Pegasus Research Consortium

Martian Weather

The Serpent Dust Devil of Mars

(http://www.nasa.gov/images/content/628423main_pia15116-43_800-600.jpg) (http://www.nasa.gov/images/content/628435main_pia15116-full_full.jpg)

The Serpent Dust Devil of Mars

A towering dust devil casts a serpentine shadow over the Martian surface in this image acquired by the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter.

The scene is a late-spring afternoon in the Amazonis Planitia region of northern Mars. The view covers an area about four-tenths of a mile (644 meters) across. North is toward the top. The length of the dusty whirlwind's shadow indicates that the dust plume reaches more than half a mile (800 meters) in height. The plume is about 30 yards or meters in diameter.

A westerly breeze partway up the height of the dust devil produced a delicate arc in the plume. The image was taken during the time of Martian year when the planet is farthest from the sun. Just as on Earth, winds on Mars are powered by solar heating. Exposure to the sun's rays declines during this season, yet even now, dust devils act relentlessly to clean the surface of freshly deposited dust, a little at a time.

This view is one product from an observation made by HiRISE on Feb. 16, 2012, at 35.8 degrees north latitude, 207 degrees east longitude. Other image products from the same observation are at http://www.uahirise.org/ESP_026051_2160 .

HiRISE is one of six instruments on NASA's Mars Reconnaissance Orbiter. The University of Arizona, Tucson, operates the orbiter's HiRISE camera, which was built by Ball Aerospace & Technologies Corp., Boulder, Colo. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Mars Reconnaissance Orbiter Project for the NASA Science Mission Directorate, Washington. Lockheed Martin Space Systems, Denver, built the spacecraft.

Image credit: NASA/JPL-Caltech/Univ. of Arizona

http://www.youtube.com/watch?v=zb94PxX_q38

12-Mile-High Martian Dust Devil Caught In Act

PIA15545: Mars' Whirling Dust Devil

(http://photojournal.jpl.nasa.gov/ipbrowse/PIA15545_ip.jpg) (http://photojournal.jpl.nasa.gov/jpeg/PIA15545.jpg)

(http://photojournal.jpl.nasa.gov/figures/PIA15545_fig1_thumb.jpg) (http://photojournal.jpl.nasa.gov/archive/PIA15545_HiRISE-Dust-Devil-Move-03-30-12.mov)

(http://photojournal.jpl.nasa.gov/figures/PIA15545_fig2_thumb.jpg) (http://photojournal.jpl.nasa.gov/archive/PIA15545_Monster-DustDevil-R003.mov)

    A Martian dust devil roughly 12 miles (20 kilometers) high was captured winding its way along the Amazonis Planitia region of Northern Mars on March 14, 2012 by the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter. Despite its height, the plume is little more than three-quarters of a football field wide (70 yards, or 70 meters).

    HiRISE is operated by the University of Arizona, Tucson. The instrument was built by Ball Aerospace & Technologies Corp., Boulder, Colo. The Mars Reconnaissance Orbiter Project and the Mars Exploration Rover Project are managed by the Jet Propulsion Laboratory, Pasadena, Calif., for NASA's Science Mission Directorate, Washington. JPL is a division of the California Institute of Technology, also in Pasadena. Lockheed Martin Space Systems, Denver, built the orbiter.

    For more about the Mars Reconnaissance Orbiter, see http://www.nasa.gov/mro.
Image Credit:
    NASA/JPL-Caltech/Univ. of Arizona Animation Credit: NASA/JPL-Caltech

Image Addition Date:
    2012-04-04

PIA15545: Mars' Whirling Dust Devil  (http://photojournal.jpl.nasa.gov/catalog/PIA15545)

A Monster Dust Devil Stalks the Martian Landscape

(http://www.uahirise.org/images/2012/details/cut/ESP_026394_2160_ctx.jpg) (http://www.uahirise.org/images/2012/details/cut/ESP_026394_2160_ctx.jpg)

A dust devil the size of a terrestrial tornado towers above the Martian surface in this late springtime afternoon image of Amazonis Planitia.

Also captured by the Context Camera on MRO, the length of the shadow indicates that the dust plume reached a height of 20 kilometers (12 miles) above the surface! This height refers to the top of the disconnected dust clouds above the plume; the continuous column of dust reached about half that altitude. Despite its gargantuan height, the plume is only 140 meters (140 yards) in diameter, giving it a snake-like appearance that is twisted by high altitude winds, similar to another dust devil spotted recently in this region.

Typical tornadoes on Earth are less than 10 miles tall, while dust devils on our planet seldom reach more than a few hundred yards in height. So, why do we classify this plume as a monster dust devil and not a Martian tornado? Dust devils differ from tornadoes in their energy sources. Dust devils are driven by the heat of the surface, absorbed from sunlight and re-radiated to warm the atmosphere. The warm air rises and spins as it contracts, much as a figure skater spins faster as she draws her arms to her sides.

Tornadoes have an additional energy source: the heat given off as water vapor condenses into liquid rain. The condensing water vapor produces the visible part of a tornado, called the condensation funnel, which is made up of water droplets. On Mars, there is too little water vapor in the atmosphere to contribute significantly to atmospheric convection on local scales. The cloud that we see in this image is produced by dust particles, not raindrops. The astounding heights of Martian dust devils are made possible because mass of an atmospheric column on Mars is less than 1 percent than that of a column on Earth. Transfer of heat from the surface into this less dense atmosphere can produce more vigorous convection, which will penetrate higher into the Martian atmosphere than its counterparts do on Earth.

Now, what would happen if you were caught in its path? Because the density of Mars' atmosphere is so low, even a high velocity dust devil is unlikely to knock you over. However, you might be blasted by any sand or dust particles carried along by the dust devil, which might scratch the visor of your space suit quickly if you were caught outside by this monster!

This vortex left behind a bright track as its winds disturbed the dust-covered surface, tracing the path of the dust devil from the northwest towards the southeast. A dust "skirt" twice as wide as the plume itself is seen near the base of the dust devil, but the bright track is the size of the plume and not the skirt. Dozens of smaller dust devils were also spotted in the same Context Camera scene, steadily vacuuming the surface and pumping dust up into the Martian atmosphere.

Written by: Paul Geissler   (4 April 2012)

A Monster Dust Devil Stalks the Martian Landscape (http://www.uahirise.org/ESP_026394_2160)

The Serpent Dust Devil of Mars (http://www.uahirise.org/ESP_026051_2160)

(http://www.astrowetter.com/planeten/bilder/mars/kraternebel.jpg)


http://www.marsroverblog.com/discuss-128378-remember-red-mars.html

(http://apod.nasa.gov/apod/image/0803/avalanche_hirise_big.jpg)

Viking 1 & 2- 1976/80 - "Project Viking"
Color images from the Viking landers - Image processing

http://www.astrosurf.com/nunes/explor/explor_vik.htm#2

Quote from: robomont on June 11, 2013, 09:32:10 AM
wtf.i thought there was no atmosphere on mars?

