Some of the demonstrations are not working correctly, at least on my machine (Windows + MS Edge). Any demo with a "reference image" is not correctly updating the reference.
Why is the sky blue?
61–70 of 279 posts
Re: Why is the sky blue?
#62Really cool article! Tangential: > “Scattering” is the scientific term of art for molecules deflecting photons. Linguistically, it’s used somewhat inconsistently. You’ll hear both “blue light scatters more” (the subject is the light) and “atmospheric molecules scatter blue light more” (the subject is the molecule). In any case, they means the same thing There's nothing ambiguous or inconsistent about this. In English…
Now do clam steamers and shrimp fried rice.
Re: Why is the sky blue?
#63Earlier quoted context omitted.
Not just butterflies, birds too! But what selection pressure drove the evolution of these structural colors? Presumably signaling, the opposite of muted, camouflaging colors. Also, as many might know, blue eyes are the result of a lack of pigment (eumelanin). The iris is translucent, but Rayleigh scattering preferentially backscatters blue photons. Green eyes have some pigment, making them a mix of brown and blue.
Also the blood veins that you see as bluish through the skin are blue for the same reason, due to light scattered in their walls.
I thought they are green.
Re: Why is the sky blue?
#64In The Cuckoo's Egg Cliff Stoll recounts an episode from the oral defense of his astrophysics PhD thesis. A bunch of people ask questions but one prof holds back until... """ “I’ve got just one question, Cliff,” he says, carving his way through the Eberhard-Faber. “Why is the sky blue?” My mind is absolutely, profoundly blank. I have no idea. I look out the window at the sky with the primitive, uncomprehending wonder…
"Could you be more specific" is a great question to find out more what the person knows and how they thing. You give an answer that, just due to the nature of knowledge and the limitation of language, has some black boxes. And "could you be more specific" is basically asking to go through the black boxes. Its like asking how does Java work or something like that? You can go from "The JVM interprets java byte code" to…
i used something like this in unstructured technical interviews all the time.
"you type a phrase into google search, you press enter, get some results. tell me, in technical detail, what happened in that chain of actions"
the diversity of replies is fascinating, you learn a lot about a "full stack" candidate this way.
Feynman's classic "Why?" chain: https://www.youtube.com/watch?v=36GT2zI8lVA
Re: Why is the sky blue?
#65Really cool article! Tangential: > “Scattering” is the scientific term of art for molecules deflecting photons. Linguistically, it’s used somewhat inconsistently. You’ll hear both “blue light scatters more” (the subject is the light) and “atmospheric molecules scatter blue light more” (the subject is the molecule). In any case, they means the same thing There's nothing ambiguous or inconsistent about this. In English…
I have always wondered about this. The verb for the first person is to 'see'. To a third person you 'show'
For the first person there is 'listen' (or 'hear'). Does English not have a corresponding word for the third person ?
What about Germanaic or Nordic languages ? Do they have a third person analogue of 'listen' ?
Re: Why is the sky blue?
#66I have a related but deeper question about sun and colors: Sunlight in space is considered white. When it reaches earth surface, it's considered a warmer color. Why human eyes that never (during evolution) saw sunlight without the atmosphere, consider it true white, and not colder color?
I think at this point you need to consider how the human eye see color. It's not like each wavelength gets picked up and then communicated perfectly.
(I'm going to skip over some basic stuff, and use some generalities)
Each Cone in the eye responds to a range of frequencies. This means that things that unless it's on the extreme low, or high, end of the frequencies that the human eye can discern you are going to have two, or all three, Cone types responding. The strength of those responses is what your brain uses to interpret the color that you see.
The real problem is that out in space there is no attenuation of sunlight, it's bright. Super crazy bright. It basically overloads all of your Cones, and Rods, all at once, there is no way for your brain to find a signal of "oh there's more higher wavelengths here so interpret bluer than normal" because all of the signals got maxed out. If you max out all of the signals, you get white. It doesn't matter that in absolute terms there's more blue, the lower and mid frequencies are also maxed out.
Re: Why is the sky blue?
#67In The Cuckoo's Egg Cliff Stoll recounts an episode from the oral defense of his astrophysics PhD thesis. A bunch of people ask questions but one prof holds back until... """ “I’ve got just one question, Cliff,” he says, carving his way through the Eberhard-Faber. “Why is the sky blue?” My mind is absolutely, profoundly blank. I have no idea. I look out the window at the sky with the primitive, uncomprehending wonder…
"Could you be more specific" is a great question to find out more what the person knows and how they thing. You give an answer that, just due to the nature of knowledge and the limitation of language, has some black boxes. And "could you be more specific" is basically asking to go through the black boxes. Its like asking how does Java work or something like that? You can go from "The JVM interprets java byte code" to…
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Re: Why is the sky blue?
#68Air is mostly nitrogen. Nitrogen gas is blue. There.
Oxygen is blue actually. That only contributes to the sky blueness a little tho.
Re: Why is the sky blue?
#69I have a related but deeper question about sun and colors: Sunlight in space is considered white. When it reaches earth surface, it's considered a warmer color. Why human eyes that never (during evolution) saw sunlight without the atmosphere, consider it true white, and not colder color?
Is it considered a warmer color on the surface?
Mid-day sun in a clear sky is very white, in the 5k-6k color temperature range. It's hard to get a sense of how white it is because of how bright it is. In fact, the color temperature on the surface can be even higher than in outer-space!
Compare this to a "warm" light bulb, which is around 2.5K. Sunrise/sunset is also around that range.
Perhaps the "warm color" sun mindset comes from the only times that people can look directly at it. That is to say, around sunrise or sunset.
Re: Why is the sky blue?
#70Really cool article! Tangential: > “Scattering” is the scientific term of art for molecules deflecting photons. Linguistically, it’s used somewhat inconsistently. You’ll hear both “blue light scatters more” (the subject is the light) and “atmospheric molecules scatter blue light more” (the subject is the molecule). In any case, they means the same thing There's nothing ambiguous or inconsistent about this. In English…
I have always wondered about this. The verb for the first person is to 'see'. To a third person you 'show' For the first person there is 'listen' (or 'hear'). Does English not have a corresponding word for the third person ? What about Germanaic or Nordic languages ? Do they have a third person analogue of 'listen' ?
"tell"?