It comprises thousands of images acquired by the spacecraft during its first year in orbit. This is not how we would see Mercury, which would look like a dull, brownish-grey globe to our eyes.
Rather, the map represents an exaggerated view of the planet that is intended to highlight variations in the composition of its rock.
“Messenger’s camera has filters that go from the blue to the near-infrared of the spectrum, and we are able to use computer processing to enhance the very subtle but real colour differences that are present on Mercury’s surface,” explained Dr David Blewett from the Johns Hopkins University Applied Physics Lab.
“The areas that you see that are orange – those are volcanic plains. There are some areas that are deep blue that are richer in an opaque mineral which is somewhat mysterious – we don’t really know what that is yet.
“And then you see beautiful light-blue streaks across Mercury’s surface. Those are crater rays formed in impacts when fresh, ground-up rock is strewn across the surface of the planet,” the mission scientist told BBC News.
Dr Blewett displayed the map here in Boston at the annual meeting of the American Association for the Advancement of Science (AAAS).
He was giving a sneak preview of the data that is about to be deposited in Nasa’s planetary archive.
This will include a black-and-white, or monochrome, map of the entire surface of Mercury at a resolution of 200m per pixel (the colour map has a resolution of 1km per pixel and is just short of 100% coverage).
Mercury was visited first by the Mariner 10 probe in the 1970s; and by Messenger currently
The planet’s diameter is 4,880km – about one-third the size of Earth
It is the second densest planet in Solar System; 5.
( via bbc.co.uk )