perspective occurs in all directions/dimensions. If something gets farther away from you, it will appear smaller... period, no exceptions whatsoever (under natural/normal circumstances - obviously magnification and such things can be used to counter/nullify that angular size difference)
It is true that it is harder to gauge the relative size of something in the sky (without fixed reference to compare it to), but yes we can perceive the apparent size difference of things in the sky (such as planes) as they recede as well.
As for the sun, it too changes size as it changes distance to us and this is measurable - even if it is difficult for us to perceive with the naked eye. Plane has nothing to do with it. The rules of optics work the same no matter which direction/dimension you look, or how far away things are.
As you said, any light traveling from one medium to another with a differing refraction index does refract! This includes air, which behaves as a fluid. Do you think refraction doesn’t happen in water too? Although gas and liquid are certainly different states of matter, they both act similarly - as fluids.
Not really, no. However there are physicists that agree with you that there is no significant difference between diffraction and refraction - they are one and the same. In my view diffraction is caused by light blocking/absorption/reflection and refraction is caused by altering the speed of the light wave. Refraction happens with frequencies of light where the medium (air) they are traveling through is largely transparent. Transparent things that cannot absorb/block/reflect light cannot diffract, but as i said - there are capable physicists and textbook authors that disagree with this view and declare that both are exactly the same. I think this is largely a semantical sinkhole. Wether we call the phenomenon of the light being curved convexly towards the ground as refraction or diffraction doesn’t change its reality at all.
That has to do with the distance to the object, its size, and the distance between our two eyes. It may appear 2D to us, but we can rest assured that like everything else in reality - it is, in fact, 3D. We don’t see it that way, but it is all the same. Do you disagree?
Sort of. I don’t exactly disagree, but the horizon (the distance limit of our vision through air) is NOT the same towards the horizon as it is towards the sky. The horizon is an optical illusion.
We can see farther than the distance to the horizon when looking through less air (i.e. looking up).
i think this is word salad nonsense. The “2D” background is still plainly visible as the sun sets. There is no “occulting” by the 3D world closer, nor is such a thing possible. The sun can, and does, go far enough away that the amount of atmosphere between us and it is too great for the light to directly reach us anymore (we call it night) - and is “occulted” (I would say blocked) by it. However, if this were the cause of the sunset the sun would never set. It would remain the same size and fade until too dim to see. The bottom of it and/or ships would never disappear.
Again, can you demonstrate this believed principle/phenomena on a smaller scale? If not, why not? It should be easy to make an apparatus with smaller eyes (or use a small child) much closer together to test and observe this in a scale test if it existed - right?
I did watch the video, but am happy to admit that i may well have not understood it.
Let’s assume you are correct - how can we observe this occulting phenomenon in a controlled repeatable way? I can demonstrate a mockup of my explanation, and although that does not mean that is for certain what is happening in reality - it is at least conceivable and demonstrable. It sounds like your explanation may not be demonstrable/testable, which makes it far less likely as a possibility.
“Plane has nothing to do with it.” - wrong “Perspective occurs in all directions/dimensions.” correct “If something gets farther away from you, it will appear smaller.” correct, something 1 foot away from you moving to 100 feet away will get smaller, but what if that thing is already 100 feet away from you and moves along as dimension that is not depth , let say width, should it still get smaller as it does so? No. Does this apparent size change with perspective last forever? No. Thats why thing in the sky are only refereed to in 2 dimensions , Right Ascension and Declination or Length and width, never depth. “we can perceive the apparent size difference of things in the sky (such as planes) as they recede as well. Nice baseless claim, please show me a shot of the iss crossing the sky with showing apparent size change. Cant do that , how bout a spy plane already at 15 miles high, plz i wont hold my breath while yuo make up crap. “any light traveling from one medium to another with a differing refraction index does refract” wrong, a slight density charge is not enough to cause refraction. Air does not cause any noticeable refraction, Lets say your viewing something from 3 miles away, and its fuzzy, thats not refraction, thats atmospheric diffraction, refraction is the distinct angling of light, when it YOUR PERCEPTION of light over distance, thats caused by atmospheric diffraction. “diffraction and refraction - they are one and the same.” wrong, refraction is the angling of light, Diffusion is the spreading out of light at a point, and diffraction is the spreading out of light over distance. “Wether we call the phenomenon of the light being curved convexly towards the ground as refraction or diffraction doesn’t change its reality at all.” Well i suppose in causal conversation it would matter but you making specific claims and using the globr explanation of “light being curved convexly towards the ground” due to refraction , when that is not whats going on at all. This slippery slope false explanation allows glob'rs to claim things are magically refracted up, when they are not.
