over years heard various ideas on this:
Is the sky of Athas orange/brown, or is it dark olive green?
Dark olive green may give orangy brown at sunest by the way
and which moon is larger, and which is green? and is the other cratered or what? 
Ral is the closer (apparently larger) green moon, covered with seas and mountainous islands. Guthay is the more distant (apparently smaller) golden-yellow one, with scarlet jungles and marshes beneath a thick layer of mist.
IIRC the wonderful colors of the steps of Kalak's ziggurat correspond to the colors of the sky during the day; one or two colors for daytime, the rest at sunrise and sunset.
You mean to tell me Kalak wasn't trying to build Athas' biggest ever Gay Pride parade float?
so that could only happen by "magic"
been testing stuff out
I seem to recall several places in the novels mentioning the sky as being an olive green. I suspect this is because of the reflection from the vast semi-arid grasslands of the Kreen-empire. Sort of like how ours is blue because of the reflections from the ocean.
No
Our atmosphere is blue, because Oxygen/nitrogen scatter blue light (and soem green)
so light from the sun, of many colours, comes down
but, blue light gets bounced around in the air much more than red or green (though some green does too iirc)
so the air seems blue
and, when the light goes very LONG distances through the atmosphere, like as the sun rises/sets so it's on horizon and goes through many miles of air, it scatters out all the blue leaving it red/orange
if you see a Lunar Eclipse, it loosk red, because the light of the Sun, on far side, gets boucned through the edge of the atmosphere, so it's red, onto the Moon. So, ecolpise moons are that eerie orange red
I seem to recall several places in the novels mentioning the sky as being an olive green. I suspect this is because of the reflection from the vast semi-arid grasslands of the Kreen-empire. Sort of like how ours is blue because of the reflections from the ocean.
This always seems to come up every couple years, but this is not true. Our sky is not blue because of reflection off the oceans (also keep in mind that water is colorless). The sky is blue because short wavelength blue light "scatters" more easily in the atmosphere than longer wavelength light, so more of it reaches our eyes.
Note: it also has nothing to do with the composition of atmospheric gases. The sky on Mars and the sky on Jupiter would both be blue on a clear day (that would be upper atmosphere for Jupiter, obviously), despite neither being oxygen-nitrogen. Mars' sky appears more pink/brown in various images because of color-range issues with the cameras used, and the large amount of dust in the atmosphere.
But as to why the sky is olive on Athas? Magic works. The land has spirits in it. People fly giant insects. Why can't the sky be olive instead of blue? Or the sun appear black? It's a fantasy world.
Ral is the closer (apparently larger) green moon, covered with seas and mountainous islands. Guthay is the more distant (apparently smaller) golden-yellow one, with scarlet jungles and marshes beneath a thick layer of mist.
Is that new information from 4E, or is that from a prior source? (I forget)
I seem to recall several places in the novels mentioning the sky as being an olive green. I suspect this is because of the reflection from the vast semi-arid grasslands of the Kreen-empire. Sort of like how ours is blue because of the reflections from the ocean.
This always seems to come up every couple years, but this is not true. Our sky is not blue because of reflection off the oceans (also keep in mind that water is colorless). The sky is blue because short wavelength blue light "scatters" more easily in the atmosphere than longer wavelength light, so more of it reaches our eyes.
Note: it also has nothing to do with the composition of atmospheric gases. The sky on Mars and the sky on Jupiter would both be blue on a clear day (that would be upper atmosphere for Jupiter, obviously), despite neither being oxygen-nitrogen. Mars' sky appears more pink/brown in various images because of color-range issues with the cameras used, and the large amount of dust in the atmosphere.
But as to why the sky is olive on Athas? Magic works. The land has spirits in it. People fly giant insects. Why can't the sky be olive instead of blue? Or the sun appear black? It's a fantasy world.
actually it DOES
it's the size of the molecules nitrogen and oygen form that have a particular resonance with Blue wavelengthsthings like ammonia would have a different effect due to larger size.
Burntscrispy
but the artwork shows mostly an orange sky....which do you go by, then? ;)
Burntscrispy
but the artwork shows mostly an orange sky....which do you go by, then? ;)
The novels, seeing as how most of them were written by the guy who wrote the setting.
Though in looking back, the art of both the original and revised boxed sets depicts olive skies.
I seem to recall several places in the novels mentioning the sky as being an olive green. I suspect this is because of the reflection from the vast semi-arid grasslands of the Kreen-empire. Sort of like how ours is blue because of the reflections from the ocean.
This always seems to come up every couple years, but this is not true. Our sky is not blue because of reflection off the oceans (also keep in mind that water is colorless). The sky is blue because short wavelength blue light "scatters" more easily in the atmosphere than longer wavelength light, so more of it reaches our eyes.
Note: it also has nothing to do with the composition of atmospheric gases. The sky on Mars and the sky on Jupiter would both be blue on a clear day (that would be upper atmosphere for Jupiter, obviously), despite neither being oxygen-nitrogen. Mars' sky appears more pink/brown in various images because of color-range issues with the cameras used, and the large amount of dust in the atmosphere.
