The weather conditions on Mars are chaotic
and unpredictable. The sky can be pink and cloudless, filled with dust
blown from the Martian surface or filled with ice clouds which form as
the temperature drops. The shift in weather is due to three important
factors: the thin atmosphere, the elliptical orbit around the sun, and
the strong interactions between dust and ice clouds in the atmosphere.
Mars has permanent ice caps at both poles composed mainly of solid carbon
dioxide (dry ice). They exhibit a layered structure with alternating layers
of ice and dust. In the north, during summer, the carbon dioxide completely
sublimes (converts from solid to gas), leaving a residual layer of water
ice. It is unknown if a similar layer of water ice exists below the southern
caps since its carbon dioxide layer never completely disappears. The mechanism
responsible for the layering may be the climate changes in the inclination
of Mars' equator to the plane of it's orbit. There may also be water ice
hidden below the surface at lower latitudes. In addition, seasonal changes
cause changes in the global atmospheric pressure by about 25% (as measured
at the Viking lander sites).
Mr Slingsby has guests
Mr Slingsby was happy with his brand new home way out in the middle of
the Hellas basin, but he was more than a little concerned when representatives
of the area's original inhabitants paid him a visit. He strongly suspected
they were not about to engage him in small talk and ask after his health.
On reflection he thought the use of nuclear weapons to terraform the region
was just a little insensitive to the native species rights and requirements.
Dogs make very good pets, but very poor neigbours.