Dalo

"edit: like I said, spectrometers do not tell you anything about the atmosphere, only about the elements themselves. They cannot therefore be used as an argument. "

I think you should be the one to explain how a prism is the same thing as a spectrometer.

no prisms, only, among other things, spectrometers.

do you have a reference, or a link? That would be a fitting end to this conversation. Is that you said when you were a kid? "who? Me?!"

@Strange You must be very unhappy with your life if you need to bash people all the time. You should take a more scientific attitude towards opponents in a debate, instead of attacking them personally all the time. It does not do you honor. edit: like I said, spectrometers do not tell you anything about the atmosphere, only about the elements themselves. They cannot therefore be used as an argument.

this is overkill. I will be happy to answer any reasonable question instead of repeating what I have said. My experiment is the same as Bragg's, the only difference is in the light source used.

Let us leave it at that for until the empirical proof can be found on Mars. There is no need to continue this discussion any longer. There are many things in the theory (of the dual nature) of light, that I find disturbing. I will continue expressing my doubts and learn from the reactions how to refine the questions I have. I might end up as strong a believer in the theory as you all are, or not.

and we are back to the unanswered questions of a couple days ago. That is what I said on Tuesday: You will understand that spectrograph's would not really be conclusive. We do not need to go to Mars for that. It is already undeniably proven that different elements show different absorption patterns. What I would find interesting is to see an experiment comparable to that originally done by Newton whereby a ray of sunshine is let through a small opening and then through a prism. That would be the definite proof that the atmosphere and/or the prism play no role in the composition of the spectrum. It would be a little bit like Armstrong's experiment where he dropped a feather and a heavy object on the moon, and they fell at the same speed. That was in fact the first empirical proof of the Galilean and Newtonian concept of gravity outside of earth conditions. So, your "prediction" is certainly understandable. What goes for Earth should be valid on Mars also. Still, conviction is not proof.

please don't. I promise I won't tell anybody.

or there is nothing to be illuminated. Let us take all potential observers away, and put a light sensor among the 'scatterers". We can say by looking at the sensor afterwards whether it has received light or not. That does not depend on our vision organ and its idiosyncrasies. We could also have the sensor indicate the wavelength of light received, and then imagine that all particles in the air are such sensors. All the sensors, I think, would tell us the same story, that they have received light, and that it was blue. This way we will have confirmed that the sky is blue without once having appealed to scattering or vision. Am I missing something here?

so is the interstellar space, or vacuum.

This certainly makes sense. How does it relate to a thread title being shown in bold, and then in regular font once you have visited the thread, and no new content has been posted? To then become "bold" with new content?

This is a circular argument. I am asking why we need scattering if light is already everywhere and you answer that otherwise the sky would be black. But that this exactly the issue. If light is already everywhere then how could the sky be black?

how is this clear?

that the sky is blue is a fact. Now we have to explain scattering of light when light is already everywhere.

Here is what Goldstein (polarized light, 2011) says about the color of the sky: "Light from the sun interacts with the molecules of our atmosphere such that the light that we see coming from the dome of air over our heads is scattered sunlight (or moonlight)." But then I wonder: The Sun is many times larger than Earth, and its light encompasses about half of the planet at once. Why do we need scattering to explain the color of the sky? Why would it be relevant since light would be everywhere at the same time?

I suppose it is a company secret, since no official has reacted.

I apologize for my tone. I have not changed anything to Bragg's experiment, and the description I gave is I think accurate.

Besides, I had exactly the same results as in the link. What is the point of your question? for those who can't watch the video: youtube.com/watch?v=eWbOXAEZyQA&t=615s

so, if I come back 10 times to the thread, it will become +10 even if nothing has been changed?

How does it work? In some forums the number get raised by 1 anytime you visit a thread,even it is your own! Which I find rather strange. That is luckily not the case here. If I visit one of my threads the number of views remains unchanged, and I like it this way. But when happens when I visit somebody else's thread? Does the number get raised only the first time, or only if there has been a new post?

In my own experiment I could see the beam in the water (and not reflected on the mirror) however I stood around the water tank. Not only from the long sides, but also from above and from any side, and however I bent my head. Since there was no mirror reflection, I shouldn't have been able to see it, should I? I think that is probably the most important point of all the discussion: what does "being preferentially absorbed" mean? When you consider a Polaroid sheet with vertical chains or arrays, do all the vertical light rays that reach the sheet get absorbed, or only those which find the arrays on their way? Let us not forget that the gaps are generally smaller than the width of the crystals, according to Land. So, what happens to those vertical rays that face gaps directly. Should they also be stopped, like the other vertical rays? If so, how and why? And if they are not, then only, approximately, half of the vertical rays will be absorbed, which should still make them visible.

You are right of course. And that is at the same time one of the questions I still have. Polarization is an effect created by the filter. When em waves collide with an array the light is absorbed. But then, there are also gaps, in fact, there is a gap between each two arrays. How come light does not simply get through?

I suppose you are right, and I must formulate my idea more carefully. We are talking about the particles present in air or water.

I realize that. That is what I find so puzzling. edit: in the water tank we must of course speak of water (and other) molecules.