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George
2004-Jan-22, 11:46 PM
The Sun is yellow (or maybe it is white). Some say it is "peachy pink".

Certainly the land is red or is it redish-brown.

Rayleigh Scattering should produce a fair amount blue.

Mie Scattering due to dust should make it more white.

The dust color itself might dominate the sky color even when it is "calm".

Etc...

What do you think?

JPL will be color correcting at a later date once time is available and then we should know. I think.

Antice
2004-Jan-23, 12:19 AM
I voted bluish white... i think the sky would be very pale due to the low amount of atmosphere... and there could be large difuse dust colored clouds if there is a storm nearby.

just one of my uneducated wild gueesses i gues. :wink:

Moosehead
2004-Jan-23, 10:32 AM
The Sun is yellow (or maybe it is white). Some say it is "peachy pink".

I thought I'd read somewhere that Sol is actually slightly green in colour and it was our eyes that make over bright things yellow.

George
2004-Jan-23, 01:42 PM
The Sun is yellow (or maybe it is white). Some say it is "peachy pink".

I thought I'd read somewhere that Sol is actually slightly green in colour and it was our eyes that make over bright things yellow.

The irradiance curve of sunlight is greatest in the blue and green portion of the spectrum. However, both these colors get reduced in intensity as it travels through our atmosphere to about the same level as the other colors. This makes it look white to Earthlings until it is close to the horizon where more things happen such as refraction.

The BA has an informative chapter about the color of the Sun in his book.

As a result of that chapter, this thread is dedicated to that topic....>>> Sun' Color (http://www.badastronomy.com/phpBB/viewtopic.php?t=8123) <<<

It may be the Sun (if we're in space) would actually look blueish or maybe it is "peachy pink" (computer version of what we should see).

Maybe the color of the Martian sky will reveal something which will help us see the truth in this matter.

George
2004-Jan-24, 02:01 AM
I thought I'd read somewhere that Sol is actually slightly green in colour and it was our eyes that make over bright things yellow.

I'll bet you read it in Astronomy Magazine about 8 or 9 months ago. I read it also and emailed the author, but no response.

Glom
2004-Jan-24, 01:16 PM
I believe Rayleigh Scattering that produces a blue sky is due to nitrogen, of which there is far less on Mars. The atmosphere is mostly carbon dioxide.

Ikyoto
2004-Jan-24, 01:44 PM
I'm not voting cause you don't have the two other choices:

- plaid
- not a clue

So NYAH! [-(

(if anyone wants me, i'll be in the corner waiting for the coffee to creep up my neck and wash all the fog out of my brain)

Gmann
2004-Jan-24, 01:58 PM
I didn't vote for any of them since I have seen pictures both from Mars, and from Hubble that indicate there is a slight bluish tint, but red/pink is more common due to dust particles. My thinking tells me that if there has been a recent dust storm, the sky will probably be red for the most part. I had been taught that rayliegh scattering resulting in bluish colors was because of water vapor. Given that evidence of some water has been found on Mars, it would not to too much of a leap to suspect that there may be a small amount suspended in the atmosphere.

George
2004-Jan-24, 03:43 PM
I believe Rayleigh Scattering that produces a blue sky is due to nitrogen, of which there is far less on Mars. The atmosphere is mostly carbon dioxide.

I would guess that nitrogen does more scattering in our atmosphere due to its greater presence only.

One site claimed oxygen is the reason our sky is blue as "it [oxygen] is blue". Is there a special resonance at 400 or so nm for oxygen? I don't know. I do recall seeing blue light radiated by water which was excited by the nuclear reactor it surrounded. That was truly a cool sight.

According to the equations dealing with Rayleigh Scattering, wavelength (4th power issue) and particle size (2nd power issue, I think) are the more dominant variables. Refraction index, molecular density, etc. are others.

I found one site that shows CO2 and Oxygen and Nitrogen as being about 2.8 angstroms in "molecule critical diam.". It was from a sieve supplier.

If this is true, the CO2 may not be a problem for blue scattering.


I didn't vote for any of them since I have seen pictures both from Mars, and from Hubble that indicate there is a slight bluish tint, but red/pink is more common due to dust particles.

Can you show me any? I went to a Hubble picture gallery but did not see an atompshere view. I am not sure I would completely trust the color but it probably would be close.


My thinking tells me that if there has been a recent dust storm, the sky will probably be red for the most part. I had been taught that rayliegh scattering resulting in bluish colors was because of water vapor. Given that evidence of some water has been found on Mars, it would not to too much of a leap to suspect that there may be a small amount suspended in the atmosphere.

You may be partially correct about water vapor. However, water is noted for its ability to absorb red and longer light. Blue color from water is a result. I am unclear how water really works with scattering. Put a little milk in an aquarium and you get good Rayeigh Scattering of blue out the sides. Why do you need the milk for that?

There was quite a Martian storm last fall but I think things are pretty calm. I do not know if this is true, howerver.

Glom
2004-Jan-24, 04:17 PM
I do recall seeing blue light radiated by water which was excited by the nuclear reactor it surrounded.

That's slightly different. It's Cerenkov radiation. Electrons travel faster than the speed of light in water and you get the sonic boom effect.

§rv
2004-Jan-24, 05:07 PM
There are some pics on NASA's http://antwrp.gsfc.nasa.gov/apod/astropix.html picture of the day site that show a bit of the sky...

George
2004-Jan-24, 05:34 PM
I do recall seeing blue light radiated by water which was excited by the nuclear reactor it surrounded.

That's slightly different. It's Cerenkov radiation. Electrons travel faster than the speed of light in water and you get the sonic boom effect.

Yep, I thought it was high energy beta particles, but I did not know of them exceeding the speed of light (after adjusting for the refractive index). Thanks. The amazement of seeing water glow is now even more amazing. 8)

2004-Jan-24, 05:58 PM
http://www.badastronomy.com/phpBB/viewtopic.php?p=197710#197710

George
2004-Jan-24, 06:26 PM
Hub... #-o

Rudimentry english or Texican or dBase III+ is my level. :)

Gmann
2004-Jan-26, 01:48 PM
To George
There was a hubble picture of mars that was linked by "enterprise" (Hoaxland) that showed a very slight bluish tint to part of the atmosphere. I also recall a pic very similar on another astronomy site showing the same thing, but I cant find that one either. There may be something on Hoaxlands archives, since he likes to keep links that support his claims (and drops ones that later turn out to be frauds) so far I haven't stumbled into it, but if I do I will post it for your consideration.

Phobos
2004-Jan-26, 03:41 PM
Vairable;

http://nssdc.gsfc.nasa.gov/planetary/thumbnail/marspath_83621f.gif

http://nssdc.gsfc.nasa.gov/planetary/thumbnail/marspath_83616f.gif

http://nssdc.gsfc.nasa.gov/planetary/thumbnail/marspath_clouds_s39.gif

http://nssdc.gsfc.nasa.gov/planetary/thumbnail/marspath_ss24_1.gif

All images were taken from pathfinder and can be found here;
http://nssdc.gsfc.nasa.gov/planetary/marspath_images.html

Phobos

Glom
2004-Jan-26, 03:42 PM
It all depends of the filters, conditions and response of the detector.

George
2004-Jan-26, 04:35 PM
Thanks Phobos! I was hoping someone would have such images.

So, are you voting for each of the categories? :lol: (Sorry I left out green as a sky color) :)

Hopefully, the proper rendering of these filtered images will be done soon.

Does anyone know what current weather coniditions? If the imaging is done when the sky has been calm, we might have our answer. At least we know it's not raining. :)