MESSENGER completed its flyby of Earth on August 2, 2005. In exchange for the gravity assist Earth provided to aid the spacecraft in its journey to Mercury, MESSENGER sent back a picture postcard of our home planet. South America sits in the center of the globe, tilted to the right.
NASA / JHUAPL
Earth in visible and near-infrared wavelengths
MESSENGER's Mercury Dual Imaging System's wide-angle camera utilizes 11 filters across visible and near-infrared wavelengths (400 to 1,100 nanometers) to gather compositional data of the planet's surface.
This side-by-side look at Earth illustrates the value of multiple-wavelength imaging. The three-band composite at left is made from filters with peak sensitivities near 480 nm, 560 nm and 630 nm. These filters help distinguish materials with distinct visible color differences (ilmenite, volcanic glasses) but are also very close to the sensitivity of the human eye. (Natural color is somewhat subjective, so this combination of bands is "approximate" natural color.) The spacecraft was 102,918 kilometres above Earth when the images were taken.