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The
South Pole of Mars
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Location
of frozen water on Mars
The place on Mars where scientists know
there is most water is the martian polar ice
caps. They are very similar to our own polar ice
caps here on Earth. The martian north ice cap is
about 4 kilometers thick. If all that water were
spead evenly over the surface of Mars it would
make a layer about 15 meters thick. The next
likely place to find alot of frozen water is
ice-rich permafrost. The Martian permafrost is
several kilometers thick all over the globe and
could be as much as 50% ice, but scientists don't
know for sure how much ice is in the permafrost.
Moisture
in Mars soil
The atmosphere is not saturated with water
vapor for most of the day. If liquid water were
present in the top few millimeters of the soil,
it would quickly evaporate and diffuse into the
atmosphere. The water molecules that are left
behind are bound more strongly to the grains, so
they do not evaporate as readily.
Given the primary
function of liquid water in living organisms--as
a medium through which nutrients can diffuse in
and waste products can diffuse out-- it is
unlikely that adsorbed water can do the job. This
does not rule out the possibility of Martian
life. However, to find the life, you should look
for places where water is both present and stable
as liquid. This might be deep below the surface
(where temperatures are higher and diffusion to
the surface is inhibited) or near the most recent
volcanism (where liquid water might be present in
hot springs or hydrothermal systems).
from Questions and Answers about
Water and Ice on Mars
-- Mars
Team Online, Nasa
Water
Droplets from Mars
Six of the [Martian] meteorites
were used in the water extraction procedure. ...
heated in steps in a small vacuum system at JSC
[Johnson Space Center] to extract trace amounts
of water. The water samples were hand-carried to
the University of Chicago for analysis of oxygen
isotopes. Although the water droplets were less
than 1/64ths of an inch in diameter, it was
enough to do the analysis.
The analysis
determined that the oxygen isotopes in the water
were different from the oxygen isotopes in the
silicate portion of the meteorites. In other
words, the water had a different parent source
than the oxygen in the silicate minerals in the
meteorites. That parent source could have been
the Martian atmosphere, an ancient Martian ocean
or even a comet that impacted the planet.
The lack of
homogeneous oxygen isotopes on Mars supports the
theory that Mars does not have plate tectonics.
If such a process had been active on Mars, the
oxygen isotopes would have been homogenized as
they are on Earth.
from Water Extracted From Mars
Meteorites Provide Clue to Red Planet's Past
-- Jet
Propulsion Laboratory
Water
from Mars (H. Karlsson, E. Gibson,
JSC). This drop of water extracted
from a martian meteorite has the
unique stable isotope composition of
martian crust.
from Water on Mars
"The
morphology of Mars indicates that abundant liquid
water existed in its early history. Where did
this water come from and where did it go?"
-- Life on Mars? Nasa
Alternative
Hypothesis for the Presence of Liquid Water on
Mars
Dr. Levin [principal investigator
on the Viking Mission Labeled Release Experiment
in 1976] described a dynamic daily cycle on Mars
in which the extreme cold of the Martian
atmosphere greatly restricts its ability to hold
water vapor. Thus, the scant water vapor on Mars
is forced down to the surface, where it is
deposited in frozen form. As the sun rises, the
ice melts, but its evaporation is restricted by
the low vapor capacity of the overlying cold
atmosphere. Levin cited Pathfinder's results to
show that the atmosphere immediately above the
surface warms considerably, equaling a spring day
on Earth, but, just a couple of feet above the
surface, temperatures are sub-freezing. The
warmed surface layer of air absorbs water vapor
until saturated. No more water can then evaporate
from the surface, and the ice remaining there
melts into liquid water. As the sun mounts, the
temperature of the atmosphere above the surface
warms sufficiently to permit any remaining water
and ice to evaporate. However, during this daily
cycle, the soil has been moistened with enough
water to sustain microorganisms.
Researcher presents case
for liquid water on Mars
-- Press
release
A New Case for Liquid Water
on Mars
"A
father-son team of scientists, including one who
worked on the Viking missions in the mid-1970s,
believe that liquid water -- in limited amounts
and for limited times -- can exist on present-day
Mars."
-- Spaceviews.com, National Space Society,
7/23/98
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