The Flat Earth Society

Flat Earth Discussion Boards => Flat Earth Investigations => Topic started by: Pinky on May 01, 2019, 12:59:52 PM

Title: Why crepuscular rays aren't proof for the position of the Sun.
Post by: Pinky on May 01, 2019, 12:59:52 PM
(https://upload.wikimedia.org/wikipedia/commons/thumb/0/0b/Crepuscular_rays_over_Plymouth_Sound_crop.jpg/1200px-Crepuscular_rays_over_Plymouth_Sound_crop.jpg)

Let's ignore the mainstream-science explanation for crepuscular rays with light-scattering and perspective.
https://en.wikipedia.org/wiki/Crepuscular_rays
Let us ignore that. Let's instead assume that what we see with our unaided eyes were true: That the rays emanate DIRECTLY from a light-source.



You cannot use the angles of the crepuscular rays to deduce the position of the Sun, because you don't know how far away the cloud is.

A simple experiment to demonstrate my geometric argument:
Shine a light on a wall. In front of the light hold a piece of paper, so you can see its shadow. (Or just hold a paper in front of your face and squint your eyes.) Hold the paper in such a way that a corner points up.
If you hold the paper upright, the shadow of the corner has the same angle as the corner. 90°
Now, as you tilt the paper, the angle of the shadow of the corner gets bigger and bigger than 90°, even though the corner still has 90°.



My point is: What you see in the crepuscular rays is not an upright triangle. You see a tilted triangle and you have no idea how far away the top corner is. From the crepuscular rays you could deduce the vector from the position of your eye to the position of the source of light, but you don't know where on that line the source of light is.

Now, if we were to triangulate the directions of crepuscular rays from several positions on Earth, THEN we could calculate where the top corner of the triangle is, but a single observer cannot measure the tilt of the triangle. He sees only the projection of the triangle.

Therefore, observing crepuscular rays as shown in the image above is no proof for the distance of the Sun or for Flat Earth.
Title: Re: Why crepuscular rays aren't proof for the position of the Sun.
Post by: Dr David Thork on May 01, 2019, 02:09:47 PM
Light travels in straight lines. Parallel lines if from a source infinitely far away.

If you can't just follow those lines and complete the triangle, round earth needs to explain why this light bends. This distance of the clouds is not important. That distance is small compared to the millions of miles the sun is purportedly supposed to be.

If ever with your eyes you want proof that the sun is not millions of miles away, your picture is an excellent example.
Title: Re: Why crepuscular rays aren't proof for the position of the Sun.
Post by: markjo on May 01, 2019, 02:22:30 PM
Light travels in straight lines. Parallel lines if from a source infinitely far away.

If you can't just follow those lines and complete the triangle, round earth needs to explain why this light bends.
The light doesn't bend.  Perspective says that parallel lines appear to converge in the distance, even though they never actually get any closer together.  Crepuscular rays are akin to an artistic technique known as foreshortening.
https://www.britannica.com/art/foreshortening
Title: Re: Why crepuscular rays aren't proof for the position of the Sun.
Post by: Curious Squirrel on May 01, 2019, 02:58:32 PM
Crepuscular rays have been discussed many times before. I don't know why Thork is taking the stance he is, it's well known tracing the ray paths back doesn't work for RE OR FE sun height claims. Here's a good post with info on things.

Yes, "crepuscular" is the search term which will give you some results.

Meanwhile a have a similar "grounded" example for you, not so striking, as the length of the field is limited.
https://il9.picdn.net/shutterstock/videos/11234123/thumb/1.jpg
(France, Lavender fields)
Reason is: Perspective.

The rays are practically parallel due to Sun being very far. Here is a very simple explanation: http://www.atoptics.co.uk/atoptics/rayform.htm

Thank you both. The explanation makes perfect sense for either FE/RE. I like the picture of the rows of heather (or whatever it is). That is a good way to visualize and understand the perspective.
Title: Re: Why crepuscular rays aren't proof for the position of the Sun.
Post by: AATW on May 01, 2019, 03:10:38 PM
If ever with your eyes you want proof that the sun is not millions of miles away, your picture is an excellent example.
I keep on hearing that train tracks are parallel but look at this!

