Schiaparelli (Martian crater)
Elevation map of the Martian crater Schiaparelli, as seen by Mars Global Surveyor.
Schiaparelli is an impact crater on Mars named after Giovanni Schiaparelli located near Mars' equator. It is 461 kilometers (286 mi) in diameter and located at latitude 3° South and longitude 344°. A crater within Schiaparelli shows many layers that may have formed by the wind, volcanoes, or deposition under water.
Layers can be a few meters thick or tens of meters thick. Recent research on these layers by scientists at California Institute of Technology (Caltech) suggest that ancient climate change on Mars caused by regular variation in the planet's tilt, may have caused the patterns in layers. On Earth, similar changes (astronomical forcing) of climate results in ice-age cycles.
The regular appearance of rock layers suggests that regular changes in climate may be the root cause. Regular changes in climate may be due to variations of a planet's tilt (called obliquity). The tilt of the Earth's axis changes by only a little more than 2 degrees since our moon is relatively large. In contrast Mars's tilt varies by tens of degrees. When the tilt is low (current situation on Mars), the poles are the coldest places on the planet, while the equator is the warmest (as on Earth). This could cause gases in the atmosphere, like water and carbon dioxide, to migrate poleward, where they'd freeze. When the obliquity is higher, the poles receive more sunlight, causing those materials to migrate away. When carbon dioxide moves from the Martian poles, the atmospheric pressure increases, maybe causing a difference in the ability of winds to transport and deposit sand. Also, with more water in the atmosphere sand grains may stick and cement together to form layers.
Circular structures on floor of Schiaparelli crater, as seen by HiRISE under HiWish program.
- Layers, Bedrock Ridges, and Dark Sand in Schiaparelli Crater, LPL HiRISE, includes large color photos