Before the Messenger’s mapping, less than half of the surface was mapped by NASA’s Mariner 10 spacecraft, which made several flybys of Mercury in 1974 and 1975.
It is the first time in the history of humanity that the complete mapping of Mercury has been done. Not only the spacecraft has completed the half picture but also gave the improved resolution of the previous maps.
“We can now say we have imaged every square meter of Mercury’s surface from orbit,” said Messenger principal investigator Sean Solomon of the Johns Hopkins University Applied Physics Laboratory in Laurel, Md. “Admittedly, some regions are in permanent shadow, but we’re actually peering into those shadows with our imaging systems.”
According to the spacecraft, volcanism not only occurred in the Mercury’s past but also occurred on a huge scale – it was covered with “magma ocean” in the past. It also presented some previously unseen forms of terrain on the planet, such as surface pockmarks called hollows that scientists believe are developed when volatile materials sublimate off the surface.
“Unstable material is exposed to the temperatures and space environment, and slowly over thousands, maybe millions, of years, it’s lost to Mercury’s atmosphere and to space, to create a depression or hollow in an area where there are often many such hollows that etch the terrain,” Solomon said.
Last month NASA released the video showing the colorful image of Mercury. The colorful view is not the actual view of the planet but rather the color increases the chemical, mineralogical, and physical differences between the rocks making up the Mercury’s surface.
“Medium- and dark-blue areas are a geologic unit of Mercury’s crust known as the ‘low-reflectance material,’ thought to be rich in a dark, opaque mineral,” Messenger scientists wrote. “Tan areas are plains formed by eruption of highly fluid lavas.”