Above, in this cartoon of field lines and observed signal, the white lines show schematic magnetic field lines above the surface of Mercury from magnetized crustal rocks. The MESSENGER spacecraft passed over a region of crustal magnetization and the Magnetometer instrument measured small variations in the magnetic field (illustrated by the blue wiggly line). Because the signals are small they were only observed when MESSENGER was very close to the planet.
Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
Above, in this perspective view, we look west across Suisei Planitia (blue colors), the site of some of the crustal magnetic signals. The plains are comprised of volcanic lava flows that erupted and solidified several billion years ago, filling the low areas between the higher topography (red colors). The impact crater Kosho, 65 km in diameter, is seen in the center of the image (deep blue floor), and part of the crater Strindberg, 190 km in diameter, is seen in the lower left at the edge of the image.
The background image is Mercury Dual Imaging System global mosaic, colored by surface elevation measured by the Mercury Laser Altimeter (MLA), both draped over a digital elevation model derived from MLA data.
Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington