The Sky on Mars is Blue!

reply to post by cnm1976


It's only a possibility that what they have recently observed is liquid water. There is a very real chance that it's not. However, even if it is water, it would have to be brine, in order to keep it liquid in the cold temperatures at which the liquid flow has been observed. That's brine as in extremely salty water. I'm not aware of any plant life that could survive in such excessively salty conditions. In fact, the presence of salt water and of excessive amounts of carbon dioxide in the atmosphere suggest to me that plant life hasn't existed on Mars for quite some time, if it ever did. And that says a lot about the possibility of us getting plant life to grow there.

I would say that at certain times the sky appears "blue-ish," kind of like the blue you see on a hazy day on Earth. Compared to the salmony color of the ground, it kind of looks blue. Big deal. You still can't go there and live.

Originally posted by cnm1976
reply to post by CLPrime

 

Does this mean they could plant trees in the hope the grow? I know you need water but given they have found water near the suface of late this could be an option.

Differing values have been reported for the average temperature on Mars,[15] with a common value being −55 °C (−67 °F).[16] Surface temperatures have been estimated from the Viking Orbiter Infrared Thermal Mapper data; this gives extremes from a warmest of 27 °C (81 °F) to −143 °C (−225 °F) at the winter polar caps.[17] Actual temperature measurements from the Viking landers range from −17.2 °C (1.0 °F) to −107 °C (−161 °F). It has been reported that "On the basis of the nighttime air temperature data, every northern spring and early northern summer yet observed were identical to within the level of experimental error (to within ±1 K)" but that the "daytime data, however, suggest a somewhat different story, with temperatures varying from year-to-year by up to 6 K in this season.[18] This day-night discrepancy is unexpected and not understood". In southern spring and summer variance is dominated by dust storms, which increase the value of the night low temperature and decrease the daytime peak temperature,[19] resulting in a small (20C) decrease in average surface temperature, and a moderate (30C) increase in upper atmosphere temperature.[20]

mars climate

not unless you've got trees that can survive these temperature extremes and grow foliage in that to collect sunlight and carbon dioxide. it could probably be done with genetically altered trees, but stock trees shipped up from earth? not gonna happen.

edit to add: forgot to say, the trees have to be able to survive sandstorms of epic proportions as well.

Originally posted by AutOmatIc
Amazing! So did NASA alter previous photos to reflect the general assumption that the Martian sky was red, if so, for what reason?

No need for image alteration, I have posted several images taken by the rovers with a bluish sky.

As for this photo, I don't see the photos needed to make an approximate true colour image (they need photos from the L4, L5 and L6 filters), so they used photos from filters that do not correspond to red, green and blue, so the photos in this image are the ones farther away from the truth.

And if they altered previous photos...what else have they altered???

And if they didn't?

Mars sky will vary in color as here on Earth. If there is a big dust storm on Mars I would bet the sky would be beet red. Mars has a dynamic environment and over time we are fast realizing that it is really not that dissimilar from Earth.

An example of how things are.

This is an image made with the three images from the three filters for red, green and blue. Each image had its colours "stretched" to make it brighter. Photoshop does this with the "auto-levels", I think.
[atsimg]http://files.abovetopsecret.com/images/member/884fed737154.png[/atsimg]


This is the same image, made with with radiometrically corrected images. The images are corrected with the information provided by the camera about the environment, so it shows things as someone on Mars would see them (approximately).
[atsimg]http://files.abovetopsecret.com/images/member/a23a067f97e5.png[/atsimg]


This is the same image as above, but in this case I didn't apply the correction, so this image shows the same as the first but without the autolevels change. As you can see, it's darker and has less contrast than the first version, that's why they make them brighter.
[atsimg]http://files.abovetopsecret.com/images/member/bd14521752c3.png[/atsimg]

Do you know why Mars photos look orange? Because of the dust in the air, you can see the same effect on the following photo, from Sidney.
[atsimg]http://files.abovetopsecret.com/images/member/a6af550c1112.jpg[/atsimg]

Originally posted by CLPrime
reply to post by AutOmatIc

 

The Martian atmosphere is actually predominantly carbon dioxide, which means it's mostly colourless.

The natural gases in Earth's atmosphere are more or less colorless too (not counting smog), but it's primarily Rayleigh scattering that gives the Earth its blue sky due to the higher atmospheric density compared to Mars.

