Should the sky be purple?

[lyndonashmore]

Papageno wrote,
I was pointing out that mainstream ideas have already been critically examined, just as it happens in the ATM
so why is the sky blue and not violet?
Suerly mainstream says it should be violet? Or at least banded.
Just a thought. Manstream ideas are not as 'critically examined' as we are led to believe.
Cheers,
Lyndon

[Moose]

so why is the sky blue and not violet?

Short answer: because water vapor scatters light at blue wavelengths.

Suerly mainstream says it should be violet? Or at least banded.

No.

Why on Earth would you expect mainstream to bandy something that clearly isn't true? (And don't call me "suerly". Or surely.)

[lyndonashmore]

Short answer: because water vapor scatters light at blue wavelengths.



No.

Why on Earth would you expect mainstream to bandy something that clearly isn't true? (And don't call me "suerly". Or surely.)

Come off it Moose,
Mainstream says the sky is blue because of scatter, It says that blue light is scattered most, red the least,
Ergo. sky is blue sunsets are red.
BUT Violet has a shorter wavelength than blue so why is that not scattered the most?
ergo, mainstream says sky should be violet and not blue.
Cheers,
lyndon

[Moose]

BUT Violet has a shorter wavelength than blue so why is that not scattered the most?

Well, you've pretty much proven the point of several posters in this thread about how ATMers often hijack threads with irrelevancies. Take this to ATM where it belongs, will you?

Phil quotes Twain who had a witty saying about the dangers in extrapolation beyond the bounds of observation. (It's true within, as well.)

Mark Twain said it best: "In the space of one hundred and seventy-six years the Lower Mississippi has shortened itself two hundred and forty-two miles. Therefore ... in the Old Oolitic Silurian Period the Lower Mississippi River was upward of one million three hundred thousand miles long... seven hundred and forty-two years from now the Lower Mississippi will be only a mile and three-quarters long... There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact."

ergo, mainstream says sky should be violet and not blue.
Cheers,
lyndon

Could you please show me your reference that suggests the mainstream thinks the sky should be violet? It's not like you don't know the drill by now, Ashmore. Support your assertions or retract them.

Yes, wavelength matters in how much scattering occurs, but it has nothing to do with why the sky looks blue at noon and red (at the horizon) at night. Ever consider that the amount the blue is scattered might just be affected by how much air the light has to pass through when it's skimming the horizon vs an area where it's noon?

Ashmore, the BA covers this in detail in his book in one of the first few chapters.

If you insist upon continuing this line of (un)reasoning, please take it to ATM. I'll check in at some point if you really insist upon hashing it out.

[Celestial Mechanic]

[Snip!] Mainstream says the sky is blue because of scatter, It says that blue light is scattered most, red the least,
Ergo. sky is blue sunsets are red.
BUT Violet has a shorter wavelength than blue so why is that not scattered the most?
ergo, mainstream says sky should be violet and not blue.
You can't scatter that which is not there. The atmosphere becomes opaque to wavelengths at and beyond violet (although a few bands of ultraviolet do get through). There are far more blue photons available for scattering than violet.

[lyndonashmore]

Well, you've pretty much proven the point of several posters in this thread about how ATMers often hijack threads with irrelevancies. Take this to ATM where it belongs, will you?

Phil quotes Twain who had a witty saying about the dangers in extrapolation beyond the bounds of observation. (It's true within, as well.)

[/I]
Shock horror,
What is the mainstream reason for the sky being blue?
then we will say why it is wrong
it should be violet according to mainstream. It is not, ergo we need an ATM section.
Cheers,
Lyndon



Could you please show me your reference that suggests the mainstream thinks the sky should be violet? It's not like you don't know the drill by now, Ashmore. Support your assertions or retract them.

Yes, wavelength matters in how much scattering occurs, but it has nothing to do with why the sky looks blue at noon and red (at the horizon) at night. Ever consider that the amount the blue is scattered might just be affected by how much air the light has to pass through when it's skimming the horizon vs an area where it's noon?

Ashmore, the BA covers this in detail in his book in one of the first few chapters.

