In general terms, on the Planet Mercury, the Impact Craters which are larger than approximately 10 - 12 Km (such as about 6,21 - 7,452 miles), display a Complex Morphology, mostly characterized by Slump Terraces and Central Peaks, as compared to smaller and bowl-shaped Impact Craters. At this Unnamed Complex Crater (---> the one we show you in today's APOD), that is nearly 20 Km (such as about 12,42 miles) in diameter, the Boulders (---> Ejecta Boulders) that were created by the Impact Event, can be (barely) seen outside its South/Western Rim and - which is an unusual thing - even within the Crater Interior (---> Floor). The largest Boulder observed here is around 180 meters (approx. 590,4 feet) across. For comparison, you may want to check out the Lunar House Rock Boulder, located at the Apollo 16 Site, which is (only) 24 meters across (and that, at the time, was considered really huge). Date acquired: January, 24th, 2015 This picture (which is an Original NASA - MESSENGER Spacecraft's b/w and NON Map-Projected image published on the NASA - Planetary Photojournal with the ID n. PIA 19202) has been additionally processed, contrast enhanced, Gamma corrected, magnified to aid the visibility of the details and then colorized in Absolute Natural Colors (such as the colors that a human eye would actually perceive if someone were onboard the NASA - MESSENGER Spacecraft and then looked outside, towards the Surface of Mercury), by using an original technique created - and, in time, dramatically improved - by the Lunar Explorer Italia Team. Different colors, as well as different shades of the same color, mean, among other things, the existence of different Elements (Minerals) present on the Surface of Mercury, each having a different Albedo (---> Reflectivity) and Chemical Composition. |