Anyone keen to photograph some candles, for scientific experiment?

[christop]

I'm angry because everyone has condescending attitude, even though I might very well be older and more educated in relevant subjects than most of you. So now I'm starting to act like an arrogant bum-hole too.

You might be older than most of use, and you might even be more "educated", but you have demonstrated over and over that you in fact do not have a good understanding of the relevant subjects as those with whom you are arguing. There's nothing wrong with being ignorant. It is wrong to refuse to admit to your own ignorance while being arrogant about it.

 

[christop]

Let's work with a single sensel here.

Imagine that a star covers 1% of the area of that sensel due to its distance. The brightness of that sensel will be 1% of the brightness of a single star.

Now imagine that you have 10 stars inside the area of the sensel, none of them occluding another star. The brightness of the sensel is now 10% of the brightness of a star.

Next imagine that you have 100 stars inside the same area such that no star occludes another. Now the entire sensel area is covered by stars, and "all lines of sight ends at some star". The brightness of the sensel is now 100% of the brightness of a star.

Of course, in reality you cannot have 100 stars arranged like this, but you could have some stars at 10 times the distance, each contributing 0.01% of the brightness of a star, or some stars at half the distance, each contributing 4% of the brightness of a star to the sensel. Remember, we also have infinite stars, so there could be no visible gap between stars.

However the stars are arranged, if every line of sight "ends at some star", you would have a sensel value equivalent to the brightness of one star.

 

[amolitor]

Missed the part where I said "In a continuous space/continuous time universe, Zeno's paradox is still flawed" didn't you?

I don't know, sorry if I did. I'm angry because everyone has condescending attitude, even though I might very well be older and more educated in relevant subjects than most of you. So now I'm starting to act like an arrogant bum-hole too.

Apology accepted, of course!

Assuming that you are older and better educated than others on the internet is always a risky proposition. I am about 99% sure that I am better educated in relevant subject matter than you are, for instance, but there's still that 1%. Also, I'm pretty old.

I'm surprised that you're not challenging my remarks on universes in which the sky IS white, or universes in which there are infinitely many stars simultaneously visible.

 

[tris_d]

Now you can't get that if you pack a bunch of stars very densely in the visual plane they seem very bright, despite it being an EXTREMELY well known ASTRONOMICAL FACT.

Again, can you point to any link which can confirm that EXTREMELY well known ASTRONOMICAL FACT you are talking about?


Stars do no lay on the same plane. You keep forgetting distribution of stars is 3-dimensional.

 

[tris_d]

There is no contradiction between what I am saying and what Wikipedia says. Please read what I have written more carefully.

You either agree that inverse square law makes distant stars appear less bright, or not. I take it you agree. And I agree too.

There can be an infinite number of stars, but it doesn't matter if some are blocked. There only have to be enough to fill the sensel. This is what Olbers' Paradox is all about. We have explained why they appear to be grey dots, though they aren't really grey dots.

Of course they are not actually gray dots, they appear to be from where we look at it. It is up to you now to explain why do you think they would add up to appear as uniformly bright sky.

Please give us some sign that you have begun to understand the physics of this, because so far you have shown no real understanding.

Could you state your version of Olbers' Paradox?

There is no my version of Olbers' Paradox, I am saying the premise of the paradox is wrong and thus conclusion is wrong.

Because so far you have shown no real understanding, please give us some sign that you have begun to understand the logic fallacy of your conclusion the night sky would appear uniformly bright by explaining why do you imagine dim stars would add up to appear as bright stars.

 

[christop]

Here's another thought experiment I just thought of.

Say you were taking a picture of one of those traffic lights that is made up of a bunch of LED's. If you have a high-resolution camera, you would be able to resolve each individual LED that makes up the light. If you have a low-resolution camera (like a digital camera from the 90's or one of those cheap key-chain cameras), you cannot resolve each individual LED. In fact, multiple LED's will crowd into a single pixel in your low-res camera. The overall brightness of the traffic light in each camera would be the same (when using the same exposure settings), would it not? Or would you argue that the low-res camera would produce a dimmer image of the traffic light simply because the LED's cannot be individually resolved, no matter how many LED's you put in the space of a single pixel?

Each individual LED would appear to be dim in the low-res camera image (because they are smaller than a pixel), but since there are many LED's in the same apparent area, the brightnesses of all the LED's add up.

 

[tris_d]

Let's work with a single sensel here.

Imagine that a star covers 1% of the area of that sensel due to its distance. The brightness of that sensel will be 1% of the brightness of a single star.