If you insist upon continuing this line of (un)reasoning, please take it to ATM. I'll check in at some point if you really insist upon hashing it out.
What is the mainstream reason for the sky being blue?
Extend that and one reasons that it should be violet.
Ergo, mainstream is wrong many times. That is why we need an ATM section.
Cheers,
Lyndon

[lyndonashmore]

You can't scatter that which is not there. The atmosphere becomes opaque to wavelengths at and beyond violet (although a few bands of ultraviolet do get through). There are far more blue photons available for scattering than violet.
Can't be right.
Sky blue is an exact colour. If it is to do with different wavelengths scattered at different angles then why is the colour of the sky the same no matter which angle you look at it?
This is why we need ATM.
Cheers,
Lyndon

[Celestial Mechanic]

Can't be right. Sky blue is an exact colour. If it is to do with different wavelengths scattered at different angles then why is the colour of the sky the same no matter which angle you look at it?Have you looked at the sky lately? It's not the same precise shade of blue all over. It is lighter and more "washed out" near the horizon, it is also whiter near the Sun due to Mie scattering.
This is why we need ATM.
This is why we have libraries. Get thee to one and read about Rayleigh scattering, Mie scattering, and the optics of the atmosphere in general. And let's return to the topic, "Why there is an ATM section at all?", shall we? :)

[lyndonashmore]

Have you looked at the sky lately? It's not the same precise shade of blue all over. It is lighter and more "washed out" near the horizon, it is also whiter near the Sun due to Mie scattering.

This is why we have libraries. Get thee to one and read about Rayleigh scattering, Mie scattering, and the optics of the atmosphere in general. And let's return to the topic, "Why there is an ATM section at all?", shall we? :)
rayleigh scatter (http://en.wikipedia.org/wiki/Rayleigh_scattering) is angle dependent. So why is the sky blue at every angle? Violet should be scattered more, ergo, according to Rayleigh the sky should be at least violet. Or different colours depending upon which angle one looks. Mainstream is wrong that is why we need an ATM section.
Cheers,
Lyndon

[01101001]

Blue sky: take it to ATM. Please.

[lyndonashmore]

Blue sky: take it to ATM. Please.

Why?
Blue sky is mainstream.
But according to mainstream it should be violet,
Cheers,
Lyndon

[korjik]

Come off it Moose,
Mainstream says the sky is blue because of scatter, It says that blue light is scattered most, red the least,
Ergo. sky is blue sunsets are red.
BUT Violet has a shorter wavelength than blue so why is that not scattered the most?
ergo, mainstream says sky should be violet and not blue.
Cheers,
lyndon

Because there is less violet than blue in sunlight. That should be obvious.

[lyndonashmore]

Because there is less violet than blue in sunlight. That should be obvious.
So are you saying the sky should be mauve according to mainstream?
Cheers,
Lyndon

[korjik]

apparently it is not obvious. Please take it to ATM instead of jacking this thread.

[ToSeek]

Sky color discussion moved from the "Why is there an ATM section?" thread in "About BAUT" to its own ATM thread.

EDIT: The responsibility for the title of this thread is mine, despite the appearance that it was started by Mr. Ashmore.

[korjik]

Since it has been moved:

There are two factors that determine the color of the sky. First is the intensity per unit frequency in the incoming light, and second the amount of scattering per unit frequency. Both ot these taken together give you a curve with a peak in the blue (for daytime overhead sky). The incident intensity cuts off the violet and the scattering cuts off the redder colors, giving you blue.

[lyndonashmore]

Hi all ,
Don't want to post here anymore because this is the ATM section and my views on this are mainstream. Why the sky is blue is a case of repeat a lie often enough and people believe it.
Cheers,
Lyndon

[Roy Batty]

Not sure why you keep insisting that there is a lie going around for why the sky is blue. I think you are confusing mainstream science with what you perceive the average man in the street might think. That is not really what ATM is about. Why the sky is blue is clearly mainstream science as others have explained. Your point for the ATM was therefore invalid.

[Nereid]

There is a certain Australian tree frog (Rana caerulea) which looks green, but it isn't (it's blue and yellow).

Colour is a phenomenon of the brain, not of light.

So, the sky looks 'blue' because the brains of Homo sap. individuals, with normal eyes and brains, interpret the combination of firings from the cone cells in the eyes as 'blue'. Those cone firings are a complicated function of the intensity and wavelength of the light incident on the cones, and that itself a complicated function of the intensity and wavelength of the light incident on the eyeballs.

Surely the relevant question is "what is the SED of 'blue sky' light?" Followed by "how does that SED compare with the expected SED, given the incident sunlight, atmospheric absorption, and various kinds of scattering?"

[Eta C]

Quit playing games Ashmore. You've had your question answered more than once.

a) water vapor scatters higher frequencies more.
b) it, and air, also absorb higher frequencies more. This is why sunsets are red. It's also why the sky is not violet.

You just refuse to realize it or, more likely IMO, just enjoy playing the fool. This performance is an exact repeat of your misunderstandings of statistics from a couple of months ago. Your act of "I'm taking my ball and going home" is noted. You can add it to the list of reasons why you'll never be taken seriously.

[lyndonashmore]

Hi all,
I am presently arguing the case with the powers that be. Since I did not start this thread, it was posted without my permission under my name.
I am appalled that a thread can be started under my name without my permission.
Disgusted,
Lyndon

[Nereid]

So, thread closed (at least temporarily).