Lake Shalbatana
Jun 26, 2009

"Water, water, everywhere,
Nor any drop to drink."

The Rhyme of the Ancient Mariner
--- Samuel Coleridge

In June of 2007 scientists from the University of California suggested that they had found “confirmations” for the Martian liquid ocean hypothesis. Their analysis of Martian topography seemed to show two “shorelines” extending for thousands of kilometers, although the oceans have been gone for over two billion years.

In another more recent press release, a team from the University of Colorado announced that they also found "shorelines," although in this case they are supposed to have bordered a large lake that existed around the same time as the oceans, a little over three billion years ago. Chief scientist Gaetano Di Achille wrote: "This is the first unambiguous evidence of shorelines on the surface of Mars. The identification of the shorelines and accompanying geological evidence allows us to calculate the size and volume of the lake, which appears to have formed about 3.4 billion years ago."

The lake is thought to have been 130 square kilometers in area and almost 1500 meters deep.

The Mars Global Surveyor (MGS) entered orbit in 1997 with extremely high resolution cameras onboard. Some of the first few images revealed huge outcrops of layered rock extending for thousands of kilometers through the Schiaparelli Basin and out into Valles Marineris. Hundreds more images uncovered rock layering in other locations: particularly craters and giant cliff walls with extensive faulting and pitting. The layers with similar thickness prompted NASA scientists to conclude that the strata in Schiaparelli Basin is actually sedimentary, and might have built-up in water and then been eroded by wind.

It is believed that Mars is covered with a global layer of ice because the annual temperature of the soil is approximately minus 50 Celsius. It is so cold in the northern and southern latitudes that carbon dioxide freezes into solid dry ice. Any water "must be" bound up with the icy soils or locked in underground deposits, otherwise the thin atmosphere would cause water-ice to sublime directly into vapor.

In the last few years, several Mars missions have sought to confirm the existence of water in some form or another on the Red Planet. Although there have been reports of clouds and low-lying fog, and the Phoenix polar lander is reputed to have detected water just below the surface, there has been nothing definitive that can stand up to close scrutiny. For example, although the now defunct Phoenix lander is said to have found visual evidence for water, the probes used to test for water in the soil returned a null reading. The soil was nonconductive, indicating no water molecules.

The Mars Reconnaissance Orbiter (MRO), which resumed operations after a software glitch shut down its systems on June 2, 2009, found what were said to be giant glaciers under mountainous piles of rocks and dirt near the Hellas Basin region. Several other locations in the lower Martian latitudes are thought to harbor ice deposits as large as those in Antarctica, if the radar images taken in November 2008 are interpreted correctly.

The MRO uses its radar to penetrate a few meters below the Martian surface so that it can look for variations in reflectivity. The deeper the radar penetration before it bounces back, the less dense the intervening material. Based on the strength of the return signal, the MRO's computers determined that it matched the signature of ice just beneath a shallow covering of rock, much like a glacier on Earth.

The only way that Mars researchers can imagine a radar signal's behavior is to be guided by their tests of the instrumentation. If a radar signal takes X amount of time to bounce back, it is passing though sand. If it takes Y amount of time to return, it is passing through pure ice with a thin coating of rocks. The fact that the radar signal matches a pre-loaded configuration is not necessarily an indicator of finding the desired elements. There could be factors on Mars that are so unlike those here on Earth that the radar could be acting in ways that were unanticipated, making ice the nearest match.

It is feasible, however, that there are ice deposits on Mars that were created when it underwent whatever planetary catastrophe it was that significantly altered its surface. In previous Thunderbolts Picture of the Day articles about the geology of Mars, we speculated that powerful electric arcs once excavated the planet in the recent past. These plasma discharges left behind sinuous rilles, flat-floored craters, "railroad track" patterns in canyons, intersecting gullies with no debris inside them, giant mesas with Lichtenberg "whiskers" and steep-sided ravines.

Lightning of sufficient power can compress material in the discharge channel and accelerate it along with the negative charge, forming a jet. If the jet contains water vapor, it is possible that liquid water molecules or even ice might form inside the spinning Birkeland filament due to z-pinch effects. If this phenomenon were to be scaled up to planetary dimensions, the increased electric discharges might have formed increased quantities of ice particles that clumped together and fell back into the frozen piles of debris that MRO's imagers allegedly detected.

It is still too early to tell. New Mars missions are being planned that will place robotic vehicles near the areas of greatest potential. Some will collect samples and then launch them back to Earth.

If what we find on Mars took place in the presence of interplanetary lightning bolts and was not the result of ice or water moving across the surface, should we rethink what we see on Earth? Perhaps those electric arcs formed the ice deposits on Earth, as well, and not some climatic fluctuation of whatever shape. If such is the case, then the changes in climate occurring today could be the last stages of a readjustment after an upheaval not so long ago.

Stephen Smith