Hard Evidence Of Liquid Water On Mars Today

Contrary to what we have been told, liquid water is present on Mars now

Short answer first

   Mars can indeed support liquid water on its surface during the daytimes, particularly in the summers.  This is supported by data of its temperature, air pressure, and the phase diagram for water.  Here is a NASA link stating that liquid water is responsible for many features on the planet.  Only geothermal heat and a thicker atmosphere are needed to convince the authors.  And we know that Mars had a much thicker atmosphere in its past, and that geysers are active today.  Here is a link to scientists and their results.  And here is another article where vacuum chamber tests show that water can exist on Mars' surface today.

    Here is another link showing that liquid water can exist on Mars.  This link States: ""According to the model, the highest surface pressure, 12.4 millibars, occurs at the bottom of the Hellas Basin (a low-lying area created by an ancient asteroid strike). The problem is that the boiling temperature there is only +10 °C. It can't get very hot or the water will boil away."  Take note that this would be 50° F, so it means that even without salts present, there is a range of 32° to 50° in that area where liquid water can exist.  And, as the article points out, large quantities of water ice are suspected all over the planet.  Here is the map showing the presence of water on Mars.

Cut to the chase, show me the pictures!

Long answer with technical details here

   We have always been told that due to Mars' extremely thin atmosphere, liquid water could not exist on its surface.  We have seen the evidence in the form of dune fields, dry, rocky plains and craters, and a general desert appearance overall.  The only water on Mars, we have also been told, would be in the form of frost that evaporates immediately, or as ice in the polar caps.  Lately, it has even been suggested that some ice might exist underground in the form of permafrost.  More detailed analysis of the polar ice.    Another polar ice link for THEMIS data.

   Still, we look at those Hubble pictures showing clouds over the planet, and we look at the Viking data that showed the atmosphere is at nearly 100% relative humidity all the time, and we wonder.  Could there actually be water on the surface?  Could there have been in recent times?  What, really, are the requirements for liquid water?

   First, water has a boiling point that changes with air pressure, like many liquids.  On Earth, we refer to sea level air pressure as our standard, and at that pressure (1,000 millibars) the boiling point of water is 100° C.  As we climb in altitude, the pressure decreases, and the boiling point of water drops.  That is why recipes always state different cooking times for people who live at higher altitudes.  Cities on mountains are at slightly lower atmospheric pressures, and since water boils at a lower temperature, it takes longer to cook foods.

   Pressure cookers hold an extra atmosphere of pressure inside and raise the boiling point of water- that means that foods get hotter in the water and cook much faster.  A roast in a pressure cooker can be done in 25 minutes or less.  On Mars, we have the same problem that mountain dwellers have, only much more so.

   With a low enough air pressure, the heat of a comfortable room is more than enough to cause water to boil.  In a true vacuum, water literally explodes into boiling, leaving a large amount behind as ice crystals and the rest blown into the vacuum as a gas.  But just how much air pressure does Mars have, and what would the boiling point of water be there?

Boiling point and atmospheric pressure

   If we consult a physics text, we soon learn that boiling point is controlled by something called "vapor pressure".  We also learn that adding salt to water raises its boiling point, which means that salty water or brine will be more resistant to evaporation in low air pressure.  We also know that NASA found a lot of salts on the surface of Mars, which will change the boiling point in our favor.

   Lowering air pressure, as we see above, also lower boiling point.  To find out what temperature water will boil at, we can consult a state diagram for water that takes air pressure and dissolved materials into account.  But locating that sort of thing can be difficult at best.

   Our first step is to find a standard state diagram or a boiling point vs. pressure table.  Once we have that in hand, we then have a reasonable starting point to work from.  Barring that, a good saturated vapor pressure table for water will perform just as well.

   Looking at the table, we see that if the atmospheric pressure is as high as 10 millibars (not at all unreasonable for Mars), the boiling point of water would be about 7° C or about 45° F.  This means that at that low pressure, water can indeed be a liquid.  So now we need to ask two questions- how warm is it and how much air pressure is there?

