New Mars Forums

Does Mars have enough mass to exert enough of a gravitational force to keep the right kind of atmospheric gases at the right atmospheric pressure that would allow water to ever flow in a liquid state on the surface?  Gravity and mass are directly proportional. If the atmospheric gases are not the right kind then liquid water could not exist on the surface long enough to cause the errosion formed features seen.  If the atmospheric pressure is too low then liquid water could not exist at all.  Heavy gas molecules could form an atmosphere on a low gravity planet, but would the chemical interaction between the atmosphere and any water on the surface allow the water to exist long enough to cause the type of errosion seen on the surface of Mars?

People look at surface features on Mars and see that they resemble water formed surface features on Earth and thus claim that water had to have flowed on the surface of Mars sometime in its past to form those features there, too.  There is no place on the surface of Earth that has not be affected by water, so there is no way to know if those kind of surface features could be formed by anything else.  How do we know that billions of years of fine sand blowing over a surface could not form those features on Mars?  Couldn't the canyons seen on the Mars be formed by the planet expanding and contracting due to some other force? 

  It would be fantastic if surface water could exist on Mars.  I think that we should have had a manned mission to Mars a long time ago.  It would be nice, though, if someone could address those questions I have about Mars water.