(https://image.ibb.co/eP4TgH/Tracks-Photo.jpg)

If ever with your eyes you want proof that train tracks meet, this picture is an excellent example.
I always find it weird that FE use perspective wrongly to try and explain sunsets but then forget perspective exists when thinking about pictures like this.
Title: Re: Why crepuscular rays aren't proof for the position of the Sun.
Post by: Dr David Thork on May 01, 2019, 03:20:13 PM
And the angle of those tracks is less pronounced than those sun rays. Those rays are at a greater angle than one can attribute to fore shortening.
Title: Re: Why crepuscular rays aren't proof for the position of the Sun.
Post by: AATW on May 01, 2019, 03:32:00 PM
Those rays are at a greater angle than one can attribute to fore shortening.
What is your basis for that claim?
If in my image you changed the position of the camera it would change the apparent angle. If you point it straight down at the tracks then you see them as they truly are, parallel. The angle at which they appear to converge changes as you move the camera.
If you knew your camera position and angle in relation to the tracks and the distance the tracks are apart then you could work out the apparent angle. I don't believe you have sufficient information from that image to make the claim you are making.

If the angle in that picture was caused by reality rather than perspective then the sun would be just above the clouds, we know that is not true even in your model.
Title: Re: Why crepuscular rays aren't proof for the position of the Sun.
Post by: WellRoundedIndividual on May 01, 2019, 03:59:19 PM
 But, but, but what about anticrepuscular rays????

https://en.wikipedia.org/wiki/Anticrepuscular_rays

How does the light bend one way and then the other next? OBVIOUSLY, it has nothing to do with the distance to the sun, and all about perspective. You can't change the laws of physics to bend light one way and then the next just by looking the other way.
Title: Re: Why crepuscular rays aren't proof for the position of the Sun.
Post by: Tom Bishop on May 01, 2019, 04:04:06 PM
Thork may be correct. The further the straight lines originate from you, the more parallel they should appear to each other. Go to https://www.tinkercad.com and zoom out from the standard workplane.

(https://i.imgur.com/gg3ZWu2.jpg)

(Click for Bigger (https://i.imgur.com/gg3ZWu2.jpg))
Title: Re: Why crepuscular rays aren't proof for the position of the Sun.
Post by: WellRoundedIndividual on May 01, 2019, 04:23:11 PM
False equivalency, Tom. Using CAD for perspective compared to what we see in the real world? I don't think so.
Title: Re: Why crepuscular rays aren't proof for the position of the Sun.
Post by: ChrisTP on May 01, 2019, 04:49:08 PM
Someone posted a lovely demonstration on these forums before;

https://youtu.be/cTPLqbl-HGY

Disclaimer: I watched this both times without audio so no idea if he talks, but I'm mainly referring to the visuals of the video.
Title: Re: Why crepuscular rays aren't proof for the position of the Sun.
Post by: Bastian Baasch on May 01, 2019, 04:56:01 PM
False equivalency, Tom. Using CAD for perspective compared to what we see in the real world? I don't think so.

Considering video game perspective is already mentioned on the wiki, what did you expect him to invoke?

Quote
The same effect is found on a 3D video game which assumes a flat surface. When you increase your altitude you can see farther because you are so much higher than everything else. Your computer's resolution is better able to see something below you than off on the horizon where the pixels are linearly squished.
https://wiki.tfes.org/Viewing_Distance (https://wiki.tfes.org/Viewing_Distance)
Title: Re: Why crepuscular rays aren't proof for the position of the Sun.
Post by: ChrisTP on May 01, 2019, 05:59:50 PM
False equivalency, Tom. Using CAD for perspective compared to what we see in the real world? I don't think so.

Considering video game perspective is already mentioned on the wiki, what did you expect him to invoke?

