Earlier today, planetary scientists discussed preliminary findings from the MESSENGER spacecraft’s second flyby of Mercury. The October 6 encounter revealed about 30 percent of the planet previously unseen by spacecraft — an area larger than South America.

MIT researcher Maria Zuber spoke about results from the laser altimeter used to measure topography. Her biggest surprise: The thin strip of area surveyed seen during the January flyby.

Brian Anderson from Johns Hopkins University Applied Physics Lab noted that the magnetic field seen this time around nearly matches that seen in January. This implies a symmetric magnetic field whose axis tilts no more than 2 percent to Mercury’s rotational axis.

Mark Robinson of Arizona State University discussed a small number of the 1,287 images MESSENGER returned. They included some color-enhanced views that show apparent widespread regions of material excavated from below the surface. In these enhanced images, the material appears blue.

Watch upcoming issues of Astronomy magazine for comprehensive coverage of the second MESSENGER flyby. As always, check Astronomy.com/News for mission updates.