Originally posted by ArMaP
Do you know why Mars photos look orange? Because of the dust in the air, you can see the same effect on the following photo, from Sidney.
[atsimg]http://files.abovetopsecret.com/images/member/a6af550c1112.jpg[/atsimg]

Thanks for weighing in on this with your knowledgeable information, ArMaP! Nice work, as always!
I'm not sure exactly what I'm looking at in the Sydney photos. Is there a link to the source with a caption perhaps, to explain the photo on the right?

reply to post by AutOmatIc

Your source says nothing about the color of the Martian sky. Here's a source that talks a great deal about the color of the Martian sky, and what affects it. This would have been a much better source to use to discuss the color of the Martian sky:

What color is the Martian sky?

We know the color of the Martian daytime sky from properly color-balanced pictures taken by the Viking landers in 1976 and Mars Pathfinder in 1997. The first Viking lander images broadcast over TV in the 1970s showed a blue sky, later "corrected" to a pink sky. In addition to uncertainties in the initial image processing, the lander had several color patches to calibrate the cameras, which were partially covered with Martian dust thrown up during landing. However, further analysis of Viking lander data revealed a Martian sky that is generally butterscotch in color, except for the pink or red of sunset and sunrise. In 1997, the Mars Pathfinder confirmed this finding....

While Rayleigh scattering has a very small effect in the Martian atmosphere, at certain times and in certain places, clouds of extremely small dust particles give a blue cast to images taken from overhead. These are the so-called "blue hazes" observed in some cratered regions and parts of the Valles Marineris.

The color of the Martian sky, according to that rather informative source, is generally "butterscotch", but there are patches where it can appear somewhat bluish. The Rayleigh scattering that causes such a dramatic blue sky on Earth is much less pronounced on Mars because the Mars atmosphere is so thin; it's actually less than one one-hundredth of Earth's atmosphere at sea level.

Originally posted by Arbitrageur

Originally posted by CLPrime

The Martian atmosphere is actually predominantly carbon dioxide, which means it's mostly colourless.

The natural gases in Earth's atmosphere are more or less colorless too (not counting smog), but it's primarily Rayleigh scattering that gives the Earth its blue sky due to the higher atmospheric density compared to Mars.

I wonder how many people around here understand Rayleigh scattering.
It's easier to say Martian atmospheric carbon dioxide is colourless while Terrestrial atmospheric oxygen is pale blue. (In an unrelated topic,) it's also easier to say that light appears to slow through a medium due to slower absorption/re-emission rates of the electrons in that medium. Both are inaccurate, but the descriptions of Rayleigh scattering and phonon propagation may be over many people's heads.
Or maybe it's because, every once in a while, I get tired of trying to explaining scientific concepts in layman terms. Regardless, you're right...the blue colour of the sky here on Earth is due to Rayleigh scattering, which occurs more frequently at the bluer end of the spectrum. This scattering is much less frequent across the spectrum on Mars because the Martian atmosphere is much less dense.

Still, the answer to the issue brought up in this thread is that the Martian atmosphere appears the way it does due to a combination of surface colouration, airborne material, and photographic colour exaggeration.

Originally posted by Arbitrageur
I'm not sure exactly what I'm looking at in the Sydney photos. Is there a link to the source with a caption perhaps, to explain the photo on the right?

Sure, you can see it here.

This was during the dust storm that covered Sidney on September 23, 2009.

As you can see, it was worse than the dust storms on Mars.

reply to post by ArMaP

On Mars, because it is so very dry, there is more dust and finer dust than there is on Earth. It gets carried to very high altitudes (dust devils being a very good transport method, not to mention the occasional global dust storms). At those altitudes it can affect the color of the sky without affecting surface visibility (unlike the Sydney dust storm).

You can get all into Rayleigh scattering but our sky is blue because it is the shortest visible light wavelength, and the element oxygen also has a blue cast. There is more free oxygen in the earth's atmosphere and because oxygen likes to bond with other gases and metals most of the oxygen in the Martian atmosphere and of Venus is bound to other elements and loses its blue cast. The metal oxides on Mars is like rust and is colored like rust the rest (over 95%) is bound with CO2. Pure molecular oxygen is very hard to keep as oxygen likes to become part of chemical reactions. On Earth, the oceans and to a lesser degree plants, make sure that enough oxygen is produced for keeping the oxygen levels stable.

Let me add a shot of the blue earth atmosphere.