The closest planet to our Sun, and the smallest in the solar system, is also one of the least understood. Compared to more glamorous planets like Mars, Jupiter and Saturn, Mercury has received much less attention from scientific study missions. But NASA's MESSENGER probe, which soared past Mercury Jan. 14, is set to reveal the secrets behind the odd planet. The probe recently sent back more than 1,200 detailed images of Mercury from the flyby, and will add many more when it passes again in October 2008 and September 2009, and finally settles into orbit around the planet in 2011. In the words of MESSENGER science team member Robert Strom, "The best is yet to come. What you're seeing here is just the tip of the iceberg."