But as to why the sky is olive on Athas? Magic works. The land has spirits in it. People fly giant insects. Why can't the sky be olive instead of blue? Or the sun appear black? It's a fantasy world.
actually it DOES
things like ammonia would have a different effect due to larger size.
Burntscrispy
but the artwork shows mostly an orange sky....which do you go by, then? ;)
Actually, the size of the molecules in the atmosphere matter much less on than the angle at which the light is refracted through the atmosphere. Which is why you have a different color sky at sunset.
And the molecules don't have a "resonance" with longer blue wavelengths, just at the angle the light is coming in during most of the day, the molecules to scatter shorter wavelength (such as red) light. There are several different reasons that you could have a planet whose atmosphere consisted mainly of oxygen to have a red sky.
The sunlit sky appears blue because air scatters short-wavelength light more than longer wavelengths. Since blue light is at the short wavelength end of the visible spectrum, it is more strongly scattered in the atmosphere than long wavelength red light. The result is that the human eye perceives blue when looking toward parts of the sky other than the sun.[1]
The blue of the sky is equivalent to a monochromatic blue of wavelength 474–476 nm mixed with white light, i.e., an unsaturated blue light.[2]
Near sunrise and sunset, most of the light we see comes in nearly tangent to the Earth's surface, so that the light's path through the atmosphere is so long that much of the blue and even green light is scattered out, leaving the sun rays and the clouds it illuminates red. Therefore, when looking at the sunset and sunrise, you will see the color red more than any of the other colors.
I wrote that Wiki article to deliberately mislead everyone.
Is that new information from 4E, or is that from a prior source? (I forget)
4e DSCS page 17.
The dust (sand/silt) in Athas' atmosphere would have a similar effect to that observed on Mars, where the sky looks a sort of 'butterscotch' colour most of the time. Mars' sky would be blue on a really clear day (which basically never happens naturally).
Depending on the specific dust particles in Athas' atmosphere and which wavelengths they absorb (the magnetite dust in Mars' atmosphere absorbs mostly blue light, for example), it ought to be possible to get an 'olive-tinged' sky. However, the 4th edition artwork implies the sky is blue at least some of the time.
The only way I can think of to get the sun to look anything like the 'dark with glowing cracks' appearance it has in most of the art would be to have it somehow producing light of different wavelengths from different areas of its photosphere and then have some substance in the Athasian atmosphere that selectively absorbs light matching the wavelengths emitted from some of those areas. Like looking at our sun through a filter to make its surface details visible. I wonder if an actual polarising effect would work?
lol yeah but a little logic helps deal with things ;)
personally I view the Dark Sun as "warped"
it is not at all normal I don't go with the official history, either so to me it causes the mutations etc as well as other things. I take it that the mind flayers tried to put out the Sun long ago, screwed up, gods barely stopped it going nova, got whacked in the resulting FUBAR, and you have THAT thing as a result.
Mudflats:
A broken tower for the DSCS encounter in the back of the book:
So this time around: please raise your hand if you have or are working towards a degree in astronomy or meterology and/or have been published in a peer-reviewed journal. Anyone? Ok then.
actually it DOES
I'm not certain what exactly you mean by "resonance", but the molecules you mention do not have "a particular resonance" with blue light.
The reason for the blue color is simply that shorter wavelength light scatters better, regardless of the size of the molecule in question. (This may prompt you to ask, "Why isn't the sky violet, then?"--violet being shorter than blue--the answer is, in part, because our eyes aren't built to see violet as well as they see blue, so we see blue.)
Point is, shorter wavelength light--towards the violet/blue end of the spectrum--is scattered more easily and to a greater degree than the longer wavelengths, which pass through the atmosphere mostly undisturbed and thus never reach our eyes to the same degree as the scattered blue light.
The other big reason the sky's coloration has nothing to do with the size or type of the gas molecules involved is because the difference in size of the molecules isn't enough to affect the amount of short-wavelength scattering--the molecules in question are all smaller than any wavelength of light!
Therefore no matter what the gas in question is, the violet/blue scattering remains dominant while the rest passes through mostly. As such, an ammonia or other type of atmosphere would be just as blue as our atmosphere, because the relative size of the molecules in question has no actual effect.
The reason you sometimes see a yellow or greenish sky during or before storms (or the reason Mars' atmosphere appears yellowish sometimes), is because of particulates in the atmosphere (ie: aerosols) that, unlike the gaseous components, are similarly sized to or much larger than the various wavelengths of light, and thus produce more scattering of longer wavelength light.
Note that blue light is still scattered by these particulates to a greater degree than other wavelengths, but the added color values of the higher frequency wavelengths also being scattered changes the ratio of wavelengths reaching your eye (the ratio of wavelengths reaching your eye is also why the horizon appears whitish during the day).
(Tangentially: interestingly enough, on a clear day Mars' atmosphere, because it is thinner, is actually a purer blue than our atmosphere, though less bright. This is because as pressure decreases, color quality increases while brightness decreases. And vice versa. And note: even at something like 10x our current atmospheric pressure, the sky would still appear blue(ish), and brighter.)