Who told you that?   ::)  Doesn't anyone read The Livingmoon Website?   >:( Even ArMap will tell you the skies on Mars are blue :D

Martian Clouds Above Phoenix

(http://www.thelivingmoon.com/43ancients/04images/Mars5/Phoenix/Clouds_Phoenix_vid_03.gif)

September 29, 2008

The Surface Stereo Imager onboard NASA's Phoenix Mars Lander observed clouds drifting across the horizon in the early morning on the 119th sol, or Martian day, since landing (September 25, 2008). Clouds were observed each night after Sol 80 (August 15, 2008) as the atmospheric temperature decreased.

Clouds Move Across Mars Horizon  Phoenix Lander

(http://www.thelivingmoon.com/43ancients/04images/Mars5/Phoenix/Clouds_Phoenix_vid_02.gif)

September 19, 2008

This sequence combines 32 images of clouds moving eastward across a Martian horizon. The Surface Stereo Imager on NASA's Phoenix Mars Lander took this set of images on Sept. 18, 2008, during early afternoon hours of the 113th Martian day of the mission.

The view is toward the north. The actual elapsed time between the first image and the last image is nearly half an hour. The numbers inset at lower left are the elapsed time, in seconds, after the first image of the sequence. The particles in the clouds are water-ice, as in cirrus clouds on Earth.

Phoenix landed in the northern region of Mars on May 25, 2008. The mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is led by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

Nighttime Clouds in Martian Arctic
(Accelerated Movie)

(http://www.thelivingmoon.com/43ancients/04images/Mars5/Phoenix/Clouds_Phoenix_vid_04.gif)

September 11, 2008

An angry looking sky is captured in a movie clip consisting of 10 frames taken by the Surface Stereo Imager on NASA's Phoenix Mars Lander.

The clip accelerates the motion. The images were take around 3 a.m. local solar time at the Phoenix site during Sol 95 (Aug. 30), the 95th Martian day since landing.

The swirling clouds may be moving generally in a westward direction over the lander.

The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

Ice Clouds in Martian Arctic
(Accelerated Movie)

(http://www.thelivingmoon.com/43ancients/04images/Mars5/Phoenix/Clouds_Phoenix_vid_01.gif)

September 01, 2008

Clouds scoot across the Martian sky in a movie clip consisting of 10 frames taken by the Surface Stereo Imager on NASA's Phoenix Mars Lander.

This clip accelerates the motion. The camera took these 10 frames over a 10-minute period from 2:52 p.m. to 3:02 p.m. local solar time at the Phoenix site during Sol 94 (Aug. 29), the 94th Martian day since landing.

Particles of water-ice make up these clouds, like ice-crystal cirrus clouds on Earth. Ice hazes have been common at the Phoenix site in recent days.

The camera took these images as part of a campaign by the Phoenix team to see clouds and track winds. The view is toward slightly west of due south, so the clouds are moving westward or west-northwestward.

The clouds are a dramatic visualization of the Martian water cycle. The water vapor comes off the north pole during the peak of summer. The northern-Mars summer has just passed its peak water-vapor abundance at the Phoenix site. The atmospheric water is available to form into clouds, fog and frost, such as the lander has been observing recently.

The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver. 

Martian Sunrise at Phoenix Landing Site
Sol 101

(http://www.thelivingmoon.com/43ancients/04images/Mars5/Phoenix/Sunrise_Sol_101.gif)

September 29, 2008

This sequence of nine images taken by the Surface Stereo Imager on NASA's Phoenix Mars Lander shows the sun rising on the morning of the lander's 101st Martian day after landing.

The images were taken on Sept. 5, 2008. The local solar times at the landing site for the nine images were between 1:23 a.m. and 1:41 a.m.

The landing site is on far-northern Mars, and the mission started in late northern spring. For nearly the entire first 90 Martian days of the mission, the sun never set below the horizon. As the amount of sunshine each day declined steadily after that, so has the amount of electricity available for the solar-powered spacecraft.

The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by JPL, Pasadena, Calif. Spacecraft development was by Lockheed Martin Space Systems, Denver. 

COSMIC SECRETS
The Enigmas on Mars Page 46 (http://www.thelivingmoon.com/43ancients/02files/Mars_Images_46.html#Clouds)

More Clouds on Mars
Mars Pathfinder Sol 16

(http://www.thelivingmoon.com/43ancients/04images/Mars4/Weather/82453_full.jpg)  (http://www.thelivingmoon.com/43ancients/04images/Mars4/Weather/82454_full.jpg)

Pink stratus clouds are coming from the northeast at about 15 miles per hour (6.7 meters/ second) at an appoximate height of ten miles (16 kilometers) above the surface. The clouds consist of water ice condensed on reddish dust particles suspended in the atmosphere. Clouds on Mars are sometimes localized and can sometimes cover entire regions, but have not yet been observed to cover the entire planet. The image was taken by the Imager for Mars Pathfinder (IMP) on Sol 16 about forty minutes before sunrise showing areas of the eastern Martian horizon.

(http://www.thelivingmoon.com/43ancients/04images/Mars4/Weather/82381_full.jpg)

This is the first color image ever taken from the surface of Mars of an overcast sky. The image was taken about an hour and forty minutes before sunrise by the Imager for Mars Pathfinder (IMP) on Sol 16 at about ten degrees up from the eastern Martian horizon.

(http://www.thelivingmoon.com/43ancients/04images/Mars4/Weather/82456_full.jpg)

This is the first image ever taken from the surface of Mars of an overcast sky. The "you are here" notation marks where Earth was situated in the sky at the time the image was taken. Scientists had hoped to see Earth in this image, but the cloudy conditions prevented a clear viewing. Similar images will be taken in the future with the hope of capturing a view of Earth. From Mars, Earth would appear as a tiny blue dot as a star would appear to an earthbound observer. Pathfinder's imaging system will not be able to resolve Earth's moon. The image was taken about an hour and forty minutes before sunrise by the Imager for Mars Pathfinder (IMP) on Sol 16 at about ten degrees up from the eastern Martian horizon.

Mars at Opposition, 2001
Frosty White Clouds and Dust Storms

(http://www.thelivingmoon.com/43ancients/04images/Mars4/Weather/mars-3.jpg)

Frosty white water ice clouds and swirling orange dust storms above a vivid rusty landscape reveal Mars as a dynamic planet in this sharpest view ever obtained by an Earth-based telescope.

