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Why is the sky blue?

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Re: Why is the sky blue?

#161

Post by int_19h »

reactordev wrote: post #152
daedrdev wrote: post #141

Earlier quoted context omitted.

Some animals have more cone types than humans, especially various birds, so would probably see a violet sky. We don't have this because common ancestor for all mammals lost all cones but one, perhaps due to being nocturnal, and a second was re-evolved as mammals became more dominant (after dinosaur extension). A third cone was evolved in primates due to a gene duplication that gave us our green cone https://www.scien…

maybe in 100M years we'll get a 4th cone or rod. Probably from nuclear mutation...

There's some evidence that tetrachromacy already exists in a few humans. If so we have the gene already. But why would it spread?

Re: Why is the sky blue?

#162

Post by thaumasiotes »

kazinator wrote: post #50

It's also not just why the setting or rising sun is red, but why it's yellow when high in the sky. The sun doesn't look yellow when viewed from outside the atmospheric veil.

The article has a section on "why are clouds white?", but it doesn't really address the reason I thought that question should be covered.

It just says that clouds act like a collection of randomly-oriented prisms, such that whenever light of any wavelength comes into the cloud, it is dispersed from the cloud evenly in all directions.

This would explain why a cloud was white if even white light was coming into the cloud. But the rest of the article establishes that the light coming into the cloud is predominantly blue and purple. Why isn't that also true of the light leaving the cloud?

Re: Why is the sky blue?

#163

Post by jaggederest »

reactordev wrote: post #152
daedrdev wrote: post #141

Earlier quoted context omitted.

Some animals have more cone types than humans, especially various birds, so would probably see a violet sky. We don't have this because common ancestor for all mammals lost all cones but one, perhaps due to being nocturnal, and a second was re-evolved as mammals became more dominant (after dinosaur extension). A third cone was evolved in primates due to a gene duplication that gave us our green cone https://www.scien…

maybe in 100M years we'll get a 4th cone or rod. Probably from nuclear mutation...

We already have mutations, generally in women, for tetrachromaticism, who usually have male relatives with severe or moderate color blindness, in which the X chromosome encodes a different green cone. So they end up seeing red, strange-green, green, and blue, where strange-green is somewhere closer to red than green.

Only a few on record but they tend to have absolutely insane color matching and color perception. One of note worked in the fashion industry and could match fabrics perfectly even in varying lighting (e.g. working under fluorescent but able to match colors that would stay matched in halogen/stage lighting)

Re: Why is the sky blue?

#164

Post by kazinator »

thaumasiotes wrote: post #162
kazinator wrote: post #50

It's also not just why the setting or rising sun is red, but why it's yellow when high in the sky. The sun doesn't look yellow when viewed from outside the atmospheric veil.

The article has a section on "why are clouds white?", but it doesn't really address the reason I thought that question should be covered. It just says that clouds act like a collection of randomly-oriented prisms, such that whenever light of any wavelength comes into the cloud, it is dispersed from the cloud evenly in all directions. This would explain why a cloud was white if even white light was coming into the clo…

Well, no; what's coming into the cloud is sunlight, filtered through the atmosphere. It scatters that light and so it has that color. The same like a heap of powdered salt in the palm of your hand, held up to the sun.

Clouds illuminated by the setting sun aren't white.

Re: Why is the sky blue?

#165

Post by munificent »

suzzer99 wrote: post #62
munificent wrote: post #41

Really 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.

I'm familiar with "steamer clams", but not "clam steamers".

In "shrimp fried rice", "shrimp" is a noun adjunct [1], which is when you use a noun as an adjective.

The charming ambiguity comes from it being unclear whether "shrimp" is an adjunct noun modifying "fried rice" ("shrimp fried-rice") or modifying the past participle verb "fried" ("shrimp-fried rice").

[1] https://en.wikipedia.org/wiki/Noun_adjunct

[2] https://en.wikipedia.org/wiki/Headline#Headlinese

Re: Why is the sky blue?

#166

Post by reactordev »

jaggederest wrote: post #163
reactordev wrote: post #152

Earlier quoted context omitted.

maybe in 100M years we'll get a 4th cone or rod. Probably from nuclear mutation...

We already have mutations, generally in women, for tetrachromaticism, who usually have male relatives with severe or moderate color blindness, in which the X chromosome encodes a different green cone. So they end up seeing red, strange-green, green, and blue, where strange-green is somewhere closer to red than green. Only a few on record but they tend to have absolutely insane color matching and color perception. One…

I have that already ;) it actually looks like muddy puke green than green. However, green stop lights look more “white” than green.

Some reds look like brown. I hate reds. I’m not sure about the Pantone-like color matching but I definitely see different colors than most people. To the point where my flight license is restricted.

Dichromatic but not trichromatic.

Re: Why is the sky blue?

#167

Post by reactordev »

AlotOfReading wrote: post #159
reactordev wrote: post #153

Earlier quoted context omitted.

this is fascinating because I'm red/green color deficient yet I have no problem seeing most reds or greens. I feel there's a "spectrum" of color that we all see and each of us is slightly different. My shade of green may not be your shade of green. Yet, when I point out my shade of green - it matches your shade of green because of our eyes. Even though we may be perceiving entirely different colors.

Most colorblind people aren't dichromats, they're so-called anomalous trichromats. Basically, the genes coding opsins in your eyes have a number of functional sites that tune the spectral sensitivity. Those sites are tuned as far apart as they can be in color-normal humans. Anomalous trichromats usually have a genetic error that causes their opsins' sensitivity curves to overlap more, which manifests as reduced color…

This occurs in other animals as well.

Re: Why is the sky blue?

#168

Post by reactordev »

goatlover wrote: post #158
reactordev wrote: post #99

Earlier quoted context omitted.

The real question is, is the sky blue for everyone? Some creatures can see ultraviolet. Some lack color at all…

How would Lieutenant Geordi La Forge from ST Next Generations see the sky with his visor?

You know that scene with the Nexus ribbon? Probably a huge version of that. But it depends on what timeframe we’re talking. Visor Geordi or Eye Optics Geordi?

Re: Why is the sky blue?

#169

Post by lamontcg »

jstummbillig wrote: post #74
staplung wrote: post #18

In 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…

I am positively excited about the upcoming first generation of humans who will have all their questions answered, correctly and in the way they can best understand, and as often and many of them as they want – and what that is going to enable.

Sometime around 1992, I wrote a college essay on how the Internet was going to wipe out ignorance and enable true democracy...
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