When i say “perceived in 2d” that doesnt mean they are actually 2d, there is a limit to our perception. Thee fact we have two eyes doesn't change whether something is perceived in 3d or 2d, distance to object does, that's why its called “the diffraction Limit”, depth no longer diffracts, because that aspect of the reflected light is unable to reach our eyes.
“the horizon (the distance limit of our vision through air)” wrong, its not the limit to All Vision, its the Limit to depth, the other 2 dimensions of length and width are still perceivable.
Ill say this part again – things in the sky (like the Sun + moon) are only Perceived in 2d, when the sun meets the optical limit for perceiving Depth ( the optically rising non opaque ground your standing on that goes so until the horizon) that sky is then occulted or blocked or hidden from our view. Its actually so simple to get once you get it.
“ It sounds like your explanation may not be demonstrable/testable” not true, I've seen demonstration of this with camera showing this effect on objects that's say as few inches tall at 100 feet away, that the bottom becomes occulted or “disappears” not because it went over any physical curve, because our perception of depth ends
Also, it wonderful to talk to you, but lets end this on a good note, learn what you can, but i find your just repeating what you think you know try to make learning into a debate, thats not really helpful and im not into building a wall of misunderstanding, but i hope you rewatch the video a few times until you get it , gl.
I know you believe that. The question is why? There is no plane/direction/dimension in which objects don’t appear smaller as they recede.
Yes, because width is linear not circular. As the object moves horizontally it will necessarily increase distance from the observer and appear smaller. It’s an optical law - there are no exceptions.
If the object remained the same distance from the observer then it wouldn’t change apparent size - but we are talking about when objects do increase distance from the observer. Do you honestly believe that the sun (and ships, and anything else that appears to set “over the horizon”) is really NOT increasing distance from the observer as it moves?
Yes, of course. That’s my whole point. It’s called perspective, and it always applies - regardless of size/scale or distance. Including the sun (which does decrease in apparent size as its distance increases), there are no examples of any object NOT decreasing in apparent size as they recede. Please feel free to suggest one (other than the sun), if you disagree!
This is incorrect. Astronomers talk about/calculate the distances [depth] to those objects (located by ascension and declination) all the time.
You seem to be confusing topography with topology. The sky is not 2D even if our plotting system for locating things in it was (which it also isn’t, it is conceived to be a spherical grid)
You doubt that planes change apparent size as they recede away from you? Go look at them! What better “base” for a claim is there than your own observations?!
You seem to be confusing depth and size. Depth is hard/impossible to determine at some point because the pictures received by the eyes are essentially identical (no parallax) - (apparent) size is not effected and can be easily observed monocularly (one eye, no depth).
I, personally, wouldn’t bother and there are far better/easier targets than that one. There are certainly those (with powerful, expensive, auto-tracking telescopes) who can get you this shot you want though. Again, why do you believe these silly things? There are no examples of objects receding not changing apparent [angular] size, and i cannot understand why you think there are. It is as if you don’t understand why things appear smaller as they recede...
This is obviously wrong, and trivially calculable/demonstrable. The refraction may be slight, but light ALWAYS refracts when the refractive index changes. Again, i cannot understand why you would ever believe it wouldn’t, or what reasoning you could concoct to support that view.
