What more do we know about Mars' atmosphere? It's hundreds of times
thinner than Earth's atmosphere and is made of 95% carbon dioxide, 3%
nitrogen, 1.6% argon, and contains traces of oxygen, water, and
methane. We also know, from observations that it can support dust
storms, dust devils, clouds and gusty winds. With an amazing number of
six current live probes exploring Mars (two rovers, a lander, and three
orbiters), there are many thousands of images available. Only a few,
however show atmospheric phenomena. Presented here are some of the best
images of Martian atmosphere (and beyond) in action. (17 photos total)

Mars'
northern orange sky and horizon, seen by NASA's Phoenix Mars Lander.
The lander's solar panel and Robotic Arm with a sample in the scoop are
also visible. The image was taken by the lander's Surface Stereo Imager
looking west during Phoenix's Sol 16 (June 10, 2008), or the 16th
Martian day after landing. The image was taken just before the sample
was delivered to the Optical Microscope. (NASA/JPL-Caltech/University
of Arizona/Texas A&M University)



The
brownish gray sky at sunset as it would be seen by an observer on Mars
- true color mosaic taken by Mars Pathfinder on sol 24 (June 22, 1996)
The sky near the sun is a pale blue color. (NASA/JPL)



High
ice cloud over Mars' limb. This composite of red and blue Mars Global
Surveyor (MGS) Mars Orbiter Camera (MOC) images acquired on 6 July 2005
shows an isolated water ice cloud extending more than 30 kilometers
(more than 18 miles) above the Martian surface. Clouds such as this are
common in late spring over the terrain located southwest of the Arsia
Mons volcano. (NASA/JPL/Malin Space Science Systems)



Clouds
over crater - the dust storm season in the southern hemisphere of Mars
was well underway. This image of an unnamed crater southeast of Hellas
Basin shows the encroachment of a storm in the region. Image acquired
in 2001 by Mars Odyssey orbiter (17 meter/pixel resolution).
(NASA/JPL/ASU)



Dust
devil from above. This image taken by the Hi-RISE Camera aboard NASA's
Mars Reconnaissance Orbiter catches a dust devil blowing across the
Martian surface. Dust devils generally form in the afternoon because
the sunlight needs sufficient time to warm the surface. When this image
was taken, the local time was about 3:08 p.m. The bright material is
the dust within the vortex, and a dark shadow cast by the dust devil is
visible to the left. The diameter of this dust devil is about 200
meters, but at the surface it is probably much smaller. Based on the
length of the shadow in this image, the dust devil is on the order of
500 meters tall. (NASA/JPL/University of Arizona)



Several
dust devils cross a plain in this animation of a series of images
acquired by NASA's Mars Rover Spirit in May, 2005.
(NASA/JPL-Caltech/Cornell/USGS)



A
well-defined dust devil crosses in front of the camera in this
animation of a series of images acquired by NASA's Mars Rover Spirit in
May, 2005. (NASA/JPL-Caltech/Cornell/USGS)



Martian
skies seen above a rolling horizon in this image, part of a larger
image called the "McMurdo" panorama, taken in the Martian winter of
2006 by NASA's Mars Exploration Rover Spirit. The tracks in the soil
are from Spirits wheels as it rolled through the area earlier.
(NASA/JPL/Cornell)



Clouds
above the rim of "Endurance Crater" in this image from NASA's Mars
Exploration Rover Opportunity. These clouds occur in a region of strong
vertical shear. The cloud particles (ice in this martian case) fall
out, and get dragged along away from the location where they originally
condensed, forming characteristic streamers. Opportunity took this
picture with its navigation camera during the rover's 269th martian day
(Oct. 26, 2004). (NASA/JPL)



Early
Spring Dust Storms at the North Pole of Mars. Early spring typically
brings dust storms to northern polar Mars. As the north polar cap
begins to thaw, the temperature difference between the cold frost
region and recently thawed surface results in swirling winds. The
choppy dust clouds of several dust storms are visible in this mosaic of
images taken by the Mars Global Surveyor spacecraft in 2002. The white
polar cap is frozen carbon dioxide. (NASA/JPL/Malin Space Science
Systems)



An
exaggerated color image mosaic of images from NASA's Mars Rover
Opportunity. The clouds can be composed of either carbon dioxide ice or
water ice, and can move swiftly across the sky. (NASA/JPL/Cornell)



Large
dust storms cover much of Mars' surface in this July, 2001 image,
acquired by NASA's Mars Global Surveyor Mars Orbiter Camera. By early
July, the martian atmosphere was so hazy that opportunities for high
resolution imaging of the planet were very limited. (NASA/JPL/Malin
Space Science Systems)



The
air is certainly thick enough to fill a parachute. On May 25th, 2008,
the HiRISE camera onboard the Mars Reconnaissance Orbiter acquired this
dramatic oblique image of its the arrival of its sister probe from
NASA, the Phoenix Lander, descending on its parachute. Phoenix and its
parachute can be barely seen in the larger image with 10 km wide crater
informally called "Heimdall" in the background. Although it appears
that Phoenix is descending into the crater, it is actually about 20
kilometers in front of the crater. Given the position and pointing
angle of MRO, Phoenix is at about 13 km above the surface, just a few
seconds after the parachute opened. (NASA/JPL/University of Arizona)



On
May 19th, 2005, NASA's Mars Exploration Rover Spirit captured this
stunning view as the Sun sank below the rim of Gusev crater on Mars.
This Panoramic Camera mosaic was taken around 6:07 in the evening of
the rover's 489th martian day, or sol. Spirit was commanded to stay
awake briefly after sending that sol's data to the Mars Odyssey orbiter
just before sunset. The image is a false color composite, showing the
sky similar to what a human would see, but with the colors slightly
exaggerated. (NASA/JPL/Texas A&M/Cornell)



Higher
in the Martian skies, we see one of its two moons. The HiRISE camera
onboard the Mars Reconnaissance Orbiter acquired this dramatic view of
the Martian moon, Phobos, on 23 March 2008, from a distance of 6,800
kilometers. The illuminated part of Phobos is about 21 km across. The
most prominent feature is the large impact crater Stickney, in the
upper left. With a diameter of 9 km, it is the largest feature on
Phobos. (NASA/JPL/University of Arizona)



Even
higher in the Martian sky, the Earth and Moon hang in space, as seen
from Mars. The HiRISE camera onboard the Mars Reconnaissance Orbiter
acquired this image at 5:20 a.m. MST on October 3rd, 2007, at a range
of 142 million kilometers, while orbiting Mars.

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