First images from Planet Mercury beamed home

First images of Mercury, courtesy NASA

NASA's MESSENGER space probe has finally reached the solar system's innermost planet, Mercury. To say Mercury is hot would be an epic understatement. The mean surface temperature of the planet is 440K, rising to about 725K on the sunward sign. That's about 323 degrees Fahrenheit, rising to about 845K in the sun.

CBSNews.com: Historic image of Mercury sent back to Earth

We've never really had a chance to see Mercury up close, but the MESSENGER (MErcury Surface, Space ENvironment, GEochemistry and Ranging) probe is changing all that. This week, it sent back its first image, the one at the top of this post.

MESSENGER has a long history. Here's a summary of the timeline, courtesy of NASA:

• July 1999 -- NASA selects MESSENGER as the seventh Discovery Program mission
• December 1999 -- Preliminary design begins
• July 2001 -- Final design and construction phase begins
• February 2003 -- Spacecraft integration and testing begins
• December 2003 -- MESSENGER moves to NASA's Goddard Space Flight Center for final space-environment testing
• March 2004 -- MESSENGER arrives at Astrotech Space Operations (near Kennedy Space Center) for final pre-launch preparations
• August 3, 2004 -- MESSENGER Launch
• August 2005 -- Earth flyby
• October 2006 -- Venus flyby
• June 2007 -- Venus flyby
• January 2008 -- Mercury flyby
• October 2008 -- Mercury flyby
• September 2009 -- Mercury flyby
• March 2011 -- Yearlong science orbit of Mercury begins

MESSENGER contains some amazing gear, including a dual imaging system, a gamma-ray spectrometer, a neutron spectrometer, an X-Ray spectrometer, a magnetometer, a laser altimeter, an atmospheric and surface composition spectrometer, an energetic particle and plasma spectrometer, and a variety of other instruments.

Stay tuned. We're bound to learn more about Mercury than we've ever known before.