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Tales of
Dust storms
seen on Mars (cont'd) ...
Local dust storms, regional obscurations, and discrete "yellow" clouds on Mars have been reported throughout the last century; however, it is the planet-encircling dust storms that have captured our attention in the age of spacecraft exploration of Mars. Timeline: Dust storms on Mars 1796 Astronomer H. Flaugergues noted "yellow clouds" (now known to be clouds of dust) on Mars as opposed to fleecy, whitish water-ice clouds. 1920 Patchy, yellow dust clouds observed and photographed at Lowell Observatory in Arizona. 1956 First extensive observations of a planet-encircling dust storm on Mars. 1965 Mariner 4 conducts first fly-by of Mars; sends back dust-free photographs of a narrow swath of the planet. 1969 Mariners 6 and 7 fly by Mars to photograph clear and cool atmospheric conditions. 1971 The first Mars-orbiting spacecraft (Mariner 9) arrives to find the planet already shrouded in dust the first definitive planet-wide dust storm ever seen. The dust covered everything except the poles; tall volcanic peaks poked above the dust, revealing themselves as high mountains rather than as circular basins. 1973 Ground-based telescopes detect another planet-encircling dust storm just one Martian year after the global storm viewed by Mariner 9. 1977 Viking spacecraft watch two planet-encircling Martian dust storms in succession from a Mars orbit and, for the first time, from the surface of Mars. 1982 Viking Lander 1 detects what appears to be another planet-encircling dust storm just weeks before the loss of communications ends its nearly seven-year observational record on the surface of another planet. 1994 Ground-based microwave monitoring of Mars atmospheric temperatures indicates a planet-encircling dust storm in progress, the first such planet-wide storm detected since Viking. 1997 Mars Global Surveyor begins aerobraking at Mars and finds that planet-wide warming events can be produced by as little as a regional dust storm. 2001 In late June the Hubble Space Telescope
captures a Mars opposition photograph. (Opposition occurs when Earth lies in
a straight line between the Sun and an outer planet.) The image shows seasonal
dust activity in Hellas and at the North Pole. In a few weeks, these regional
dust storms developed into a near-global, planet-encircling dust storm. Unprecedented
details of this unusually early, blossoming storm were followed by the Mars
Global Surveyor, which takes daily all-planet images and measures atmospheric
temperatures. Page: 1 2
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Capture the cosmos > Solar system > Dig deeper (cont'd) > Tales of: Dust storms on Mars |
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