NASA's Earth-orbiting Hubble Space Telescope took the picture on June 26, 2001, when Mars was approximately 43 million miles (68 million km) from Earth -- the closest Mars has ever been to Earth since 1988. Hubble can see details as small as 10 miles (16 km) across. The colors have been carefully balanced to give a realistic view of Mars' hues as they might appear through a telescope.

Especially striking is the large amount of seasonal dust storm activity seen in this image. One large storm system is churning high above the northern polar cap [top of image], and a smaller dust storm cloud can be seen nearby. Another large dust storm is spilling out of the giant Hellas impact basin in the Southern Hemisphere [lower right].

Hubble has observed Mars before, but never in such detail. The biennial close approaches of Mars and Earth are not all the same. Mars' orbit around the Sun is markedly elliptical; the close approaches to Earth can range from 35 million to 63 million miles.

Astronomers are interested in studying the changeable surface and weather conditions on Mars, in part, to help plan for a pair of NASA missions to land rovers on the planet's surface in 2004.

The Mars opposition of 2001 serves as a prelude for 2003 when Mars and Earth will come within 35 million miles of each other, the closest since 1924 and not to be matched until 2287.

Springtime on Mars Blue Skies

(http://www.thelivingmoon.com/43ancients/04images/Mars4/Weather/mars-2.jpg)

This NASA Hubble Space Telescope view of the planet Mars is the clearest picture ever taken from Earth, surpassed only by close-up shots sent back by visiting space probes. The picture was taken on February 25, 1995, when Mars was at a distance of approximately 65 million miles (103 million km) from Earth.

Because it is spring in Mars' northern hemisphere, much of the carbon dioxide frost around the permanent water-ice cap has sublimated, and the cap has receded to a core of solid water-ice several hundred miles across.

Towering 16 miles (25 km) above the surrounding plains, volcano Ascraeus Mons pokes above the cloud deck near the western or limb. This extinct volcano, measuring 250 miles (402 km) across, was discovered in the early 1970s by Mariner 9 spacecraft. Other key geologic features include (lower left) the Valles Marineris, an immense rift valley the length of the continental United States. Near the center of the disk lies the Chryse basin made up of cratered and chaotic terrain. The oval-looking Argyre impact basin (bottom), appears white due to clouds or frost.

Seasonal winds carry dust to form striking linear features reminiscent of the legendary martian "canals." Many of these "wind streaks" emanate from the bowl of these craters where dark coarse sand is swept out by winds. Hubble resolves several dozen impact craters down to 30-mile diameter. The dark areas, once misinterpreted as regions of vegetation by several early Mars watchers, are really areas of coarse sand that is less reflective than the finer, lighter dust. Seasonal changes in the surface appearance occur as winds move the dust and sand around.

This picture was taken with Hubble's Wide Field Planetary Camera 2 in PC mode. Exposures were taken through three different color filters to create this true color image. The pictures were map-projected onto a sphere for accurate registration and perspective.

Ancient Mars

(http://www.thelivingmoon.com/43ancients/04images/Mars4/Water/Ancient_Mars7_02.jpg)
Amazonis Planitia
View from the Amazonis Planitia (The Nicholson Crater) to the Medusae Fossae (left).

COSMIC SECRETS
The Enigmas on Mars
The Weather on Mars
The Blue Bird Files  (http://www.thelivingmoon.com/43ancients/02files/Mars_Blue_Bird_Weather.html)

FYI BlueBird was a space scientist and she was on ATS. She was covering a lot of the weather and water on Mars and planned to do a section on Venus with us. But suddenly she disappeared and all her links and files along with her. Fortunately I had saved that work as we went along. Mike Singh was there at the time as well

More Clouds on Mars
Lee Wave Cloud

(http://www.thelivingmoon.com/43ancients/04images/Mars4/Weather/Leewave_Viking_02.gif)
Courtesy © 1998 by Calvin J. Hamilton

Image taken by the Viking spacecraft. This is a good example of a lee wave associated with an impact crater. Note the wave periodicity in the clouds.

Lee Wave Cloud
Crater with Wavy Fog
MGS MOC Release No. MOC2-424, 17 July 2003

(http://www.thelivingmoon.com/43ancients/04images/Mars4/Weather/Leewave_MSSS_02.jpg)
Courtesy NASA/JPL/Malin Space Science Systems

Craters near the edge of the retreating south polar seasonal frost cap often have fog in them, this time of year. This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) wide angle red image was acquired just a few days ago on July 13, 2003. It shows a crater, 36 km (22 mi) across, that is enveloped in fog. This picture was taken as a context frame for a high resolution view that was intended to show dunes on the floor of the crater. That high resolution view was frustrated by thick fog that hid the dunes from view. This wide angle context frame shows that winds from the lower right (southeast) were blowing over the crater, causing the fog to bunch up in a wavy, rippled pattern. Winds streaming off the polar cap toward the north create a variety of patterns in the fogs formed by water ice or vapor as the seasonal cap retreats during southern spring. This picture is located at 66.4°S, 208.6°W, sunlight illuminates the scene from the upper left (northwest).

Image Source: Malin Space Systems 2003/07/17 R07-00964

Wave Clouds

(http://www.thelivingmoon.com/43ancients/04images/Mars4/Weather/Wave_Cloud_Viking.gif)
Courtesy © 1998 by Calvin J. Hamilton

Image taken by the Viking spacecraft. Wave clouds usually occur at the lee of a large obstacle. They are often found at the edge of the polar cap, and in the Tharsis and Lunae Planum regions of Mars.

Cloud Streets

(http://www.thelivingmoon.com/43ancients/04images/Mars4/Weather/Cloud_Streets_Viking.gif)
Courtesy © 1998 by Calvin J. Hamilton

Image taken by the Viking spacecraft. The cloud patterns illustrated by this image exhibits a double periodicity. These types of clouds usually occur close to the northern-polar cap and in the Tharsis and Syria Planum regions of Mars.

Streaky Clouds

(http://www.thelivingmoon.com/43ancients/04images/Mars4/Weather/Streaky_Clouds_Viking.gif)
Courtesy © 1998 by Calvin J. Hamilton

Image taken by the Viking spacecraft. Streaky clouds seem to be found most everywhere; however, they seem to be more concentrated in the highlands southwest of Syrtis Major on Mars.

Fog

(http://www.thelivingmoon.com/43ancients/04images/Mars4/Weather/Fog_Viking_02.gif)
Courtesy © 1998 by Calvin J. Hamilton

Image taken by the Viking spacecraft. Fog often appears in low-lying areas. It typically occurs in the southern hemisphere especially in the Argyre and Hellas basins. It forms frequently in craters. Occasionally, it occurs in higher regions such as Sinus Sabaeus and Solis Planum.