The dust (sand/silt) in Athas' atmosphere would have a similar effect to that observed on Mars, where the sky looks a sort of 'butterscotch' colour most of the time. Mars' sky would be blue on a really clear day (which basically never happens naturally).
Again, untrue. Many of the pictures returned by landers and rovers show a blue sky, with the sky being more bluish around the sun due to the intensity of the scattering effect, and more pink or orange towards the horizon due to the influence of atmospheric dust.
In those cases where pictures do not display a blue sky, the picture is often being presented in false color, or with information from the infrared photo layer added to it, which changes blue colorations into pink during the combining process (the cameras do not take true color images, they take four different "black and white" images each filtered to a specific wavelength--red, blue, green, yellow, infrared, ultraviolet, and others--which are then combined together in various ways to produce color images).
Depending on the specific dust particles in Athas' atmosphere and which wavelengths they absorb...
Unlike the color of your shirt or that fire hydrant over there, absorbtion has nothing to do with the color of the sky! (Does that blow your mind or what?) Actually, I'm lying a bit: color absorbtion by ozone does have a tiny bit to do with the color of the sky, but so little that even if we didn't have an ozone layer, the sky would be the same color (rather, the difference would be nearly imperceptible).
If anyone feels the need to double-check any of this (or learn more), I would point them to Bohren & Fraser's publications on the topic color and atmosphere, and (of course) Rayleigh's work on the same topic.
Again, untrue. Many of the pictures returned by landers and rovers show a blue sky, with the sky being more bluish around the sun due to the intensity of the scattering effect, and more pink or orange towards the horizon due to the influence of atmospheric dust.
I'll take NASA's word over yours. No offense.
Unlike the color of your shirt or that fire hydrant over there, absorbtion has nothing to do with the color of the sky! (Does that blow your mind or what?) Actually, I'm lying a bit: color absorbtion by ozone does have a tiny bit to do with the color of the sky, but so little that even if we didn't have an ozone layer, the sky would be the same color (rather, the difference would be nearly imperceptible).
Again, see the NASA link above. Selective absorbtion by dust in the Martian atmosphere changes the colour of the Martian sky from the blue colour of a 'clear' sky's normal Rayleigh effect to the butterscotch colour seen by the landers.
Generating accurate true-color images from Mars' surface is surprisingly complicated.[7] To give but one aspect to consider, there is the Purkinje effect: the human eye's response to color depends on the level of ambient light—red objects appear to darken faster than blue objects as the level of illumination goes down. There is much variation in the color of the sky as reproduced in published images, since many of those images have used filters to maximize their scientific value, and are not trying to show true color. For many years, the sky on Mars was thought to be more pinkish than it is now believed to be.
It is now known that during the Martian day, the sky is a scarlet, or bright orangeish-red color. Around sunset and sunrise, sky is rose in colour, but in the vicinity of the setting Sun it is blue.[8] This is the opposite of the situation on Earth. At times, the sky takes on a purplish color, due to the scattering of light by very small water ice particles in clouds.[9] Twilight lasts a long time after the Sun has set and before it rises, because of the dust high in Mars' atmosphere.
On Mars, Rayleigh scattering is usually a very weak effect; the red color of the sky is caused by the presence of Iron (III) oxide in the airborne dust particles.
I'll take NASA's word over yours. No offense.
None taken. Though "I'm" not saying it, as I pointed out, that's all taken from work done by two guys with PhDs.
Also I didn't say anything different than NASA (note my mention of the way particulates change the color?). Thanks for the link though...hrm, I am wondering how old that FAQ page is? It only references the landers, doesn't mention the rovers, and up until the last couple years, there were still regular arguments about the Martian sky color and whether the images NASA was producing were true color or calibrated correctly...ah, it's from 2004. Mars science and understanding of what we're seeing in the images has changed quite a bit since then.
I'm trying to find you a link on NASA's current position on martian sky color, which has quietly changed since the press started questioning the reasons for false color butterscotch and red photos in 2004 (the original answer was "it is difficult to exactly calibrate the images"). But you'll find that the "red oxide particles give the air a red look" is one of those things NASA has backed off on, and are now going with "tan" or "yellow" or "gray", even though the sky is often blue.
photojournal.jpl.nasa.gov/catalog/PIA079...
marsrover.nasa.gov/gallery/video/movies/...
science.ksc.nasa.gov/mars/science/clouds...
www.ominous-valve.com/martian_sky.html
apod.nasa.gov/apod/ap061017.html
Again, see the NASA link above. Selective absorbtion by dust in the Martian atmosphere changes the colour of the Martian sky from the blue colour of a 'clear' sky's normal Rayleigh effect to the butterscotch colour seen by the landers.
I apologize for being unclear: at that point I was talking about absorption by gas molecules, and Earth's sky color, rather than Mars'.
Interestingly things I've read from meterologists indicate particulate absorbtion is NOT generally a factor in the science invovling why a sky is any particular color (and that the belief that absorption is a factor is an old general misconception). They may have just been speaking about general Earth conditions, however, and the influence of ice crystals -- I'd have to double check.