I was prone on the living room couch Sunday, listening to rain tap-tap-blapping on the air conditioner outside, the sound of cars sloshing like motorboats along the street, and watching through the venetian blinds as rain slashed in front of the big cedar. And I thought of a remarkable discovery announced by NASA: liquid water on Mars.
Sustainer of all life on Earth, water in its liquid stage may have been photographed on the red planet.
For many decades, liquid water was thought to be impossible on Mars. Once the planet may have hosted oceans, and it certainly has ice today. Ancient channels that pour around bends prove the existence at one time of rivers, possibly created when an asteroid crashed into the surface, heating the ground enough to free water, which gushed and flowed and eventually evaporated.
Following a wet period millions of years ago, Mars lost almost all its atmosphere until today the atmospheric pressure is only 1 percent as dense as Earth’s. Just as water boils more rapidly at higher elevations than at sea level in this world, because atmospheric pressure is less, liquid water would boil off quickly on Mars. That wasn’t just the theory, it was practically an accepted truth.
But maybe it wasn’t true.
Phornix Mars Lander made important discoveries during its short working life, which was from its descent onto the Martian Arctic on May 25, 2008, until it ran out of solar power in the long shadows of winter, Nov. 2, 2008.
On Sept. 29, 2008, NASA announced that it had detected snow falling from Martian clouds. A brief movie apparently showing a few flakes heading toward ground is posted here HERE.
Earlier, white material that appeared in a trench the lander dug was verified as water ice. The little laboratory also photographed morning frost at the landing site. See a view of the frost by CLICKING HERE.
The problem is, snowfall, frost and ice are not liquid water; and as far as we know, water must be in the flowing phase to maintain life. (However, I wouldn’t rule out organisms extracting water from ice, as nitrogen-fixing bacteria free nitrogen from the soil and supply it to beans.)
The latest from Phoenix Mars Lander scientists is that they may have photographed droplets of liquid water.
“A large number of independent physical and thermodynamical evidence shows that saline water may actually be common on Mars,” said Nilton Renno, co-investigator for the Phoenix project. Renno, a professor at the University of Michigan, Ann Arbor, was quoted in a March 17 press release sent out by that university.
The lander photographed one of its legs at three different times. Droplet on the legs darkened and coalesced, says the release. Renno contended that was because they contained liquid water. To see the the three images, CLICK HERE.
Why didn’t the water freeze? It was too salty, according to the new theory. Salt is an antifreeze, insuring that Earth’s seawater won’t solidify. How did the Mars droplets get on the lander? As it settled onto the surface, the craft’s rockets melted ice, which was under a thin sheet of soil. At the same time, droplets splashed onto its legs. There they stayed, not freezing and not sublimating into the air, a salty, muddy liquid that slowly crept and merged.
“The wet chemistry lab on Phoenix found evidence of perchlorate salts, which likely include magnesium and calcium perchlorate hydrates,” the release adds. These would have freezing points of about -90 F. and -105 F., respectively, it says. The landing site’s median temperature was -75 F., although it ranged from -5 F. to -140 F. “Temperatures at the landing site were mostly warmer than this during the first months of the mission,” it adds.
In our world, water need not be liquid continuously for organisms to survive. Numerous species of plant and animal life suspend action during cold periods and revive when the temperature is more pleasant. From insects to bears, many animals hibernate.
“Certain bacteria on Earth can exist in extremely salty and cold conditions,” the release points out.
That does not mean life exists on Mars. But it does increase the possibility.
The next time you hear rain, think of Mars, its frost, snow, probable water — and life?