TY - CHAP

T1 - Polar caps

AU - Hvidberg, Christine S.

PY - 2005/1/1

Y1 - 2005/1/1

N2 - The permanent polar caps of Mars constitute the largest known reservoirs of H 2 O on the planet. The permanent caps are distinguished from the seasonal snow covers that have been known for centuries. The seasonal snow consists of CO 2 that condenses out of the atmosphere in the winter hemisphere [8]. During summer, the seasonal snow cover gradually evaporates, and the permanent cap is exposed. The permanent polar caps are recognisable as topographic domes rising about 3 km above the surrounding terrain. They have an extent of around 1000 km in the north and 400-800 km in the south. They consist of layers of H 2 O, dust and CO 2 that have been deposited through millions of years. Bright white areas indicate a currently active interaction with the Martian climate system. Dark areas reveal an extensive layering thought to preserve a record of climate changes on Mars. The caps may contain preserved samples of biological origin, and geological indications of meltwater may be a clue to subsurface environments where life might exist. The polar regions are thus particularly interesting in relation to the search for life on Mars.

AB - The permanent polar caps of Mars constitute the largest known reservoirs of H 2 O on the planet. The permanent caps are distinguished from the seasonal snow covers that have been known for centuries. The seasonal snow consists of CO 2 that condenses out of the atmosphere in the winter hemisphere [8]. During summer, the seasonal snow cover gradually evaporates, and the permanent cap is exposed. The permanent polar caps are recognisable as topographic domes rising about 3 km above the surrounding terrain. They have an extent of around 1000 km in the north and 400-800 km in the south. They consist of layers of H 2 O, dust and CO 2 that have been deposited through millions of years. Bright white areas indicate a currently active interaction with the Martian climate system. Dark areas reveal an extensive layering thought to preserve a record of climate changes on Mars. The caps may contain preserved samples of biological origin, and geological indications of meltwater may be a clue to subsurface environments where life might exist. The polar regions are thus particularly interesting in relation to the search for life on Mars.

KW - Basal melting

KW - Mars orbiter laser altimeter

KW - Seasonal snow cover

KW - Sublimation rate

KW - Thermal emission spectrometer

UR - http://www.scopus.com/inward/record.url?scp=85066052718&partnerID=8YFLogxK

U2 - 10.1007/978-3-540-31538-4_6

DO - 10.1007/978-3-540-31538-4_6

M3 - Book chapter

AN - SCOPUS:85066052718

T3 - Advances in Astrobiology and Biogeophysics

SP - 129

EP - 153

BT - Advances in Astrobiology and Biogeophysics

PB - Springer Verlag

ER -