26 October 2012, 05:00 PM ET
The rocky, metallic worlds of the inner solar system look quite different from those of the outer solar system, one theory supposes they formed in much the same way. However, a competing theory suggests they may have formed from different components.
12 October 2012, 01:46 PM ET
Cookie! A new photo from NASA's Messenger spacecraft looks a lot like Sesame Street's Cookie Monster.
27 September 2012, 02:33 PM ET
NASA's Messenger mission has spent several years mapping Mercury, which was poorly understood for decades.
24 September 2012, 07:26 AM ET
The surface of Mercury is unlike that of any other planet in our solar system.
09 August 2012, 10:19 PM ET
See sky maps to help spot the skywatching events of August 2012.
27 June 2012, 08:00 AM ET
Harvey Allen's contribution to space travel revolutionized fundamentals of the science.
23 June 2012, 06:22 AM ET
See the most amazing space images of the week, including China's mission to space and Mickey Mouse on Mercury.
18 June 2012, 12:40 PM ET
NASA's Messenger spacecraft orbiting Mercury spotted three craters that look surprisingly like Mickey Mouse.
01 June 2012, 11:28 AM ET
NASA's Solar and Heliospheric Observatory (SOHO) snapped imagery of Venus, almost past Mercury, in anticipation of the Venus Transit of the Sun on June 5-6, 2012 (depending where you are in the world).
22 May 2012, 02:01 PM ET
NASA's Solar and Heliospheric Observatory (SOHO) caught Jupiter, Mercury and the Pleiades Star Cluster converging within its camera's field of view.
09 April 2012, 07:41 AM ET
On April 7th 2012, a coronal mass ejection was lofted towards Mercury and set to slam into its ultra-thin atmosphere on April 9th. The Solar Dynamics Observatory captured the blast in extreme ultraviolet.
04 April 2012, 12:56 PM ET
Mercury is nearly as bright as other naked-eye planets, but there's a trick to spotting the elusive planet.
31 March 2012, 01:59 PM ET
From water on Mars to fake feline astronauts, it's been a busy week in space. Vote for the week's best space story.
26 March 2012, 02:57 PM ET
Mercury's poles may have ice deposits, according to new findings from NASA's Messenger probe.
26 March 2012, 02:10 PM ET
NASA's MESSENGER spacecraft is the first to ever to orbit the planet closest to the Sun. It has delivered 89 wide angle camera images that have been compiled into a complete picture of the planet's south pole in this time-lapse video.
25 March 2012, 04:58 AM ET
From runaway planets to a submarine on Jupiter, it's been a busy week in space. Vote for the week's best space story.
22 March 2012, 04:45 PM ET
The Messenger spacecraft began a one-year bonus mission at Mercury, and the twin Grail probes will get 90 more days at the moon.
21 March 2012, 09:30 AM ET
The solar system's innermost planet continues to confound and intrigue scientists.
14 March 2012, 09:14 AM ET
The velocity and inertia of high-speed charged particles ejected from the Sun during a coronal mass ejection (CME) can be measured as they slam into spacecraft; the resulting data can be presented as sound. Produced by the University of Michigan.
08 March 2012, 03:52 PM ET
Skywatchers can spot the full moon, Venus, Jupiter, Mercury and perhaps even Uranus tonight.
01 March 2012, 11:43 AM ET
The planet Mercury looks a little bit like Earth's moon.
01 March 2012, 11:24 AM ET
Mercury is the closest planet to the sun.
27 February 2012, 12:32 PM ET
Jupiter and Venus lined up with the moon, and will get even closer together in March.
27 February 2012, 12:31 PM ET
See amazing photos of Venus, Jupiter and the moon in a celestial triple conjunction.
25 February 2012, 12:02 PM ET
Venus, Jupiter and Mercury can be seen near the moon at sunset. Mars makes an appearance.
24 February 2012, 11:58 AM ET
Jupiter, Venus and the crescent moon will shine extra bright just after sunset in the western sky this weekend.
17 February 2012, 05:46 PM ET
The best time to see planet Mercury in the evening sky in 2012 is next week.
11 January 2012, 06:00 AM ET
Retired NASA spaceflyer Steven Hawley also discussed his own experiences.
22 December 2011, 02:00 PM ET
The mystery of Mercury's weak magnetic field may be solved.
21 December 2011, 02:00 PM ET
Don't miss the seven major planets of the solar system in the night sky this week.
18 December 2011, 06:25 AM ET
From new ways to get to space to fiery death plunges into the sun, it was a busy week in space.
12 December 2011, 02:08 PM ET
NASA's Dawn mission currently orbiting Vesta has revealed signs of differentiation - a process where dense materials sink to the center and less dense rise to the surface. This is a characteristic of a terrestrial planets such as our own.
11 December 2011, 01:00 PM ET
New research suggests a giant asteroid may have knocked into Mercury and changed its spin.
10 December 2011, 08:00 AM ET
From a comet diving into the sun to planets made of diamonds and more, it was a busy week in space.
17 November 2011, 08:15 AM ET
The extension will keep Messenger in orbit around Mercury until March 2013.
11 November 2011, 03:03 PM ET
The space rock apparently formed out of the same stuff that became Earth, Venus and Mercury.