Syrtis Major
From Wikipedia, the free encyclopedia
Syrtis Major Planitia is a "dark spot" (an albedo feature) located in the boundary between the northern lowlands and southern highlands of Mars. It is named after the classical Roman name for the Gulf of Sidra on the coast of Libya (classical Cyrenaica).
It is the first documented surface feature of another planet; Christiaan Huygens created a drawing that includes it dated 1659. It is centered near 290° W and 10° N, extends some 1,500 km (930 miles) north from the planet's equator, and spans 1,000 km (620 miles) from west to east. It encompasses a large slope from its western edge at Aeria dropping 4 km (2.5 miles) to its eastern edge at Isidis Planitia. It includes a high-altitude bulge that rises 6 km (3.7 miles) at 310° W.
Syrtis Major was the object of much observation due to its seasonal and long-term variations. This led to theories that it was a shallow sea and later that its variability was due to seasonal vegetation. In the 1960s and 1970s the Mariner and Viking planetary probes led scientists to conclude that the variations were caused by wind blowing dust and sand across the area. It has many windblown deposits that include light-colored halos or plumose streaks that form downwind of craters.
There are several theories about its formation. In the past, some guessed that it was liquid water, even though the temperatures and the air pressure seem to prevent this possibility. The research team that worked on the ALH84001 Martian meteorite from Antarctica have even suggested that they are bacterial growths, feeding off geothermal vents.
