These two images, published in the July 4 issue of Science
magazine, illustrate the power of using MESSENGER’s WAC multi-spectral
images to study compositional variations across the surface of Mercury.
Both images shown here were generated using a statistical method known as
principal component analysis. In this analysis, images taken through the
WAC’s 11 different narrow-band color filters are compared and contrasted
to discover significant variations. The image on the left shows Mercury in
one of the resulting principal components that enhances the largest color
differences on Mercury’s surface. The Caloris basin (labeled with a C)
is shown to be considerably different from the surrounding areas in
this view. Dark craters within Caloris (shown with white arrows), such as
Atget crater, are clearly distinct. Mozart crater (labeled with an M) and
the Tolstoj basin and material ejected from it (basin labeled with Tsp;
ejecta labeled with a T) also show significant color signatures. The
image on the right was created by displaying the negative of the left
image in red, a different principal component in green, and a ratio of
images taken in two WAC filters (430 nm/560 nm) in blue. The white arrows
identify areas of Mercury’s surface that are interpreted to be relatively
young volcanic plains, and the black arrows point to reddish areas
interpreted to be volcanoes. Most of the color differences studied here
are believed to indicate variations in the mineral composition and
physical state of the rocks at different places on Mercury.
Date Acquired: January 14, 2008
Image Mission Elapsed Time (MET): 108829678 - 108829728
Instrument: Wide Angle Camera (WAC) of the Mercury Dual Imaging
System (MDIS)
Scale: Mercury’s diameter is 4880 kilometers (3030 miles)
These images are from MESSENGER, a NASA Discovery mission to conduct the
first orbital study of the innermost planet, Mercury. For information
regarding the use of images, see the MESSENGER image use policy.