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Location: UFOUpDatesList.Com > 2007 > Jun > Jun 15

Re: Martian Colours - Shough

From: Martin Shough <parcellular.nul>
Date: Fri, 15 Jun 2007 17:15:27 +0100
Fwd Date: Fri, 15 Jun 2007 21:12:20 -0400
Subject: Re: Martian Colours - Shough


>From: Nick Balaskas <Nikolaos.nul>
>To: UFO UpDates - Toronto <ufoupdates.nul>
>Date: Thu, 14 Jun 2007 21:06:42 -0400 (Eastern Daylight Time)
>Subject: Re: Martian Colours [was: Mars Rover Finds 'Puddles'...]

>>From: Martin Shough <parcellular.nul>
>>To: <ufoupdates.nul>
>>Date: Thu, 14 Jun 2007 19:24:45 +0100
>>Subject: Re: Mars Rover Finds 'Puddles' On The Planet's Surface

><snip>

>I have seen pictures of Mars with whitish haze within deep
>craters and valleys and pictures of Martian rocks taken by the
>two Viking landers that are covered by a layer of white frost.
>Why were these clouds and layers of frost not pinkish in
>apprearance just like the pinkish looking white stripes of the
>U.S. flag? Were NASA's colour censors caught off guard this time
>or, more likely, are NASA's colour adjustments purely arbitrary
>and misleading?

I have seen pictures where frost appeared pinkish. Possibly this
is because of dust settling on it. Certainly there's a well-
known picture of polar layered ice which appears distinctly pink
for (we are told) just this reason. But there's also a lot of
variation in colour values and contrast in the thousands of
images out there, some of which are tonally skewed to bring out
different detail. Here are Viking images of frost and cloud
appearing white or blue white

http://www6.uniovi.es/solar/cap/mars/frost.htm
http://www6.uniovi.es/solar/cap/mars/noctis.htm

The frost image also shows a distinctly blue (if pale) sky. But
notice the very blue-heavy colour balance, making the terrain
appear strangely purple.

I think you're right that some of the colour representations are
misleading, and I don't find this very suprising, especially
given the lack of experience in the early Viking days. JPL's Tom
Mutch acknowledged that his "yes" to the question "Would Mars
really look like this?" could only be a very qualified "yes",
and the NASA narrative of how the whole Viking picture cock-up
occurred discloses by implication that they were not really
prepared either for the difficulty of the problem or for the
public controversy it aroused. Possibly the corrected "official"
flag colours are not perfectly "true" for Mars, and possibly
Levin's re-corrected "terrestrial" colours are not perfectly
true either. Possibly Levin's enthusiasm for an Earth-like Mars
got the better of him 30 years ago, just as it did recently when
he published shamelessly vivid false-colour images of
Mediterranean-blue "standing water" on Mars that turned out to
be dust.

>>What you seem to be alleging is that the sky of Mars seen by an
>>average human eye _should_ be what you call "a blue Earth-like
>>sky". But the pressure, gas composition and general cleanliness
>>of the Earth's atmosphere and the sun brightness are (surprise,
>>surpise!) 'just right' for producing a bright blue Earth-like
>>sky (Google a rather famous paper by Bohren and Fraser 1985),
>>whereas Mars is probably not.

>Probably not? If you, Bohren and Fraser are not sure, then just
>do this simple experiment. To replicate the lower air density or
>pressure of Mars, just simply recall what you have seen sitting
>in the window seat of a Boeing 747 that was flying higher than
>Mount Everest - a blue sky!

I think to find the equivalent air pressure you'd need to go a
mite higher. At 30,000 ft the pressure is still about 300 mbar.
To get down to just a few mbar, equivalent to Mars, you'd have
to keep going to well over three times the height of Everest.
You've never holidayed here. This is the regime of lonely
research balloons and rockets. Besides, even here I think it's
only the zenithal sky brightness that might approach being a
comparison to Mars, because of the multiple Rayleigh scattering
through the much greater depth of atmosphere at lower elevations
- even from negative elevations.

>Although the two most abundant gases in Earth's atmosphere are
>Nitrogen and Oxygen, the introduction of other gases such as
>water vapour and carbon dioxide, two key ingredient in Mars'
>atmosphere, would not make Earth's sky look red too.

Don't understand this at all.

>As for general cleanliness, there are dust storms on Earth and
>dust storms on Mars (from the many dust devils that are a common
>sight on Mars to planet-wide dust storms that last for weeks and
>reach altitudes higher than the tallest peaks obsuring the every
>surface feature) and this will make the skies on both planets
>look red - but not always.

Yes there's dust on Earth and it gets blown about, but Mars is
different in that it is covered in the fine powdery stuff and
there are, as you indicate, constant winds taking it aloft. The
uniform rust red colouration of the Mars dust also has an
effect. Spirit has observed dust devils at the rate of dozens
every day, as well as filming lateral wind gusts carrying blown
dust. Images of the typical dusty "smog" seen by Spirit at
different times and in different lights can be seen here:

http://tinyurl.com/2tpxga

No, Mars' atmosphere won't look like this in every shot, but it
will look like this a damn sight more often than on Earth, and
at least some reddish sky colouration seems to be the case more
often than not. Looking through the many Pathfinder and MER
images the skies look almost uniformly some shade of
butterscotch or nicotine, and note that this is so even when
white foreground details on the spacecraft appear as pure white.