Quote
The same effect is found on a 3D video game which assumes a flat surface. When you increase your altitude you can see farther because you are so much higher than everything else. Your computer's resolution is better able to see something below you than off on the horizon where the pixels are linearly squished.
https://wiki.tfes.org/Viewing_Distance (https://wiki.tfes.org/Viewing_Distance)
Star Citizen or No Mans Sky both look pretty flat from the ground on planets though so not really sure why that entry is there.
Title: Re: Why crepuscular rays aren't proof for the position of the Sun.
Post by: AATW on May 21, 2019, 10:07:04 AM
Thork may be correct. The further the straight lines originate from you, the more parallel they should appear to each other.

If lines are parallel then they're parallel. How far they originate from is irrelevant. Although in this case it is the distance they come from - a distant sun - which makes them so close to being parallel that we can treat them as parallel.

But the key error in your post is
the more parallel they should appear to each other.

The way things appear and the way they really are may be different.
The rays from the sun are (effectively) parallel
Train tracks are parallel.
But how they appear depends on your perspective.

If you look straight down at train tracks then you will see them parallel which is the reality. If you look at an angle then you will see them appear to converge as in my picture. The angle they converge at depends on the angle you're looking at them. That is perspective.
I can't explain it any better than that video above but this is another example of you just not understanding perspective. You use it to explain sunset (which it can't) but then misunderstand it when it comes to explaining crepuscular rays (which it can, as that video shows).
Title: Re: Why crepuscular rays aren't proof for the position of the Sun.
Post by: spherical on May 22, 2019, 05:48:51 PM
The further the straight lines originate from you, the more parallel they should appear to each other.

I wonder the middle and high school grades made by this man.

I can only answer with:
"The taller the tree that falls on a forest on the other side of the world, louder is the silence you hear here".
Title: Re: Why crepuscular rays aren't proof for the position of the Sun.
Post by: juner on May 22, 2019, 05:50:16 PM
The further the straight lines originate from you, the more parallel they should appear to each other.

I wonder the middle and high school grades made by this man.

I can only answer with:
"The taller the tree that falls on a forest on the other side of the world, louder is the silence you hear here".

Stick to the arguments and lay off the insults. Warned. FYI, you are on 3 warnings now.
Title: Re: Why crepuscular rays aren't proof for the position of the Sun.
Post by: spherical on May 23, 2019, 05:55:27 PM
The further the straight lines originate from you, the more parallel they should appear to each other.

Sorry, that is not a true statement.

Photons are projected from the Sun in all directions, each form a straight line. The ones projected at 30° from each other will not appear parallel, even being the Sun very far away.  I am stating here the "observer view aperture", not distance.

I can have a small 0.2" LED projecting photons at 2cm of distance, entering a micron slit between two separated sets of two blades and obtaining extremely parallel photons. This is a very common optical lab setup for filtering narrow parallel frequency bands, in some chromatography experiments.
   
The "parallel rays" appearance depends greatly on the observer view aperture, distance from the source is a secondary variable and can even be discarded.
Title: Re: Why crepuscular rays aren't proof for the position of the Sun.
Post by: ICanScienceThat on May 23, 2019, 08:06:13 PM
Thork may be correct. The further the straight lines originate from you, the more parallel they should appear to each other. Go to https://www.tinkercad.com and zoom out from the standard workplane.

Tom, are we to take this to mean that you support straight-line paths of light from the Sun?
Title: Re: Why crepuscular rays aren't proof for the position of the Sun.
Post by: Macarios on May 23, 2019, 08:08:04 PM
Ok, here are crepuscular rays.
If the body of that white duck is 1.5 ft (45 cm) long, how far is the Sun? :)


(https://steemitimages.com/DQmcDB2EgC2sqPVm4bZKgAy5ammwKBgf69UXye3DTZVSnHj/crepuscular%20rays%205.jpg)
Title: Re: Why crepuscular rays aren't proof for the position of the Sun.
Post by: Auditor on May 24, 2019, 10:04:59 AM
Baby Thork, the original post picture of the rays could not be used to verify the distance of the sun whether it is 93,000,000 miles or 3000 miles (however far it is in the flat Earth model) the way those ray converge would put the sun just above the clouds where planes would run into it.

The post with the sun behind the tree would put the sun like 5 feet on the other side of the tree.