Rotation value (day)of 24 hours, 37 minutes, 22.7 seconds
In July of 1965, Mariner 4, transmitted 22 close-up pictures of Mars. All that was revealed was a surface containing many craters and naturally occurring channels but no evidence of artificial canals or flowing water.
Finally, in July and September 1976, Viking Landers 1 and 2 touched down on the surface of Mars. The three biology experiments aboard the landers discovered unexpected and enigmatic chemical activity in the Martian soil, but provided no clear evidence for the presence of living microorganisms in the soil near the landing sites. According to mission biologists, Mars is self-sterilizing. They believe the combination of solar ultraviolet radiation that saturates the surface, the extreme dryness of the soil and the oxidizing nature of the soil chemistry prevent the formation of living organisms in the Martian soil. The question of life on Mars at some time in the distant past remains open
Mars Exploration Rovers - USA Two Mars Rovers - 22 May/4 June 2003
Mars Express - ESA Mars Orbiter and Lander - 1 June 2003
Mars Reconnaisance Orbiter - USA Mars Orbiter - (July 2005)
There is evidence that in the past a denser martian atmosphere may have allowed water to flow on the planet. Physical features closely resembling shorelines, gorges, riverbeds and islands suggest that great rivers once marked the planet.
Not such a bad place to visit, and you couldn't live there.
Mars has a thin atmosphere:
Here is a comparison of the atmospheric composition of Earth and Venus and Mars. I list the number of molecules per m2 of surface area of the planet in each planet's atmosphere relative to the total number of molecules per m2 in Earth's atmosphere.
Minimum surface temperature -140°C
Mean surface temperature -63°C
Maximum surface temperature 20°C
Atmospheric pressure (bars) 0.007
Carbon Dioxide (C02) 95.32%
Nitrogen (N2) 2.7%
Argon (Ar) 1,6%
Oxygen (O2 0,13%
Carbon Monoxide (CO) 0.07%
Water (H2O) 0.03%
Neon (Ne) 0.00025%
Krypton (Kr) 0.00003%
Earth Venus Mars
N2 0.79 2 3 x 10-4
O2 0.20 < 0.001 10-7
Ar 0.01 0.005 2 x 10-4
CO2 0.0003 64 0.009
H2O ~ 0.02 ~ 0.01 ~10-6
Total 1.00 90 0.01
H2O 3 km 0.5 mm small
(A technical note: This is based on a pressure ratio of 0.0056/1,
a surface gravity ratio of 0.38/1.0, and a mass per molecule
ratio of 1.5/1.0 for Mars/Earth.)
Note that Mars has more carbon dioxide in its atmosphere than does Earth, but Mars has a lot less of everything else.
In cold weather, find H2O frost on the surface.
There is CO2 ice in polar caps. Most of it evaporates in summer.
Water ice in the polar caps. Maybe some under the surface. But how much?
How about liquid water?
Really, it can't exist?
Where did the atmosphere go?
·Presumably it started out something like Venus.
·Put most of CO2 in rocks (using rainfall), as on Earth.
·Then the weaker gravity of Mars wasn't able to hold the rest of the atmosphere.
oUltraviolet light helps by breaking up molecules so that they are light enough to escape.
·Not enough volcanos to replenish the atmosphere.
oNo plate tectonics.
ASTR 121 Home http://zebu.uoregon.edu/~soper/Mars/water.html
Davison E. Soper, Institute of Theoretical Science, University of Oregon, Eugene OR 97403 USA email@example.com
copyright bluediamonds 2004
This artist's rendition depicts the response of the solar wind to the obstacle - the planet Mars - in it's path. A supersonic 'solar wind' consisting of electrically charged particles (ions and electrons) streams off the Sun into space. It is slowed to subsonic speeds in the vicinity of Mars at a parabolic surface called a 'bow shock' upstream of the planet. Here, the magnetic field fluctuates wildly and the flow of the solar wind becomes chaotic. Part of the orbital trajectory of the Mars Global Surveyor is indicated, with MGS approaching the planet just prior to over-flight of the pole