>Finally, as for the lower sun brightness on Mars, just recall
>that the colour of the sky on Earth at midday is the same colour
>as the sky at dawn - blue! (even when the Sun is still below the
>horizon and Sun brightness is even much less than when the Sun
>is high above the Martian sky).

Earth's sky at dawn - or dusk - is indeed blue, towards the
zenith at least, if not near the horizon where Mie scattering
from particulates dominates over Rayleigh scattering and will
desaturate the blue to a milky haze or, very often, produce
those longer wavelengths much admired by photographers and
painters. This is not the point. There is no dispute that Mars'
atmosphere will experience some amount of Rayleigh scattering
and therefore show some blue in some cases. But you need to
establish that the Martian sky is _so_ blue, _so_ often, and
down to _so_ near the horizon, that the few Mars lander images
showing blue among the much greater number showing tan horizon
colours must be evidence of ongoing scientific incompetence or
systematic fraud.

>>>This morning commuters from the suburbs driving to work in
>>>Toronto will have noticed a brown haze low over the city. Like
>>>the Mars landers pictures, if a commuter were to snap a picture
>>>of the city skyline and send it to a friend who has never been
>>>to Toronto, he/she may also come to the erroneous conclusion
>>>that the colour of the sky over Toronto is brown! In fact, the
>>>sky above the brown haze all the way to the zenith was a
>>>bright clear blue colour.

>>So you acknowledge that even on a planet with your bright and
>>clear "blue Earth-like sky", photos could show a sepia-coloured
>>skyline caused by dust haze. How much _more_ likely is this
>>under a much darker Mars-like sky filled with suspended oxide
>>dust? The Viking sky colour therefore doesn't make your case
>>for a conspiracy of suppression, even if your guess about the
>>bright blue of the Martian zenith is correct.

>This brown haze seen over cities is a gas or photochemical smog
>that is created when Nitrogen and Oxygen gas molecules in our
>atmophere are combined together to form NOx gas molecules from
>the heat energy inside the internal combustion engines of cars.
>Since NOx quickly breaks down in sunlight to form Nitrogen and
>Oxygen gases again, brown haze is most evident during early
>morning rush hour and again at dusk when people are driving
>home from work.

>As for your Martian sky filled with suspended oxide dust (not
>the same as NOx which is a gas and not particulate matter),

I'd be embarrassed if you really thought I didn't realise
that...

>how could Mars' atmosphere which is supposed to be 1/100 times
>the pressure of Earth's keep all that dust suspended for very
>long?

There's such a tremendous amount of it, virtually the whole
planet is one vast desert of it, there's no great swathes of
vegetation and marshlands to bind it, Mars' gravity is low, it's
very fine and being lofted continually by winds and dust devils,
and there's nowhere for it to go, no oceans and river systems to
trap it, and no water precipitation to wash it out of the
atrmosphere in the first place. It collects on spacecraft and
degrades solar cell efficiency.

>>The Levins themselves (father and son) wrote a paper in 2003
>>called Solving The Color Callibration Problem which (by
>>definition), acknowledges that there is a problem and points
>>out that there is "no consensus" on what are the properly
>>callibrated colours of soil, rocks and sky on Mars, precisely

>>"great uncertainty in the illumination spectrum"

>>which means that

>>"whilst the reflectivity of the [callibration] charts is well
>>known, the spectrum of their illumination on Mars is not."

><snip>

>>Maybe soon someone will be able to go there and have a proper
>>look. Then they can paint the scene for us. We'll just have to
>>hope they have 'normal' colour vision.

>The weather station on the Phoenix Mars lander which will be
>launched towards the Red Planet this summer was designed and
>built by planetary scientists here at York University in  Toronto
>where I work. Using Lidar technology that was perfected here,
>Pheonix will, for the first time, be able to accurately measure
>the thickness of the Martian atmosphere and the amounts of
>particulate matter at various elevations. I think that there
>will be big and unexpected surprises and many old beliefs that
>atmospheric scientists had about Mars will have to be discarded
>or revised.

>If Phoenix has a successful landing (its the resurrection of the
>failed Mars Polar Lander) we will not have much longer to wait
>before we can confidently say if either you or I are correct.

All I'm advocating is a sceptical open mind, and I think I've
been clear that whilst I don't disagree there may be some
discussion still to be had about the Martian daylight I don't
see convincing evidence of your NASA conspiracy of suppression.

Instead I see evidence of the usual human fumbling towards the
truth in difficult circumstances.

Obviously if you are right, and if there is a conspiracy of
suppression, then one thing we can confidently predict is that
all those intriguing measurements are at risk of being fiddled
and corrupted before you see them - unless, that is, they do
show what you hope to see.


Martin Shough



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