Chasma Australe Fog
MGS MOC Release No. MOC2-528, 29 October 2003

(http://www.thelivingmoon.com/43ancients/04images/Mars4/Weather/Fog_MSSS_M0904025_02.gif)
Courtesy NASA/JPL/Malin Space Science Systems

Fog is a common occurrence in some areas of the retreating south polar seasonal frost cap. Fogs are commonly banked-up against steep slopes or found inside defrosting craters. This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image captured mid-afternoon fog banked against the layered walls of Chasma Australe, a trough in the south polar region of Mars. The frost-covered layers of Chasma Australe can be seen on the right side of this image, the billowy fog is to the left. Sunlight illuminates this scene from the upper left. The fog, probably composed of water ice crystals, casts shadows on the chasm wall. This picture is located near 83.5°S, 257.9°W, and covers an area 3 km (1.9 mi) wide.

Image Source: Malin Space Systems 2003/10/29 M09 04025

COSMIC SECRETS
The Enigmas on Mars
The Weather on Mars
The Blue Bird Files  (http://www.thelivingmoon.com/43ancients/02files/Mars_Blue_Bird_Weather.html)

Water Clouds in Noctis Labyrinthis

(http://www.thelivingmoon.com/43ancients/04images/Mars4/Weather/Clouds_Noctis_Viking_01.gif)
Courtesy NASA/LPI

Image taken by the Viking spacecraft. This image shows early morning fog in the Noctis Labyrinthis, at the westernmost end of Valles Marineris. This fog, which is probably composed of water ice, is confined primarily to the low-lying troughs, but occasionally extends over the adjacent plateau. The region shown is about 300 kilometers (186 miles) across.

Colorful Water Clouds Over Mars 

(http://www.thelivingmoon.com/43ancients/04images/Mars4/Weather/marsclouds_viking_big.jpg)
Credit:  Viking Project, USGS, JPL, NASA

Explanation: One place where water can be found on Mars is in clouds. In the above picture colorful water clouds are visible just after sunrise in and around a maze of canyons known as Noctis Labyrinthus (the labyrinth of the night). Scientists don't yet know, however, why these clouds formed, and why some stick to the canyons. One exciting possibility is that water sometimes condenses in shaded regions of the canyons, only to evaporate into clouds when exposed to the morning Sun. Water in any form on the Martian surface might be important to sustaining life and possible future human exploration. Viking Orbiter 1, which visited Mars in 1976, took the above picture. The region shown is about 100 kilometers across.

SOURCE: NASA APOD April 17, 2001

Wispy Clouds Passing Overhead
Opportunity Rover Sol 950

(http://www.thelivingmoon.com/43ancients/04images/Mars4/Weather/1N212516144EDN76ACP1585L0M1-BR.JPG)
Image credit: NASA/JPL-Caltech

Opportunity acquired images of clouds passing over Victoria Crater using the navigation camera on the rover's 950th sol (martian day) of exploration on Mars (Sept. 25, 2006). Both rovers will continue searching the Martian sky for clouds during solar conjunction.

Left Navigation Camera Non-linearized Downsampled EDR acquired on Sol 950 of Opportunity's mission to Meridiani Planum at approximately 11:37:32 Mars local solar time. Credit: NASA/JPL

Wispy Afternoon Clouds
Rover Opportunity Sol 956

(http://www.thelivingmoon.com/43ancients/04images/Mars4/Weather/Clouds_PIA09170.gif)

NASA's Mars Exploration Rover Opportunity captured a view of wispy afternoon clouds, not unlike fair weather clouds on Earth, passing overhead on the rover's 956th sol, or Martian day (Oct. 2, 2006). With Opportunity facing northeast, the clouds appear to drift gently toward the west in this movie taken with the rover's navigation camera.

The 10 frames, taken 32 seconds apart, show the formation and evolution of what are likely mid-level, convective water clouds. Such clouds are common near Mars' equator at this time of the Martian year. They have been observed by both of NASA's Mars Exploration Rovers, by satellites orbiting Mars, and by the Hubble Space Telescope. In this case, the clouds appear to develop at a fixed location, in the center of the frame about 25 degrees above the horizon. This style of origin suggests that a thermal plume is rising over a surface feature. In spite of apparent winds aloft, the thermal plume appears to remain stationary for the 5-minute duration of the movie.

Though scientists have determined from the images that the wind bearing is east-northeast, approximately 80 degrees, it is not possible on the basis of the movie to unambiguously determine the height and speed of the clouds. Scientists estimate, based on models of atmospheric wind profiles and the apparent displacement of the clouds, that all of the clouds in the movie are at about the same height somewhere between 5 kilometers and 25 kilometers (3 to 20 miles) above the surface. The clouds are estimated to be moving at 2.5 meters per second, if they are low, to 12.5 meters per second, if they are high (8 feet per second to 41 feet per second).

Like clouds on Earth, these Martian clouds are probably composed of ice crystals and possibly supercooled water droplets. They are similar in appearance to terrestrial cirrocumulus or high altocumulus clouds. On Earth, such clouds are relatively transient and consist of small, individual cloudlets arranged in rippled patterns. They usually form 6 kilometers to 12 kilometers (4 to 7 miles) above Earth's surface by a process known as convection, during which warm air rises and cools, with clouds condensing from the moist air once it has cooled sufficiently.

These Martian clouds appear to be associated with a broader layer of ice-crystal clouds fanning out toward the upper right of the frames at the end of the movie. This is similar to the occurrence of terrestrial cirrocumulus and altocumulus clouds within layers of cirrus or cirrostratus clouds on Earth. Also apparent in this movie are prominent waves in the clouds, a result of the effect of gravity waves on cloud thickness, as on Earth.

Though both rovers now have the ability to autonomously detect clouds, these images were taken prior to the first use of the new abilities. The images shown here were stored on Opportunity and were transmitted to Earth on sol 1056 (Jan. 12, 2007) during a routine communications pass.

Image Credit: NASA/JPL/Texas A&M/Cornell
Image Source: PIA09170

COSMIC SECRETS
The Enigmas on Mars
The Weather on Mars
The Blue Bird Files  (http://www.thelivingmoon.com/43ancients/02files/Mars_Blue_Bird_Weather.html)

Dust Plume

(http://www.thelivingmoon.com/43ancients/04images/Mars4/Weather/Dust_Plume_Viking_02.gif)
Courtesy © 1998 by Calvin J. Hamilton

Image taken by the Viking spacecraft. This is an example of a dust plume in the Solis Planum region. This image was taken during the springtime for this region. Plumes are found primarily in the southern hemisphere, in highlands such as Syrtis Major and in elevated regions such as Tharsis. (Click image for larger view)

Planet Gobbling Dust Storms on Mars

(http://www.thelivingmoon.com/43ancients/04images/Mars4/Weather/Dust_Storms_01.jpg)
Image credit: NASA/JPL
July 16, 2001

Mariner 9 arrived at Mars in 1971 -- the first spacecraft to orbit the Red Planet. Scientists were anxious to study the crisp new pictures it was expected to send back. Much of Mars had never been seen in any detail, and Mariner 9 would lift the veil at last.