   Just consulting the vapor pressure table clears things up nicely- now we only need the atmospheric pressure on Mars to tell the rest of the story.  There are significant variations from location to location- due to the "altitude", just as on Earth.  And, seasonal variations make a huge difference, as Viking found.  Melting of the polar caps introduces lots more carbon dioxide into the atmosphere, raising both the pressure and the temperature greatly.

   This site provides a great deal of weather and air pressure information from both Viking and Pathfinder.  We can see that the air pressure in Meridiani Planum should vary from about 6 millibars to about 9 millibars over the course of the year.  With those numbers in hand, we can calculate the boiling point of water from the vapor pressure table.  We find that water will boil at about 1° C (34° F) during the winter when air pressure is lowest, and at about 7.5° C (or 45° F) during the summer.

   Now we only need to know the temperatures to determine if Mars gets hot enough to boil water.  In the winter, it can be expected that pure water will exist only as ice, and it will sublimate away slowly.  In the summer, water can exist quite nicely as a liquid, as the surface temperatures do not get very hot- Mars is very much like Antarctica in that respect.  Overall, Mars has a maximum temperature of 20° C (68° F) and a minimum of -140° C (-220° F).

   As it turns out, once we add salt to the equation, water can be liquid in a broad range of temperatures on Mars.  It can be cooled to about -22° C (-7.6° F) without freezing, and can take temperatures of up to about 7.2° C (45° F) before it boils.  So the answer is "yes, liquid water can exist on Mars".

    As an aside, recent work by NASA has confirmed this.  I would think that as important as this information is, they would publicize this result.  However, I have heard nothing on the news and had to resort to web searching to locate it in some unpublicized items.  This is very important and to not capitalize on it is a shame.  NASA could gain great increases in support and funding with this one bit of information.

    Quote:  "First of all, you have to remember that the average atmospheric pressure on Mars is very close to the triple point of water," explains Richard Hoover, an astrobiologist at the Marshall Space Flight Center. "You only have to increase the pressure a little bit to make liquid water possible."

    Quote:  "I have also seen liquid water running from snow melting on dark rocks heated by sunlight in Antarctica, even though the air temperature was below -20 °C."  Richard Hoover, astrobiologist, on his visit to the Matanuska Glacier in Alaska

Is there water on Mars?

   There is lots of evidence from satellites orbiting the planet now.  Here is one such article.  There is also huge evidence of oceans and large lakes on the planet in the past, all confirmed by NASA.  And NASA has also stated that Mars was once "drenched in water" in their words.  Furthermore, satellites suggest that there is more ice than soil in some locations and that is supported by Viking lander's footpads sinking 16 inches into the soil, and by the poor traction that Opportunity had getting out of Eagle Crater.  The soil is a fluffy mass that has been laced with ice crystals and compresses very easily.  Here is a neutron absorption map of water ice on Mars today.

    Quote from this article in Space.com:

One scientist eagerly awaiting the news from Mars, particularly from Opportunity, is Gilbert Levin. He is Chairman of the Board and Executive Officer for Science of Spherix Incorporated in Beltsville, Maryland.

Levin is a former Viking Mars lander investigator. He has long argued that his 1976 Viking Labeled Release (LR) life detection experiment found living microorganisms in the soil of Mars.

In 1997, Levin reported that simple laws of physics require water to occur as a liquid on the surface of Mars. Subsequent experiments and research have bolstered this view, he said, and reaffirms his Viking LR data regarding microbial life on Mars.

Levin detailed his Mars views in a Space.com phone interview and via email.

"It's hard to image why such bullet-proof evidence was denied for such a long time, and why those so vigorously denying it never did so by meeting the science, but merely by brushing it away," Levin said.

"Of course, now that it must be acknowledged by all that there is liquid water on the surface of Mars," Levin added, "this starts those denying the validity of the Mars LR data down the slippery slope leading to life."

    So is there water on the planet now?  We can see for ourselves from these images that have been returned by Opportunity.

NEXT

Thanks to R. H. Logan, Instructor of Chemistry, Dallas County Community College District, North Lake College for a great page on solutes and boiling point.

Thanks to James E. Tillman for the excellent pages summarizing Viking and Pathfinder weather data for Mars.