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#1
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More Mars color controversies.
I was watching those news conferences and that image did *not* have a blue
sky like the one shown on this web page! It may be because of the video projector used and the cameras which took that image in the auditorium, or that image may have been altered by those who put it up on the web site. The Martian sky is not that blue! -- David W. Knisely Assuming ONLY "normal" gases in the atmosphere, the sun being high in the martian sky, virtually NO water vapor, and (the big IF here) no supsended dust particles....mars should be as blue or "bluer" than any blue sky seen here on earth....of course deciding when blue fades to black is a whole other issue..... take care Blll |
#2
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Blll posted:
Assuming ONLY "normal" gases in the atmosphere, the sun being high in the martian sky, virtually NO water vapor, and (the big IF here) no supsended dust particles....mars should be as blue or "bluer" than any blue sky seen here on earth....of course deciding when blue fades to black is a whole other issue..... The dominant coloring mechanism of the Martian atmosphere is the dust component. The only time blues are often seen is either with high-altitude clouds or near sunset. This has been demonstrated by properly calibrated images taken by Viking and Pathfinder. Other than this, the sky on Mars isn't blue. -- David W. Knisely Prairie Astronomy Club: http://www.prairieastronomyclub.org Hyde Memorial Observatory: http://www.hydeobservatory.info/ ********************************************** * Attend the 11th Annual NEBRASKA STAR PARTY * * July 18-23, 2004, Merritt Reservoir * * http://www.NebraskaStarParty.org * ********************************************** |
#3
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Note I said NO or little dust...
And there are times when the dust settles out....though most of the time there is plenty of it suspended.... I guess I was trying to point out that mars sky COULD be a very nice blue....but most of the time it sure isnt... take care Blll |
#4
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David Knisely wrote in message .. .
Blll posted: Assuming ONLY "normal" gases in the atmosphere, the sun being high in the martian sky, virtually NO water vapor, and (the big IF here) no supsended dust particles....mars should be as blue or "bluer" than any blue sky seen here on earth....of course deciding when blue fades to black is a whole other issue..... The dominant coloring mechanism of the Martian atmosphere is the dust component. The only time blues are often seen is either with high-altitude clouds or near sunset. This has been demonstrated by properly calibrated images taken by Viking and Pathfinder. Other than this, the sky on Mars isn't blue. The component of Mars skylight resulting from the scattering by atmospheric gasses is blue, only quite faint because of the thinness of the Martian atmosphere. Forward scattering by dust causes the pink color and completely dominates the blue. It is interesting that at sunset the sky turns blue just before the sun sets. Clif Ashcraft |
#5
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In message , Clif
writes David Knisely wrote in message . .. Blll posted: Assuming ONLY "normal" gases in the atmosphere, the sun being high in the martian sky, virtually NO water vapor, and (the big IF here) no supsended dust particles....mars should be as blue or "bluer" than any blue sky seen here on earth....of course deciding when blue fades to black is a whole other issue..... The dominant coloring mechanism of the Martian atmosphere is the dust component. The only time blues are often seen is either with high-altitude clouds or near sunset. This has been demonstrated by properly calibrated images taken by Viking and Pathfinder. Other than this, the sky on Mars isn't blue. The component of Mars skylight resulting from the scattering by atmospheric gasses is blue, only quite faint because of the thinness of the Martian atmosphere. Forward scattering by dust causes the pink color and completely dominates the blue. It is interesting that at sunset the sky turns blue just before the sun sets. Clif Ashcraft When I was a boy (don't ask :-) amateur astronomers and some professionals talked about a "violet layer" in the atmosphere, and "blue clearing" when the layer disappeared and the surface was visible in blue and violet light. Are those ideas still current, and could it be due to dust in the atmosphere settling out? -- Rabbit arithmetic - 1 plus 1 equals 10 Remove spam and invalid from address to reply. |
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Jonathan Silverlight wrote:
When I was a boy (don't ask :-) amateur astronomers and some professionals talked about a "violet layer" in the atmosphere, and "blue clearing" when the layer disappeared and the surface was visible in blue and violet light. Are those ideas still current, and could it be due to dust in the atmosphere settling out? The "blue clearing" is something of a mere contrast effect rather than any sort of "clearing". The classical albedo markings do not show up well at all in the blue and violet parts of the spectrum. As such, if the light areas surrounding them become brighter or lighter due to some dust activity, the darker areas will appear with a bit more contrast with respect to the lighter regions. The effect is most dramatic in the blue because these images normally show no markings and any slight increase in contrast will cause the markings to emerge. Similarly, the so-called "wave of darkening" is also a contrast effect in which the lighter regions are becoming lighter in color and brightness due to dust activity, which makes the dark areas seem to stand out more strongly. Clear skies to you. -- David W. Knisely Prairie Astronomy Club: http://www.prairieastronomyclub.org Hyde Memorial Observatory: http://www.hydeobservatory.info/ ********************************************** * Attend the 11th Annual NEBRASKA STAR PARTY * * July 18-23, 2004, Merritt Reservoir * * http://www.NebraskaStarParty.org * ********************************************** |
#7
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Mars color comes from iron oxide given off by its volcanoes when they
were active.It now lies on the ground,and is picked up by Mars dust storms,and dust devils. This gives the air its reddish hue. The Earth is a blue planet because our atmosphere,scatters the sun's high energy photons. At sun rise,and sun sets we see red because the dust in our air lets low energy photons through.and blocks out high energy photons. I have sun glasses on that are red. The glass lens only lets red photons through. I can't see Mars having a blue sky,but I could be wrong. Maybe the spirit will look straight up. Bert |
#8
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Well I found pictures I had stored away on the true color of Mars
surface. These pictures were radioed back and are close ups in true color by the pathfinder. The surface is a true red. The rocks are black,and have red dust on their tops. The horizon goes to a white sky. The picture is in great focus,and shows part of the lander,and it has some red markings to compare the red with. The next picture I have is so very great. It shows a Martian sun set. The sun is setting in back of hills(there very black) There is a very faint hint of blue near the sun,and the rest going up in the sky is light hazy red. Well Mars reflects back red light. It is literally a red planet. Red makes mammals mad,and that is why Mars is used as a simile.of war. Bert |
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