Mark Showalter (SETI Institute) just discovered a fourth moon orbiting Pluto, designated P4 for now. It is quite small, about 15 miles across, and its orbit resides between satellites Nix and Hydra. This discovery was quite accidental, because Showalter was observing the Pluto system to look for signs of any planetary rings there; see the Hubble website for more details. Since Pluto seems ripe with satellites, we might expect the New Horizons spacecraft, which flies by Pluto in 2015, to find even more tiny satellites.
Cassini snapped this picture of a monster storm on Saturn on Feb. 25, 2011. This storm started in December 2010, and has since wrapped itself all the way around the planet, spanning an area about 8 times that of the Earth's total surface. The thin dark band at the equator is Saturn's rings seen edge on, and the broader dark bands below are the shadows cast by the rings.
The image below is color coded to indicate the altitude of the various cloud layers in the storm. Blue, white, and yellow indicate clouds at higher altitudes, with green, red, and brown colors showing clouds that are deeper in this gas giant planet's atmosphere. Check the CICLOPS website for more information and Cassini images of Saturn.
The Dawn spacecraft's view of Vesta's rugged surface gets a little sharper as the spacecraft approaches this very large asteroid. Dawn is still 100,000 miles away from Vesta, but it arrives and goes into orbit about that giant asteroid soon on July 16! Meanwhile, keep an eye on the Dawn website for the latest images that will get more dramatic over time as the spacecraft nears.