NASA's Wide-field Infrared Survey Explorer, or WISE, captured this color-coded picture of a star-forming nebula that resembles a Christmas wreath. The cloud of gas and dust, known as Barnard 3, lies in the constellation Perseus, about 1,000 light-years from Earth. The evergreen-colored ring is made up of tiny particles of warm dust. The red cloud, which stands in for the wreath's bow, is probably made of dust that is more metallic and cooler than the surrounding regions. Astronomers say the bright star in the middle of the red cloud, called HD 278942, has cleared out the dust in the central regions to create the glowing wreathlike shape. Bluish background and foreground stars are sprinkled through the scene like silver bells.

This picture of a "celestial bauble" combines X-ray imagery (in blue) from NASA's Chandra X-Ray Observatory and the European Space Agency's XMM-Newton probe with optical data (in red and green) from the Cerro Tololo Inter-American Observatory in Chile. The bright blue spark at right is a pulsar known as SXP 1062, surrounded by the shell of a supernova remnant. The optical data also reveals spectacular formations of gas and dust in a star-forming region on the left side.

The colorful globe of Saturn's largest moon, Titan, passes in front of the planet and its rings in this true-color snapshot from NASA's Cassini spacecraft. The imagery was obtained on May 21 when Cassini was 1.4 million miles from Titan.

Saturn's third-largest moon, Dione, can be seen through the haze of Titan, with the planet and its rings in the background, in a May 21 picture from Cassini.

Dione, the bright-colored Saturnian moon seen at top in this picture from the Cassini spacecraft, is about 700 miles wide. Titan, which appears to sit below Dione, is 3,200 miles wide. The reason Dione looks bigger is because Cassini was much closer to Dione when the picture was taken on Nov. 6. Dione is 85,000 miles away, while Titan is 684,000 miles away.

A close-up view of the Saturnian moon Titan reveals a depression within the moon's orange and blue haze layers, near the moon's south pole. The picture was taken by the Cassini spacecraft on Sept. 11. The moon's high altitude haze layer appears blue here, while the main atmospheric haze is orange. The difference in color could be due to particle size of the haze. The blue haze likely consists of smaller particles than the orange haze.