Soshanna Cole, an assistant professor at Ithaca College, appears to have discovered evidence of acidic fog altering the surface of Mars. The discovery was made via an analysis of data collected by NASA's Spirit rover over the course of its exploration of the Red Planet.
Spirit landed on Mars in January 2004, and, prior to becoming embedded in soft soil, made numerous breakthroughs that revolutionized our understanding of Mars. Eventually, the rover stopped transmitting, with the last communication with the robotic pioneer taking place on March 22, 2010.
As is so often the case with NASA's flagship missions, Spirit is living up to its name, and continuing to provide insights into the Martian environment long after falling into its perennial slumber.
Cole analyzed data collected by Spirit from a dozen locations in the Cumberland Ridge and the Husband Hill summit focusing on "watchtower class" rocky outcrops. It was discovered that the formations exhibited notable abnormalities that hinted at a strangely Earth-like process occurring on the Red Planet.
Images displaying the disfiguration on the surface of watchtower rocks, possibly caused by volcanically induced acidic water vapor
It is believed that a chemical reaction between volcanically induced acidic water vapor, otherwise known as vog, and the watchtower class outcrops could account for the abnormalities. The phenomenon is similar to instances of vog occurring on Earth created by the Kilauea volcano in Hawaii.
When the vapor landed on the rocks, it is possible that it had the effect of oxidizing the iron present in the watchtowers, causing the mineral deposits to lose their shape, and take on a gel-like consistency.
Once the water from the vog evaporates, the gel essentially becomes a cementing agent, hardening to form unusual patterns on the rock surface. According to Cole the process happened incrementally over prolonged periods of time.
Variations in the level of iron oxidization in the distinctive rocks could be the result of differing exposure to the elements. For example, rocks that are more exposed to sunlight, the gel evaporates faster, allowing for less oxidization.