Their feelings must have been mixed indeed when the first images arrived at mission control and revealed .... a world-wide haze. The surface of the entire planet was hidden by the biggest dust storm anyone had ever seen! Only Olympus Mons, a giant volcano 24 kilometers high, peeked above the clouds.

After a month the dust settled and Mariner 9 mapped the Red Planet with great success. Scientists have since learned that huge dust storms, dwarfing desert dust clouds on Earth, are fairly common on Mars. The Mariner 9 event still holds the record as the thickest and longest-lasting we have observed -- but perhaps not for long.

(http://www.thelivingmoon.com/43ancients/04images/Mars4/Weather/Mars_Dust_Storm_Viking.jpeg)
Image credit: Viking NASA/JPL

Mars dust storm viewed from orbit, note craters with snowy rims.

Planet Gobbling Dust Storms on Mars Part 2

(http://www.thelivingmoon.com/43ancients/04images/Mars4/Weather/Mars_Dust_Storm_Hubble.jpg)

Scientists Track "Perfect Storm" on Mars

Both images are in natural color, taken with Hubble's Wide Field Planetary Camera 2.
Credit: NASA, James Bell (Cornell Univ.), Michael Wolff (Space Science Inst.), and the Hubble Heritage Team (STScI/AURA)

Two dramatically different faces of our Red Planet neighbor appear in these comparison images showing how a global dust storm engulfed Mars with the onset of Martian spring in the Southern Hemisphere. When NASA's Hubble Space Telescope imaged Mars in June, the seeds of the storm were caught brewing in the giant Hellas Basin (oval at 4 o'clock position on disk) and in another storm at the northern polar cap.

When Hubble photographed Mars in early September, the storm had already been raging across the planet for nearly two months obscuring all surface features. The fine airborne dust blocks a significant amount of sunlight from reaching the Martian surface. Because the airborne dust is absorbing this sunlight, it heats the upper atmosphere. Seasonal global Mars dust storms have been observed from telescopes for over a century, but this is the biggest storm ever seen in the past several decades.

Mars looks gibbous in the right photograph because it is 26 million miles farther from Earth than in the left photo (though the pictures have been scaled to the same angular size), and our viewing angle has changed. The left picture was taken when Mars was near its closest approach to Earth for 2001 (an event called opposition); at that point the disk of Mars was fully illuminated as seen from Earth because Mars was exactly opposite the Sun.

Source - Cosmic Light

Recent Mars and Earth Dust Storms Compared

In this figure, we compare a recent dust storm on Mars with one that occurred earlier this year on Earth. The top image shows a martian north polar dust storm observed on 29 August 2000. This image is part of the Mars Orbiter Camera (MOC) daily global map--a low resolution, two-color view of Mars acquired from pole to pole every orbit. The storm is moving as a front, outward from a central "jet," and marginal "vortices" can be seen. In this image it extends about 900 km (560 mi) out from the north polar seasonal frost cap. The region on the right side of the Mars picture includes the north pole. The bottom image shows a terrestrial dust storm, seen in a SeaWiFS image, acquired on 26 February 2000. This storm exends about 1800 km (1100 mi) off the coast of northwest Africa near the Earth's equator. Both images are shown at the same scale; 4 km (2.5 mi) per pixel.

(http://www.thelivingmoon.com/43ancients/04images/Mars4/Weather/mars_and_earth_storms_a.jpg) (http://www.thelivingmoon.com/43ancients/04images/Mars4/Weather/mars_and_earth_storms.jpg)
Image Source: MGS MOC Release No. MOC2-249, 12 September 2000 Click image for full size


COSMIC SECRETS
The Enigmas on Mars
The Weather on Mars
The Blue Bird Files  (http://www.thelivingmoon.com/43ancients/02files/Mars_Blue_Bird_Weather.html)

Seasonal Changes in the North Polar Ice Cap

(http://www.thelivingmoon.com/43ancients/04images/Mars4/Weather/Mars_Polarcap.jpg)
Credit: Phil James (Univ. Toledo), Todd Clancy (Space Science Inst., Boulder, CO),
Steve Lee (Univ. Colorado), and NASA

These images, which seem to have been taken while NASA's Hubble Space Telescope (HST) was looking directly down on the Martian North Pole, were actually created by assembling mosaics of three sets of images taken by HST in October, 1996 and in January and March, 1997 and projecting them to appear as they would if seen from above the pole. This first mosaic is a view which could not actually be seen in nature because at this season a portion of the pole would have actually been in shadow; the last view, taken near the summer solstice, would correspond to the Midnight Sun on Earth with the pole fully illuminated all day. The resulting polar maps begin at 50 degrees N latitude and are oriented with 0 degrees longitude at the 12 o'clock position. This series of pictures captures the seasonal retreat of Mars' north polar cap.

October 1996 (early spring in the Northern hemisphere): In this map, assembled from images obtained between Oct. 8 and 15, the cap extends down to 60 degrees N latitude, nearly it's maximum winter extent. (The notches are areas where Hubble data were not available). A thin, comma-shaped cloud of dust can be seen as a salmon-colored crescent at the 7 o'clock position. The cap is actually fairly circular about the geographic pole at this season; the bluish "knobs" where the cap seems to extend further are actually clouds that occurred near the edges of the three separate sets of images used to make the mosaic.

January 1997 (mid-spring): Increased warming as spring progresses in the northern hemisphere has sublimated the carbon dioxide ice and frost below 70 degrees north latitude. The faint darker circle inside the cap boundary marks the location of circumpolar sand dunes (see March '97 map); these dark dunes are warmed more by solar heating than are the brighter surroundings, so the surface frost sublimates from the dunes earlier than from the neighboring areas. Particularly evident is the marked hexagonal shape of the polar cap at this season, noted previously by HST in 1995 and Mariner 9 in 1972; this may be due to topography, which isn't well known, or to wave structure in the circulation. This map was assembled from WFPC2 images obtained between Dec. 30, 1996 and Jan. 4, 1997.

March 30, 1997 (early summer): The cap has fully retreated to its remnant core of water-ice. This residual cap is actually almost cut into two by a large, horn-shaped canyon called Chasma Borealis which is cut deeply into the polar terrain. The HST images also reveal a curious layered terrain which is evidence of past climatic changes on Mars. The sublimation of all of the carbon dioxide has exposed the ring of dark sand dunes which encircle the North Polar Cap. Outliers of ice persist south of the polar sand sea (between the 3 o'clock and 9 o'clock positions). The bright circular features at 3, 6, and 9 o'clock are ice-filled craters.

