On Wednesday, the Phoenix lander performed the first-ever wet chemistry experiments on the Martian surface. According to the scientists behind the Microscopy, Electrochemistry and Conductivity Analyzer, the data coming back is like "winning the lottery." So far, the first round of wet-chemistry experiments are approximately 80 percent complete, and the lander has three more chemistry sets on board to use at a later date.
This week's results are from a single scoop of Martian soil. The science pack was designed to understand the wet chemistry of the soil: what is dissolved in it, and how acidic or alkaline it is. The initial results showed that the soil is very basic, as the pH was measured at between eight and nine. In addition to the basic nature of the soil, the instrument found a host of salt components. Those identified so far include magnesium, sodium, potassium, and chlorine, and the analysis is not yet complete. According to co-investigator Sam Kounaves of Tufts University, science lead for the wet chemistry investigation, these salt findings are simply further evidence of water.
How does this out-of-the-world soil compare to Earth? According to Kounaves, "This soil appears to be a close analog to surface soils found in the upper dry valleys in Antarctica. [...] Over time, I've come to the conclusion that the amazing thing about Mars is not that it's an alien world, but that in many aspects, like mineralogy, it's very much like Earth."
While this instrument has provided a wealth of data, it is not the only chemical analysis currently being undertaken on the Martian surface. The Thermal and Evolved-Gas Analyzer (TEGA) has baked a soil sample up to 1,800oF to examine the gases released at various temperatures, which can provide a large amount of data. In this case, the analysis is very complicated and it's expected to take a few more weeks until the results are known.
Coupled with the previous results, where the lander uncovered water ice that later sublimed, these new discoveries strengthen the idea that liquid water once existed on the surface. "At this point, we can say that the soil has clearly interacted with water in the past. We don't know whether that interaction occurred in this particular area in the northern polar region, or whether it might have happened elsewhere and blown up to this area as dust," said William Boynton of the University of Arizona, lead TEGA scientist.