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explorer appears awestruck as an oncoming dust storm - although still some 40
kilometers away - moves across the surface at speeds up to one-hundred kilometers
per hour. These dust storms can rise to great heights as fine iron-oxide dust
particles race through the mostly carbon dioxide atmosphere.
Such dust storms are caused by the planets extremely thin atmospheric pressure
- little more than 1% compared to the atmospheric pressure on Earth - which creates
large temperature differentials resulting in high winds as adjacent areas of the
planet rapidly heat up or cool down. This
condition of 'heating-up-and-cooling down' is further enhanced when the planets'
southern hemisphere is tilted towards the sun - which occurs during Mars' closest
approach to the sun during the Martian 'summer'.
Typical temperature range at the surface is 100-degrees F. (38-degrees C.) between
the warmest and coldest part of the day - with the average daily temperature being
-60 degrees F - about the same as a nice day in Antartica on Earth. This
storm is moving over the far wall of a dune-filled crater as it approaches. Although
the astronaut should be seeking shelter - such storms are not considered unusual,
and several planet-wide storms that have lasted for months have been recorded. But
caution should always be the norm - as this storm lifts untold numbers of extremely
fine particles of dust and grit that can scour a helmets' face-plate opaque, or
even find its way into space-suit flex-joints or into precision life-support equipment.
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