The Moon Gallery

Saturn silhouetted, Cassini image

Saturn silhouetted. Cassini spacecraft image of Saturn and its ring system with the Sun directly behind. The view revealed two previously unknown rings. One, associated with the orbits of the moons Janus and Epimetheus, lies in between the outer edge of the bright main rings and the thin grey/brown G Ring. The other, associated with the orbit of the moon Pallene, lies just inside the broad and diffuse outer E ring. Earth is seen as a bright dot at the ten o'clock position between the bright main rings and the G Ring. This is a composite of 165 images taken at infrared, visible light and ultraviolet wavelengths by the Cassini spacecraft on 15th September 2006, while it was around 2.2 million kilometres from Saturn

© Nasa/Jpl/Space Science Institute/Science Photo Library

Guard Hall at the Jet Propulsion Laboratory (JPL)

Guard Hall, Operations Chief of "mission control" at NASA's Jet Propulsion Laboratory (JPL). He is seen in the Network Operations Control Center, the mission control room. Hall is responsible for real-time management of the Deep Space Network, NASA's wordwide tracking & communications complex which sends commands to & acquires data from plan- etary spacecraft. Among other missions, Hall (born 1948) was "Ops Chief" for the Voyager Project. Launched in 1977, the two Voyager craft acquired images & scientific data from encounters with Jupiter, Saturn, Uranus, Neptune & their moons. This portrait was taken in August 1989, at the time of Voyager 2's encounter with Neptune

© DAVID PARKER/SCIENCE PHOTO LIBRARY

Cygnus Loop Supernova Blast Wave

This is an image of a small portion of the Cygnus Loop supernova remnant, which marks the edge of a bubble-like, expanding blast wave from a colossal stellar explosion, occurring about 15, 000 years ago. The HST image shows the structure behind the shock waves, allowing astronomers for the first time to directly compare the actual structure of the shock with theoretical model calculations. Besides supernova remnants, these shock models are important in understanding a wide range of astrophysical phenomena, from winds in newly-formed stars to cataclysmic stellar outbursts. The supernova blast is slamming into tenuous clouds of insterstellar gas. This collision heats and compresses the gas, causing it to glow. The shock thus acts as a searchlight revealing the structure of the interstellar medium. The detailed HST image shows the blast wave overrunning dense clumps of gas, which despite HST's high resolution, cannot be resolved. This means that the clumps of gas must be small enough to fit inside our solar system, making them relatively small structures by interstellar standards. A bluish ribbon of light stretching left to right across the picture might be a knot of gas ejected by the supernova; this interstellar "bullet" traveling over three million miles per hour (5 million kilometres) is just catching up with the shock front, which has slowed down by ploughing into interstellar material. The Cygnus Loop appears as a faint ring of glowing gases about three degrees across (six times the diameter of the full Moon), located in the northern constellation, Cygnus the Swan. The supernova remnant is within the plane of our Milky Way galaxy and is 2, 600 light-years away. The photo is a combination of separate images taken in three colors, oxygen atoms (blue) emit light at temperatures of 30, 000 to 60, 000 degrees Celsius (50, 000 to 100, 000 degrees Farenheit). Hydrogen atoms (green) arise throughout the region of shocked gas. Sulfur atoms (red) form when the gas cools to around 10, 000 degrees Celsius (18, 000 degrees Farenheit)

© NASA