The MESSENGER mission to Mercury is featured on Space.com as one of the "Top 5 Amazing Astronomy Discoveries" of 2008. The MESSENGER probe completed two flybys of the innermost planet in January and October 2008, respectively, imaging the surface of Mercury never before been seen by spacecraft. Click here for more information on this and Space.com's other 2008 top discoveries.

Image: 2008: Looking Back at the Year with MESSENGER Images. JHU/APL.