All images were taken with the Wide Field and Planetary Camera 2. The color is constructed from images taken in red (673 nm) , blue (410 nm) and green (502 nm) light. The resolution at the North Pole ranges from about 115 km/pixel in October '96 to about 45 km/pixel in March '97.

Source - Cosmic Light

Northern Summer

(http://www.thelivingmoon.com/43ancients/04images/Mars4/Weather/Mars_Summer.jpg)
Credit: Steve Lee (Univ. Colorado), Todd Clancy (Space Science Inst., Boulder, CO),
Phil James (Univ. Toledo), and NASA.

Four faces of Mars as seen on March 30, 1997 are presented in this montage of NASA Hubble Space Telescope images. Proceeding in the order upper-left, upper-right, lower-left, lower-right, Mars has rotated about ninety degrees between each successive time step. For example the Tharsis volcanoes, which are seen (between 7:30 and 9 o'clock positions) in mid-morning in the upper-left view, are seen near the late afternoon edge of the planet (about 3 o'clock position) in the lower-left image. All of these color images are composed of individual red (673 nanometers), green (502 nm), and blue (410 nm) Planetary Camera exposures.

Upper left: This view is centered on Ares Valles, where Pathfinder will land on July 4, 1997; the Valles Marineris canyon system stretches to the west across the lower left portion of the planet, while the bright, orangish desert of Arabia Planitia is to the east. The bright polar water-ice cap, surrounded by a dark ring of sand dunes, is obvious in the north; since it is northern summer and the pole is tilted toward us, the residual north polar cap is seen in its entirety in all four images. Acidalia Planitia, the prominent dark area fanning southward from the polar region, is thought to have a surface covered with dark sand. Numerous "dark wind streaks" are visible to the south of Acidalia, resulting from wind-blown sand streaming out of the interiors of craters.

Upper right: The Tharsis volcanos and associated clouds are prominent in the western half of this view. Olympus Mons, spanning 340 miles (550 km) across its base and reaching an elevation of 16 miles (25 km), extends through the cloud deck near the western limb, while (from the south) Arsia Mons, Pavonis Mons, and Ascraeus Mons are to the west of center. Valles Marineris stretches to the east, and the Pathfinder landing site is shrouded in clouds near the afternoon limb.

Lower left: This relatively featureless sector of Mars stretches from the Elysium volcanic region in the west to the Tharsis volcanoes (shrouded by the bright clouds near the afternoon limb) in the east. The group of three dark specks just left of center are all that remain of Cerberus, a very prominent dark region during the Viking and Mariner 9 missions. This is an example of the remarkable large scale changes which can occur on Mars due to windblown dust: the former dark area has now been covered by a layer of bright dust, masking the underlying material.

Lower right: The dark Syrtis Major region dominates this image. Syrtis Major is one of the most prominent dark features on Mars, and has been visible since ground-based observers first peered at Mars through telescopes. The bright cloud at 3 o'clock is associated with Elysium Mons. The bright bluish-white feature near the southern limb of the planet is Hellas, a 1,200 mile (2,000 km)diameter impact basin formed by the collision of a large body with Mars long ago. Hellas is covered with dry ice frost and clouds during this season (winter in the south).

Source - Cosmic Light


COSMIC SECRETS
The Enigmas on Mars
The Weather on Mars
The Blue Bird Files  (http://www.thelivingmoon.com/43ancients/02files/Mars_Blue_Bird_Weather.html)

Dust Devils on Mars

(http://www.thelivingmoon.com/43ancients/04images/Mars4/Weather/dustdevil5_spirit.gif)
A Martian Dust Devil Passes
Credit: Mars Exploration Rover Mission, JPL, NASA

Explanation: What goes there across the plains of Mars? A dust devil. For the first time, definitive movies of the famous spinning dust towers have been created from ground level. The robot rover Spirit has now imaged several dust devils from its hillside perch just within the past two months. Each image in the above sequence was taken about 20 seconds apart. Inspection of the digitally resized images show the passing dust devil raising Martian dust so thick that it casts a shadow. The new dust devil movies have been made possible by a new hybrid interaction system where the robot Spirit on Mars takes many images and humans on Earth inspect thumbnails and decide which full resolution images to send back.

Source: NASA Astronomy Picture of the Day

A Dust Devil Crater on Mars

(http://www.thelivingmoon.com/43ancients/04images/Mars4/Weather/craterdevil_mgs.jpg)
A Dust Devil Crater on Mars
Credit: Malin Space Science Systems, MGS, JPL, NASA

Explanation: What caused the streaks in this Martian crater? Since the above image shows streaks occurring both inside and outside the crater, they were surely created after the crater-causing impact. Newly formed trails like these presented researchers with a tantalizing martian mystery but have now been identified as likely the work of miniature wind vortices known to occur on the red planet - martian dust devils. Another example of wind processes on an active Mars, dust devils had been detected passing near the Viking and Mars Pathfinder landers. Such spinning columns of rising air heated by the warm surface are common in dry and desert areas on planet Earth. Typically lasting only a few minutes, they becoming visible as they pick up loose dust. On Mars, dust devils can be up to 8 kilometers high and leave dark trails as they disturb the bright, reflective surface dust.

Source: NASA Astronomy Picture of the Day

A Dust Devil on Mars Climbs Crater Wall

(http://www.thelivingmoon.com/43ancients/04images/Mars4/Weather/dustdevil_mgs.jpg)
A Dust Devil on Mars
Credit: Malin Space Science Systems, MGS, JPL, NASA

Explanation: Does the surface of Mars change? When inspecting yearly images of the Martian surface taken by the robot spacecraft Mars Global Surveyor currently orbiting Mars, sometimes new dark trails are visible. Although originally a mystery, the culprit is now usually known to be a dust devil, a huge swirling gas-cloud with similarities to a terrestrial tornado. Pictured above, a recent image has not only captured a new dark trail but the actual dust devil itself climbing a crater wall. Dust devils are created when Martian air is heated by a warm surface and begins to spin as it rises. Dust devils can stretch 8 kilometers high but usually last only a few minutes.

Source: NASA Astronomy Picture of the Day

Martian Dust Devil Trails 

(http://www.thelivingmoon.com/43ancients/04images/Mars4/Weather/ddtrails_mgs.jpg)
Martian Dust Devil Trails
Credit: Malin Space Science Systems, MGS, JPL, NASA

Explanation: Who's been marking up Mars? This portion of a recent high-resolution picture from the orbiting Mars Global Surveyor spacecraft shows twisting dark trails criss-crossing a relatively flat rippled region about 3 kilometers wide on the martian surface. Newly formed trails like these presented researchers with a tantalizing martian mystery but have now been identified as likely the work of miniature wind vortices known to occur on the red planet - martian dust devils. Another example of wind processes on an active Mars, dust devils had been detected passing near the Viking and Mars Pathfinder landers. Such spinning columns of rising air heated by the warm surface are common in dry and desert areas on planet Earth. Typically lasting only a few minutes, they becoming visible as they pick up loose dust. On Mars, dust devils can be up to 8 kilometers high and leave dark trails as they disturb the bright, reflective surface dust.