Of course it does. Over short distances (and depending on angle of the light) it is imperceptible, but it is always there (just like angular size differences and for somewhat analogous reasons).
The more air the light travels through and the further it traverses through/across the gradient the more it refracts towards the ground. This is also the reason why the visible horizon appears slightly lower as you increase in altitude. It isn’t actually lower... it is being refracted.
No, diffraction (like refraction) is also objective and has nothing to do with perception. The object appears fuzzy because the light from it has been scattered by the air/matter in the way. I am not talking about diffraction, i am talking about refraction.
Hey, you’ll get no argument from me. I was just mentioning that many scientists and textbook authors define it that way.
Diffraction is caused by blocking light, refraction is caused by changing lights speed.
There are no “globr” explanations. There are just explanations, and they either right or wrong (usually the latter). Refraction does occur in our air, and though this is commonly used as an “out”/rationalization/excuse by those obligated to the globe model in order to ignore observable evidence of a (mostly) planar earth - that is NOT what i’m doing!
And what if it was? Would you want to know? If it wasn’t, and i were wrong - i would like to know that and to know how i can validate/demonstrate that!
They can (and do/will) claim anything they want - though the refraction i am talking about tends to curve things down - not up again. If you assumed the world was spherical, as they are required to, then this could be used to explain why things can be seen “too far”. I don’t care about the tactical soundness in regards to the base pageantry and silly game of debate - i care about what is actually happening. Just because the fact that the air refracts can serve their rationalizations, doesn’t make what i am saying incorrect/false in and of itself.
You are mistaken. The diffraction limit has nothing to do with depth. It happens with monocular vision (one eye, no depth). I don’t know where you picked this up.
This is an interesting claim - but i think it is wrong. The distance to the horizon changes with weather, the limits of the human eye are fixed (assuming you don’t grow old that is!).
Although the brain, and eye, has many ways of interpreting depth (one eyed people can do it too!) - the chief one that most are familiar with is parallax. If the picture the right and left eye receive are different, their comparison can be used to estimate/experience depth. At a certain distance (i expect well beyond the measly few miles to the visible horizon) - the pictures that the eyes receive are not different enough to reliably use that method. This is certainly a limit/function of human sight, but doesn’t have anything to do with the visible horizon or the angular resolution limits (aka diffraction limit).
I think i get it, and have encountered and considered such ideas before. I also think it is clearly wrong, and if it were right - we should be able to observe such an effect on a smaller scale (perhaps with much smaller eyes and much closer together with less pixel density - which IS diffraction limit). The fact that we can’t is very telling.
Depth perception isn’t necessary for sight in any significant way. Closing one eye doesn’t make anything disappear / “occult” anything. I have seen such demonstrations as well and the cause is likely (once again) refraction (this time caused by the ground temperature causing air column gradient inversion) - the mirror on the hot road effect and/or actual obstruction by the road itself (which is not perfectly flat, sadly).
If “perception” were the cause, then magnification could restore the “occulted” portion. This cannot be done. The reason is because it isn’t perceptional - the light from the bottom of the “set” object is no longer reaching the distant observer.
Likewise, and agreed!
Repetition is, alas, necessary for effective communication. I do try to avoid it, but if you misunderstand my position - repeating/rephrasing it is prudent. I would hope you would do, and are doing, the same in order for your perspective to be fully understood in kind. I know it is tedious, but education and effective communication are worth it!
Never! I loathe the base pageantry of debate. It’s for fools.
I prefer civil rational discourse and the collaborative pursuit of the truth - as all competent/capable students do.
I will always disagree when it is appropriate, and explain my reasoning/evidence at length - and i hope you can also do the same without letting it devolve into (or feel like it is) an argument/mindless debate.
Debate is a stupid game, and it is best avoided by the intelligent.
I may do that, but i think you have helped me “get it”. Now i want to validate/test it. I currently think it is simply wrong.