That Pale Blue Dot

This is an updated version of the Pale Blue Dot image taken by the Voyager 1 spacecraft 30 years ago today. It was created using modern image-processing software and techniques while trying to remain faithful to the original. Like the original, this new color view shows the Earth as a single blue pixel in the vastness of space. Rays of sunlight scattered within the camera optics stretch across the scene, one of which intersects with Earth. Look closely at the stripe just right of center. That speck a bit past half way up isn’t dust on your screen. It’s the Earth.

The image was taken just before Voyager 1’s cameras were turned off to conserve power because the probe would not make another planetary flyby. Shutting down instruments and other systems on the two Voyager spacecraft has been a gradual and ongoing process that has helped keep them running as they have left the Solar System.

Image Credit: NASA

Jupiter’s Rings

Saturn’s rings are so prominent that they can be seen through a small telescope from Earth, but the other gas giant planets, Jupiter, Uranus, and Neptune, have ring systems as well. Jupiter's Rings

Jupiter’s rings were discovered by Voyager 1 in a single image that was targeted specifically to search for a possible ring system. Voyager 2 was reprogrammed en route to take a more complete set of pictures. The image above is from that series. We now known that the system has three major components. The Main ring is about 7,000 km wide and has an abrupt outer boundary roughly 129,000 km from the center of the planet. This ring encompasses the orbits of two small moons, Adrastea and Metis, which probably are the source for the material that makes up most of the ring. The main ring merges gradually into the Halo on the side toward Jupiter. The halo is a broad, faint, donut of material about 20,000 km thick and extending halfway from the main ring down to the planet’s cloudtops.

Around the main ring is the broad and exceedingly faint Gossamer ring. It extends out beyond the orbit of the moon Amalthea and is probably composed of dust particles less than 10 µm in diameter. That’s roughly the size of cigarette smoke particles. It extends to an outer edge of about 129,000 km from the center of the planet and inward to about 30,000 km. The origin of the ring is probably material knocked loose by micrometeorite bombardment of the tiny moons orbiting within the ring.

Jupiter’s rings and moons exist within an intense radiation belt of electrons and ions trapped in the planet’s magnetic field. These particles and fields make up the Jovian magnetosphere or magnetic environment which extends up to 7 million km toward the Sun and stretches outward 750 million km in a windsock shape to Saturn’s orbit.

Image Credit: NASA

Voyager 1 Looks Back

voyager1looksback-smallIn this artist’s rendering the Voyager 1 spacecraft has a outsider’s view of the Solar System. The circles represent the orbits of the major planets—Jupiter, Saturn, Uranus, and Neptune. Voyager 1 visited the planets Jupiter and Saturn, and the spacecraft is now almost 21 billion km from Earth, making it the farthest and fastest-moving human-made object ever built. It’s is now moving through interstellar space, the region between the stars that is filled with gas, dust, and material recycled from dying stars.

Image Credits: NASA, ESA, and G. Bacon (STScI)