Source: NASA Astronomy Picture of the Day

COSMIC SECRETS
The Enigmas on Mars
The Weather on Mars
The Blue Bird Files  (http://www.thelivingmoon.com/43ancients/02files/Mars_Blue_Bird_Weather.html)

Martian Dust Devils in Action
Spirit Rover

(http://www.thelivingmoon.com/43ancients/04images/Mars4/Weather/spirit_sol587nav.gif)
Spirit Sol 587

(http://www.thelivingmoon.com/43ancients/04images/Mars4/Weather/spirit_sol632nav.gif)
Spirit Sol 632

(http://www.thelivingmoon.com/43ancients/04images/Mars4/Weather/spirit_sol640nav.gif)
Spirit Sol 640

(http://www.thelivingmoon.com/43ancients/04images/Mars4/Weather/spirit_sol568nav.gif)
Spirit Sol 640


COSMIC SECRETS
The Enigmas on Mars
The Weather on Mars
The Blue Bird Files  (http://www.thelivingmoon.com/43ancients/02files/Mars_Blue_Bird_Weather.html)

Colossal Polar Cyclone

(http://www.thelivingmoon.com/43ancients/04images/Mars4/Weather/Cyclone_Hubble_01.jpg)
Credit: Jim Bell (Cornell U.), Steve Lee (U. Colorado), Mike Wolff (SSI), and NASA

A Bright Clear and Sunny Day
Spirit :: Panorama Camera :: Sol 1507

(http://www.thelivingmoon.com/43ancients/04images/Mars4/Spirit_Sol_1505/Sol_1507_Raw_2P260146739ESFAY00P2111L234567M1.JPG)

(http://www.thelivingmoon.com/43ancients/04images/Mars4/Spirit_Sol_1505/Sol_1507_Raw_2P260146399EFFAY00P2288L234567M1.JPG)
Image Source: Lyle.org Private Directory  #1

Spirit :: Panorama Camera :: Sol 1508

(http://www.thelivingmoon.com/43ancients/04images/Mars4/Spirit_Sol_1505/Sol_1508_Raw_2P260233647EFFAY00P2289L234567M1.JPG)
Image Source: Lyle.org Private Directory  #2

Spirit :: Panorama Camera :: Sol 1515

(http://www.thelivingmoon.com/43ancients/04images/Mars4/Spirit_Sol_1505/Sol_1515_Raw_2P260856830EFFAY00P2292L234567M1.JPG)
Image Source: Lyle.org Private Directory  #3

Spirit :: Panorama Camera :: Sol 1526

(http://www.thelivingmoon.com/43ancients/04images/Mars4/Spirit_Sol_1505/Sol_1526_Raw_2P261833484EFFAY00P2298L234567M1.JPG)
Image Source: Lyle.org Private Directory  #4

COSMIC SECRETS
The Enigmas on Mars Page 44 (http://www.thelivingmoon.com/43ancients/02files/Mars_Images_44.html)

Blue Skies over Mars
Twilight on a Cloudy Day - Pathfinder

(http://www.thelivingmoon.com/43ancients/04images/Mars/228523888_4078677bbd.jpg)
Image Credit NASA
Twilight on a Cloudy Day - Pathfinder

This true color image was taken in the twilight by the rover Pathfinder on Mars in August 1997. The clouds are of the same type as those discovered by SPICAM at a much higher altitude. The sky on Mars is BLUE

An Image Frozen in Time
Spirit Rover

(http://www.thelivingmoon.com/43ancients/04images/Mars/PIA07997.jpg)
Image Credit NASA Click image for full size
A Moment Frozen in Time - June 10, 2005

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 (Pancam) 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. This small panorama of the western sky was obtained using Pancam's 750-nanometer, 530-nanometer and 430-nanometer color filters. This filter combination allows false color images to be generated that are similar to what a human would see, but with the colors slightly exaggerated. In this image, the bluish glow in the sky above the Sun would be visible to us if we were there, but an artifact of the Pancam's infrared imaging capabilities is that with this filter combination the redness of the sky farther from the sunset is exaggerated compared to the daytime colors of the martian sky. Because Mars is farther from the Sun than the Earth is, the Sun appears only about two-thirds the size that it appears in a sunset seen from the Earth.

An Image Frozen in Time
Opportunity  Rover

(http://www.thelivingmoon.com/43ancients/04images/Mars/040226_martian_sun_hmed12p_h2.jpg)
Image Credit NASA

A view from the Opportunity rover's panoramic camera shows the sun setting in the Martian west. The sky near the horizon is reddish because the sun's light is being scattered by red dust suspended in the atmosphere.

Rover Captures Martian Sunset

For the first time in almost seven years, scientists watched a blue-and-red sunset from Mars, courtesy of NASA's Opportunity rover. The new view is appealing from an inspirational as well as a scientific point of view, scientists said Thursday.

"You're observing the sun setting on another planet — how often do you get to do that?" Cornell astronomer Jim Bell, team leader for the Mars rovers' panoramic cameras, told journalists at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "It's important not to forget that what we're doing does have special inspirational moments like this."

Mars - Viking 1 Lander

(http://www.thelivingmoon.com/43ancients/04images/Mars/vl1_12a240.png)
Image Credit NASA - Click image for full size
Sunset at the Viking 1 Lander site

Viking 1 Lander image of a martian sunset over Chryse Planitia. In this image the sun is 2 degrees below the local horizon. The banding in the sky is an artifact produced by the incremental brightness levels of the camera. This image was taken on the 30th martian day (sol) after touchdown, at 19:13 local time. The camera is pointing towards the southwest.

COSMIC SECRETS
The Enigmas on Mars Page 03 (http://www.thelivingmoon.com/43ancients/02files/Mars_Images_03.html#Blue)

Martian Dust Devil Videos

(http://apod.nasa.gov/apod/image/0504/dustdevil5_spirit_big.gif)
A Martian Dust Devil Passes
Credit: Mars Exploration Rover Mission, JPL, NASA

Explanation: What goes there across the plains of Mars? A dust devil. For the first time, definitive movies of the famous spinning dust towers have been created from ground level. The robot rover Spirit has now imaged several dust devils from its hillside perch just within the past two months. Each image in the above sequence was taken about 20 seconds apart. Inspection of the digitally resized images show the passing dust devil raising Martian dust so thick that it casts a shadow. The new dust devil movies have been made possible by a new hybrid interaction system where the robot Spirit on Mars takes many images and humans on Earth inspect thumbnails and decide which full resolution images to send back.


