Skywatchers set your alarm clocks: On Tuesday morning, Mercury will appear to have a close encounter with Mars.Full story
NASA's Messenger probe has released some of the first close-ups ever of Mercury's surface. NBC's Brian Williams reports.
NASA's Messenger probe is the first spacecraft to orbit the planet Mercury, and it sent back the first pictures taken from orbit on March 29, 2011. This image of Mercury's horizon was acquired as the spacecraft was flying northward along the first orbit during which its dual-camera system was turned
The planets Mercury and Mars will be in close conjunction on the morning of April 19.
The first image sent back to Earth from Mercury orbit shows a rayed crater known as Debussy and a smaller crater with unusual dark rays, called Matabei. The picture was transmitted to Earth by NASA's Messenger spacecraft.