With Jupiter and now Saturn getting attention, NASA is setting its eyes further out in the Solar System - on Neptune. A mission to this "ice giant" could launch in a decade, and arrive at the 8th planet by 2035. It would be powered by a nuclear-electric propulsion system, similar to the one being considered for the Jupiter Icy Moons Orbiter (JIMO) mission. Because it is so far from the Sun, Neptune has had less interaction with the solar wind, asteroids and comets, so studying it would give scientists a better understanding of the conditions that led to the formation of the Solar System.

Cassini took this image of Saturn's outer C ring on October 29, 2004 when it was 838,000 km (521,000 miles) away from the planet. It shows the tremendous difference in brightness in the rings, as well as the large scale wavy formations that were discovered by Voyager 24 years ago.

The European Space Agency's Mars Express took this image of Reull Vallis, a region in the southern hemisphere of Mars. It's an outflow channel 20 km (12.4 miles) wide that extends 1,500 km (932 miles) long, cutting deeply into the terrain. There are many impact craters in the area which have been filled with material from flowing glaciers which have long since disappeared.

NASA released Cassini's photos of Iapetus this week, taken when the spacecraft was within 1.1 million km (684,000 miles) of Saturn's moon. The 1,436 km (892 mile) moon is famous for its two faces: one hemisphere and the poles are snowy white, while the other side is very dark. You can see many impact craters in the bright areas, and in the transition between the two hemispheres. The string of dots are mountains that may rival some of the tallest mountains on Earth, Io, and maybe even Mars.

The main camera for NASA's Mars Reconnaissance Orbiter (MRO) was delivered to NASA this week to be installed on the spacecraft. This camera will be capable of viewing 6 km (3.5 mile) swaths of Mars at a resolution of 25 cm (10 inches) per pixel (Mars Express' camera can resolve down to 2 metres per pixel). MRO is due to launch in August 2005 when the next Earth-Mars launch window opens up, and it's expected to arrive at the Red Planet in March 2006. The orbiter will also serve as a communications link for upcoming lander and rover missions.

It's been a 7-year journey, but now it's almost over; Huygens will detach from Cassini on December 25th. On January 14th, it'll reach Titan and plunge into the moon's thick clouds and parachute down to its surface. It'll be transferring data back to Cassini for the whole journey, and if it survives the landing, it'll be able to send back data for an additional 2 hours until Cassini moves out of range. If everything goes well, scientists will get new insights into Titan's unique environment, which could be similar to the Earth's early history.

Greetings fellow sky watchers. This will be an exciting week for both hemispheres! Our own solar system continues to put on a wonderful show before dawn and the Moon will occult Jupiter for a substantial portion of North America on December 7. The Southern Hemisphere is favoured for four meteor showers, as the Phoenicid, Puppid-Velid, Monocerotid and Sygma Hydrids all peak during this week. For evening observers, Comet Tucker reaches perihelion, as well as Comet Tsuchinshan for the early morning. Other high "lights" for the week include viewing two southern globular clusters (M30 and M2), a look into one of our galactic neighbors as we locate the M33, an introduction to stellar spectra and two unusually colorful planetary nebulae. As always, you will find things of interest here for all observers, be it with binoculars, telescopes, or just with your eyes. So look forward to this week's dark skies and let me take you higher...

Because here's what's up!

The 2-man crew onboard the International Space Station are going to be rationing their food carefully between now and the arrival of a Progress cargo ship on December 25 which will be carrying additional supplies. It appears that these astronauts, and the previous occupants, have been eating more food than engineers were predicting. This next Progress flight will contain extra food supplies, but if there's a problem with the mission and the cargo ship is destroyed, Commander Leroy Chiao and Russian flight engineer Salizhan Sharipov may have to evacuate the station, as additional supplies can't reach them in time.

This sweeping view of Saturn's rings shows the incredible detail and grandeur of the system, from the outer F ring to the inner C ring. The difference in brightness at each spot in the rings highlights the different concentrations of ring particles. Cassini took this image from below the ring plane, looking up; the top is closer to the spacecraft, and the bottom is farther away. Cassini took the picture when it was 836,000 km (519,000 miles) away.

Cassini took this amazing photograph of Prometheus, one of Saturn's small shepherd moons as it's tugging material away from the planet's F ring. The F ring resolves into 5 separate strands, and you can see how tiny Prometheus has a stream of material flowing towards it. Prometheus is only 102 km (63 miles) across, and scientists still aren't sure exactly why it creates the different knots and breaks in the F ring.

A series of research papers about past water on Mars have been published in the Journal Science by various scientists involved with the Mars Exploration Rovers. Although the team went public with their discoveries many months ago, these research papers provide the full evidence from the Opportunity rover, and have been exhaustively peer reviewed. They hypothesize that the Meridiani Planum region was once saturated with liquid water for a long enough time to support life.

Scientists have used satellite photographs to track the movements of a relatively fast moving glacier in Greenland, and found that it's picking up speed, doubling its velocity in the last few years. While the glacier is speeding up, it's also thinning, losing ice at a rate of 15 metres (16.4 yards) in thickness each year. The amount of ice melting into the ocean is more than double the output that traditional climate models were predicting, and demonstrates that the world's ice caps and glaciers are much more sensitive to rising temperatures than previously believed.

Here's an interesting black and white image of Saturn's rings that I think makes a nice 1024x768 desktop wallpaper. The photograph was taken by NASA's Cassini spacecraft on October 29, 2004 when it was 819,000 km (509,000 miles) away, and it shows the different rings and gaps in tremendous detail.

Alpha Centauri is the nearest star to our Earth and Sun. Often, science fiction novels extol its ability to nurture new life or expound it as a destination for humankind. Paul Gilster in Centauri Dreams: Imagining and Planning Interstellar Exploration brings science and science fiction together in providing us with an up to date view on who's doing what to get people there, possibly starting as soon as this generation. He has only two exciting things to say about planning for the trip; it's here and it's now!

The early Universe was much dustier than astronomers were expecting, according to new data gathered by the Spitzer Space Telescope. This leads to the question, how did it get so dusty so early? Regular stars take billions of years before they star giving off large amounts of dust. But massive stars can form quickly and then explode as supernovae within 10 million years. The problem is that these explosions produce enormous amounts of hot dust, but very little cold dust, which is the kind found in the early Universe. So, the mystery continues.

Astronomers from the Harvard-Smithsonian Center for Astrophysics believe it's possible that our own Sun could have stolen some material from other stars billions of years ago. They came to this conclusion while trying to understand the orbit of Sedna, which takes 10,000 years to go around the Sun, in a highly elliptical orbit far beyond the Kuiper Belt. When our Sun was younger than 200 million years old, it could have swept past another star, disrupting the Kuiper Belt, and trading large objects (like Sedna) with each other.

Cassini took this image of the Encke Gap in Saturn's Rings. It's a small division 300 km (190 miles) wide near the outer edge of the rings. A tiny moon called Pan orbits within this region, maintains the gap, and ties the particles into this knotted shape with its gravity. The image was taken while Cassini was 807,000 km (501,000 miles) away from Saturn.