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Mars
has always aroused a particular interest in science because
of its characteristics that make it in many ways similar to
planet Earth. Already in the past, until today, has often dreamed
about any forms of life. This thanks to the initial comments
made by early astronomers as the various Herschel, Cassini,
Fraunhofer and so on until famous Schiapparelli: the Italian
scientist, at the end of the nineteenth century, identified
on the Red Planet some "channels" attributed to a technologically
advanced civilization. With the advent of the Space Age, after
the many failures of the first probes, the Mariner 4 close on
July 14, 1965 at Mars taking 22 images at a distance of 16,900
kilometers from the surface. These photos taken in the so-called
Amazonis Area showed a surface covered with craters and volcanoes,
according to the images and other factors argued that the pressure
should be between about 4.0 and 6.0 millibars, then much lower
than Earth's, while the atmosphere was probably composed of
95% carbon dioxide, 2.7% nitrogen and just 0.13% oxygen. |
The probe did not
see trace of water, which at least liquid was non-existent: a planet
almost completely barren and dead. All this was assumed that the
Martian surface did not exist any form of life. It was after several
other attempts which in May '71 finally the American probe Mariner
9 arrived on the surface. Due to a sudden storm of sand, the shots
were not very clear, it could only see the southern polar cap, while
the rest were just messy details. A few days later, however, after
the storm, the spacecraft was able to map the planet in the south,
showing an area intensely covered with craters, huge volcanoes,
dissect beds of rivers and a vast canyon renamed in his honor Valles
Marineris. All the particulars that order today are thinking that
this world has been seemingly dead in reality, in a distant past,
rich in water and life. But a detail had not yet been able to know:
what was the true color of the surface of the planet, since the
photos were all in black and white. From the observations made in
the history until now it was known that the ground was covered with
red sand, then according to scientist the sky had to take a kind
of pinkish color, due to dust raised in the same way as happens
in desert lands during the storms. They were added as new artificial
colors (explicitly admitted by the same NASA) in order to achieve
a result quite realistic. Then with the new missions of the Viking
probes, orbital and terrestrial, and the robot Spirit, Opportunity
and Sojourner who have walked for hundreds of kilometers on Mars,
has managed to get much more detailed images both of that particular
color. Some singularity did not return: many pictures differ in
tone, and we can see that on some pictures the land is red-brownish
similar to tennis courts, in other the color is much more pronounced,
with a very intense red so as to take even the sky coloring rather
strange, almost "falsified". In fact sometimes the sky is dark green,
sometimes almost red fire, sometimes dark beige or even purple.
These changes of color are bit strange, even if a couple of photos
appear to have the perfectly blue sky just like our planet Earth.
As for the old photos, these were necessarily colored, because in
black and white and the result at the time was enough realistic,
but today watching these strange colors, it is clear that were revised,
but why do they needs to do so? One question comes to mind. What
if the atmosphere of Mars is not so different from that of the Earth?
We analyze now with a sequence of photos in our artificially colored:
we will clean the pictures with filters of digital graphics program
"Photoshop". True or false it may be, at least try to imagine how
it would be Mars with the blue sky.
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(Left) The
first photos of the Martian soil was taken in 1975 with the
Viking probes: As we can see, Nasa colorized the photo with
this reddish-shades of the soil that the sky was becoming
a dark gray-green. But already the first computer graphics
programs were able to clean up images revealing what could
be the true color of the sky. (Bottom left) The same photo
of Viking cleaned from the yellowish filter, it shows how
change the color of the ground and the sky, which becomes
a beautiful blue. (At the center and right) Other pictures
of the two Viking spacecraft show a decidedly more clear sky
and a vivid sun.
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(Above left)
To tell the truth already in the Nasa Years '70 had widespread
very different image from those of today, which showed Mars
with frost and a blue sky. (Top right) The same area without
frost, in the summer ... (Right) Nasa even today, spreads
photos similar to these, but defining in "false colors", as
this picture by the rover Opportunity.
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An
image of a 360° by rover Spirit shows a pink sky ... |
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Our
cleaning up in reality shows the presence of a storm. |
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A
curiosity: the panoramic photo taken by the probe Venera 13
in 1983 on the planet Venus shows a surprising brightness for
a dense atmosphere as this. Could it be that Mars, which has
a more rarefied, should appear darker? |
| (Above)
A Martian sunset without filters and with the Spirit rover to
observe the hill: the sky is not red as in the other photo,
but adeguate to thin atmosphere. The question is: why to color
these photos? Scientists have argued that the pink color was
due to the dust storms on Mars, but it not seems possible that
the Martian atmosphere is constantly surrounded by storms, not
least because in satellite photos clouds appear white (not red)
and differently from the Earth, has always said that Mars has
thin atmosphere without water and oxygen. If there are not seas,
if there is not evaporation, what gives the planet the energy
to unleash these storms? Clearly, the phenomenon is not clear
... If Mars had a dense atmosphere? |
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