It is not the first time that I photograph this formation, but it is the first time that I can photograph it in a different way and it is possible to perceive its characteristic format.

It is always rewarding to wander around the surface of the Moon using the archive of images captured by the Lunar Reconnaissance Orbiter Camera (http://target.lroc.asu.edu/q3/). It is full of images that show the beauty of the moon, images so sharp that you can see even individual stones on the surface. Exploring the craters, crests and rilles seen in the archive usually causes a "Wow!".

It's quite unusual to find something different, but that's what happens when you visit the area near the Yangel crater and come across INA.

There is a D-shaped depression about two kilometers wide and 30 meters deep. It is filled with domes of dark and smooth material that rises above the lightweight raw material, mostly without craters. Its characteristics appear exceptionally sharp (and therefore probably relatively young).

The unusual morphology and appearance of Ina, originally referred to as "D-Caldera" because of its unique shape, have been of interest to lunar scientists since it was first identified in Apollo images. Early studies of this 2.8-km-wide depression interpreted it as a lunar caldera or collapse, based in part on its location, near the summit of a broad, low-relief dome. The interior of Ina contains smooth mounds and small positive relief plateaus encased by brighter and harsher floor materials and lower floors. Several lines of evidence suggest the presence of relatively fresh surfaces on the floor of Ina depression

Ina was first noticed only in 1971 when photographed by astronauts aboard Apollo 15. Recent photos taken by the low-flying Lunar Reconnaissance Orbiter (LRO) show a level of detail (picture enlarging below right) that reveals how original this curious feature really is. So, what's going on in Ina?

Theories abound. In a real volcano, the boilers are caused by the collapse of the material at the top of the volcano, after the bottom magma was drained after a eruption. Perhaps the top of the low volcanic dome in which Ina rests collapsed unevenly and relatively recently to form the patchwork we see today. Another possibility is the magma of gases trapped below heated as carbon dioxide and water at high pressures, they violently exploded through the crust, sending rocks and debris flying for miles.

LRO researchers agree that Ina's two lands are a contrast of young and old, but they do not think the brightest areas are as young as they were supposed to be. Additional high resolution photographs of the orbiter show a good number of craters there.

What happened there, created an enigmatic lunar landscape that scientists are still trying to understand. In many ways, the moon is an undiscovered world. With only six short visits during the Apollo era and 150 lunar meteorites collected on Earth.

 Preliminary data analysis The recently acquired reflection data from the Moon Mineralogy Mapper (M3) for the Ina structure is consistent with previous studies that identified relatively unfilled high titanium basalts within the block pavement materials. These results support the interpretation that materials on the ground within Ina have been disturbed recently, enough to be spectrally similar to the small, fresh craters within Mare Tranquillitatis. Calibrations and analysis of the M3 Ina data are in progress and have not yet been fully corrected for thermal emission and scattered light. Future research will more fully explore these new data and associated lunar resources for maturity and mineralogical information, as well as the possible presence of volatile components.

We know the Moon better than any place outside Earth. The strange topography of Ina, however, serves as a reminder that the Moon still holds some of its most interesting secrets.

Sources: AstroBob - Bob King (AAVSO)

             Planetary Society - Bill Dunford

             Lunar Networks - 42nd Lunar and Planetary Science Conference

Research and Adaptation: Avani Soares