Dust Devil in Gusev Crater, Sol 445

(http://marsrovers.nasa.gov/gallery/press/spirit/20050506a/dd_enhanced_455e-A476R1.gif)

This movie clip shows a single dust devil -- a whirlwind that lofts dust into the air -- about 2 kilometers (1 mile) away, moving across a plain inside Mars' Gusev Crater for several minutes. The dust devil appears in 21 frames. The number of seconds elapsed since the first frame is indicated at lower left of the images, typically 20 seconds between frames. The navigation camera on NASA's Mars Exploration Rover Spirit took these images on the rover's 445th martian day, or sol (April 14, 2005.) Contrast has been enhanced for anything in the images that changes from frame to frame, that is, for the dust devil.

Scientists expected dust devils since before Spirit landed. The landing area inside Gusev Crater is filled with dark streaks left behind when dust devils pick dust up from an area. It is also filled with bright "hollows", which are dust-filled miniature craters. Dust covers most of the terrain. Winds flow into and out of Gusev crater every day. The Sun heats the surface so that the surface is warm to the touch even though the atmosphere at 2 meters (6 feet) above the surface would be chilly. That temperature contrast causes convection. Mixing the dust, winds, and convection can trigger dust devils.

Image credit: NASA/JPL

Dust Devil Near Spirit, Sol 446

(http://marsrovers.nasa.gov/gallery/press/spirit/20050506a/dd_enhanced_456e-A476R1.gif)

This movie clip shows a single dust devil -- a whirlwind that lofts dust into the air -- that passed near the bottom of the hillside where NASA's Mars Exploration Rover Spirit was located at the time. A shorter clip of the same dust devil was release previously PIA-07861, but an additional frame of the sequence was sent later by the rover. The proximity of the dust devil makes this sequence the best obtained so far for showing details of its structure. Spirit's navigation camera took these images on the rover's 446th martian day, or sol (April 15, 2005.) Contrast has been enhanced for anything in the images that changes from frame to frame, that is, for the dust devil.

Scientists expected dust devils since before Spirit landed. The landing area inside Gusev Crater is filled with dark streaks left behind when dust devils pick dust up from an area. It is also filled with bright "hollows", which are dust-filled miniature craters. Dust covers most of the terrain. Winds flow into and out of Gusev crater every day. The Sun heats the surface so that the surface is warm to the touch even though the atmosphere at 2 meters (6 feet) above the surface would be chilly. That temperature contrast causes convection. Mixing the dust, winds, and convection can trigger dust devils.

Image credit: NASA/JPL

Several Dust Devils in Gusev Crater, Sol 461

(http://marsrovers.nasa.gov/gallery/press/spirit/20050506a/dd_enhanced_461be-A476R1.gif)

This movie clip shows a several dust devils -- whirlwinds that loft dust into the air -- moving across a plain below the hillside vantage point of NASA's Mars Exploration Rover Spirit. Several of the dust devils are visible at once in some of the 21 frames in this sequence. The local solar time was about 2 p.m., when the ground temperature was high enough to cause turbulence that kicks up dust devils as the wind blows across the plain. The number of seconds elapsed since the first frame is indicated at lower left of the images, typically 20 seconds between frames. Spirit's navigation camera took these images on the rover's 461st martian day, or sol (April 20, 2005.) Contrast has been enhanced for anything in the images that changes from frame to frame, that is, for the dust devil.

Scientists expected dust devils since before Spirit landed. The landing area inside Gusev Crater is filled with dark streaks left behind when dust devils pick dust up from an area. It is also filled with bright "hollows", which are dust-filled miniature craters. Dust covers most of the terrain. Winds flow into and out of Gusev crater every day. The Sun heats the surface so that the surface is warm to the touch even though the atmosphere at 2 meters (6 feet) above the surface would be chilly. That temperature contrast causes convection. Mixing the dust, winds, and convection can trigger dust devils.

Image credit: NASA/JPL

Dust Devils in Gusev Crater, Sol 463

(http://marsrovers.nasa.gov/gallery/press/spirit/20050506a/dd_enhanced_463e-A476R1.gif)

This movie clip shows a several dust devils -- whirlwinds that loft dust into the air -- moving across a plain below the hillside vantage point of NASA's Mars Exploration Rover Spirit. Several of the dust devils are visible at once in some of the frames in this sequence. The local solar time was about 2 p.m., when the ground temperature was high enough to cause turbulence that kicks up dust devils as the wind blows across the plain. The number of seconds elapsed since the first frame is indicated at lower left of the images, typically 20 seconds between frames. Spirit's navigation camera took these images on the rover's 463rd martian day, or sol (April 22, 2005.) Contrast has been enhanced for anything in the images that changes from frame to frame, that is, for the dust devil.

Scientists expected dust devils since before Spirit landed. The landing area inside Gusev Crater is filled with dark streaks left behind when dust devils pick dust up from an area. It is also filled with bright "hollows", which are dust-filled miniature craters. Dust covers most of the terrain. Winds flow into and out of Gusev crater every day. The Sun heats the surface so that the surface is warm to the touch even though the atmosphere at 2 meters (6 feet) above the surface would be chilly. That temperature contrast causes convection. Mixing the dust, winds, and convection can trigger dust devils.

Image credit: NASA/JPL

Large Dust Devil on Horizon, Sol 468

(http://marsrovers.nasa.gov/gallery/press/spirit/20050506a/dd_enhanced_468-A476R1.gif)

This movie clip shows a large, distant dust devil -- a whirlwind that lofts dust into the air -- as a dark shape on the horizon near the right side of the images. This dust devil was about 5 kilometers (3 miles) away from NASA's Mars Exploration Rover Spirit, and may have been up to 200 meters or yards in diameter. Smaller dust devils closer to the rover appear bright against the dark ground. Spirit's navigation camera took these images on the rover's 468th martian day, or sol (April 27, 2005.) Contrast has been enhanced for anything in the images that changes from frame to frame, that is, for the dust devil. The number of seconds elapsed since the first frame is indicated at lower left of the images, typically 20 seconds between frames.

Scientists expected dust devils since before Spirit landed. The landing area inside Gusev Crater is filled with dark streaks left behind when dust devils pick dust up from an area. It is also filled with bright "hollows", which are dust-filled miniature craters. Dust covers most of the terrain. Winds flow into and out of Gusev crater every day. The Sun heats the surface so that the surface is warm to the touch even though the atmosphere at 2 meters (6 feet) above the surface would be chilly. That temperature contrast causes convection. Mixing the dust, winds, and convection can trigger dust devils.

Image credit: NASA/JPL

COSMIC SECRETS
The Enigmas on Mars Page 51a (http://www.thelivingmoon.com/43ancients/02files/Mars_Images_51a_Dust_Devil.html)
Dust Devil Videos [/url]