5
votes
2answers
142 views

Why must an integrating sphere be a sphere?

Why must an integrating sphere be a sphere? Why can't it be an integrating cube? What is the difference? Could I use a cube to measure total illuminance like an integrating sphere does?
11
votes
1answer
136 views

Why do some sunsets have a green flash?

Some sunsets exhibit a phenomenon called "green flash," where there is a quick flash of green light right as the sun is setting. I have seen this myself several times, and sort of understand it. I am ...
0
votes
1answer
63 views

Why isn't steam/cloud blue like liquid and solid water?

Most of us here are aware as I think that pure water has a natural quest to absorb visible red colour wavelength slightly due do which liquid water and sometimes even ice appears to have a blue colour ...
4
votes
1answer
47 views

Sunrise/Sunset on a planet with an A-Class or B-Class Star

I'm a sci-fi writer, and I have a question regarding a hypothetical planet that orbits an A-class or B-class Star. Assuming Rayleigh Scattering occurs roughly the same way on this planet as it does ...
4
votes
2answers
88 views

Is ocean color affected by Rayleigh Scattering?

We know that sky color is due primarily to Rayleigh scattering. Is Rayleigh scattering the dominant effect for ocean color too?
2
votes
1answer
66 views

What is the intensity of this light?

I am struggling with a derivation that calculates the cross sections for Mie scattering and since the incident light is considered to be a x-polarized plane wave I thought that we would have $$I_i = ...
1
vote
1answer
1k views

Star visibility in outer space even during the day?

Say I am in a space shuttle and have reached outer space. Is it true that during the day it possible to see stars outside through the window? Do I have to wait until night? Why is this the case?
0
votes
0answers
47 views

Color of sky scattering by sky dust [duplicate]

Why does we see sky like blue in maximum time? We know violet has less wavelength, so we should see sky like violet. My assumption is that, violet is not primary color and not sufficient in the ...
4
votes
2answers
198 views

Attenuation mass-thickness for sunset light

We are able to look directly at the sun near sunset and sunrise, which clearly demonstrates the fact that our atmosphere attenuates visible light. Let's imagine it follows the typical attenuation ...
0
votes
0answers
122 views

Are EM waves scattered the most when the wavelength and the obstacle have a similar size?

I heard that when the wavelength and obstacle are similar in size, the scattering is the greatest. Is this true?
2
votes
2answers
336 views

How does scattering work?

Why is the sky blue? I was always taught in high school that light with wavelength $\lambda$ acts like a little particle that wiggles up and down through space (in proportion to its magnitude). I was ...
2
votes
3answers
866 views

Why is the colour of sunlight yellow?

I was going through the preliminary papers of other schools and found a question that I did not know. It was "Why sunlight appears yellow?". Can anyone answer it?
6
votes
2answers
327 views

Blue-shifting as opposed to violet-shifting

A recent XKCD comic implies that the sky is blue as opposed to violet due to human physiology, and that animals more sensitive to shorter wavelengths will perceive the Earth's sky as the shortest ...
0
votes
2answers
222 views

Why is the sky blue? [duplicate]

Possible Duplicate: Why does the sky change color? Basically what the title says. What mechanisms are significant and how do they contribute to make the sky blue. Also when the sky is not ...
0
votes
1answer
105 views

Light in the absence of colloids?

If Earth had no colloids (Don't take LIFE into account) or any kind of scattering medium (like atmosphere) that promote to Tyndall effect, how would we able to receive the sun's rays? In the other ...
2
votes
2answers
3k views

If blue light has a higher energy than red light, why does it scatter more?

As $E=hf=\frac{hc}{\lambda}$, blue light - with a smaller wavelength - should have a higher energy. However, it is the case that blue light scatters the most. Why is it that higher energy rays scatter ...
15
votes
3answers
46k views

Why does the moon sometimes appear giant and a orange red color near the horizon?

I've read various ideas about why the moon looks larger on the horizon. The most reasonable one in my opinion is that it is due to how our brain calculates (perceives) distance, with objects high ...
22
votes
4answers
1k views

Why does the sky change color?

Why the sky is blue during the day, red during sunrise/set and black during the night?