Planetary Science

The F ring shows off a rich variety of phenomena in this image from the Cassini spacecraft. Near the lower-right of the F ring are two ''fans'' of material radiating out of the main strand (or ''core'') of the ring. Kinks are apparent all along the core, and dark ''channels'' cut into the main strand can be seen in places, the result of a recent interaction with the shepherd moon Prometheus (which cannot be seen in this image).

NASA's Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft is assembled and is undergoing environmental testing at Lockheed Martin Space Systems facilities, near Denver, Colo. MAVEN is the next mission to Mars and will be the first mission devoted to understanding the Martian upper atmosphere.

A space rock a few metres across exploded in Earth's atmosphere above the city of Chelyabinsk, Russia today at about 03:15 GMT. The numerous injuries and significant damage remind us that what happens in space can affect us all.

While precise information on the size, mass and composition of the object are yet to be confirmed, videos show a fireball and explosion consistent with an asteroid up to a few metres in size exploding in the atmosphere, possibly several to ten kilometres above the surface.

This is an image of magnetic loops on the sun, captured by NASA's Solar Dynamics Observatory (SDO). It has been processed to highlight the edges of each loop to make the structure more clear.

A series of loops such as this is known as a flux rope, and these lie at the heart of eruptions on the sun known as coronal mass ejections (CMEs.) This is the first time scientists were able to discern the timing of a flux rope's formation. (Blended 131 Angstrom and 171 Angstrom images of July 19, 2012 flare and CME.)

NASA Television will provide commentary starting at 11 a.m. PST (2 p.m. EST) on Friday, Feb. 15, during the close, but safe, flyby of a small near-Earth asteroid named 2012 DA14. NASA places a high priority on tracking asteroids and protecting our home planet from them. This flyby will provide a unique opportunity for researchers to study a near-Earth object up close.