The rings of Saturn have puzzled astronomers since Galileo Galilei discovered them with his telescope in 1610. Detailed study by the Voyager 1 and Voyager 2 spacecraft in the 1980s only increased the mystery.
There are billions of ring particles in the entire ring system. The ring particle sizes range from tiny, dust-sized icy grains to a few particles as large as mountains. Two tiny moons orbit in gaps (Encke and Keeler gaps) in the rings and keep the gaps open. Other particles (10s to 100s of meters) are too tiny to see, but create propeller-shaped objects in the rings that let us know they are there. The rings are believed to be pieces of comets, asteroids or shattered moons that broke up before they reached the planet. Each ring orbits at a different speed around the planet. Information from NASA’s Cassini mission will help reveal how they formed, how they maintain their orbit and, above all, why they are there in the first place.
Titan is the largest moon of Saturn, 50% larger than our moon. This world has a thick nitrogen atmosphere with lakes of liquid methane and ethane on the surface. Underneath, a thick shell of ice covers an ocean of liquid water and a rocky core. The dark areas in this image are hydrocarbon dunes named “Fensal” and “Aztlan”.
Infant Stars in Serpens Infant stars are glowing gloriously in this infrared image of the Serpens star-forming region, captured by NASA’s Spitzer Space Telescope.
The reddish-pink dots are baby stars deeply embedded in the cosmic cloud of gas and dust that collapsed to create it. A dusty disk of cosmic debris, or “protoplanetary disk,” that may eventually form planets, surrounds the infant stars.
Wisps of green throughout the image indicate the presence of carbon rich molecules called, Polycyclic Aromatic Hydrocarbons (PAHs). On Earth, PAHs can be found on charred barbecue grills and in automobile exhaust. Blue specks sprinkled throughout the image are background stars in our Milky Way Galaxy.
The Serpens star-forming region is located approximately 848 light-years away in the Serpens constellation.
The image is a three-channel false-color composite, where emission at 4.5 microns is blue, emission at 8.0 microns is green, and 24 micron emission is red.
Image credit: NASA/JPL-Caltech/L. Cieza (University of Texas at Austin)
Galactic Cirrus billows and obscures the background Universe in this direction. NGC 7497 is seen through partly cloudy skies. These galactic clouds of dust are sculpted by the winds of nearby stars. They are relatively close to us (only hundreds of light years away) and there are few stars in the foreground to hinder of view of them. The color of the clouds is odd due to the fact they are illuminated mostly by diffuse galactic star light.
Image: Adam Block/Mount Lemmon SkyCenter/University of Arizona [high-resolution]