Now imagine that you have 10 stars inside the area of the sensel, none of them occluding another star. The brightness of the sensel is now 10% of the brightness of a star.

Next imagine that you have 100 stars inside the same area such that no star occludes another. Now the entire sensel area is covered by stars, and "all lines of sight ends at some star". The brightness of the sensel is now 100% of the brightness of a star.

That's exactly what is wrong with the original calculation. It ignores image resolution and sums all the intensity into only one pixel. If your eyes had 1x1 resolution you would indeed see nothing but "bright night sky".

 

[christop]

That's exactly what is wrong with the original calculation. It ignores image resolution and sums all the intensity into only one pixel. If your eyes had 1x1 resolution you would indeed see nothing but "bright night sky".

So now you're saying that image resolution affects brightness? Fascinating!

 

[pgriz]

Tris_d, what is your motivation for pursuing this discussion, both on this forum and on the other ones? And why are you so doggedly persistent when it appears your question has been answered?

 

[amolitor]

That's exactly what is wrong with the original calculation. It ignores image resolution and sums all the intensity into only one pixel. If your eyes had 1x1 resolution you would indeed see nothing but "bright night sky".

Huh? It would see the average brightness of the night sky, which is pretty darn close to black.

Are now claiming that Olber's paradox is resolved by "proper" consideration of sensor resolution?

 

[tris_d]

I'm surprised that you're not challenging my remarks on universes in which the sky IS white, or universes in which there are infinitely many stars simultaneously visible.

There is a difference between night sky being UNIFORMLY bright and just bright. Owls see the night sky is quite bright, but not uniformly bright. Olbers' paradox concludes the night sky would be uniformly bright, given its original premise and the way it's treated, and that's what I am trying to prove is wrong.

Is the night sky on this photo bright or not? Take that image with longer exposure, or adjust the contrast, or use more sensitive film or... well, you know better, but the point is the brightness is in the eye of the beholder. So I'm not talking about whether the night sky is bright or not, that's relative, I'm saying original treatment of Olbers' paradox wrongly concluded the night sky would be UNIFORMLY bright. But if some stars are less bright than others, due to inverse square law as Wikipedia says, then I say it is inverse square law that makes the night sky appear just the way we see it, that is NOT UNIFORMLY or EQUALLY bright at every point you look at it.

 

[tris_d]

That's exactly what is wrong with the original calculation. It ignores image resolution and sums all the intensity into only one pixel. If your eyes had 1x1 resolution you would indeed see nothing but "bright night sky".

So now you're saying that image resolution affects brightness? Fascinating!

That's what you said too. In your example you added stars in the field of view and accordingly the brightness of the single pixel increased. But if you had sufficient resolution each star would project onto its own spatial location and the intensity would not get summed up but each dot would have its own brightness. Yes?

Many gray dots dispersed over some surface area is not the same thing as many gray dots summed at one pixel, is it?

 

[christop]

That's exactly what is wrong with the original calculation. It ignores image resolution and sums all the intensity into only one pixel. If your eyes had 1x1 resolution you would indeed see nothing but "bright night sky".

So now you're saying that image resolution affects brightness? Fascinating!

That's what you said too. In your example you added stars in the field of view and accordingly the brightness of the single pixel increased. But if you had sufficient resolution each star would project onto its own spatial location and the intensity would not get summed up but each dot would have its own brightness. Yes?

Many gray dots dispersed over some surface area is not the same thing as many gray dots summed at one pixel, is it?

Ok... read (or re-read) my thought experiment about taking pictures of an LED traffic light which pretty much summed up the issue of different resolutions.

 

[tris_d]

That's exactly what is wrong with the original calculation. It ignores image resolution and sums all the intensity into only one pixel. If your eyes had 1x1 resolution you would indeed see nothing but "bright night sky".

Huh? It would see the average brightness of the night sky, which is pretty darn close to black.

Are now claiming that Olber's paradox is resolved by "proper" consideration of sensor resolution?

I said that at the very beginning. Now you tell me, if you photograph 10 street lights at night with image resolution of 1000x1000 and then once more with image resolution 1x1, would 1x1 image be brighter than 1000x1000 image? Can image with 1x1 resolution have any other brightness than UNIFORM? That's why original treatment of Olbers's paradox gets the result indicating uniform brightness, because by ignoring image resolution they sum up all the intensity into only one pixel and of course they will get uniform brightness. Ok?

 

[tris_d]

Ok... read (or re-read) my thought experiment about taking pictures of an LED traffic light which pretty much summed up the issue of different resolutions.

You re-read what I said. Can image with resolution of only one pixel give you any other brightness than uniform?